Basic characteristics of the working movement in swimming. Sports swimming technique. Forces that ensure the progress of a swimmer
A completed system of movements of a swimmer, repeated many times, is called a cycle. In a single flow of movements, one cycle is replaced by another. Conventionally, we can distinguish the beginning and end of the cycle, as well as its phases. A phase is a part of movements during which significant changes in the nature of movements do not occur. At the same time, the swimmer's boundary poses are also highlighted - instantaneous body positions at the moment of phase change. Boundary poses can serve as specific guidelines for pedagogical control and self-control of swimming technique.
The phases are combined into periods. There are two such periods:
- 1) the period of main working movements (the period of active support);
- 2) the period of final and preparatory movements.
During the grasping phase, the working planes of the hands actively interact with the water flow, creating lifting and driving forces. At this time it is necessary:
- 1) with the help of lifting and minimal driving forces, keep the intra-cycle speed at a relatively high level, and the body in a high and most streamlined position;
- 2) move the working planes of the arms to a position that is rational for performing the main part of the stroke, along the most effective trajectory and with a high elbow position;
- 3) insert your hand into a smooth flow so that you feel the effective pressure of the water on the surface of the hand and forearm.
The grip is performed vigorously, but with optimal muscle effort. In modern versions of front crawl and backstroke swimming, the phase of grasping the water with the hands coincides with the transfer of the stroke from one hand to the other, and in most versions of breaststroke and butterfly swimming, with the transition from the working movement of the legs to the working movements of the arms.
In the pull-up phase, the swimmer's shoulder girdle approaches the working planes of the arms. In all swimming methods, except breaststroke, by the end of the phase he is above them. During this time, it is necessary to ensure such acceleration of the swimmer’s body so that he can perform the subsequent phase of the cycle most effectively. The pull-up phase also marks the beginning of the lifting of individual parts of the body to the highest part of their trajectory of movement above the surface of the water. The optimal ratio of driving and lifting forces on the working planes of the hands is achieved as a result of their slight deviation from the frontal plane. For example, when swimming front crawl and butterfly, at the end of the pull-up phase, the working hand-forearm plane is still deviated from the frontal plane by 10-15 degrees. Hundredths of a second after the transition to the repulsion phase, this plane of the hand reaches a vertical position. Nevertheless, from the very beginning of the stroke, it is methodically justified for the swimmer to immediately bring the working plane of the hand to a position close to the vertical.
The beginning of the pull-up phase is performed with the help of active tension of the muscles that flex the arm at the elbow joint and rotate it inward, with partial participation of the muscle groups of the shoulder girdle and back. This part of the pull-up phase is rightly called the “acceleration” phase. Then the most powerful muscle groups that extend and adduct the shoulder are fully involved in the work. By this time, the “hand-forearm” working plane is already inclined to the general line of progress of the swimmer
Push-off is the most powerful phase of the stroke. Vigorous extension and adduction of the shoulder continues, the shoulder girdle moves away from the working planes of the arms. At this time, it is necessary to ensure the highest speed of the swimmer’s movement forward and move the arms to a position convenient for the beginning of the next period of movements.
The exit of the hand from the water, movement above the water and entry into the water are phases that make up the period of final and preparatory movements when swimming crawl, butterfly and backstroke. In the breaststroke swimming method, this phase is bringing the arms forward. At this time, it is necessary to move the arms to the original working position with minimal water resistance, disturbing the streamlined position of the body as little as possible, and in a single rhythm with the swimmer’s other movements.
With a well-established swimming technique, certain preparatory movements of the arms (for example, swinging the arm over the water with a high elbow position in the front crawl or carrying the arm high over the body when swimming on the back) increase the efficiency of the working movements performed at the same time. It is logical to call such movements auxiliary.
The end of bringing the arms forward in breaststroke or entering the water in other swimming methods immediately precedes a new period of working movements. At this time, the shoulder girdle is sent following the hands. The message helps to stretch the large muscles of the back and chest and maintain an optimal trajectory of the body moving forward.
The phases of leg movements and generalized phases of the swimmer’s full cycle of movements are considered when describing the technique of sports swimming methods. The beginning of the cycle of movements is conventionally accepted as: the beginning of the phase of grasping water with the hands when swimming front crawl, backstroke and butterfly; the beginning of the kick-off phase of breaststroke swimming.
Coaches, swimmers, and triathletes use specific terms for each component of swimming technique and conventions for concepts such as speed or stroke length. Don't be intimidated, the jargon is quite simple and you will master it with success. The good news is that much of the terminology used in this book is generally accepted throughout the world, which means that after reading this chapter you will be able to understand most of the swimming and training materials available on the Internet.
Feeling the water
Feeling the water- this term is used to describe the sensation of water on a swimmer’s arms and hands that appears during a swim. When a swimmer “feels the water” well, he better calculates his movements in it and, due to this, achieves the most effective progress forward.
We use special exercises, supported by clear examples, that help develop this quality.
First, let's look at the parts of the freestyle stroke cycle and the terminology we'll use around it. In general terms, the stroke cycle can be divided into two components:
1) working movements under water (phases of “grabbing”, “pulling” and “pushing”, ensuring the movement of the swimmer’s body forward);
2) preparatory movements above the water (“carrying”, when the hand passes over the surface of the water, after which it returns to the initial position, where the hand “enters the water” and “stretches forward”).
Body rotation, or body roll, shown in the figure below. This is a rotational movement of the swimmer’s body relative to the longitudinal axis of the spine; this picture is a bit like the rotation of a kebab on a skewer (yes, that’s right!). Rotating the body helps the swimmer generate more force, reduces water resistance, and helps the swimmer perform a carry.
Body position refers to how close the swimmer is to the surface of the water, especially at the hips and legs. The low position creates additional resistance because it increases the frontal surface of the body.
A wave formed as a swimmer's body moves through the water; This term is borrowed from rowing, in this sport such a wave is formed when water breaks against the bow of the boat. The forward wave is formed at the moment when the swimmer's head, cutting through the water, lifts the water surface in front. At the same time, a depression is formed around the head and neck area, called a “funnel.”
At the moment when the swimmer's head and body move forward,
a front wave is formed.
It is the appearance of the front wave that gives an advantage to a swimmer with the correct breathing technique, since he can breathe inside the resulting vortex funnel and, thanks to this, keep his head as low as possible. Experts call this method “ breathing inside the funnel».
Bilateral, unilateral and hypoxic breathing
Bilateral breathing means breathing in water on both sides, in which there is, if not alternate, then at least a regular change of side for inhalation.
One-way breathing means that the swimmer periodically inhales from only one side he prefers: right or left. We strongly advise you to learn the technique of bilateral breathing, the benefits of this method are described in Chapter 7, Part III, devoted to adaptation to open water.
Hypoxic respiration- the process of passing a distance with limited inhaled oxygen. In this case, the swimmer inhales less frequently than usual (usually every five, seven or nine strokes). Many trainers claim that it helps increase lung capacity and aerobic endurance, but this has not yet been proven through research.
In our training, we use rate-limiting exercises to allow swimmers to focus on exhaling deeper into the water, with less distraction from holding their breath. With rarer breaths, you need to achieve inner calm and take your time, concentrating all your attention on the symmetry of movements.
Stroke length
Stroke length is one of the most actively discussed topics in swimming, as you can see from this book. Typically, this length is measured by counting the number of strokes required to swim across a pool (including strokes with both hands). Fewer strokes means a longer stride. When referring to stroke count data, always consider the length of the pool - it can vary: 25 yards, 25 meters, 33 meters, 50 yards, 50 meters. A standard rate measured in a 25 meter pool would be between 11 and 30 strokes per pool. To denote this indicator, the abbreviation DG is often used - “ stroke length».
Stroke frequency
Stroke frequency(not to be confused with stroke length!) - this is the number of strokes you manage to do per minute, again taking into account strokes with both hands. This can be compared to the cadence of a bicycle, except that when you pedal, you only count the movement of one leg, not both. The higher these indicators, the more strokes you make in a certain amount of time. The abbreviation for this indicator is G/min - the number of strokes per minute. The standard number of strokes per minute ranges from 35 to 110; for swimmers who do not belong to the elite group - from 50 to 65.
Until recently, it was difficult for swimmers to control their strokes per minute, but with the invention of special audio metronomes such as the Wetronome or Finis Tempo Trainer Pro (detailed in Chapter 3), this has become much easier. The metronome can be set to a set number of beats per minute - then you can coordinate the number of strokes and control the pace in the swim. Taking into account the number of strokes and their frequency can be extremely useful for improving swimming technique.
In open water, stroke frequency, unlike stroke length, is quite easy to measure, and there swimmers give preference to this indicator. In general, compared to pool swimmers, their open water counterparts perform more strokes per minute with a shorter stride length. This technique helps them more effectively break through waves, cutting them, and constantly keep other swimmers in sight. In Chapters 14 and 39 we'll go into more detail about the changes you need to make to your technique when swimming in open water.
In some publications you can also find such an indicator as “the number of cycles completed per minute.” A cycle is a combination of strokes with both hands. In other words, 30 cycles per minute is the same as 60 strokes per minute. Some sources also indicate the frequency of the cycle in seconds (one cycle lasts up to 2 s and is equivalent to 60 G/min). Personally, we prefer to measure frequency in minutes. Because: a) we are always dealing with whole numbers, not decimals, and b) by measuring frequency using an audio metronome, the swimmer can match each hand entry into the water with an audio signal - this helps to constantly monitor the symmetry of the movements of the right and left hands .
Swimming speed
Swimming speed usually measured as the time taken to cover a certain distance. This can be the time it takes to cover a distance of 400 or 1000 meters, but, as a rule, the speed is determined by the time (in minutes and seconds) required to cover a 100-meter distance. Thus, a result of 1:30/100 m means that it takes the swimmer one and a half minutes to complete each 100-meter segment.
Elite swimmers can do 0:50/100m sprints and slow down to 1:00-1:05/100m over longer distances (if you can even call that slowing down!). The performance of swimmers whom we classify as a sports improvement group will fluctuate between 1:10-1:30/100 m in long swims. The figures for swimmers of the intermediate level group will be 1:30-2:10/100 m, and the time required for beginners will be up to 3:00/100 m.
This is a special watch for pools that is really worth learning how to use. They do not have a minute hand, only a double seconds hand, one part of which is painted red and the other black. Elite swimmers do not use wristwatches when timing their races; instead, they rely on a centralized one located on the wall of the pool. You, too, sooner or later will learn to calculate the time of completion of any distance, using only the second hands of a “general” watch.
The key to mastering this skill lies in knowing approximately how long it will take you to swim a particular distance. For example, you know that you can swim 400 meters in about eight minutes. If you start when the red needle is at 12 (or, as the English say, "reaches the red limit"), you should finish when it is up again. Thus, if you finish the distance when the red arrow is at the “10” mark, then you swam it in 8:10, and if at the “45” mark, then in 7:45.
A wall clock in a swimming pool is a very useful tool, because many people believe that wristwatches interfere with the “sense of water” due to the deteriorated streamlining of the hand. Moreover, with practice, you will be able to use the common clock during the start. For example, if you swim 100-meter segments, starting at 2:15 each time, then the first start will be at the black mark in the middle, the second at the black mark “15”, the third at the black mark “30”, etc. d. This is a simple way to control time during training, when you don’t have to constantly look at the clock, filling your head with unnecessary arithmetic!
Torpedo push and slide
Torpedo push and slide- these are the positions that a swimmer’s body takes when pushing off the wall of the pool. This sliding is accompanied by lower water resistance than during normal swimming.
The pool clock has two multi-directional seconds hands. Over time, they will help you time your swims at different distances.
You'll get the fastest start by pushing off the wall and continuing to glide through the water until your speed drops to your usual average swimming speed, after which you should perform a full stroke. The length of this "torpedo" push is usually about 5 meters (15 feet), but under the rules set by FINA (International Swimming Federation), elite swimmers can perform a glide push over a distance of 15 meters (45 feet). We'll talk more about the benefits of a powerful push in Chapters 9 and 10.
Short water and long water
"Short water" and "long water" in pools are technical terms for 25-meter and 50-meter pools (the same applies to pools measured in yards). At the Olympic Games, competitions are held in 50-meter pools, in which the speed of completing the distances is slightly lower than in short courses. This occurs due to the fact that the swimmer performs fewer turns and does not have the opportunity to maximize the speed advantages that the ability to push off well from the wall of the pool gives him. FINA holds world championships in both long and short courses. Accordingly, there are separate world records for competitions in 25- and 50-meter pools. Wikipedia has a separate page that provides a complete table of world records, including the most recent ones. We believe you will be interested in reading them and at the same time comparing them with your own results.
Review
Review: During an open water swim, the swimmer raises his head above the surface to look around and adjust the trajectory of his movement. As soon as the swimmer raises his head, his legs begin to go down, and his shoulders continue to rotate relative to the longitudinal axis. Because of this, additional water resistance arises. In Chapter 35 we will analyze how good viewing technique with minimal head lift can minimize this additional resistance.
(ability to stay behind the leader) - a maneuver in which you swim immediately behind or next to another swimmer, gaining a certain advantage from this. Drafting is acceptable in open water swimming, including triathlon competitions, and is considered fair play in which the swimmer strives to improve his position as much as possible. Chapter 36 will tell you that there are two basic positions for successful open water drafting: staying directly behind the leader or to the side and slightly behind the leader.
In open water, swimmers can gain an advantage by swimming just behind or to the side of other swimmers. This is called drafting - staying behind the leader.
FORCES THAT ENSURE THE PROGRESS OF A SWIMMER Take it to your wall and read it in the evening! The question of what law underlies human advancement in water has not been resolved to this day and is quite controversial. Many believe that Bernoulli's theorem, according to which movement is ensured by the difference in pressure on the back of the hand and the palm that creates 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, who concluded that the stroke is not performed strictly backwards, 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. The hand is angled, the thumb is higher than the rest, and this is what basically pushes the water 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. Propulsion during swimming is well illustrated by the principle of operation of a boat engine propeller. 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, and in the final, or push-off phase, outward, up and back . 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.
SWIMMING
1. What was the name in Ancient Greece for a person who could not read or swim?
Answer: such a person was called uneducated.
2. What is swimming?
Answer: a person’s ability to stay on the water (static swimming) and move in the right direction (dynamic swimming).
3. Which of the great Russian commanders paid special attention to swimming in preparing troops for combat?
Answer: Alexander Vasilievich Suvorov.
4. When was butterfly swimming included in the program of the modern Olympic Games?
Answer: in 1956 at the Olympics in Melbourne (Australia).
5. When did our country's athletes first win an Olympic gold medal in swimming?
Answer: in 1964, at the Olympic Games in Tokyo (Japan), a 16-year-old schoolgirl from the city won the first gold medal in the history of Russian swimming, completing the 200 m breaststroke fastest in 2 minutes 46.4 seconds (Olympic record).
6. At what Olympics did our country’s swimmers manage to become medalists for the first time in the unofficial team event?
Answer: at the Olympics in Mexico City (Mexico) in 1968, our swimming team took third place in the team event.
7. Was there a case when at the Olympic Games our swimmers occupied the entire podium?
Answer: in 1976, at the Games in Montreal (Canada), athletes Marina Koshevaya, Marina Yurchenya and Lyubov Rusanova won gold, silver and bronze in the 200 m breaststroke competition.
Answer: The Olympic Games in 1980 in Moscow were the most successful for our swimmers. The main hero of the swimming competition was Vladimir Salnikov, who for the first time covered the 1500 m freestyle distance in less than 15 minutes (his result was 14 minutes 58.27 seconds).
9. Which Russian swimmer has performed most successfully in recent years?
Answer: four-time Olympic champion from.
10. Which method of competitive swimming is the fastest?
Answer: front crawl.
11. What types does swimming include as a type of motor activity?
Answer: sports, applied, synchronized, underwater, game swimming, diving.
12. What are the main forces acting on a swimmer while swimming?
Answer: gravity (it is directed downward and drowns a person), water pressure force (directed upward, this is a lifting force, which, according to Archimedes’ law, is equal to the weight of the displaced fluid and is applied at its center of gravity), water resistance force (prevents the swimmer from moving forward) , traction force (this force is developed by the swimmer through his active muscular efforts).
13. What movements does a full cycle of the front crawl technique consist of?
Answer: the cycle includes two strokes with the arms (right and left) and six kicking movements with the legs (three with each leg).
14. What is the name of the “folk” way of swimming, the prototype of the front crawl?
Answer: swimming in seedlings.
15. What is the name of the main movement in swimming that ensures the progress of the swimmer?
Answer: stroke.
16. What methods of competitive swimming exist?
Answer: front crawl, back crawl, breaststroke, butterfly (dolphin).
17. What is the quietest method of sport swimming?
Answer: breaststroke.
18. At what point should a swimmer's legs begin to move during breaststroke?
Answer: immediately after completing the arm stroke.
19. What are the different ways to start swimming?
Answer: start by jumping from the bedside table, start by pushing from the wall of the pool.
20. What are the phases of the swimming turn technique?
Answer: swimming, the turn itself, the starting position before pushing off, pushing off, sliding, the first stroke movements.
21. How to perform a turn when swimming front crawl?
Answer: somersault forward.
22. What is studied in swimming first of all - the technique of swimming methods or the technique of making turns?
Answer: first they learn how to swim, and then they learn how to make turns.
23. From which side is it best to swim to a drowning person in order to help him?
Answer: it is better to swim up to a drowning person from behind, this is the safest.
24. Which grip of a drowning person is most dangerous for a rescuer and how to free himself from it?
Answer: the most dangerous thing is to grab a drowning rescuer from behind by the torso and arms down; it is best to free yourself from such a grab by a sharp movement of the hands to the sides while simultaneous deep immersion in the water.
Answer: at a water temperature below +15 C (with the exception of swimmers specially prepared for swimming and hardening in cold water).
26. What should be done first if a person rescued from water lacks consciousness, breathing and pulse?
Answer: first of all, it is necessary to free the victim’s stomach and respiratory tract from water; to do this, you need to put him with his stomach on your knee and press on his back.
27. How can a rescuer free himself from the grip of a drowning rescuer?
Answer: by turning the rescuer's hands towards the drowning person's thumbs.
28. What should a person who cannot swim immediately do when he gets into the water?
Answer: calm down, take a position above the water that is comfortable for breathing, do not make fast chaotic movements, calmly get rid of shoes and clothes, call for help and try to move towards the shore.
29. Which direction is best to perform exercises when learning to swim in open water?
Answer: towards the shore.
30. How can I eliminate a sudden cramp in the calf muscle while swimming?
Answer: you need to grab your toes with your hands and pull them towards you several times in a row, and then massage the calf muscle.
31. What should you do before you start swimming in an unknown body of water?
Answer: inspect the swimming area (including the bottom of the reservoir) and make sure that swimming will be safe.
32. Which grip of a drowning person for transportation by a rescuer is the most reliable and safe?
Answer: “sea grab”, when the rescuer passes his hand under the drowning person’s arm and grabs his other hand by the forearm or elbow, turns the victim on his back and transports him on his side, performing swimming movements with his legs and free hand.
33. Can a competitive swimming competitor move from one lane to another?
Answer: No, he must swim in his own lane only, otherwise he will be disqualified.
34. In what case is the start of a swim considered completed correctly?
Answer: if before the command “March!” or the starting shot, all swimmers were motionless.
35. After what number of false starts can the starter judge remove the athlete from the competition?
swimming?
Answer: after the third false start.
36. How many stroke movements with arms and legs can a swimmer perform underwater immediately after a start or turn?
Answer: no more than one rowing movement with arms and legs.
37. Is it possible for a swimmer to pull himself up by any objects during the distance (for example, floating ropes, handrails, ladders, etc.)?
Answer: the swimmer is prohibited from pulling himself up by any objects while covering the distance.
38. Is it considered a violation of competition rules if a swimmer accidentally touches any objects?
Answer: it doesn't count.
39. How is the performance of a swimming competitor determined?
Answer: this result is determined by the time elapsed from the moment the command “March!” was given. (or the starting shot) until the swimmer’s hand touches the side of the pool at the finish line.
40. Are there any differences in the competition rules for different types of competitive swimming?
Answer: such differences exist.
41. Is a swimmer allowed to push off from the bottom of the pool while completing the race?
Answer: It is not allowed to push off not only from the bottom of the pool, but also from any other objects.
42. Which swimming method has the least restrictions in the competition rules?
Answer: for crawl swimming.
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 et al.) TASKS: PHASE I – INCREASE SPEED, PHASE II – INCREASE THE SPEED AS HIGHER AS POSSIBLE, PHASE III – MINIMIZE THE DROP IN SPEED, PHASE IV – AS LOW AS POSSIBLE 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 FORCE 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 . 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 THE TECHNIQUES AND TACTICS OF A SWIMMER 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.
