3.1. Swimming technique concept
For a more complete understanding of swimming technique, it is necessary to reveal the essence of the very concept of technique.
Motor action technique — a method of its implementation, characterized by certain parameters, such as trajectory, amplitude, frequency, voltage, etc.
Sports equipment — This is a way of performing movements (motor actions) in a given sport. The technique that is used to achieve the highest athletic results (that is, the one used by the strongest athletes in the world) is considered the most advanced. Therefore, the concept of “sports technique” is often perceived as the most rational, effective way of performing physical actions in a given sport.
Meanwhile, biomechanical analysis often reveals a number of errors in the movements of even the most highly qualified athletes. And the difference between someone who achieves high athletic results and a representative of mass sports is that the first strives for perfection of movements, and the second does not set such a task to the proper extent. However, both the first and the second can master the perfect structure of movements. In this case, they will be distinguished mainly not by the pattern of movements performed, but by speed, strength and other aspects that characterize the degree of development of motor qualities, in unity, manifested in a given sport, in a given athlete.
V.M. Dyachkov, D.D. Donskoy, V.D. Maznichenko, N.G. Ozolin understand “technique” as a separate, unified, specific movement (system of movements). L.P. Matveev believes that “technique” can be understood as a model of competitive action and as a specific method of action that actually exists in someone’s performance.
MM. Bogen believes that the authors' stance on sports technique justifies the existence of many techniques. “Exemplary” (or reference) technique is a generalized model of a rational system of movements for solving a given motor task. It would be advisable to have an individual technique for each athlete, which is an adaptation of an exemplary version to his individual characteristics. The technique can be initial, advanced, transitional, operational.
D.D. Donskoy: “Technology does not stand still, but develops... And in every period of time there is modern, that is, the most advanced technology — the most effective of the existing ones... Both accidentally and purposefully, in tens and hundreds of thousands of attempts, they are looking for new options. Main source of progress — searching for these options.”
The criterion for the rationality of sports equipment is the level of relative efficiency: specific actions of specific performers are compared, and the winner’s action is recognized as the standard.
However, winning the competition — an imperfect criterion of quality, because technique depends not only on the quality of movements. “What if there are two winners and they demonstrate different techniques? What criteria should the winner, whose technique is considered a reference in the search for further improvement, focus on?” — asks M.M. Bogen.
Therefore, the so frequently encountered concept of “ideal” technique is incorrect and can rather be applied only in emotional responses to a performer’s victory.
Constant, even minor changes in technique among leading athletes and subsequent victories in connection with this push others to copy and imitate the winner. Recently, the concept of a “model of technology” has been formulated, which is oriented towards and which is constantly being improved, i.e. it is not considered ideal, but at this stage it is the most optimal for achieving high results.
In swimming, depending on its type, technique is directly related to solving certain problems. So, when overcoming a water obstacle, and even with a possible load, — The goal is not to swim at speed, just like when doing recreational swimming.
In sport swimming, the task is to overcome a regulated distance at the highest speed in a minimum period of time. Criterion for sports performance in swimming — time.
L.P. Makarenko: “The technique of sports swimming is understood as a system of movements that allows you to realize your motor abilities into high results. The concept covers the form, character, relationship of movements, as well as the swimmer’s ability to sense and use all the forces acting on his body to move forward.”
Swimming technique — a set of rational movements with the help of which the task is most effectively solved.
The swimmer’s body is located near the surface of the water and is in a well-streamlined, close to horizontal position with an angle of attack of 2-6° (the range of the angle of attack can fluctuate within 0-8°, for highly qualified swimmers this range is more strict — 4-5°). The head is lowered into the water (face down) so that the water level is approximately at the top of the forehead. The swimmer looks forward and down under the water, casually holding his head almost strictly on the longitudinal axis.
Breast crawl is characterized by alternating and symmetrical movements of the arms and legs. The swimmer's legs, rhythmically and moderately bending and unbending at the hip, knee and ankle joints, move alternately up and down, foaming the surface of the water. The working part of the leg movement is the downward kick. The most effective is a sharp blow executed from the hip. In this case, the thigh, moving down, slightly overtakes the shin-foot. The distance between the feet in the extreme lower and upper positions reaches approximately 40 cm. The toes are pulled out and turned slightly inward, the big toes are almost touching. The movements of the legs ensure a stable horizontal position of the body and maintain the speed of advancement. The arms (primarily the hands and forearms), which move along curved trajectories, provide the main forward movement of the body. During swimming, due to the work of the arms, the body rotates around the longitudinal axis of the body by 35-50°. The greatest tilt occurs at the moment of inhalation (in some cases, the rotation can increase to 60-65°). The sway of the torso strengthens the stroke and helps to carry the arm and inhale. The greatest angles of inclination are observed in the thoracic part of the body, the smallest in the lumbar and pelvic parts.
There are 3 varieties of the crawl method depending on the frequency of the legs: 2-impact, 4-impact and 6-impact, when for one cycle of arm work (2 arm strokes) there are 2, 4 or 6 kicks (see Fig. 6, 7, 8). 2- and 4-stroke crawl is used, as a rule, at medium and long distances, and 6-stroke — on sprint and finishing accelerations.
Breath.With normal breathing, one inhalation and one exhalation are performed per cycle of movements (2 strokes with the arms). To inhale, the head is turned relative to the longitudinal axis of the swimmer’s body towards the rowing hand (to the right or left) so that the mouth is above the water. Inhalation is performed quickly and actively through a wide open mouth at the beginning of raising the hand above the water when the body is tilted. After this, the head quickly turns into the water (face down) and a gradual exhalation immediately begins, first through the mouth, then through the nose. Exhalation is longer than inhalation. The respiratory cycle ends with a sharp exhalation of the remaining air through the mouth at the moment when the mouth again appears above the water - the mouth and lips are freed from the water, the swimmer is ready to begin the next inhalation. There should be no pauses between inhalation and exhalation, as well as between exhalation and inhalation.
When breathing for one cycle, the swimmer breathes under one hand - either under the left or under the right. Inhalation and exhalation can also be done every third stroke (1.5 cycles) or even every fifth stroke (2.5 cycles), thus inhaling alternately under the right and then under the left hand.
Leg movements. The legs perform continuously alternating counter movements from top to bottom and bottom to top with a small amplitude. The movements of the legs ensure a stable horizontal position of the body and maintain the speed of advancement. The movement of the legs consists of two phases - working (supporting) and preparatory (non-supporting). The downward movement of the leg (support phase) is also called a stroke, or kick (it contributes to some movement of the body forward), and the upward movement of the leg — preparatory (it does not affect the movement of the body forward). Since the movements of both legs are exactly the same, we can consider the technique using the example of the movement of one leg.
Reference (working) phase (movement from top to bottom). The downward movement of the leg begins with sequential extension at the knee and ankle (at the very end of the stroke) joints and simultaneous flexion at the hip joint. At this moment, all parts of the leg move downwards. Then the lower leg and foot continue to move downwards until the leg is fully extended at the knee joint, and the thigh, ahead of the lower leg and foot, begins to move upward. This movement of the hip helps increase the speed of the downward movement of the foot due to the whip-like motion of the leg as a whole. With this movement of the leg, the foot creates some lifting and traction forces, which help maintain the body on the surface of the water and propel it forward. The working movement is considered complete when the leg is fully straightened at the knee joint.
Preparatory phase (movement from bottom to top). In the initial (lowest position) the leg is straightened at the knee joint, and the foot is turned inward and relaxed. In relation to the body, the leg takes an inclined position, as it remains bent at the hip joint. The upward movement begins with straight leg extension at the hip joint. Until the horizontal position, the leg moves straight. Next, the leg begins to bend at the knee joint, and the lower leg and foot continue to move upward. At this moment, the thigh begins to move downward due to flexion at the hip joint. When the angle between the front surface of the thigh and the torso (at the hip joint) is 160-170°, and between the back surface of the leg and thigh (at the knee joint) — 130-140°, the movement of the leg from bottom to top is considered complete.
Coordination of footwork movements. From the extreme upper position, one leg moves down, while the other moves upward from the extreme lower position. The greatest amplitude of movements between the ankle joints is approximately 30-40 cm. It depends on the speed of swimming: at high speeds, the amplitude of movements can decrease, as the speed of movements of the feet increases, and their path (vertically) is shortened. Since the legs make continuous movements in the water and there is little movement from them, they should move freely with little effort.
When swimming the six-beat freestyle, the hip movements are performed with rapid changes of direction. In the four-beat crawl, the legs perform a crossing motion: one moves diagonally downward-inward, while the other moves smoothly upward, causing the legs to cross for a brief moment. The amplitude of such cross movements is small. In the double-stroke crawl version, the downward movement of the leg resembles an energetic sweeping stroke, as in butterfly swimming, with the active involvement of the pelvis in this movement.
Hand movements.In front crawl, the main forward movement of the body is provided by the arms (hands and forearms), which move along curved trajectories (see Fig. 7). The cycle of movements of each hand consists of the following phases:
— hand entry into water;
— capture;
— supporting part (two subphases - pulling and pushing);
— hand coming out of the water;
— raising your hand above the water.
The duration of a full cycle of hand movement is approximately 0.92-1.36 s.
As a rule, the phase composition of hand movements begins to be considered from the hand’s entry into the water, which is quite justified from visual considerations. However, the entry of the hand into the water completes the preparation for the next stroke, therefore, in some literary sources (for example, in the book by N.Zh. Bulgakov “Sport Swimming”, 1996), consideration of the technique of hand movement and phase composition begins with the next phase, so as not to violate the integrity working and preparatory periods. At the same time, the semantic content and order of alternation of the phases themselves in the cycle remain unchanged in both cases.
The phase of hand entry into the water. After being carried through the air, the arm bent at the elbow quickly enters the water at an acute angle in front of the shoulder joint of the same name, the palm is facing down and back, the fingers are connected. Immersion of the hand in water is carried out in the following sequence: hand, forearm, shoulder. The arm extends at the elbow and the grip begins.
The hand enters the water close to the longitudinal axis of the body or between it and a parallel line drawn at shoulder width. At the moment the hand touches the water, the angle of body roll to the opposite side is still 10-15°; at the moment the entry into the water is completed, it is zero.
The duration of the phase is about 0.07-0.17 s (7-12% of the time of the entire cycle).
Rice. 7
The phase is captured.In tempo variations of the freestyle it is short-lived; in variations with a long power stroke, the arm is extended more forward, as a result of which the hand and forearm interact with the flow longer. At the beginning of the grip, the hand, moving forward and down, bends slightly at the elbow joint, and the hand turns slightly with the palm outward. At this moment, the hand makes an angle with the surface of the water approximately equal to 15-20°. Moving further, the arm continues to bend at the elbow joint, and the hand, at a slight angle of attack, changing direction (downwards and inwards), moves under the longitudinal axis of the body. By the end of this phase, the hand takes the best position for performing the stroke: the angle between the horizontal and the forearm is 30-40°, the angle of flexion at the elbow joint — 120-140°, angle of attack of the hand — 40-50°.
The duration of the capture phase is approximately 0.08-0.30 s (10-25% of the time of the full cycle of movements).
Reference phase (2 subphases — pulling and pushing).
Pull-up subphase begins with a pronounced rotation of the arm inward and flexion of the forearm by gradually increasing the pressure on the wrist. The brush begins to move backward relative to the water. At the beginning of the pull-up, the arm is bent at the elbow joint to an angle of 130-150 ° , the hand is oriented to the frontal plane at an angle of about 45 ° .
Moving under the body with acceleration, the arm continues to bend at the elbow joint; forming an angle between the shoulder and forearm in the middle of the stroke equal to 90-110°. Here the hand moves from front to back in an inclined plane with simultaneous rotation of the forearm outward.
Repulsion subphase — the most energetic part of the cycle. The hand moves with acceleration under the abdomen and pelvis from front to back and slightly outward, maintaining a position close to the front. The arm is extended at the elbow joint. The swimmer, due to good support in the water, accelerates the forward movement of the body. The subphase ends with a sliding movement of the hand up and back and slightly outward, mainly due to the extension of the forearm. Optimal completion is facilitated by the beginning of the body roll to the opposite side.
The support phase ends when the arm reaches the pelvic line. At this moment, the arm (forearm and hand) moves up and back.
The duration of the main part of the stroke is 0.35-0.60 s (30-45% of the time of the entire cycle of movements).
The phase when the hand comes out of the water. The phase coincides with the roll of the body to the opposite side. When the hand reaches the thigh, active muscular efforts aimed at moving the body forward cease, and the elbow rises out of the water. At the next moment, the shoulder, forearm and hand rise out of the water in sequence and the movement (carrying) of the hand above the water begins. The brush comes out of the water behind the pelvic line, at the hip. The muscles of the forearm and hand should be relaxed if possible.
The duration of this phase is 0.05-0.08 s (5-8% of the time of the entire cycle of movements).
The phase of carrying the hand above the water. The bent arm, without undue tension, quickly sweeps over the water in the shortest possible way and enters the water. During the sweep, the elbow is in a high position and directed up and to the side, and the hand is held at the surface of the water. The movement of the arm is facilitated by the high position of the shoulder joint of the same name, which is ensured by the low position of the shoulder joint of the other arm, which is performing the beginning of the stroke at this time. The duration of the phase is 0.30-0.50 s (25-40% of the full cycle time).
Coordination of hand movements. Correct coordination of hand movements in the front crawl is based on obtaining the highest, relatively uniform speed of the swimmer's movement throughout each cycle. Therefore, the pause between the end of the main part of the stroke with one hand and the beginning of the main part of the stroke with the other hand should be such that the achieved speed of the swimmer’s movement is maintained. This depends on the continuous production of traction forces throughout the swimmer's movement cycle. Therefore, when the left hand performs the second half of the main part of the stroke, the right one at that moment enters the water and begins to capture. The removal of the left hand from the water and the beginning of the carry should coincide with the end of the grip phase of the right hand. At the moment the left hand finishes sweeping, the right hand finishes the first half of the main part of the stroke. Entering the water and starting to grab the left hand should coincide with the execution of the second half of the main part of the right hand stroke. Next, the left hand carries out the catching phase, and the right hand comes out of the water and begins the carry. The cycle of movements is completed when the left hand completes the first half of the main part of the stroke, and the right hand completes the sweep.
General coordination of movements. In front crawl, high, uniform speed is achieved due to the continuity of working movements of the arms and legs, and clear coordination of movements with breathing. The full cycle of movements consists of a stroke with the left and right hands and a certain number of kicks (two, four or six) and breathing, which, as already noted, is also variable (inhalation can be done through 2 or 3 strokes with the hands, in some cases through more number of strokes).
Let's consider the main 3 options for coordinating movements in the front crawl method, depending on the work of the legs.
Fig.8
Double-beat crawl . In a two-impact crawl (see Fig. 8), for two alternate strokes with the arms there are two successive kicks with the legs. The basis of the two-beat crawl is continuous strokes with the arms. Any delay in arm movements leads to loss of balance and body sinking, which forces the swimmer to make additional movements with his legs. The pace of arm movements at the same distance is always noticeably higher than with other options, especially with the six-beat freestyle.
I.p. — the left hand finishes the stroke (the hand is at the surface of the water), the right begins the second half of the main part of the stroke (the hand is under the chest), the left leg moves up (the foot is near the horizontal), the right is bent at the knee joint, it is at the top (the foot is at the surface of the water) .
From the starting position, the left (right) hand enters the water, performs a grab and approaches the middle of the first half of the supporting part of the stroke, the right one finishes the second half of the supporting part of the stroke, leaves the water and approaches the middle of the stroke, the left leg rises up (crosses the horizontal), and the right one strikes downwards. Moving further, the left hand enters the second half of the supporting part of the stroke, the right one finishes the sweep, the left leg bends at the knee joint (the foot approaches the surface of the water), and the right one moves up (the foot approaches the horizontal). At the next moment, the left hand carries out the second half of the support part of the stroke, leaves the water and approaches the middle of the carry, the right one enters the water, makes a grab and approaches the middle of the first half of the support part of the stroke, the left leg kicks down, and the right leg rises up (crosses horizontal). Completing the cycle of movements, the left hand finishes the sweep, the right one enters the second half of the supporting part of the stroke, the left leg moves up (the foot is near the horizontal), and the right one bends at the knee joint (the foot approaches the surface of the water).
Then the cycle of movements is repeated. Thus, the downward kick of one leg coincides with the most efficient part of the stroke of the same arm (the second half of the main part of the stroke). In a two-beat crawl, the hand produces a strong and fast stroke. Therefore, swimmers who have perfectly mastered the technique of this version of the freestyle develop a higher tempo of movement than athletes who use the six-beat freestyle at the same distance.
Inhalation in a two-beat freestyle is performed between the end of the phase of the hand coming out of the water and the beginning of the phase of carrying this hand. The other hand at this moment is respectively at the end of the catch phase and at the beginning of the supporting part of the stroke.
Rice. 9
Four-beat crawl (see Fig. 9). A distinctive feature of the four-strike freestyle is the sequential execution of the main kicks: right down, left down-in (surrounding), left down and right down-in (surrounding).
I. p. — The left hand enters the water (the hand is in the water), the right begins the second half of the supporting part of the stroke (the hand is under the chest), the left leg takes a horizontal position, the right is bent at the knee joint, located at the top (the foot is at the surface of the water).
From the starting position, the left (right) hand enters the water, makes a grab and begins the first half of the supporting part of the stroke, the right one carries out the second half of the supporting part of the stroke and begins to exit the water, the left leg rises to the surface of the water, bending at the knee joint, and the right one produces blow down. Next, the left hand approaches the middle of the first half of the main part of the stroke, and the right one comes out of the water and approaches the middle of the stroke, the left leg performs a circular downward-inward kick, and the right one slowly rises up (its foot is lower than the foot of the left leg — legs are crossed). Continuing the movement, the left hand, having completed the first, enters the second half of the supporting part of the stroke, the right one finishes the movement above the water and begins to enter the water. The left leg, bending at the knee joint, moves in the opposite direction up and out (the foot is at the surface of the water), and the right leg freely rises to a horizontal position. At the next moment, the left hand performs the second half of the supporting part of the stroke and begins to leave the water, the right one enters the water, makes a grab and begins the first half of the supporting part of the stroke, the left leg strikes down, and the right bends at the knee joint and continues to move upward (foot reaches the surface of the water). Finishing the stroke, the left hand comes out of the water and approaches the middle of the stroke, and the right hand passes the middle of the first half of the main part of the stroke, the left leg slowly rises up, and the right one performs a downward-inward kick (the foot remains above the foot of the left leg — legs are crossed).
The cycle of movements ends when the left hand finishes the sweep, the right one enters the second half of the supporting part of the stroke, the left leg freely rises to a horizontal position, and the right one bends at the knee joint and moves up and out (foot at the surface of the water).
In the four-beat crawl, the breathing technique is not much different from the two-beat crawl. However, at the moment of inhalation, the swimmer performs a cross kick: if the inhalation is performed under the right hand — cross kick is done by the left leg, if under the left — right leg.
Rice. 10
Six-beat crawl (see Fig. 10). The coordination of movements in the six-stroke freestyle is a cross-coordination that gives the body the most stable position in the water.
I. p. — the right hand is in the middle of the stroke, the left begins the supporting part of the stroke, the right leg is at the bottom (foot 30-40 cm from the surface of the water), the left is bent at the knee joint, located at the top (foot at the surface of the water).
When the right hand finishes the sweep and enters the water, the left one finishes the first half of the support part of the stroke, the right leg moves up, and the left kicks downwards.
Moving further, the right hand makes a grab, the left one finishes the supporting part of the stroke and begins to leave the water, the right leg strikes from top to bottom, the left one moves up. Then the right hand finishes the catch and begins the support part of the stroke, the left comes out of the water and performs the first half of the carry, the right leg rises up, and the left kicks downwards. Next, the right hand finishes the first half of the supporting part of the stroke, the left one finishes the carry and enters the water, the right leg strikes from top to bottom, and the left one moves up. At the next moment, the right hand finishes the supporting part of the stroke and begins to leave the water, the left one makes a grab, the right leg rises up, and the left one strikes from top to bottom. The cycle ends when the right hand comes out of the water, completes the first half of the sweep, the left finishes the catch and begins the support portion of the stroke, the right leg kicks down, and the left moves up.
If a swimmer inhales under his right arm, then at this moment the right arm comes out of the water and begins the sweep, the left begins the supporting part of the stroke, the right leg kicks from top to bottom, and the left moves upward. If the inhalation is made under the left hand, then the positions of the right and left arms and legs change accordingly.
3.3. Back crawl swimming technique
Body position and general characteristics of the method. The swimmer’s body is located at the surface of the water and is in a well-streamlined, close to horizontal position (angle of “attack” 4-10°), the shoulders are slightly raised. The head lies on the water (its position when swimming is relatively stable), the face is turned upward, and the chin is slightly lowered onto the chest. The neck is relaxed. The swimmer looks up and slightly back (the gaze is fixed at approximately an angle of 40-45° relative to the surface of the water). The water level is slightly above the ears.
The crawl on the back is characterized by alternating continuous movements of the arms and legs (see Fig. 11). During swimming, the shoulder girdle rhythmically rotates left and right relative to the longitudinal axis with each stroke. Such rolls help to strengthen the hand stroke, perform it at an unnecessary depth, and also carry the hand above the water with minimal resistance. The degree of roll when swimming crawl on the back is slightly less than on the chest, and is approximately 25-40°.
Its main difference from other swimming methods is the position of the body and relatively free breathing (exhalation is performed above the water).
Each cycle of movements in this method consists of two alternating movements of the arms, six alternating movements of the legs, one inhalation and one exhalation. This most common variation of the technique is called the six-beat back crawl.
Breath.In back crawl, breathing does not depend on environmental conditions: inhalation and exhalation are performed over water. However, even in this method, breathing should be continuous and rhythmic. Breathing is most often coordinated with a full cycle of movements of one hand. Inhale through a wide open mouth while raising your hand above the water, exhale during the stroke and exit of this hand from the water.
In this case, the completed respiratory cycle occurs in two strokes with the arms. Skilled swimmers can perform one inhalation and exhalation for 3 arm strokes, mainly during acceleration.
Leg movements. Just like in front crawl,legsWhen swimming backstroke, continuous alternating counter-movements are performed from top to bottom and bottom to top with an amplitude equal to approximately a third of the swimmer’s height. These movements provide the body with a stable horizontal position and maintain forward speed. The upward movement of the leg is called rowing (working), and the downward movement is called preparatory. The range of motion of the hips is moderate. They stay close to the surface of the water. The legs bend at the knee joints up to 130-140°, the feet move in the water with a fairly moderate amplitude. Too small movements of the feet at the surface of the water are considered ineffective.
Preparatory phase (movement top down). In the initial (extreme upper) position, the leg straightened at the knee joint with the relaxed foot turned inward is at the surface of the water and occupies a slightly inclined position relative to the body. The downward movement begins with straight leg extension at the hip joint. Having passed the horizontal position, the straight leg continues to move downwards, bending at the hip joint (backwards) to approximately an angle of 170°. Next, the leg begins to bend at the knee joint, while the lower leg and foot continue to move downward, and the thigh, extending at the hip joint, begins to move upward. When the angle between the front surface of the thigh and the torso (at the hip joint) is approximately 130-140°, the movement of the leg from top to bottom is considered complete.
Reference phase(movement down up). The upward movement begins with sequential extension of the leg at the knee and ankle joints (in the latter, extension is carried out at the very end of the stroke), the thigh continues to flex at the hip joint. At this moment, the thigh, lower leg and foot move upward. When the knee joint reaches the surface of the water, the thigh begins to move downward (extending at the hip joint), ahead of the lower leg and foot, which continue to move upward. The advanced downward movement of the hip promotes rapid extension of the leg at the knee joint and thereby increases the speed of the whip-like movement of the foot up and back. As a result of this movement of the leg, the foot creates a certain traction force, which helps propel it forward. When the leg straightens at the knee joint, the working movement is considered complete.
Coordination of footwork movements . From the lowest position, one leg moves up, and the other simultaneously moves down from the highest position. When swimming back crawl, the leg can go down to a greater depth than in the front crawl method. As the swimmer's speed increases, the amplitude of leg movements decreases.
Rice. eleven
Hand movements.Just as in the front crawl method, the forward movement of the body when swimming the back crawl is mainly carried out through arm movements. An approximate trajectory of hand movement is shown in Fig. 12. The movements of the arms are also coordinately subordinate to the movements of the legs and breathing.
The cycle of movements of each hand consists of the following phases:
- hand entry into the water;
- capture;
— supporting part (two subphases - pulling and pushing);
- hand coming out of the water;
- raising your hands above the water.
The duration of the movement cycle is 1.10-1.4 s.
The phase of hand entry into the water. After being carried through the air, the straight arm is lowered into the water on a line passing through the shoulder joint of the same name and located either parallel to the longitudinal axis of the body, or at a certain angle to this axis (no more than 15° to the side from it). When immersed in water, the palm faces outward and the hand is rotated so that the little finger enters the water first. The duration of the phase is 0.08-0.10 s (6-8% of the time of the full cycle of movements).
Capture phase.After the hand enters the water, the body begins to rotate around the longitudinal axis towards the hand that entered the water. This helps the straight arm quickly descend down and forward to a depth of 15-20 cm. As it descends, the arm begins to bend at the elbow joint, and the hand moves forward, down, and outward to a position perpendicular to the direction of movement and begins to capture water. Continuing the movement down-forward-to the side, the arm bends at the elbow joint to an angle of 150°, while the elbow goes down and the hand is immersed in the water up to 30 cm (for some swimmers up to 40 cm) and is located perpendicular to the direction of body movement, remaining higher elbow. The shoulder girdle rotates with the hand, facilitating a deeper grip.
The duration of the capture phase is 0.15-0.20 s (10-15% of the time of the entire cycle).
Pull-up subphase begins at the moment when the hand begins to move back and up due to flexion of the arm at the elbow joint and rotation of the forearm. Moving backward along the body, the arm turns the rowing surfaces in this direction and continues to bend at the elbow joint, forming an angle between the shoulder and forearm in the middle of the stroke equal to 70-100°. The hand rises to the surface of the water (without disturbing it), and the elbow remains turned down.
IN repulsion subphase, which begins when the hand passes the line of the shoulder joints, the arm gradually extends at the elbow joint and ends with an overflowing movement of the hand back-down-inside. At this moment, the arm is fully straightened, and the hand is lowered to a depth of 30-40 cm from the surface of the water. When performing a push-off, it is important that the swimmer strives not just to push the water back with his hand, but to lean on it, sending the shoulder girdle forward and slightly upward. This is expressed in the suspension of the back-down movement of the elbow of the rowing arm and optimal fixation of the shoulder. At the end of the subphase, the hand is slightly below the buttocks, at approximately the same depth as at the end of the grip phase.
Throughout the entire support phase of the stroke, the hand moves along a curved path and, maintaining a position perpendicular to the direction of its movement, is located near the surface of the water. The perpendicular position of the hand ensures throughout the entire supporting part the maximum effect of the traction force that occurs on the rowing surfaces of the hand and forearm. The rotation of the body around the longitudinal axis also enhances the stroke movement.
The duration of the support phase of the stroke is 0.40-0.50 s (30-40% of the time of the entire cycle).
Rice. 12
The phase when the hand comes out of the water. By the time the hand moves in the water, the tension in the muscles involved in the stroke stops. The next moment, the swimmer, rotating the forearm, turns the palm to the thigh and successively lifts the hand, forearm and shoulder out of the water. Then the movement (carrying) of the hand above the water begins. The exit of the arm from the water is facilitated by the roll of the body to the opposite side and the active raising of part of the shoulder girdle of the arm that has completed the stroke above the surface of the water.
The duration of this phase is 0.10-0.15 s (8-15% of the time of the full cycle of movements).
The phase of bringing the hand above the water . The movement of the straight arm above the water is carried out in a vertical plane passing through the shoulder joint. The hand moves through the air straight, relaxed, with minimal muscle effort. During the carry, the palm turns outward. The hand is carried above the water evenly, in accordance with the stroke speed of the other hand.
The duration of the phase is 0.40-0.45 s (30-35% of the time of the entire cycle).
Coordination of hand movements. When the right hand is in front (the catching phase), the left hand at this moment is removed from the water and begins to carry. Next, the right hand performs the supporting part of the stroke, and the left one sweeps over the water and enters the water. After this, the right hand rises out of the water and begins to carry, and the left finishes the grab. The right hand then sweeps over the water and enters the water, while the left performs the supporting part of the stroke. Next, the cycle of hand movement is repeated again.
The uniformity of the forward movement when swimming on the back is ensured by a minimal break in the execution of arm movements in the supporting part of the stroke: at the moment the supporting part of the stroke ends with one hand, the other should begin this part of the stroke as early as possible. To meet this requirement, it is necessary to shorten the capture phase.
General coordination of movements. When swimming on your back, the most rational, providing the body with uniform forward movement and creating the most stable position in the water, is the six-stroke crawl. The coordination of the movements of the arms and legs is carried out as follows.
I. p. - the left hand is in the water in front of the shoulder joint, the right has completed the supporting part of the stroke (the hand near the hip), the left leg is below, the right is at the surface of the water.
From the starting position, the left hand makes a grab, the right one comes out of the water and begins to carry, the left leg kicks from the bottom up, and the right one goes down. Continuing the movement, the left hand performs the first half of the support part of the stroke, the right goes through the middle of the carry, the left leg moves down, and the right kicks from the bottom up. Then the left hand carries out the second half of the main part of the stroke, the right one finishes the sweep and enters the water, the left leg makes an upward kick, and the right one moves downwards. Next, the left hand comes out of the water and begins to carry it, the right one makes a grab, the left leg moves down, and the right leg moves from bottom to top. At the next moment, the left hand is in the middle of the stroke, the right one performs the first half of the supporting part of the stroke, the left leg performs an upward kick, and the right one goes down. The cycle ends when the left arm finishes the sweep and enters the water, the right arm finishes the support portion of the stroke, the left leg drops down, and the right kicks upward.
3.4. Breaststroke swimming technique
Body position and general characteristics of the method. When swimming breaststroke, the swimmer's body is located at the surface of the water in a straightened position, and the head is lowered with the face into the water. However, during periods of performing strokes with arms and legs, as well as at the time of inhalation, the body position and angles of attack are constantly changing.
Depending on the position of the body, there are two options for breaststroke swimming techniques. In the first option, the angle of attack of the body and the magnitude of its change within the cycle are insignificant (2-10°). In the second, the angle of attack and its changes within the cycle are much greater (8-20°). Both techniques are effective and are used to achieve high athletic results. In the first case, the position of the body creates the best streamlining, ensures slight oscillation of the body in the cycle of movements, and helps to increase the advancement of the body when performing supporting (working) movements of the legs. In the second case, the body position ensures a more uniform action of the traction force within the cycle, increases the efficiency of moving the arms forward, and reduces body sway during the period of inhalation.
Breaststroke is characterized by simultaneous and symmetrical movements of the arms and legs (see Fig. 13). Unlike butterfly, the entire cycle of arm movements is carried out in the water.
Each cycle of movements in this method consists of one movement of the arms, one movement of the legs, one inhalation and one exhalation into the water.
Hands and feet are equally movers. Hands set the pace and rhythm, overall coordination of movements and are closely related to breathing.
Breath.To inhale, the swimmer must raise his head so that his mouth is above the water. This position of the head depends on the position of the shoulder girdle. The highest position of the shoulder girdle is observed at the end of the arm stroke. It is at this moment that the breath is taken. Then the head is lowered face into the water and after a short pause, exhalation begins through the mouth and nose and continues for the rest of the cycle.
In breaststroke there is a so-called “late breath”. It begins at the end of the arm stroke, when the hands and elbows of the bent arms are directed inward and forward. The “late breath” technique is most suitable for high-speed breaststroke variations, as it helps keep the body in a well-streamlined position during the arm stroke with high elbows, and also allows you to perform the second half of the stroke with the most power.
Rice. 13
Body position and general characteristics of the method. When swimming in the butterfly stroke, the swimmer's body is located on the surface of the water in an extended position. The head is placed face down in the water. Due to the wave-like movements of the torso (raising the pelvis during the downward strike of the feet) and some oscillation in the vertical plane of the shoulder girdle, the angle of attack changes during one cycle within ±15-20°.
Butterfly is characterized by simultaneous symmetrical movements of the arms and legs, as well as wave-like movements of the torso, which help the movements of the arms and enhance the work of the legs (Fig. 15). Individual elements of the technique of this method of swimming (movement of the arms and legs) are not much different from the front crawl technique.
As a rule, when swimming butterfly, swimmers use its high-speed variety - dolphin (when the legs move up and down like a dolphin's tail). Hence, in many literary sources the description of this method is called dolphin.
When swimming butterfly, there are several options for coordinating movements (one-beat, two-beat and three-beat coordination). The most common is the two-impact version. Each cycle of movements in this variation consists of one arm movement, two kicks, one inhalation and one exhalation. In this cycle, the movements of the arms and legs are performed in a certain sequence. Unlike other methods, when swimming butterfly, the torso takes an active part in the movements of the legs.
Breath.The shoulder girdle occupies the highest position at the end of the main phase of the arm stroke. At this moment, the head rises out of the water and the inhalation begins, which ends at the beginning of carrying the hands above the water. Then the head is lowered face into the water, and the hands finish carrying it. After a short pause, exhalation begins, which is done through the mouth and nose and continues throughout the rest of the cycle.
When swimming butterfly, one inhalation and exhalation is usually used for a full cycle of arm movements. Well-trained swimmers inhale and exhale once for two full cycles of arm movements.
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Movements of the legs and torso. In the butterfly style, the legs perform continuous, simultaneous and symmetrical movements from top to bottom and bottom to top. The swimmer’s torso is actively involved in these movements, which also contributes to the best movement of the arms above the water and inhalation. The general rhythm of movement of the torso and legs is determined by the rhythm of movement of the upper body. The cycle of leg movements consists of 2 phases - support (movement from top to bottom, called kick) and preparatory (movement of legs from bottom to top).
Preparatory phase (movement down up). In the lowest position, both legs are straightened at the knee joints, and the feet are slightly turned inward. In relation to the body, the legs occupy an inclined position (bent at the hip joints to approximately an angle of 145-160°), the pelvis is on the surface of the water, the upper part of the body is lowered into the water. The upward movement begins with straight leg extension at the hip joints with simultaneous flexion of the torso at the waist (backward) and lowering of the pelvis. Until approximately a horizontal position, the legs move straight up, and then, following the pelvis, the hips begin to move down, the legs bend at the knee joints, and the feet continue to move up. Next, the hips quickly drop down, the knees continue to bend, and the feet rise to the surface of the water. When the knees are bent to an angle of 90°, the pelvis is in the extreme position below, and the feet are bent at the ankle joint - the legs are ready for a downward strike (the angle between the thigh and the torso is 150-165°).
Reference phase(downward kick) begins when the hips continue to move downwards, dragging the lower legs and feet with them. The latter perform a downward movement with acceleration and, under the influence of the counter resistance of the water, bend at the ankle joints. As the legs move downwards, they begin to extend at the knee joints. As the shins and feet approach a horizontal position, the pelvis and hips begin to rise toward the surface of the water. At this moment, the legs continue to extend at the knee joints, and the legs and feet move energetically downward. Next, the pelvis and hips come to the surface of the water, the legs quickly straighten at the knee joints and accelerate with a whip-like movement downwards. The support phase is considered complete at the moment when the buttocks appear on the surface of the water and the legs are fully straightened at the knee joints. During the downward kick, the feet rotate inward. Towards the end of the downward kick, the swimmer extends the torso in the lumbar region.
Hand movements.In butterfly, the forward movement of the body is mainly ensured by the arms, which move in the water along curved trajectories (see Fig. 16). When swimming butterfly, the cycle of arm movement consists of the following phases:
— hand entry into the water;
- capture;
- support phase (2 subphases - pulling and pushing);
- taking your hands out of the water;
- raising your hands above the water.
The duration of a full cycle of hand movements is 1.07-1.20 s.
Phase of entering the hands into the water. When the movement above the water is completed, straight but tense arms are lowered into the water approximately shoulder width apart in the following sequence: hands, forearms and shoulders. When entering the water, the hands are facing outward and down, and the elbows are at the top. The head is lowered into the water, the face is turned down and slightly forward. After entering the water, both straight arms should actively move forward and downward.
The duration of this phase is 0.06-0.09 s (6-10% of the full cycle of hand movements).
Capture phase.This part of the stroke is characterized by slight bending of the arms at the wrist and elbow joints. The beginning of the grip is carried out by moving the arms forward, down and to the sides. The rowing surfaces of the hands perform movements at a small angle of attack. In the second half of the grip, the hands move down, back and to the sides, also with a small angle of attack. During the grab, the elbows remain high, the arms move quickly, and the upper body moves down with a small amplitude. The grip ends at the moment when the angle between the surface of the water and the forearm is approximately 30°, and the hands are at the maximum distance from each other. In the capture phase, the head is lowered into the water, the face is turned forward and down.
The duration of the phase is 0.18-0.24 s (15-20% of the time of the full cycle of hand movement).
Support phase (2 subphases - pulling and pushing).
Pull-up subphase begins from the moment when the hands and forearms, changing the direction of movement, move inward, downward, and backward. Moving in this direction, the arms continue to bend at the elbow joints, providing rotation to the forearms and forward movement to the hands from front to back along a curved path. By the middle of the first half of the main part of the stroke, the rowing planes of the hand and forearm occupy the best position for support on the water and subsequent repulsion (the angle of the forearm with the surface of the water is 50°, and the plane of the hand is 60°). Elbows point up and out and are held in a high position. By the end of the pulling subphase, the hand and forearm make an angle of 75-85° with the surface of the water. At this moment, the hands are located under the shoulder joints at a short distance from each other, and the angle of flexion of the arms at the elbow joints reaches 90°.
In the second half of the support phase, in repulsion subphase, the swimmer strives to push off from a large mass of water and propel his body forward. The elbows continue to be held high, and the rowing planes of the hands and forearms remain facing backward and moving quickly in that direction. After the hands and forearms have crossed the vertical plane passing through the shoulder joints, the arms, continuing a powerful movement back, gradually straighten at the elbow joints and finish the main part of the stroke at the hips almost straight.
To make it easier to lift their arms out of the water, many swimmers, in the final part of the support phase of the stroke, move their hands back and up and slightly outward.
The duration of this phase is 0.42-0.50 s (40-45% of the full cycle time).
The phase when hands come out of the water. The arms rise from the water in the following sequence: shoulders, forearms and hands. At the moment of leaving the water, the arms are slightly bent at the elbow joints, and the hands are turned with the palms back and up (in another option, inward).
The duration of the phase is 0.04-0.08 s (5-7% of the total cycle time).
The phase of bringing your hands above the water. After leaving the water, the arms bent at the elbow joints (flexion angle is 140-165°) simultaneously perform a swing movement over the water from the sides forward without unnecessary muscle tension and at high speed, while the elbow is higher than the hand. At the beginning of the stroke, the backs of the hands are turned towards the water. At the moment when the hands reach the shoulder line, the palms are facing outward. Before entering the water, keep the elbow above the hand and palms facing down.
The duration of the phase is 0.30-0.38 s (30-35% of the full cycle time).
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General coordination of movements.
The most rational coordination of movements when swimming butterfly is observed with two-stroke coordination. It ensures to the greatest extent the continuity of working movements of the arms and legs, the streamlined position of the body and, as a result, the uniformity of the swimmer’s forward movement throughout each cycle.
Coordination of movements is carried out as follows.
I. p. - arms are extended forward (end of the phase of entering the hands into the water), head is lowered into the water - face is turned down, feet are down (end of the downward stroke).
From the starting position, the arms perform a grab, and the legs freely rise to a horizontal position. Next, the arms bend at the elbow joints and carry out the first half of the supporting part of the stroke, and the legs, bending as much as possible at the knee joints, send the feet to the surface of the water. At the next moment, the arms perform the second half of the supporting part of the stroke, and the legs make a whip-like downward blow. At this moment, the torso moves forward and upward, and the pelvis and hips rise to the surface of the water, providing good streamlining. After this, the arms are taken out of the water and carry out the first half of the stroke (the swimmer takes a breath), the legs are straightened and then bent at the knee joints again, the feet approach the surface of the water. The cycle ends when the arms enter the water and the legs perform a second whip-like downward stroke.
3.6. Technique for performing starts
Performing a start when swimming using sports methods is important in overcoming the distance. The outcome of the fight in competitions largely depends on how well the starting technique is mastered, since sometimes success is determined by the difference in hundredths of a second. Sometimes the advantage gained at the start cannot be regained over the course of the race, especially at sprint distances. Losing at the start puts the swimmer in a disadvantageous psychological position as a catcher.
A fairly effective start consists of many components - attentiveness, speed of reaction, technique of executing the start itself. Special requirements for these components are also imposed in relay races, when each team has to not only perform the initial start, but also when passing the baton.
In accordance with the rules of the competition, all starts are divided into 2 categories: starts from the bed (for freestyle or front crawl, breaststroke and butterfly) and from the water (backstroke).
The start itself is preceded by certain actions of the swimmer, called by the team of the starter judge and regulated by the rules of the competition, the result of which should be the starting position for the start itself.
Technique for starting from a bedside table
At the preliminary command of the judge “Participants to take their places” (or a sound signal), the athletes approach the table and stand on its rear edge in anticipation of the next command.
After the preparatory command “To start,” they stand on the front edge of the bedside table and must take a stationary starting position to start. A fixed starting position makes it possible to place all competition participants in relatively equal conditions, as well as to record a false start (an athlete starting before the judge’s command).
A shot (sound signal, command “March”) serves as a signal to begin the starting actions. A certain period of time passes between the shot and the actions themselves, called the starting reaction time. For the most part, human reaction speed is innate and can hardly be trained. However, the starting reaction is the object of targeted improvement.
Initial position The swimmer’s start pressure should be such that he can perform a more effective starting jump in the least amount of time.
There are several common options for starting positions when starting from a bedside table (see Fig. 17). The choice of the starting position for the start is determined by the individual psychophysiological characteristics of the athlete, as well as the type of competitive program.
a)b)
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In all cases, the feet are placed hip-width or shoulder-width apart and the toes are on (or gripping) the front edge of the bedside table. The degree of flexion in the knee joints can be different. The angle between the thigh and lower leg ranges from 100-150°. It is believed that bending the legs to an angle of 90° or less does not increase the force of the push and leads to loss of time.
In the initial position, the torso is tilted forward, the swimmer’s center of gravity is above the front edge of the bedside table with the feet in a stable position. The angle between the front surface of the thighs and the torso ranges from 10 to 60°.
With the traditional start version (Fig. 17b), the arms of the swimmer, who has taken the starting position on the bedside table, are extended to swing forward and down or pulled back. The face is facing down or towards the distance.
When starting with a grab (Fig. 17a), the swimmer’s hands grab the edge of the table from the front or sides. In this case, the feet are on the same line, grasping the front edge of the bedside table with your fingers, or one foot (the jogging leg) grabs the front edge of the bedside table with your fingers, and the other is located behind. In this position, the swimmer's knees are over the toes (except when one leg is in front of the other), the shoulder girdle and head are slightly forward. The head is lowered, breathing is held. The weight is transferred to the front of the feet (or one foot), the swimmer is ready to instantly begin the starting actions.
The technique of starting from a bedside table consists of the following phases:
- squat;
— flight;
— entry into the water;
— sliding;
- exit to the surface.
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Squat phasebegins from the initial (stationary) position and lasts until the legs begin to extend at the knee joints. The athlete quickly throws the body out of balance and performs an energetic squat with the body and head moving forward and upward.
Depending on the initial position, the squat may be with a swing of the arms (in the initial position with a grip, there is no swing of the arms). This is either an energetic movement of the arms back and forth, and then down and forward, or a circular movement of the arms up, back, down and forward. The arms must perform this movement as quickly as possible, in strict coordination with the energetic movement of the body and the squat.
Push-off phase with arm swing (see Fig. 18a ) lasts until you lift your legs off the bedside table. At the moment of repulsion, the torso and legs are straightened, the longitudinal axis of the body is directed forward and upward at an angle of 15-25° to the horizon, straight arms are extended forward, the angle between them and the longitudinal axis of the body is 40-80°, the face is directed forward and slightly downward. The main task of the phase is to provide the body with the maximum possible amount of movement in a minimum period of time and send it flying at high speed along the optimal trajectory. As a rule, at the end of the phase, inhalation begins.
In many literary sources, the squat and push-off phases are combined. In total, approximately 0.35-0.50 seconds are spent on the starting movements on the stand, and the time from the signal to the lifting of the legs from the stand, i.e., taking into account the swimmer’s starting reaction to the signal (shot), is 0.65-0 .95s.
Flight phase(see Fig. 18b) lasts 0.35-0.40 s (until the hands touch the water) and is performed along the optimal trajectory, which, of course, is set with the help of a push in the previous phase. The athlete's flight speed at the moment of lifting his legs off the bedside table is approximately 4.0-4.5 m/s. Highly skilled athletes manage to fly through the air about 3.3 m (maximum up to 4.0-4.2 m). At the beginning of the flight, the swimmer’s arms, having completed the swing, are extended forward, the head takes a position between the arms. Next, the swimmer’s body turns in such a way that the entry into the water is made at one point. During the flight, inhalation ends.
Entry phase (see Fig. 18c) . At the moment of completion of the flight, the arms and torso enter the water at an angle of 20-40°. The swimmer's body is immersed in the water in a well-streamlined position, the head is between the hands, the legs are slightly bent at the hip joints, and the pelvis is raised. The entry speed into the water is approximately 5.0-5.5 m/s. This phase takes approximately 0.25-0.30 s.
In butterfly and breaststroke swims, athletes sometimes use a start with a steeper entry into the water (30-40°), which provides them with a deeper glide under water.
Sliding phase(see Fig. 18d) . This phase lasts until the start of the first arm stroke with the task of maintaining speed over a larger segment of the path. This part of the start, taking into account the time of entry into the water, takes 1.5-1.9 s, and the total length of the slide is 2-3.5 m. By changing the position of the arms, head and torso deflection, the athlete adjusts the depth of the dive.
Depending on the method of swimming, the athlete, at the moment of losing the initial speed of entering the water, begins to move under water. When swimming crawl and butterfly, the swimmer begins the movements with his legs. When swimming breaststroke, the athlete performs a stroke with his arms up to the hips, to the sides, down, in, and back, increasing the gliding speed and also called the “second glide.”
Phase reaching the surface(see Fig. 18d ). Reaching the surface is carried out through strokes with the arms and legs and lasts until the moment when the swimmer finds himself in a position characteristic of the beginning of the first generalized phase of the swimming technique in this way. In this phase, it is necessary to “pick up” the high gliding speed with rowing movements. For example, when swimming crawl, an athlete performs a stroke with his hand, coordinating it with active movements of his legs. At this point, the distance covered by the athlete is: 6.0-7.5 m in freestyle, 7.0-8.5 m in dolphin and breaststroke.
The exit after the start when swimming breaststroke is different from the exit in other swimming methods. After the “second slide,” the arms are brought forward while the legs are simultaneously pulled up to perform a strike.
In relay swimming, the start is taken at the moment the swimmer touches the wall of the pool, finishing the previous stage. The starter’s task is to quickly react to the touch and at the same time not get ahead of it (the touch) by pushing off and jumping prematurely, so as not to be disqualified.
Water start technique
The start from the water is performed when swimming on the back.
At a preliminary command (signal), athletes jump into the water and grab the handrails of the bedside table with their hands, standing facing it. In this position, the arms are almost straight, the legs are bent and rest securely against the wall of the pool just below the water level, while the knees remain between the hands.
At the command “Start!” the swimmer bends his arms, pulling his body slightly towards the handrails, and takes his starting position.
After the shot (sound signal or the “March” command), the athlete begins the start.
Initial position: The swimmer, with his elbows bent, holds the handrails shoulder-width apart with an overhand (or side) grip and carefully waits for the signal. The shoulder girdle is raised as high as possible, the head is lowered between the hands. The body is bent at the hip and knee joints, the feet are hip-width apart and firmly rest against the wall of the pool below the water level (see Fig. 19a).
The technique of launching from water is usually divided into the following phases:
- push-off with arm swing;
— flight;
— entry into the water;
— sliding;
- exit to the surface.
Push-off phase with arm swing (see Fig. 19b) lasts until the feet lift off the wall. Pushing off with the legs occurs with a simultaneous thrust of the pelvis upward, a sharp throwing back of the head and an energetic swing of the arms forward. At the moment of completion of the repulsion, the body is located completely above the water, the legs and torso are straightened, the head is thrown back, the hands are in front and slightly above the shoulders. At this time, a quick exhalation and inhalation is performed.
From the moment the start signal is given until the end of the repulsion phase, about 0.70-0.95 s passes.
Flight phase(see Fig. 19c) lasts 0.06-0.15 s and continues until your hands touch the surface of the water with the goal of flying as far as possible. In this case, the swimmer’s body flies through the air in a bent position, arms extended forward, hands together. In flight, a man covers a distance of approximately 2.4-2.7 m, a woman - 2.2-2.5 m.
Entry phase (see Fig. 19d). The swimmer's body is immersed in the water in a streamlined position and optimally tense. The hands touch the water first, then the back of the head, shoulder girdle, and back.
Sliding phase(see Fig. 19e) is short-term and lasts until the start of the first hand stroke. At this moment, the speed is 4.5-4.7 m/s. After being completely immersed in the water, the swimmer immediately begins to move his legs. At first it is 2-3 (possibly more) simultaneous dolphin-like movements of the legs, then the transition to alternating movements of the legs. Based on the depth and speed of swimming, the swimmer prepares to begin the first stroke with his arms.
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Surface phase (see Fig. 19e) is carried out through a strong hand stroke and alternating crawl movements of the legs. At this time, the other arm remains extended forward to the limit, the face at the end of the stroke appears on the surface of the water. The task is to catch the high gliding speed in a timely manner and bring the body to the surface in such a way as to move on to swimming at a distance without loss of speed and optimal rhythm. On the 2-3rd stroke with the arms, the swimmer should give the body a streamlined and high position with the pelvis at the surface of the water and the optimal position of the head (fix the gaze at approximately an angle of 45° to the surface of the water).
3.7. Turning technique
When covering the distance in competition, a swimmer must be able to effectively make turns at the wall of the pool. A correctly executed turn allows the swimmer to reduce the time it takes to cover the distance, save strength and maintain the necessary rhythm and tempo of movements and breathing. A swimmer also encounters navigating turns during regular training sessions.
The turning section of the distance is taken to be 7.5 m before and 7.5 m after the turning wall. The turn itself begins with the head diving under the water immediately in front of the pool wall or touching it with the hands and continues until the first cycle of normal swimming movements on the surface of the water begins after the turn.
Performing a turn is conventionally divided into phases:
— swimming (approach) with touching (or without touching);
— rotation;
- repulsion;
— sliding;
- exit to the surface.
Rotations can be performed predominantly in a horizontal plane around a vertical axis and predominantly in a vertical plane around a horizontal axis. When performing a turn in the horizontal plane, the swimmer, after the rotation, maintains the body position that was before the turn. Turns in the horizontal plane are much easier, but they take more time to complete. Turns performed in the vertical plane have a number of advantages. The main one is the ability to group and reduce the moment of inertia to a minimum. In addition, during these turns, the energy of the forward motion of the body is used, and the resistance of the water can be somewhat reduced by the movement of some parts of the body above the water during the rotation.
All turns are divided into two large groups: open and closed. Open turns are easy to perform and are most suitable for teaching beginner swimmers. The features of an open turn also include the ability of the athlete to take a breath. If you inhale before turning, and the rotation is performed with holding your breath and exhaling, then the turn is called closed.
Technique for performing turns when swimming breaststroke and butterfly. A feature of turns when swimming butterfly and breaststroke is the symmetrical touching of the side with both hands and a turn (rotation) in any direction convenient for the swimmer. For high-speed breaststroke and butterfly swimming, an open “pendulum” type turn is used (Fig. 20).
Swim and touch phase . When swimming up to the side, the athlete touches it with both hands at the same time at the same level and close to the surface of the water. At the moment the hands touch the wall, the swimmer’s body is horizontal, legs and arms are extended, and the head is between the arms. Then the athlete bends his arms at the elbow joints, bringing his head and shoulder girdle closer to the wall, bends his legs and, pushing off the wall of the pool with his hands, begins to rotate.
Rotation phase.Rotation is performed in a lateral plane close to the vertical. The hand of the same name on the side of the turn comes off the wall and is brought forward under the water, the other hand moves above the water and enters it in front of the head. At this moment, the shoulder girdle is above the water, the swimmer takes a breath. The rotation lasts 0.80-0.95 s and ends with placing the feet on the wall of the pool.
Repulsion phase. The rotation turns into repulsion, which lasts on average 0.32 s until the legs lift off the wall. After the rotation, the swimmer plunges into the water for a slight dip before pushing off with his legs, ending up partially in a position on his side. Repulsion occurs while holding your breath, maintaining a horizontal and streamlined body position relative to the water. During the push-off, a rollover occurs on the chest
Sliding phase. Sliding is in many ways similar to similar phases of movements when starting from a bedside table. However, the sliding speed of the body after the turn is noticeably lower than after the start (at the initial moment of the phase it is 2.20-1.90 m/s).
Fig.20
Surface phase. The swimmer has to start the first hand stroke much earlier than in a similar phase after the start due to short-term sliding.
The distance covered by the athlete after pushing off to the moment of reaching the surface of the water is 4.2-5.4 m when swimming with a dolphin, and 4.8-6.4 m when swimming with breaststroke.
In the practice of sports breaststroke and butterfly swimming, simpler flat turns are used, mainly in the horizontal plane (Fig. 21), which are recommended in the initial stages of training. Their main drawback is that it takes too long to turn relative to a horizontal plane with great resistance. This turn can be either open or closed (with holding your breath), as it is faster.
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Technique for performing turns when swimming front crawl. When swimming crawl, all the turns described when swimming breaststroke and butterfly are used, i.e. simple flat turns, both open, with inhalation, and closed, when the head is in the water and the turn is performed with breath holding (Fig. 22) and “pendulum” (Fig. 23). The only differences are touching with one hand and turning (rotating) strictly in the opposite direction from the touching hand.
Fig.22
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When swimming crawl, where the rules allow you to touch the wall with any part of the body, a forward somersault turn is used (see Fig. 24). Swimmers do not touch the wall with their hand, which reduces the turn time and makes it more dynamic, but only place both feet on it to take off. This is a basic turn for skilled athletes. Let us consider the phase composition of this rotation.
Swimming phase. The athlete accelerates onto the wall of the pool, finishes the stroke with one hand, and then with the other (about 1.5 m before the wall), leaving them at the hips.
Rotation phase.The swimmer begins diving forward and down and slightly to the side. The upper part of the body goes under the water, the outstretched legs move along the surface of the water towards the wall, the hands are directed in the direction opposite to the wall. Then the swimmer vigorously bends his legs at the hip joints, trying to touch his knees with his forehead. The pelvis and legs move towards the wall with increasing speed. Next, the pelvis follows the body under the water, the legs bend at the knee joints and are placed on the wall with acceleration. During rotation, the swimmer's arms, resting their palms on the water, help the movements of the legs and torso. When placing his feet on the wall of the pool, the athlete finds himself in a position on his side, with his arms pointing forward.
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Repulsion phase. Precise placement of the feet after the previous phase allows for a fairly good push-off. You begin pushing away from the wall with your legs while simultaneously stretching your body forward and turning it over to a position on your chest.
Sliding phaseAnd surface phase.
Technique for performing turns when swimming backstroke.
Until recently, backstroke swimming used two types of turns: a regular closed turn and an open flat turn.
The regular closed turn used to be one of the main turns for backstroke swimming. Let's consider its main phases (see Fig. 25).
Swimming and touching phase. A few meters before the wall of the pool, the swimmer decides which hand to touch and, accordingly, which direction to turn. The swimmer touches the wall of the pool with his hand at a depth of 30-40 cm. The wall is touched with the palm facing down opposite the shoulder of the opposite hand. Until you touch the wall, intense leg movements do not stop, and you take a breath. At the moment of contact, the shoulders and head drop under the water.
Rotation phase.The rotation is in the direction of the touching hand. The swimmer's head goes under the water, the hips and pelvis rise to the surface due to the arching of the back and lower back. The swimmer vigorously bends his legs, maintaining a high pelvic position, and with a swinging motion throws his legs out of the water onto the wall of the pool. Then the hand touching the wall is pushed off from it and, together with the other, is brought forward. And the legs are placed on the wall almost in the same place where the hand just touched it.
Repulsion phase. An energetic push is made with the legs at an acute angle to the surface of the water. During the push and further sliding, the swimmer finally turns onto his back.
Sliding phaseAnd surface phase. The swimmer's movements during sliding and reaching the surface after a turn are similar to movements in similar phases when performing a backstroke start.
Fig.25
The open flat turn is easier to perform and is accessible to beginners. It begins and ends with the starting position on the back (see Fig. 26).
Swimming and touching phase. A few meters before the wall of the pool, the swimmer decides which hand to touch and, accordingly, which direction to turn. The swimmer touches the wall of the pool with his hand at a shallow depth of 15-20 cm.
Rotation phase.The rotation goes in the direction of the touching hand, i.e. when touching with the right hand, the rotation is performed in the right direction, when touching with the left - in the left. This is followed by the support part of the rotation phase, during which the swimmer turns 90°. The torque is created by supporting the hand on the wall (and therefore the first half of the rotation phase is called the support phase) and simultaneously raking the other hand in the water. During the rotation phase, the swimmer groups himself by strongly bending his legs at the knee joints. At the end of the support part of the rotation phase, the swimmer has a sufficiently high speed of rotation, which allows him to move to the next unsupported part of the phase, when the legs are placed on the wall for a push at a depth of approximately 40-45 cm. The hand that was rowing in the water is brought forward, and that , which was leaning against the wall, flies over the water.
Repulsion phase. In the take-off phase, the swimmer makes a powerful push with his legs, while simultaneously ensuring an optimally streamlined body position by extending his arms and positioning his head between them.
Sliding phaseAnd surface phase. The swimmer's movements during sliding and reaching the surface after a turn are similar to movements in similar phases when performing a freestyle start.
Fig.26
In 1991, new competition rules allowed the athlete to touch the wall of the pool with any part of his body during a turn while swimming on his back. Therefore, highly skilled swimmers began to use a forward somersault turn without touching the pool wall with their hand, but only with their feet placed on the wall to push off (see Fig. 27).
In other words, the swimmer turns on his chest before the turn and takes the starting position before the turn, as in the front crawl. All other actions have similar moments with a turn on the chest - somersault forward. The peculiarity is that when doing back crawl, after rotation and push, you need to get into a position on your back.
The technique for performing this turn consists of the following phases.
Swimming phase. Approaching the turning wall, the swimmer completes the stroke with one hand in a supine position and leaves it at the hip; then with the other hand he performs a long, energetic stroke up to the thigh while simultaneously turning onto his side (towards the rowing hand) and immediately onto his chest (Fig. 27a, 27b).
Rotation phase.After which the head sharply plunges under the water in a forward-downward direction, the body bends, the athlete performs a quick forward somersault, similar to what is done in a forward somersault when swimming front crawl (Fig. 27b, 27c, 27d, 27d).
Fig.27
Repulsion phase. After placing the legs with the feet on the wall, the swimmer finds himself in a position on his back, arms extended forward and instantly begins to push off from the wall (Fig. 27d, 27f).
The sliding phase and the surface phase. The athlete’s movements during sliding and reaching the surface (Fig. 27g, 27h) are in many ways similar to the movements in the same phases of movements when performing a start from the water on the back.
IN comprehensive In swimming, when transitioning from the butterfly method to the backstroke method and from the breaststroke method to the front crawl method, turns are used that are similar in the structure of movements to the “pendulum” type turn discussed above. When transitioning from the backstroke to the breaststroke, a somersault turn can be used.
SWIMMING IS AN IMPORTANT PART OF HUMAN MOTOR CULTURE. IN ANCIENT GREECE THEY SAID ABOUT AN UNCULTURED PERSON: “HE CAN’T SWIM OR READ.” A HEALTHY PERSON, ACCORDING TO THE LAWS OF PHYSICS, CANNOT DROWN IN WARM AND CALM WATER. THE HUMAN BODY IS MORE THAN 60% WATER, AND THE LUNGS CONTAIN SEVERAL LITERS OF AIR. STANDING CHEST UP IN WATER, TAKE AS MUCH AIR INTO YOUR LUNGS AND LIE ON THE WATER. IN THIS WAY, YOUR BODY WILL BE LOCATED NEAR THE SURFACE OF THE WATER. IF YOU START TO GRADUALLY RELEASE THE AIR FROM THE LUNG, THE BODY WILL ALSO BE GRADUALLY SUBMITTED INTO WATER. WITH GREAT WILLPOWER, YOU CAN CONTINUE EXHALEING UNTIL YOUR BODY SLOWS TO THE BOTTOM OF THE RESERVOIR. THE SPECIFIC BODY WEIGHT AT INSPIRATION IN MALE SWIMMERS IS ON AVERAGE 0.98 G/CM, AND IN WOMEN IS 0.96 G/CM 3 (WHAT IS EXPLAINED BY THE LARGE VOLUME OF ADITY TISSUE IN THE BODY OF WOMEN). ON EXHALETION, THE AVERAGE VALUES OF SPECIFIC GRAVITY ARE HIGHER: FOR MEN 1.06 G/CM 3 AND FOR WOMEN 1.04 G/CM 3. RECALL THAT THE SPECIFIC GRAVITY OF FRESH WATER IS 1.00 G/CM 3 AND THAT THE BODY IMMEDIED IN WATER IT CAN DROWN ONLY IF ITS SPECIFIC GRAVITY IS GREATER THAN THE SPECIFIC GRAVITY OF WATER. A FLOATING PERSON HAS HIGHER BUILDING THAN A STATIONARY PERSON.
KINEMATICS OF SWIMMING: CRAWL 1 - EXIT OF THE LEFT HAND ELBOW FROM THE WATER; 2 — EXIT OF THE LEFT HAND FROM THE WATER; 3 - PASSING THE ELBOW OF THE RIGHT ARM PAST THE SHOULDER; 4 – MOMENT OF COMPLETE IMMERSION OF THE LEFT HAND INTO WATER; THE SECOND HALF-CYCLE IS SIMILAR TO THE FIRST, IT STARTS WITH THE ELBOW OF THE RIGHT HAND COMING OUT OF THE WATER (according to R. KHALYAND) THE SIX-HIT CRAWLINE IS USED AT SPRINTING DISTANCES, AND THE DOUBLE-HIT CRULLY IS USED AT STAYER DISTANCES. CHILDREN'S TRAINING STARTS WITH A SIX-HIT OPTION. TASKS: Phase I - lose forward speed as little as possible, Phase II - start increasing speed, Phase III - increase speed, Phase IV - increase speed as much as possible. Exhalation (when turning the head to the right) occurs in phases III and IV of the first hemicycle, and inhalation occurs in phases I and II of the hemicycle.
KINEMATICS OF SWIMMING: BRACE Stroke 1 – BEGINNING OF EXTENSION IN THE KNEE JOINTS; 2 – MOMENT OF LEGS STRAIGHTENING AT THE KNEE JOINTS; 3 – END OF BACKWARD MOVEMENT; 4 – BEGINNING OF EXTENSION OF THE ARM IN THE ELBOW JOINTS (according to R. KHALYAND AND CO-AUTH.) OBJECTIVES: PHASE I – INCREASE SPEED, PHASE II – INCREASE SPEED AS HIGHER AS POSSIBLE, PHASE III – MINIMIZE THE DROP IN SPEED, PHASE IV – AS LOW AS POSSIBLE SHE LOSE SPEED. EXHALITION IS CARRIED OUT IN PHASE II AND THE BEGINNING OF PHASE III, AND INHALATION IS OCCURRED AT THE END OF PHASE III AND THE BEGINNING OF PHASE IV. FROM THE END OF PHASE IV TO THE BEGINNING OF PHASE II - BREATH HOLDING.
SWIMMING DYNAMICS VERTICALLY DIRECTED FORCES: GRAVITY FORCES; PUSH FORCE; LIFTING FORCE. HORIZONTALLY DIRECTED FORCES - PROMOTIONAL FORCE; FORCE OF FRONTAL RESISTANCE; VORTEX FORMATION RESISTANCE FORCE. (A PRESSURE DIFFERENCE IS CREATED, WHICH SEEMING TO SUCK THE BODY BACK). DURING SLIDING, LOWERING THE SWIMMER'S HEAD DOWN INCREASES RESISTANCE BY 8-12%, AND ITS DEVIATION UP FROM THE OPTIMAL POSITION IS BY 10-20%; FRICTION FORCE ABOUT WATER; WAVE FORMATION RESISTANCE FORCE; FORCES OF INERTIA.
FORCES ACTING WHEN SWIMMING G - GRAVITY; FT - TRACTION FORCE CREATED BY THE SWIMMER'S MOVEMENTS; FA - PUSHING (ARCHIMEDEAN) FORCE; FIN - INERTIA FORCE ARISING WHEN ACCELERATING AND BRAKING THE SWIMMER'S BODY. FTR - FRICTION FORCE; FВ - FRONTAL RESISTANCE FORCE OF WATER. FTB - BRAKING FORCE OF VORTEX FORMATION (AND WAVE FORMATION ACTING IN THE SAME DIRECTION)
THE SIZE OF THE MIDDLE (FRONTAL) SECTION OF THE BODY AND THE SWIRKING OF WATER JETS AT DIFFERENT POSITIONS OF THE SWIMMER IN THE WATER (according to L.P. MAKARENKO; COUNCILMEN)
TOPOGRAPHY OF WORKING MUSCLES EFFECTIVE USE OF STROKES WITH ARM AND LEGS IS POSSIBLE IF THE SWIMPER'S TORSK IS A SUFFICIENTLY RIGID STRUCTURE WHICH IS IN A STREAMED AND BALANCED POSITION ENII. THIS IS PROVIDED DUE TO THE TENSION OF THE ABDOMINAL AND BACK MUSCLES. THE REST OF THE TORSO MUSCLES SHOULD BE RELAXED. WHEN SWIMMING IN CRAWLINE, THE MUSCLES THAT FLEX THE WRUSH ARE MOST ACTIVE. BRACE STROKING HAS HIGH ACTIVITY OF THE LEG MUSCLES.
ENERGY OF SWIMMING THE FORCES ON WHICH THE RESISTANCE OF WATER DEPENDS ARE THE BASIC THOSE THAT A SWIMMER HAS TO OVERCOME. SINCE THE DENSITY OF WATER IS 800 TIMES GREATER THAN THE DENSITY OF AIR, SWIMMING REQUIRES HIGH ENERGY AND IS THE LEAST ECONOMICAL TYPE OF HUMAN LOCOMOTION. EFFICIENCY COEFFICIENT FOR SWIMMERS 1 -5%; DURING HUMAN GROUND LOCOMOTION - 20 -40%; IN GREEN TURTLE, TROUT AND GOLDFISH (10, 14 AND 40%), IN MAN IN FINS ABOUT 17%. BRASS (AT SPEED 0.3 - 0.5 M/S) IS 30% MORE ECONOMICAL THAN CRAWL.
OPTIMIZATION OF SWIMMING THE BASIC REQUIREMENTS FOR A SWIMMER'S TECHNIQUES AND TACTICS ARE THE REQUIREMENTS TO MAXIMIZE THE TRAFFIC FORCE AND MINIMIZE THE SUM OF BRAKING FORCES. IT IS IMPORTANT TO ELIMINATE UNPRODUCTIVE ENERGY EXPENDITURES: ELIMINATE EXTRA MOVEMENTS; CHOOSE THE OPTIMUM PACE OF MOVEMENT; REDUCE THE VALUES OF BRAKING FORCES; ELIMINATE UNPRODUCTIVE MUSCLE TENSIONS. IN SWIMMING, LIKE IN NO OTHER SPORT, IT IS IMPORTANT TO BE ABLE TO RELAX THOSE MUSCLES THAT ARE NOT CURRENTLY PARTICIPATED IN THE PERFORMANCE OF PROMOTIONAL WORK. PULLING YOUR HANDS THROUGH THE AIR REDUCES THE HARMFUL RESISTANCE OF THE WATER AND ALLOWS YOU TO TAKE THE STARTING POSITION FOR THE NEXT STROKE MORE QUICKLY, i.e. INCREASES THE PACE OF SWIMMING MOVEMENTS. ON THE OTHER HAND, RULING YOUR HANDS IN THE AIR WORSES THE BODY'S BUOYANTNESS.
THE SMALLER THE ANGLE OF ATTACK, THE LESS: THE MIDDLE OF THE BODY AND, THEREFORE, THE FORCE OF FRONTAL RESISTANCE; JET SEPARATION SURFACE AND, THEREFORE, VORTEX FORMATION RESISTANCE FORCE. THE SWIMMER MUST CHOOSE A BODY POSITION THAT IS AS HORIZONTAL AND EXTENDED IN THE DIRECTION OF MOVEMENT AS POSSIBLE. TO REDUCE UNPRODUCTIVE ENERGY EXPENDITURES, INTRACYCLE SPEED FLUCTUATIONS SHOULD BE REDUCED. THEY ARE SMALLER IN THE RABBLE THAN IN THE BREASTREST. THIS IS ACHIEVED BY CONTINUOUS WORK OF THE CRAWLIST'S LEGS AND BY THE FACT THAT ONE HAND STARTS THE ROW WITH A GRIP AT THE MOMENT WHEN THE OTHER HAND HAS NOT COMPLETED THE Push-Off. ALL OF THE FOREGOING EXPLAINS WHY CRAWL IS A FASTER STYLE THAN BRACE Stroke. THE KINEMATICS OF MOTOR ACTIONS ADOPTED WHEN SWIMMING IN THE CRAWLINE PROVIDES SMALLER VALUES OF FRONTAL DRAG FORCES, VORTEX FORMATION RESISTANCE AND INERTIA FORCES OF ACCELERATED AND BRAKED BODY LINK.
n1.doc
Rice. 1.5
Correct (1)
and incorrect (2)
body position
when swimming
on the back(s),
breaststroke (b)
and butterfly (c)
The current force does not allow the swimmer to maintain the body position at which the resistance is least. When swimming front and back crawl, turns of the body to the right and left are inevitable, and when swimming butterfly and breaststroke, wave-like movements up and down (Fig. 1.5). High technical skill of a swimmer requires a streamlined body position that at the same time promotes the effective development of driving force. In practice, this comes down to movements of the legs that are deep enough for effective advancement, but do not greatly increase resistance, and turns of the body that are sufficient to develop significant driving force, but do not lead to “wobble.” Rice. 1.4-1.6 illustrate the inappropriateness of the opposite option. The body position of an athlete swimming on her back is very unfortunate (Fig. 1.5, a). Her head is
Too high and hips too low. And an athlete swimming on his back has a more advantageous body position. The head is located almost horizontally and only slightly bent at the neck, and the legs are at a depth that allows for effective movements. Rice. 1.6 illustrates the fact that “wobble” when swimming backstroke is caused by too wide or narrow entry of the hand into the water. Rotations of the torso relative to its longitudinal axis are inevitable, since when performing a stroke with one hand, the other carries out a carry and the torso turns from side to side, following the movement of the arms. Naturally, these turns should not be too sharp, so as not to lead to “falling over” on the side. At the same time, an attempt to limit them would lead to shocks of the body with rowing movements from side to side and strong “wagging”. The question of the optimal
13
PART 1
Sports swimming technique
Rice. 1.6
Impact on value
excessive resistance
body movements to the sides
when swimming crawl
on the back (bottom view)
The body position when swimming breaststroke is not so clear. Proponents of the “wave” and flat styles have not yet completed the debate about which of them is associated with less shape resistance. With the wave, despite the wave-like movements, it is probably still less, since the hips are pulled up with almost no flexion at the hip joints (it is the pulling of the legs in breaststroke that causes the greatest braking) and not against the flow of water, as happens with the flat style.
The wave-like movements of an athlete swimming butterfly (Fig. 1.5, c) are sufficient to provide an effective driving force and are not so great as to greatly increase the resistance. An athlete swimming butterfly, on the contrary, plunges her head and legs too deep. At the moment her hands enter the water, her torso and hips form almost a right angle, thereby creating excessive resistance.
The analysis of the dependence of resistance on swimming speed is mainly theoretical, since the athlete will not reduce speed to reduce resistance. However, the fact that the greatest economic benefit of evenly covering distances is largely due to overcoming less average resistance also has a certain practical significance. Please remember
Due to the resistance caused by the shape of the body and its orientation (position) in the water, the athlete also overcomes shock wave (also called frontal or frontal) and friction resistance or, in other words, friction resistance.
Shock wave resistance caused by frontal frontal waves and is mainly determined by the swimmer's body position, swimming speed and, to a certain extent, the quality of the pool. Such frontal waves are created by the swimmer's head and torso as they move forward, sideways and up and down, as well as by arm movements when swimming in any way and by pulling up the legs when swimming breaststroke. The torso, arms and legs are “pushed” forward, compacting the water molecules in the oncoming flow and thereby increasing the pressure of the water in front of it and, accordingly, the resistance to movement. An athlete swimming crawl literally “drives” his hands into the water, thereby creating a large shock wave resistance. “Pushing” the back of the hand when entering the water also increases it. And only their entry with the edge of the palm reduces the area they occupy and, accordingly, the resistance encountered.
Frictional resistance. As a result of friction between skin and water, water molecules are retained on the surface of the skin, which, colliding with other molecules in front of them, chaotically rebound and, “interfering” with neighboring flows, increase their turbulence and thereby create additional resistance to movement. The frictional resistance created in this case is mainly determined by the area of the body, the roughness of its surface and the speed of movement. Naturally, less friction is created near smoother skin.
For almost forty years, swimmers have achieved more than
14
CHAPTER 1 Basic Swimming Techniques
High performers have their hair shaved off before competition. And the debate continues about what actually provides this well-known effect - whether it is simply an increase in self-confidence due to belief in the effectiveness of shaving, an increased sense of water in irritated skin, or a decrease in resistance. And if all these factors are combined, then which one is the most important? Meanwhile, there is reason to assert that, if not to a decisive extent, then to a large extent, the third of those listed. They were, in particular, given by the results of the research of Sharp and Costill (1989). At an interval of 9 days, a group of qualified swimmers before and after shaving were measured for their stride and lactate concentration while covering a distance at a given pace, oxygen consumption while swimming “tethered” at maximum intensity, and the length of the slide after pushing off from the side of the pool. The average step and lactate concentrations were 207 cm and 8.48 mmol-L~ 1 and 236 cm and 6.48 mmol-l - ! after shaving, which indicates a significant increase in the efficiency of work and* the efficiency of movements. The sliding length has also increased significantly. The only thing that has not changed is the energy cost of work when swimming “tethered” and, accordingly, with negligible frictional resistance. There is no doubt that the improvement in shaving results is mainly due to a decrease in frictional resistance.
1.2. FORCES THAT ENSURE THE PROGRESS OF A SWAMMAN
The question of what law underlies human advancement in water has not been resolved to this day and is quite controversial. Many people believe that the theorem
Bernoulli, according to which advancement is ensured by the difference in pressure on the back of the hand and the palm that creates a lifting force. This difference, combined with the pressure acting on the arm, creates a net force that propels the swimmer, in other words, the traction force. The approval of this point of view was greatly facilitated by the studies of Brown and Councilman (1971), who concluded that the stroke is not performed strictly backward, but also diagonally. However, there is no less reason to assert that the basis of a swimmer’s progress is Newton’s third law: an action always corresponds to an equal and opposite reaction. In relation to the phenomenon under consideration, the law can be expressed by the following formula: the acceleration that a swimmer gives to his body is proportional to the force with which he pushes away the water. Moreover, the fact that the traction force is predominantly provided by pushing the water back, and not by its accelerated flow at the back of the arm, confirms the significant difference in this force with different bending of the arm at the elbow joint during the stroke. Otherwise, its degree would not be as significant as it actually is.
With a diagonal movement of the arms, the swimmer pushes the water back. As we see from Fig. 1.7, the hand is located at an angle, the thumb is located higher than the rest, and this is what mainly ensures that the water is pushed back. A force directed backwards causes, according to Newton's third law, an equal and opposing force, which propels the swimmer.
Thus, both Bernoulli's theorem and Newton's law explain a swimmer's progress, but Newton's law appears to play a more significant role.
15
PART 1 Sports swimming technique
Rice. 1.7
Moving water backwards with a diagonal movement of the hand
Rice. 1.8
Promotion principle
using a propeller
Rice. 1.9
Similarities between
swimmers' wrist movements
and rotation of the blades
propeller
Progress during swimming is well illustrated by the principle of operation of a boat engine propeller (Fig. 1.8). Although the propeller blades rotate in a circular path, their curved shape ensures that when water passes from the leading edges to the rear, it moves backward and the boat moves forward. In Fig. 1.9 clearly shows how similar the movements of the swimmer’s hands and the rotation of the propeller blades are: in the initial part of the stroke, or, in other words, when pulling up, the hand moves inward, up and back (Fig. 1.9, a), and in the final, or phase repulsion - outward, upward and backward (Fig. 1.9, b).
The curvilinearity of the trajectory of the hands is associated with providing greater traction force when pushing away slowly moving water. Having accelerated the movement of some of its layers, the hand moves to layers that have not yet been disturbed, etc. This trajectory of movements ensures greater efficiency of the stroke and by increasing its length.
1.3. GENERAL CHARACTERISTICS OF MOVEMENTS ENSURING THE PROGRESS OF A SWAMMAN
The efficiency of swimming propulsion is mainly determined by three characteristics of limb movements - direction, angle of attack and speed.
The direction of movement is characterized by a trajectory relative to water, which is usually called absolute. Its analysis is of paramount importance, since it is the influence of the limbs on the water that mainly determines the force driving the swimmer. The trajectory relative to the body of the swimmer is called relative, since it is assumed that the athlete, while performing a stroke, remains in place. Its analysis allows us to better understand the mechanics of the stroke. In Fig. Figure 1.10 shows the absolute trajectory of arm movements, typical of high-class swimmers. As we can see, regardless of the method of swimming, it is mainly characterized by horizontal and vertical directions of movements. In Fig. Figure 1.11 shows the backward movement necessary to push away the optimal amount of water (side view).
The angle of attack is formed by the inclination of the hand or foot relative to the direction of their movement. The dependence of the driving force on the angle of attack is shown in Fig. 1.12. As we can see, in the absence of such an angle, the driving force is minimal, since the hand almost does not move the water back and the force propelling the swimmer is very small. At an angle of 40° it is greater because the water flowing under the palm from the thumb to the little finger or, if we compare the hand with a propeller blade, from its leading edge to the rear, is subject to a significant force directed backwards. This angle of attack is close to optimal. At an angle of 70°, the palm is too flat a surface;
16
CHAPTER 1 Basic Swimming Techniques
Rice. 1.10
Trajectory of strokesmovements relativewater when swimmingdifferent ways: breaststroke (a); on the back (b); butterfly (c); front crawl (g)
Rice. 1.11
Changing the angle of attack
in the final phase
swimming stroke
front crawl
The effect of the leading edge of the blade changes, which leads to a decrease in the speed of movement of some molecules passing under the palm and the rebound of others. They collide with the molecules of the remaining layers and the resulting chain reaction causes significant turbulence. Moreover, these molecules are not able to sharply change the direction of movement in order to follow the contour of the “blade” from it. leading edge to trailing edge. As a result, only a small amount of water is pushed back. And it is completely ineffective to place the brush perpendicular to the direction of its movement. In this case, the blade effect disappears. The flat surface of the palm only pushes the flow of water in different directions. With a quick movement of the hand, an effect is created similar to pouring a bucket of water onto the wall. Some of the molecules bounce chaotically from the hand, and those “lagging behind” move in the opposite direction, producing a force that pushes the swimmer to the side, moving forward.
Opposite to the direction of movement.
Thus, the angle of attack should vary from 20° to 60° depending on the phase of the stroke. The irrationality of the angle of attack and direction of movement is indicated by a large number of bubbles, indicating turbulence and loss of driving force by the swimmer. Qualified swimmers create them in much smaller quantities. The formation of air bubbles around the hands as they enter the water when swimming front crawl, backstroke and butterfly is completely normal. However, if this happens during the pull-up phase, it indicates an irrational movement and, probably, an excessive angle of attack. Its arcuate trajectory helps ensure an effective angle of attack in each phase of the stroke.
Speed of movement. Councilman and Vasilyak (1982) revealed the acceleration of hand movement as the stroke is performed, and Schleihauf (1984) - its unevenness and dependence on the direction of its movement. Rice. Figure 1.13 illustrates the change in the speed of wrist movement during the stroke when swimming front crawl. As you can see, the speed of the left hand after it enters the water decreases and is 1.8 m-s -1 in the capture phase, increases to 3m"S -1 in the pulling phase, and up to 5 m-s -1 in the repulsion phase. In the final phase of the stroke, when the pressure on the water weakens somewhat, the speed of arm movement decreases.
17
PART 1
Sports swimming technique
Rice. 1.12
The influence of the angle of attack on the direction of water movement
Rice. 1.13
Dynamics of wrist speed when swimming front crawl
The speed of the right hand at the moment of grip is 1.8 m-s -1 , in the pulling phase - about 4 m-s -1 , during the transition to repulsion it decreases slightly - 3.4 m-s -1 , and at its completion it reaches b m-s -1 . The dynamics of the speed of swimming almost coincides with the dynamics of the speed of movement of the hand, which, however, is also typical for other methods of swimming. The speed of arm movement decreases during each major change in direction of movement. There is probably an optimal relationship between hand speed and angle of attack in each
Do the stroke phase. There is no doubt that there is an optimum speed of hand movement in each phase of the stroke. When comparing Fig. 1.13 and 1.14, one can note the close relationship between the speed of movement of the hand and the traction force in various phases of the stroke.
Meaning of capture. Catch is the phase of the stroke in which the driving force begins to develop. It should not begin until the arm has moved about a third of the length of the stroke, and until a third of its total time has passed. In this case, vigorous effort should not be applied until the elbows are higher than the hands and the hands are facing back.
The main movements of the hands when performing a stroke are - to the sides, down, inward and upward (Table 1.1).
Hand movements to the sides. This movement begins the stroke when swimming breaststroke and butterfly (Fig. 1.15). It is not promoting, but preparatory to the capture. When swimming butterfly, immediately after the hands enter the water, and when swimming breaststroke, before moving them forward, the hands are spread to the sides along a curved path until the hands are wider than the shoulders in a position favorable for starting the grip. At the beginning of this movement, the palms are turned down, the angle of attack is close to 0°, until the hands take a position favorable for the development of the driving force. As it is performed, the palms turn outward and backward, and the speed of movement of the hands decreases.
Hand movement down is typical for swimming crawl on the front and back (Fig. 1.16). It precedes and accompanies the catch and, like the lateral movement during breaststroke and butterfly, is not advancing. After entering the water, the hand moves down along a curved path. At the same time, the hands are bent, and as they approach the grip, they slightly unfold
18
CHAPTER 1
Basics of swimming technique
Rice. 1.14
Traction force dynamics
when performing a stroke
eightfold
Olympic champion
Matthew Biondi
TABLE 1.1
Basic hand movements
when performing a stroke
Rice. 1.15
Hand movements to the sides
when swimming breaststroke
and butterfly
| Direction | Way | Phase |
| movement | swimming | stroke |
| To the sides | Breaststroke, butterfly | Capture |
| Down | Crawl on the chest, on the back | Capture |
| Inside | All | Pull up |
| ways | gagging |
|
| Up | Crawl | Ottal- |
| chest, butterfly | nodding |
Huddle outside. The grip begins no earlier than the elbows are higher than the hands, which usually occurs at a depth of 40 - 60 cm.
Hand movement inward replaces the downward movement of the arms when swimming front crawl and backstroke and the movement to the sides when swimming breaststroke and butterfly. And when swimming in all ways except the backstroke, it is the first “promoting” movement. This movement begins in the catching phase and continues in the pulling phase.
(except for backstroke swimming). As it is performed, the hand moves down and inward, and then up and back until it is under the body in the area of the midline of the body. Moreover, individual deviations from this line are due to the characteristics of the technique, and these, in turn, are due to the morphofunctional characteristics of the swimmers. It should be noted, however, that although all qualified swimmers specializing in breaststroke have their hands crossing the midline of the body at the end of the movement in question, some athletes stop pressing the water when their hands are still at a considerable distance from each other, while others do not They do this right up to joining hands.
Hands moving up when swimming front crawl and butterfly, it is replaced by an inward movement of the arms and ends when the hand reaches the thigh. In this case, the semicircular movement of the hand outward, upward and backward is accompanied by its rapid turn and the palm at the end point of the movement in question is turned back and outward (Fig. 1.17), the pressure of the hand on the water weakens. The speed of the hand during the transition from inward to upward movement decreases and then increases to a maximum. The existing idea that the arm quickly straightens at the elbow joint when moving upward is incorrect. It remains bent until the start of the swing, which ensures that the forearm participates in the production of the driving force. If the arm straightens too quickly, it does not push the water straight back. The upward movement of the arms when swimming butterfly is similar to the movement of the arms when swimming front crawl. And only some high-class swimmers, and only at the beginning of the stroke, fully straighten their arms at the elbow joints.
It should be noted that the effectiveness of the movement in question
PART 1
Sports swimming technique
Rice. 1.16
Downward movement of the arm when swimming crawl on the front (a) and on the back (b)
Rice. 1.17
Water repulsion
when moving your hand up
during the stroke:
Side view, b - bottom view
Rice. 1.18
Promotion
when performing dolphin-
figurative leg movement
Niya largely depends on the swimmer's ability to maintain a bent arm position in the final part. If this is successful, then the water is pushed back in the desired direction even with a not very rational position of the forearm. And this is especially true for butterfly. The most common mistake when moving the arms up is “pushing” the hands up and back into a bent position, in which they are perpendicular to the surface of the water. The angle of attack is such that the water is pushed upward rather than backward, which naturally reduces swimming speed. The movement of water back when moving the arms up is illustrated in Fig. 1.17. As the hand moves up and out along a diagonal path, it and the side of the hand from the little finger serve as the leading edge.
The ki are the propeller blades, and the fingertips and the side of the hand from the thumb are its trailing edge.
Rice. 1.17.6 illustrates the beginning of the movement under consideration. As you can see, the brush moves outward and backward, being rotated accordingly. In this case, the leading edge of the propeller blade is the side of the hand from the little finger, and the back edge is from the thumb. Water passing under the palm in the opposite direction is moved by the angular attack of the hand. In Fig. 1.17, and the final stage of the movement under consideration is shown. As you can see, the hand is facing back and slightly upward, which provides a great contribution to the development of the driving force of the forearm. The role of the leading edge of the propeller blade is played by the elbow, and the rear edge by the fingertips.
The meaning of leg movements. Many experts believed that when swimming front crawl, butterfly and breaststroke, the legs are practically not involved in the production of driving force. The main argument in this case was the direction of movement of the legs not back, but up and down, which supposedly only maintained the balance of the body in the water. At the same time, it is known that swimmers still move forward using only their legs, and high-class athletes quite quickly. And it is quite obvious that with the movement of the legs the swimmer moves the water backward in the same way as with the vertical movements of the arms. As can be seen in Fig. 1.18, although the feet move almost straight down when swimming butterfly, bending the knees and straightening the feet provides a hydrofoil effect. The function of its front edge is performed by the knee part, and the rear edge is performed by the forefoot. Bending the knees creates an angle of attack that allows the swimmer to move the water backwards. Similarly, the legs provide propulsion when swimming crawl.
20
CHAPTER 2 Hydrodynamics of driving force during swimming
Hydrodynamics
driving force
when swimming
The properties of a moving fluid differ significantly from the properties of a fluid at rest, therefore, as soon as the hand and water begin to move relative to each other, hydrodynamic resistance arises - a force that ensures the movement of an object in the fluid. Analysis of stroke mechanics has usually been done without taking into account such drag and the resulting flow reactions.
When analyzing a stroke, you can take the principles of hydrodynamics as a basis. This makes it possible to: understand the essence of the driving force and understand the features of the impact on water when rowing with different trajectories; analyze the driving force by relating the flow reactions to the characteristics of the stroke mechanics by assessing the size and shape of the vortices, as well as the location of their origin; analyze the conditions for providing the greatest driving force.
Like any liquid, under the influence of force, water changes its shape, which is manifested in flow and changes in its elasticity, which, in turn, is due to viscosity. Flow and elasticity are characteristics of moving water that any qualified swimmer can evaluate fairly objectively.
The streamline (streamline), indicating the direction and speed of the flow, is defined as a curve that is always tangent to the flow. Therefore, the liquid cannot cross
Roll a current line, it only flows along it. The speed of fluid movement is higher where the streamlines are closer to each other, and lower where the distance between them is greater.
If the streamlines retain the same shape, we can talk about flow uniformity. It is much easier to analyze the structure of a uniform flow than an uneven flow.
The flow around a submerged object can be represented on a diagram by streamlines. If the fluid velocity at a given point depends not only on its position, but also on time, the streamlines are constantly changing. The totality of all streamlines at one time or another forms a momentary flow structure, which can be represented by streamlines showing the direction of flow at various points. From the countless number of streamlines, five to ten lines are usually chosen to divide the flow into several "channels", each of which carries the same amount of water in an equal amount of time. Reducing the width helps to increase the flow speed. The structure of the flow determines not only its direction, but also the speed at any point in the water flow (Fig. 2.1), and knowing it, specialists in the field of hydroaerodynamics can also determine the pressure force within the boundaries of the flow.
Back in the 18th century. Euler and Bernoulli founded the school of classical hydrodynamics to study the motion
21
PART 1
Sports swimming technique
Rice. 2.1
The structure of the flow around the wing indicating the direction and speed of the flow; smaller spacing between streamlines shows areas of highest velocity
Rice. 2.2
Classical hydrodynamic model of the flow structure of an “ideally” flowing medium without taking into account the viscosity of the liquid; The figure illustrates the structure of the flow around a cylindrical obstacle
Rice. 2.3
Turbulent flowbehind submerged bodies: cylindrical shape (a); streamlined shape (b); the boundary layers of the “slow” fluid are shaded
Living in a hypothetical “ideal” liquid. However, the lines on the diagrams of the flow structure of such a liquid are correct, constant (Fig. 2.2) and do not explain the phenomena in which the role of viscosity is important. Without arrows indicating the direction of flow, it would be impossible to determine it due to the absolute symmetry of the flow and pressure structures. In addition, according to the theory of an ideal fluid, it slides behind the body without “sticking” to it and without forming a boundary layer. The symmetry of the flow structure and the absence of a layer of “retaining” fluid in this ideal inviscid fluid means that there is no drag force acting on the cylinder.
Due to the relatively low viscosity of water and air, at least compared to liquids such as oil, the ideal fluid theory could be accepted in some cases, but not in analysis
The structures of their flow past a solid object when their viscosity cannot be neglected (Fig. 2.3).
Thin lines in Fig. 2.3 reflect the average flow trajectories. There is also a boundary layer of "slow" fluid around the front half of the cylinder (shaded), in which the fluid elements stick to the object, which increases the viscosity and slows down the movement of their "neighbors". On the other hand, the moving “neighbors” act in a downward direction on the “adhesive” elements, which, in turn, impart to its body in the form of surface resistance.
Water cannot accelerate indefinitely precisely because of its viscosity (internal friction), in the absence of which the flow speed in rivers would reach hundreds of kilometers per hour, which would have quite disastrous consequences. A swimmer is able to "grab" water only because the viscosity of the water promotes a separation of the flow, and this leads to a difference in pressure around the hand. Under certain conditions, this pressure differential provides the resistance that produces the driving force (Councilman, 1982). However, viscosity not only helps the swimmer move forward, but also creates shape resistance that impedes his progress, as a result of which the liquid elements in contact with it “stick” to the body. Those adjacent to them move relative to these elements, which “turns on” resistance forces opposing the movement and causing friction.
Most viscous deformation occurs within the boundary layer - a relatively thin zone immediately adjacent to the surface of a body that moves in an aqueous environment. The boundary layer, which consists of a number of very thin layers, always has a velocity gradient;
Body position and general characteristics of the method. The swimmer’s body is located near the surface of the water and is in a well-streamlined, close to horizontal position with an angle of attack of 2–6° (the range of the angle of attack can vary from 0–8°; for highly qualified swimmers this range is more strict - 4–5°). The head is lowered into the water (face down) so that the water level is approximately at the top of the forehead. The swimmer looks forward and down under the water, effortlessly holding his head almost strictly on the longitudinal axis.
Breast crawl is characterized by alternating and symmetrical movements of the arms and legs. The swimmer's legs, rhythmically and moderately bending and unbending at the hip, knee and ankle joints, move alternately up and down, foaming the surface of the water. The working part of the leg movement is the downward kick. The most effective is a sharp blow executed from the hip. In this case, the thigh, moving down, slightly overtakes the shin-foot. The distance between the feet in the extreme lower and upper positions reaches approximately 40 cm. The toes are pulled out and turned slightly inward, the big toes are almost touching. The movements of the legs ensure a stable horizontal position of the body and maintain the speed of advancement. The arms (primarily the hands and forearms), which move along curved trajectories, provide the main forward movement of the body. During swimming, due to the work of the arms, the body rotates around the longitudinal axis of the body by 35–50°. The greatest tilt occurs at the moment of inhalation (in some cases, the rotation can increase to 60–65°). The sway of the torso strengthens the stroke and helps to carry the arm and inhale. The greatest angles of inclination are observed in the thoracic part of the body, the smallest in the lumbar and pelvic parts.
There are 3 varieties of the crawl method depending on the frequency of the legs: 2-impact, 4-impact and 6-impact, when for one cycle of arm work (2 arm strokes) there are 2, 4 or 6 kicks (see Fig. 6, 7, 8). The 2- and 4-beat crawl is used, as a rule, at medium and long distances, and the 6-beat - on sprint and finishing accelerations.
2. Breathing.
Breath.With normal breathing, one inhalation and one exhalation are performed per cycle of movements (2 strokes with the arms). To inhale, the head is turned relative to the longitudinal axis of the swimmer’s body towards the rowing hand (to the right or left) so that the mouth is above the water. Inhalation is performed quickly and actively through a wide open mouth at the beginning of raising the hand above the water when the body is tilted. After this, the head quickly turns into the water (face down) and a gradual exhalation immediately begins, first through the mouth, then through the nose. Exhalation is longer than inhalation. The respiratory cycle ends with a sharp exhalation of the remaining air through the mouth at the moment when the mouth again appears above the water - the mouth and lips are freed from the water, the swimmer is ready to begin the next inhalation. There should be no pauses between inhalation and exhalation, as well as between exhalation and inhalation.
When breathing for one cycle, the swimmer breathes under one hand - either the left or the right. Inhalation and exhalation can also be done every third stroke (1.5 cycles) or even every fifth stroke (2.5 cycles), thus inhaling alternately under the right and then under the left hand.
3. Leg movements.
Leg movements. The legs perform continuously alternating counter movements from top to bottom and bottom to top with a small amplitude. The movements of the legs ensure a stable horizontal position of the body and maintain the speed of advancement. The movement of the legs consists of two phases - working (supporting) and preparatory (non-supporting). The downward movement of the leg (support phase) is also called a stroke, or kick (it contributes to some movement of the body forward), and the upward movement of the leg - preparatory (it does not affect the movement of the body forward). Since the movements of both legs are exactly the same, we can consider the technique using the example of the movement of one leg.
Reference (working) phase (movement from top to bottom). The downward movement of the leg begins with sequential extension at the knee and ankle (at the very end of the stroke) joints and simultaneous flexion at the hip joint. At this moment, all parts of the leg move downwards. Then the lower leg and foot continue to move downwards until the leg is fully extended at the knee joint, and the thigh, ahead of the lower leg and foot, begins to move upward. This movement of the hip helps increase the speed of the downward movement of the foot due to the whip-like motion of the leg as a whole. With this movement of the leg, the foot creates some lifting and traction forces, which help maintain the body on the surface of the water and propel it forward. The working movement is considered complete when the leg is fully straightened at the knee joint.
Preparatory phase (movement from bottom to top). In the initial (lowest position) the leg is straightened at the knee joint, and the foot is turned inward and relaxed. In relation to the body, the leg takes an inclined position, as it remains bent at the hip joint. The upward movement begins with straight leg extension at the hip joint. Until the horizontal position, the leg moves straight. Next, the leg begins to bend at the knee joint, and the lower leg and foot continue to move upward. At this moment, the thigh begins to move downward due to flexion at the hip joint. When the angle between the front surface of the thigh and the torso (at the hip joint) is 160–170°, and between the back surface of the leg and thigh (at the knee joint) - 130–140°, the movement of the leg from bottom to top is considered complete.
Coordination of footwork movements. From the extreme upper position, one leg moves down, while the other moves upward from the extreme lower position. The greatest amplitude of movements between the ankle joints is approximately 30–40 cm. It depends on the speed of swimming: at high speeds, the amplitude of movements may decrease, as the speed of movement of the feet increases, and their path (vertically) is shortened. Since the legs make continuous movements in the water and there is little movement from them, they should move freely with little effort.
When swimming the six-beat freestyle, the hip movements are performed with rapid changes of direction. In the four-beat crawl, the legs perform a crossing motion: one moves diagonally downward-inward, while the other moves smoothly upward, causing the legs to cross for a brief moment. The amplitude of such cross movements is small. In the double-stroke crawl version, the downward movement of the leg resembles an energetic sweeping stroke, as in butterfly swimming, with the active involvement of the pelvis in this movement.
4. Hand movements.
Hand movements.In front crawl, the main forward movement of the body is provided by the arms (hands and forearms), which move along curved trajectories (see Fig. 7). The cycle of movements of each hand consists of the following phases:
- hand entry into water;
- capture;
- supporting part (two subphases - pulling and pushing);
- hand coming out of the water;
- raising your hand above the water.
The duration of a full cycle of arm movement is approximately 0.92–1.36 s.
As a rule, the phase composition of hand movements begins to be considered from the hand’s entry into the water, which is quite justified from visual considerations. However, the entry of the hand into the water completes the preparation for the next stroke, therefore, in some literary sources (for example, in the book by N.Zh. Bulgakov “Sport Swimming”, 1996), consideration of the technique of hand movement and phase composition begins with the next phase, so as not to violate the integrity working and preparatory periods. At the same time, the semantic content and order of alternation of the phases themselves in the cycle remain unchanged in both cases.
The phase of hand entry into the water. After being carried through the air, the arm bent at the elbow quickly enters the water at an acute angle in front of the shoulder joint of the same name, the palm is facing down and back, the fingers are connected. Immersion of the hand in water is carried out in the following sequence: hand, forearm, shoulder. The arm extends at the elbow and the grip begins.
The hand enters the water close to the longitudinal axis of the body or between it and a parallel line drawn at shoulder width. At the moment the hand touches the water, the angle of body roll to the opposite side is still 10–15°; at the moment the entry into the water is complete, it is zero.
The duration of the phase is about 0.07–0.17 s (7–12% of the time of the entire cycle).
The phase is captured.In tempo variations of the freestyle it is short-lived; in variations with a long power stroke, the arm is extended more forward, as a result of which the hand and forearm interact with the flow longer. At the beginning of the grip, the hand, moving forward and down, bends slightly at the elbow joint, and the hand turns slightly with the palm outward. At this moment, the hand makes an angle with the surface of the water approximately equal to 15–20°. Moving further, the arm continues to bend at the elbow joint, and the hand, at a slight angle of attack, changing direction (downward-inward), moves under the longitudinal axis of the body. By the end of this phase, the arm is in the best position for performing the stroke: the angle between the horizontal and the forearm is 30–40°, the angle of flexion at the elbow joint - 120–140°, angle of attack of the hand - 40–50°.
The duration of the capture phase is approximately 0.08–0.30 s (10–25% of the time of the full cycle of movements).
Reference phase (2 subphases - pulling and pushing).
Pull-up subphase begins with a pronounced rotation of the arm inward and flexion of the forearm by gradually increasing the pressure of the hand on the water. The brush begins to move backward relative to the water. At the beginning of the pull-up, the arm is bent at the elbow joint to an angle of 130–150 ° , the hand is oriented to the frontal plane at an angle of about 45 ° .
Moving under the body with acceleration, the arm continues to bend at the elbow joint; forming an angle between the shoulder and forearm in the middle of the stroke equal to 90–110°. Here the hand moves from front to back in an inclined plane with simultaneous rotation of the forearm outward.
Repulsion subphase - the most energetic part of the cycle. The hand moves with acceleration under the abdomen and pelvis from front to back and slightly outward, maintaining a position close to the front. The arm is extended at the elbow joint. The swimmer, due to good support in the water, accelerates the forward movement of the body. The subphase ends with a sliding movement of the hand up and back and slightly outward, mainly due to the extension of the forearm. Optimal completion is facilitated by the beginning of the body roll to the opposite side.
The support phase ends when the arm reaches the pelvic line. At this moment, the arm (forearm and hand) moves up and back.
The duration of the main part of the stroke is 0.35–0.60 s (30–45% of the time of the entire cycle of movements).
The phase when the hand comes out of the water. The phase coincides with the roll of the body to the opposite side. When the hand reaches the thigh, active muscular efforts aimed at moving the body forward cease, and the elbow rises out of the water. At the next moment, the shoulder, forearm and hand rise out of the water in sequence and the movement (carrying) of the hand above the water begins. The brush comes out of the water behind the pelvic line, at the hip. The muscles of the forearm and hand should be relaxed if possible.
The duration of this phase is 0.05–0.08 s (5–8% of the time of the entire cycle of movements).
The phase of carrying the hand above the water. The bent arm, without undue tension, quickly sweeps over the water in the shortest possible way and enters the water. During the sweep, the elbow is in a high position and directed up and to the side, and the hand is kept at the surface of the water. The movement of the arm is facilitated by the high position of the shoulder joint of the same name, which is ensured by the low position of the shoulder joint of the other arm, which is performing the beginning of the stroke at this time. The duration of the phase is 0.30–0.50 s (25–40% of the full cycle time).
Coordination of hand movements. Correct coordination of hand movements in the front crawl is based on obtaining the highest, relatively uniform speed of the swimmer's movement throughout each cycle. Therefore, the pause between the end of the main part of the stroke with one hand and the beginning of the main part of the stroke with the other hand should be such that the achieved speed of the swimmer’s movement is maintained. This depends on the continuous production of traction forces throughout the swimmer's movement cycle. Therefore, when the left hand performs the second half of the main part of the stroke, the right one at that moment enters the water and begins to capture. The removal of the left hand from the water and the beginning of the carry should coincide with the end of the grip phase of the right hand. At the moment the left hand finishes sweeping, the right hand finishes the first half of the main part of the stroke. Entering the water and starting to grab the left hand should coincide with the execution of the second half of the main part of the right hand stroke. Next, the left hand carries out the catching phase, and the right hand comes out of the water and begins the carry. The cycle of movements is completed when the left hand completes the first half of the main part of the stroke, and the right hand completes the sweep.
5. General coordination of movements.
General coordination of movements. In front crawl, high, uniform speed is achieved due to the continuity of working movements of the arms and legs, and clear coordination of movements with breathing. The full cycle of movements consists of a stroke with the left and right hands and a certain number of kicks (two, four or six) and breathing, which, as already noted, is also variable (inhalation can be done through 2 or 3 strokes with the hands, in some cases through more number of strokes).
Let's consider the main 3 options for coordinating movements in the front crawl method, depending on the work of the legs.
Fig.8
Double-beat crawl . In a two-impact crawl (see Fig. 8), for two alternate strokes with the arms there are two successive kicks with the legs. The basis of the two-beat crawl is continuous strokes with the arms. Any delay in arm movements leads to loss of balance and body sinking, which forces the swimmer to make additional movements with his legs. The pace of arm movements at the same distance is always noticeably higher than with other options, especially with the six-beat freestyle.
I.p. - the left hand finishes the stroke (the hand is at the surface of the water), the right begins the second half of the main part of the stroke (the hand is under the chest), the left leg moves up (the foot is near the horizontal), the right is bent at the knee joint, it is at the top (the foot is at the surface of the water) .
From the starting position, the left (right) hand enters the water, performs a grab and approaches the middle of the first half of the supporting part of the stroke, the right one finishes the second half of the supporting part of the stroke, leaves the water and approaches the middle of the stroke, the left leg rises up (crosses the horizontal), and the right one strikes downwards. Moving further, the left hand enters the second half of the supporting part of the stroke, the right one finishes the sweep, the left leg bends at the knee joint (the foot approaches the surface of the water), and the right one moves up (the foot approaches the horizontal). At the next moment, the left hand carries out the second half of the support part of the stroke, leaves the water and approaches the middle of the carry, the right one enters the water, makes a grab and approaches the middle of the first half of the support part of the stroke, the left leg kicks down, and the right leg rises up (crosses horizontal). Completing the cycle of movements, the left hand finishes the sweep, the right one enters the second half of the supporting part of the stroke, the left leg moves up (the foot is near the horizontal), and the right one bends at the knee joint (the foot approaches the surface of the water).
Then the cycle of movements is repeated. Thus, the downward kick of one leg coincides with the most efficient part of the stroke of the same arm (the second half of the main part of the stroke). In a two-beat crawl, the hand produces a strong and fast stroke. Therefore, swimmers who have perfectly mastered the technique of this version of the freestyle develop a higher tempo of movement than athletes who use the six-beat freestyle at the same distance.
Inhalation in a two-beat freestyle is performed between the end of the phase of the hand coming out of the water and the beginning of the phase of carrying this hand. The other hand at this moment is respectively at the end of the catch phase and at the beginning of the supporting part of the stroke.
Rice. 9
Four-beat crawl (see Fig. 9). A distinctive feature of the four-beat crawl is the sequential execution of the main kicks: right down, left down-in (circular), left down and right down-in (circular).
I. p. - The left hand enters the water (the hand is in the water), the right begins the second half of the supporting part of the stroke (the hand is under the chest), the left leg takes a horizontal position, the right is bent at the knee joint, located at the top (the foot is at the surface of the water).
From the starting position, the left (right) hand enters the water, makes a grab and begins the first half of the supporting part of the stroke, the right one carries out the second half of the supporting part of the stroke and begins to exit the water, the left leg rises to the surface of the water, bending at the knee joint, and the right one produces blow down. Next, the left hand approaches the middle of the first half of the main part of the stroke, and the right one comes out of the water and approaches the middle of the stroke, the left leg performs a circular downward-inward kick, and the right one slowly rises up (its foot is lower than the foot of the left leg - legs are crossed). Continuing the movement, the left hand, having completed the first, enters the second half of the supporting part of the stroke, the right one finishes the movement above the water and begins to enter the water. The left leg, bending at the knee joint, moves in the opposite direction up and out (the foot is at the surface of the water), and the right leg freely rises to a horizontal position. At the next moment, the left hand performs the second half of the supporting part of the stroke and begins to leave the water, the right one enters the water, makes a grab and begins the first half of the supporting part of the stroke, the left leg strikes down, and the right bends at the knee joint and continues to move upward (foot reaches the surface of the water). Finishing the stroke, the left hand comes out of the water and approaches the middle of the stroke, and the right hand passes the middle of the first half of the main part of the stroke, the left leg slowly rises up, and the right one performs a downward-inward kick (the foot remains above the foot of the left leg - legs are crossed).
The cycle of movements ends when the left hand finishes the sweep, the right one enters the second half of the supporting part of the stroke, the left leg freely rises to a horizontal position, and the right one bends at the knee joint and moves up and out (foot at the surface of the water).
In the four-beat crawl, the breathing technique is not much different from the two-beat crawl. However, at the moment of inhalation, the swimmer performs a cross kick: if the inhalation is performed under the right hand - cross kick is done by the left leg, if under the left - right leg.
Rice. 10
Six-beat crawl (see Fig. 10). The coordination of movements in the six-stroke freestyle is a cross-coordination that gives the body the most stable position in the water.
I. p. - the right hand is in the middle of the stroke, the left begins the supporting part of the stroke, the right leg is at the bottom (foot 30–40 cm from the surface of the water), the left is bent at the knee joint, located at the top (foot at the surface of the water).
When the right hand finishes the sweep and enters the water, the left one finishes the first half of the support part of the stroke, the right leg moves up, and the left kicks downwards.
Moving further, the right hand makes a grab, the left one finishes the supporting part of the stroke and begins to leave the water, the right leg strikes from top to bottom, the left one moves up. Then the right hand finishes the catch and begins the support part of the stroke, the left comes out of the water and performs the first half of the carry, the right leg rises up, and the left kicks downwards. Next, the right hand finishes the first half of the supporting part of the stroke, the left one finishes the carry and enters the water, the right leg strikes from top to bottom, and the left one moves up. At the next moment, the right hand finishes the supporting part of the stroke and begins to leave the water, the left one makes a grab, the right leg rises up, and the left one strikes from top to bottom. The cycle ends when the right hand comes out of the water, completes the first half of the sweep, the left finishes the catch and begins the support portion of the stroke, the right leg kicks down, and the left moves up.
If a swimmer inhales under his right arm, then at this moment the right arm comes out of the water and begins the sweep, the left begins the supporting part of the stroke, the right leg kicks from top to bottom, and the left moves upward. If the inhalation is made under the left hand, then the positions of the right and left arms and legs change accordingly.
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