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The Common Threads of Successful Swimming Technique
By Marshall Adams
Introduction Discussions presented in this paper are centered on the importance of the adductor muscles of the shoulder in all competitive strokes. The majority of examples cited are from the crawl stroke and butterfly, but the threads of common factors to success run through every stroke. The paper draws it conclusions from discussions of the core muscles of technique, the nervous system organization that provides the conscious and unconscious control of these muscles, the water that compounds the problem of movement within an unfamiliar medium, and the peculiarities of the shoulder joint that limits our movements. This unique view of human swimming propulsion draws upon principals, when analyzed in their entirety, that have profound implications for swimming instruction.
The progression of swimming since the beginning of the modem Olympic era has resulted in a variety of successful techniques performed within the parameters provided by the rules governing each competitive stroke. Much research and analysis has been conducted in order to explain the successes of the techniques used by the most successful swimmers. Yet, the search goes on to find the stroke techniques and scientific explanations that explain why one technique is superior to another. The variables involved with this analysis make the endeavor a difficult task. It is one thing to know the concept such as the potential of the shoulder’s third class lever in human motion, but it is difficult to rate this factor, or anyone factor, with all the other variables involved in swimming success.
A common approach for success has been to try to emulate the techniques used by the world’s best. It is in the techniques of the athletes that have broken the mold, and had success, that much insight into the technical truths is often revealed. This paper will discuss the factors that form common threads in successful technique and explore the truth revealed in the variables of success. It is understood that there is no magic bullet of technique perfection that results in success. However, superior technique is a key component in a champion’s design for success.
The performances of Mary T. Maher in the late 70′s and early 80′s in the Janet Evan’s 400 meters in the 1988 Olympics, in the 1992 Olympics, Grant Hackett’s 1500 as well as Ian Thorpe’s 200, 400 the competition and old records were left way back in the rear view mirror and shattered well beyond what could reasonably be expected. These people have broken the mold.
It is obvious to the casual observer that all the participants in the Olympic finals possess superior athletic body types and are highly trained and motivated. What may not be as obvious are the technique peculiarities that happen too quickly to be apparent or are obscured because they happen under water. It is apparent to this observer that the peculiarities of technique exhibited by the swimmers that have broken the mold and shattered records are observable and are significant components in these notable swims.
The Body Core The ‘Body Core’ is the most current phrase used to describe what was written more then three decades ago by Charles E. Silvia to describe the importance of the large trunk muscles to producing efficient swimming motion. All body movement come from the contraction of muscle, but obviously, some muscles are more effective than others in producing efficient motion specific to a particular swimming stroke. The large muscles of the trunk are anchored to the central ‘core’ or the body and thus, the term ‘body core’ has some basis for its origin. The use of the term ‘body core,’ however, means little without defining the particular muscles involved with its application to technique. The ‘body core’ could easily be defined as the body’s trunk excluding the extremities and would include all the muscles both large and small attached to the trunk. Emphasis of the ‘Body Core’ that includes all of the muscles of the trunk for swimming would not be an efficient use of the most important muscles of the trunk. Thus, the use of the term ‘Body Core’ does not do justice to the particular muscles needed for emphasis, but rather loosely defines the important area from which these muscles originate. At least the coiners of the term ‘Body Core’ are in the right area to note where the most power originates for effective swimming propulsion.
The proliferation of materials and programs directed at the strengthening the body ‘Core’ has brought the area to the attention of swimming enthusiasts. However, the programs and exercises that are being promoted are not new and they are no more or less effective than they were 50 years ago. The use of medicine balls and calisthenics are a recycling of old methods, just as the knowledge of the ‘Core’s’ importance is an updating of old ideas, albeit not as accurate as first described. This is in reference to Silvia’s identification of the primary muscles of shoulder adduction used in effective competitive swimming. No one can argue that the general conditioning of the body’s core is detrimental. It can be argued, though, that general conditioning of the body’s core is not the magic pill for success. Core conditioning is one piece of a training program puzzle, but without the specifics of muscle emphasis peculiar to the sport of swimming, no program of general body core conditioning will produce the desired swimming improvement.
The lack of precise definition of ‘Body Core’ as it relates to the effective muscles of shoulder adduction is not helpful to an athlete trying to learn how to use his strength effectively for a particular stroke. A good analogy would be the advice to a young child to use a utensil to eat ice cream when the spoon is what is most effective. An instruction to swim with the ‘Body Core’ is too general to have meaningful effect. General conditioning can never replace the exercise physiological law of ‘Specificity of Training.’ Recruitment of efficient muscle motor units is specific to the task. The most important part of swimming training is the swimming and nothing can replace it. The so-called ‘feel’ for the water is actually the efficient recruitment of muscle fibers specific for the task Over recruitment of muscles by inefficient swimmers could be the result of non-specific training and/or the lack of specific training
The Muscles of the Body Core The effective ‘core’ muscles for shoulder adduction used in all swimming strokes are the great trunk muscles that originate from the chest and back of the body (core) and have their insertions on the upper arm (humerus) bone. Many muscles originate from the chest and back but these muscles are the major adductors that work to bring the arm (humerus) in toward the mid-line of the body (adduction). The muscles include the latissimus dorsi, and teres major on the back (posterior) and the pectoralis major on the front (anterior). The teres major originates along the lateral boarder of the scapula, thus this important adductor muscle does not completely follow the definition of a core muscle since it does not arise from the trunk but arises from a bone that is close to the trunk. The scapula glides on the surface of the body’s rib cage. Why are these major muscles that for the most part originate from the ‘body core’ so important for effective swimming technique over and above other muscles which are also capable of producing or assisting in shoulder adduction? The answer can be found in the structure of the shoulder joint and the nature of these major ‘core’ muscles. These muscles are large, relatively powerful and are served well by the proximity of the heart’s fresh blood supply. The use of the description ‘relatively’ has to do with comparing these muscles to the other muscles in the body. The shoulder joint itself is not a joint designed for strong movements in a ‘relative’ sense. The shoulder joint serves as the fulcrum for a third class lever system designed for mobility and speed of movement, not for strength. The latissimus dorsi, teres major and the pectoralis major muscles are the most powerful muscles associated with the joint. All three muscles work to pull the humerus toward the mid-line of the body as well as to rotate the humerus medially (internally). In all four competitive strokes the action of shoulder adduction is associated with the most propulsive phases of the stroke. Thus, the over simplified coaching instruction to ‘swim with your core’ has some basis in truth. (Relatively speaking)
The emphasis of certain muscles implies an unstated understanding that other muscles are not emphasized but are involved in an action. Fluid motion demands a synergy of action from all the parts that are moved. Very rarely does a muscle act alone and never in swimming. The large adductors of the shoulder have to work in synergy with the muscles of the arm, forearm and hand because the action of the shoulder adductors will move these segments whether their muscles are contracted or not contracted. Efficiency in a skill such as swimming demands that during the propulsive phase of the stroke the large muscles of the trunk be emphasized over the smaller muscles or the arm, forearm and hand. The larger muscles of the trunk are well supplied with blood, are involved with large movements and by their nature (relative sizes) able to tolerate large and repetitive workloads. The smaller muscles of the arm, forearm and hand are harder to supply with blood due to their distance from the heart and their relatively small sizes. It is apparent that if a movement can emphasize the larger and more vascular muscles for a repetitive movement, the more efficient the movement will be from both a strength and endurance standpoint. The only drawback to this idealistic technique description lies in the mechanical necessities of a particular stroke. This would include espoused techniques that require the fine manipulation of the smaller muscles of the arm, forearm and hand to produce stroke patterns deemed necessary for efficient propulsion.
Stroke patterns that emphasize more refined movements of the arm, forearm and hand add an increased energy cost for their application. A stroke with exaggerated out-sweeps, in-sweeps, up-sweeps and S patterns during the propulsive phase must rely upon muscles other than the great shoulder adductors of the trunk. The inefficiency of these small muscle actions is readily apparent to those who try to swim with these techniques. Any repetitive action that does not rely for the most part upon major muscle groups produces quick fatigue.
The challenge for the swimmer is to find the right synergistic applications of all the muscles involved in a stroke. The ideal stroke emphasizes the great adductors of the shoulder during the propulsive phase coupled with the optimum use of the small muscles of the arm, forearm and hand. The small muscles are used to position the extremity in its most advantageous propulsive position as it moves through the water in a particular stroke. The skilled swimmer makes this task appear to be easy because they do not over recruit muscles at inappropriate times and rely as much as possible upon the moving inertia of their repetitive and explosive propulsive phases to carry the stoke during the recovery and initial catch phases. They let the stroke carry them instead of working the stroke at the expense of their limited energy. This inertial and ‘easy’ stroke does require great muscular effort. Even the most ‘natural’ of athletes requires time to acquire the skill of an inertial stroke. The learning curve is different from athlete to athlete and the quality of the individual’ s nervous systems that determines the ultimate degree of success in the acquisition of swimming skill. Michelangelo’s ideal ‘David’ would not be a successful swimmer if he did not spend the specific time to learn the motor skill of swimming.
The Importance of Nervous System Organization Efficient use of the ‘body core’ adductors of the shoulder joint during the propulsive phase of swimming is directly related to the organization of the human nervous system. Charles Silvia of Springfield College wrote about the difference between good and poor motor performance being determined by the quality of the sensory input. (18) Successful competitive performance, as stated in the last paragraph, is not possible without the ability to translate input (feel, touch, kinesthetic awareness) into effective motor output (recruitment of muscular force by the most appropriate muscles at the most appropriate times).
There is a paradox to this question for the successful acquisition of swimming skill. It lies in the understanding of the importance of the major core adductors of the shoulder and the difficulties involved with the tapping into their power. The nervous system is not organized to receive extensive sensory input from the major muscles of the trunk. The quality of sensory input from this area is limited in everyone. The organization of the cerebral cortex of the brain (motor and sensory homunculi) puts a distorted emphasis upon sensory input originating from the extremities and specifically from the hands and feet. The majority of the sensory nerve endings give input for motor control in the hands and feet, not in the muscles of the trunk. The sensitivity of the extremities is easily understood when comparing the results of injuries. A cut on the hand hurts much more than a similar cut on the shoulder. This lack of sensation from the area of the body core illustrates the paradox of body core emphasis. It is almost a “blind” move. The sensory information that arrives from the extremities is much more distinct to the processing brain than the information arriving from the body’s core muscles at the same time. The synergy of shoulder and arm/hand movement must rely upon sensory input coming from an area not directly associated with the muscles which produce the desired movement. The hands must provide the ‘feel’ while the major ‘core’ adductors of the shoulder provide the propulsive power.
The relative lack of sensory input from of the ‘body core,’ and more specifically the major adductors of the shoulder, could be used to explain the great variety of individual techniques. (Even by swimmers taught by the same instructors) It also points to the difficulties in teaching and learning swimming skills. Man’s presumptuous brain allows for creativity and variety regardless of a technique’s relative merits. Trout don’t vary their swimming technique; humans have the choice to decide their course of action. Humans, also, don’t have the experience of spending their whole existence in the water. The organization of the human nervous system makes it hard to learn how to emphasize the ‘core’ in an efficient manner, and water compounds the problem.
The Challenges of Performance in Water Water immerses a swimmer in a liquid that envelops the body and gives no point of reference. Gravity is essentially neutralized. Down feels like up and back feels like any other direction. The sense of pressure exerted against the body is the same in all directions. Internal cues for successful technique are muted by the medium. Even the most sensitive areas for sensory feedback located in the hands and feet have no external reference point to base effective motor output. There is no cue of solid resistance indicating where and when to apply effective force. The laver system of the shoulder and arm provide an increased sense of resistance at the most inefficient positions in the stroke. An outstretched arm in the water is in its weakest mechanical position. Yet, without a solid reference point, a novice swimmer interprets the vigorous downward application of force, with the arm stretched out straight, as a helpful movement due to the added resistance caused by the weak lever position. The result is a bracing action with little propulsive component. The bracing movement feels forceful to the swimmer when, in reality, it is a weak and inefficient movement.
It is obvious that the world-class athlete has discovered the correct synergistic mix to produce the most efficient techniques. An analysis of the peculiarities of their individual techniques can reveal much about what is humanly possible. It is difficult to compare athletes of different eras beyond their inherent human qualities. But, as techniques have evolved there are similarities of technique that are universal because of the limits of movement defined by the rules of the sport.
Outstanding Performance Examples The effective use of the body core and specifically the adductors of the shoulder joint has been a trait of many great freestylers in the recent historic past. One remarkable swim was the World Record and Olympic gold medal performance of Kieren Perkins in the 500 meters at the 1992 Barcelona Game. The under water television shots of the performance exposed Perkins’ superior positioning of both arms as they assumed the initial catch position. This positioning movement put the forearm and hand in a position almost perpendicular to the surface of the water very early in the stroke. From this position Perkins maintained the forearm and hand in position perpendicular to the direction of travel throughout the most propulsive phase of the stroke as the shoulder adductors brought the humerus toward the mid-line of the body. The performance followed the kinesiological description of the ideal stroke first described by Charles Silvia in his 1970 book (18). Silvia’s description was inspired by his study of 1956 and 1960 Olympic freestyle Champion Murray Rose. It was in the technique of Murray Rose that Silvia saw the potential of the shoulder joint to produce its most efficient swimming motion. Perkins’ stroke, while not a mirror image of Rose’s technique, clearly followed the same mechanical principles. Perkins coach John Carew, in an article for American Swimming Magazine the following year identified Murray Roses’ stroke as the model for Perkins technique (2). This technique has to be considered one of the key factors in Perkins’ dominating performance in 1992.
Identifying the Core’s Importance Within a Stroke Silvia’s description of superior crawl stroke mechanics included four key parts upon which an efficient stroke depend: 1. Inertial shoulder girdle elevation and upward scapular rotation. 2. Shoulder joint medial rotation and elbow flexion. 3. Shoulder joint adduction and downward scapular rotation. 4. Inertial round off and release (partial supination of the forearm and hand and shoulder joint lateral rotation)(18)
The synergistic blend of all four parts of Silvia’ s description is what the viewer sees in the performance of superior freestyle swimming. The application of part 3, shoulder joint adduction and downward scapular rotation, is the most propulsive phase. It is during this most propulsive phase that the core adductors of the shoulder joint contract vigorously against the resistance of the water to bring the humerus bone toward the midline of the body. A coach who instructs his swimmers to’ swim with your cores’ is telling his swimmers to emphasize point number 3 of Silvia’ s 4-part craw stroke description. However, the emphasis of the core adductors is only effective during the propulsive phase of the stroke and any undue tension of theses muscles at different times in the stroke is detrimental to efficiency. Thus, the admonition of a coach for a swimmer to swim with his ‘core’ is too general to have positive effect if shoulder adductor muscle involvement is emphasized beyond the propulsive phase of the stroke.
The critical nature of Silvia’s 3rd point of emphasis also might be used in the explanation of the great variety of successful crawl stroke techniques used at the world-class level Careful analysis reveal crawl stroke variations in current champions do not exist to any great degree during the most important propulsive phase of their strokes. The variations in technique come at times that are not critical to the ultimate propulsive efficiency of the stroke and can include the timing of the stroke; balanced recoveries, loping actions, catch up recoveries, straight elbow recoveries and kicking frequency. Olympic champion Brooke Bennett has been very successful without extending her elbows at the entry. Olympic champion Grant Hackett has been successful doing the opposite. Michael Klim exhibits a straight elbow recovery, as does Inge de Bruin. Ian Thorpe and Kieren Perkins can be observed using a bent elbow recovery. These non-critical variations come at times in the stroke that allow for great variation of action and thus, the discovery of the importance of the ‘core’ and specifically the great shoulder adductors is crucial. All of the aforementioned crawl stroke champions exhibit a vigorous and well-defined adduction and downward rotation of the shoulder that follows closely along the frontal plane of the body during the propulsive phases of their strokes. It should be noted that the total stroke must be considered in any evaluation of the shoulder without the accompanying and synergistic action of the other phases of the stroke. The three phases that comprise the release, recovery and catch leave room for individual variations due to their non-propulsive nature. There are however, kinesiological and mechanical parameters that must be followed during these stages that can affect the short-term efficiency of the stroke and the long-term integrity of the shoulder.
The shoulder can be put into a precarious position during the recovery and entry periods of the crawl and butterfly strokes. A straight elbow recovery tat does not externally rotate the humerus as the recovery progresses will result in an impingement between the coraco-acromial arch of the shoulder and the head of the humerus. Standing and trying to do a butterfly recovery with the palms of the hand facing backward limits the extent to which the hands can be raised above the head without encountering great resistance. An impingement can also occur in the front of the shoulder upon the reentry of the hand into the water after the recovery. This reentry shoulder impingement can occur if a swimmer uses a straight elbow entry with the shoulder fully flexed and abducted against the resistance of the water.
The identification of the proper application of the ‘core strength’ of the body and the associated implications of nervous system sensory organization is a positive step for anyone attempting to improve their swimming skill. It is within a synergistic application of stroke technique that the so-called ‘sweet spot’ and ‘zone’ is revealed. World-class performance reveals to the observer the appearance of effortless grace. This apparent effortless grace is often misinterpreted as relaxation. An all out performance requires and demands vigorous muscular effort, but only during the most propulsive phase of a stroke. The other phases require a dependence upon the moving inertia generated by the propulsive phase and as little vigorous muscular action as possible to facilitate blood flow and recovery. A re1axed swimmer will go nowhere. The ‘zone’ has been attained when the results appear to be greater than the effort exerted. It is a familiar site to see an Olympic gold medalist appear to have more energy during the celebration immediately after their ‘all out’ performance. All four competitive strokes can be explored for the optimum use of the core shoulder adductors and the ‘sweet spot’ their proper application expose.
It is obvious to the informed coach that there are many factors which contribute to the ultimate outcome of efficient competitive swimming. Successful manipulation of the controllable variables is the greatest challenge for coach and athlete and allows for creativity from both the coach and the athlete and allows for creativity from both the coach and the athlete. However, the almost overwhelming number of factors governing success demands that a coach and swimmer filter out the trivial from the important. Successful swimming demands an economy of motion and the understanding of mechanics for efficient human swimming propulsion. Knowledge of the important role the shoulder joint adductors play in efficient swimming is useful for anyone attempting to increase his swimming skill. Shoulder joint adductors are at the ‘core’ of a champion’s.
The differences in the approach to the entry and catch positions in two recent Olympic freestyle champions illustrate the successful variances in the non-propulsive phases. Brooke Bennett does not straighten out her elbows as the hand enters the water after the recovery phase. This action reduces the inertial lag time at the front end on the stroke and minimizes the possibility of shoulder impingement caused by the mistaken downward motion with the arm stretched out straight that was described earlier. Bennett quickly assumes the position of internal rotation of the humerus and spends no time flexing the elbow because it is never extended in front.
Ian Thorpe takes a much greater time setting up the propulsive phase of his stroke. From the point of hand entry until the hand releases and exits the water, Thorpe spends one half of that time with the hand and arm barely moving relative to his body. This huge inertial lag is more than compensated for by Thorpe’ s efficient completion of the shoulder adduction movement of the opposite arm, complete shoulder girdle elevation of the arm entering the catch phase to insure a long stroke, and the increased propulsive emphasis attributed to his kick and the completion of the strong adduction movement of the opposite arm allow him to assume the catch position inertially with very little shoulder muscular effort. Thorpe, also, has the added anatomical advantage of extra large and flexible feet. It is from the stretched out straight hand entry position that Thorpe begins the catch and propulsive phases by flexing his elbow to about 90 degrees while internally rotating the humerus bone. No downward push at the beginning of the stroke is exhibited. The elbow remains shallow relative to the water surface even as the body rotates to promote breathing and/or the recovery of the opposite hand. It could be agued that Thorpe’s added time of apparent arm inaction promotes a more efficient blood flow. thus adding another positive factor to balance the lack of propulsion during one half of the in-water phase of his stroke. Thorpe’ s nearly stationary position during the entry phase accounts for approximately 1/3 of the total stroke cycle time Thorpe does not rush his stroke and his vigorous adduction of the shoulder does not begin until the hand and forearm have been positioned for the optimal use of the shoulder adductors during the propulsive phase.
The idea that world-class swimmers take the time to fine tune the pitch of the hand, search for still waters, sweep down, sweep out, sweep in, or sweep up during the propulsive phase of their strokes is not an accurate description of the stroke. These descriptive words suggest motions that will increase fine muscle involvement of the arm and forearm and deviate from the economically powerful adduction movement of the stroke’s propulsive phase. These small muscle refinements are not the feature of the gross motor shoulder adduction movements exhibited by world-class swimmers during their propulsive phases. Adduction of the shoulder during the propulsive phase will appear to cause an outward and inward sweep of the arm as the arm rotates around the fulcrum of the shoulder joint. The vigorous and economic shoulder adduction movement only allows time for the maintenance of limb angles, and for the feel of water pressure against the hands during the propulsive phase. The sequence is true for both sprinting and distance swimming. Ideal shoulder mechanics are the same for both distances. Only the rhythm of the stroke (stroke frequency) separates the difference between efficient sprinting and distance technique. Ultimate competitive success at any distance using an efficient technique is limited by the other variables involved with success, not the least of which is the nature of the athlete’s muscular makeup, fast twitch or slow twitch muscle predominance. The example of Ian Thorpe’s successful world-class performance at distances covering the 100 to the 800 meters illustrates the universal effectiveness of one particular technique.
The strength and efficiency of shoulder adduction can be illustrated through the movement of the iron cross on the still rings in gymnastics. Although the iron cross position is a static gymnastic position, it demonstrates the most powerful and effective use of the shoulder adductors. All of the muscles of the shoulder, forearm, arm and hand are involved in the performance of an iron cross but it is the shoulder adductors that are the key to providing the support of the body’s weight. In swimming, it is the contraction of the great shoulder adductors that contribute most to moving the body’s mass. Thus, the importance of the shoulder adductors in both of these activities is in the strength they provide for support and movement of the body’s mass. Half way through the vigorous adduction movement in the crawl and butterfly strokes the action of the adductors is in a position similar to the mechanically superior position of the iron cross. The difference between the two activities is found in the difference between the static position of the iron cross and the ballistic results of the propulsive phase of the swimming stroke. Both activities use the most mechanically advantageous position of the shoulder joint to perform their skill. Swimmers also flex their elbows to increase the mechanical advantage of the shoulder’s 3rd class lever system. Deviation from the plane of the movements just described will result in the failure to hold an iron cross, or inefficiency of the swimming movement due to ineffective muscle angles of pull. An iron cross cannot be held with the arms held out straight in front of the body because the pectoralis major muscle is not at an effective angle to pull down on the humerus from this position. Adduction of the shoulder in swimming is not effective if the stroke follows a path that passes the same way as the unsuccessful iron cross. This would be a stroke that allows the hand to pull under the body.
The most important point to both Bennett’s and Thorpe’s strokes is the position they both assume with their arms that allows for a mechanically superior propulsive phase. This superior position maintains the forearm and hand in a position perpendicular to the line of travel for the longest possible time given the limitations of the shoulder joint.
Teaching Feel for the Core A program to help identify the motion and feel for the effective use of these important muscles is the logical next step in the quest for improved swimming. The primary muscles of shoulder adduction don’t have the superior nervous input associated with the hands. It is thus, very helpful to give the area added focus through artificial means. The power of the shoulder adductors can be demonstrated through the use of an imagined or real prop. The object is an inflated balloon placed in the armpit. The objective of the demonstration is to pop the balloon. By popping the balloon in the armpit the swimmer can demonstrate the vigorous use of the primary adductors of the shoulder joint in a way that is similar to their action used against water resistance during the propulsive phase of the swimming stroke.
Completion of vigorous adduction effectively finishes the propulsive phase of the stroke because the major adductors are no longer in play at the end of adduction. Once the balloon is popped, the stroke should be redirected to enable an inertial recovery. Further pushing after the balloon is popped would not involve the prime movers of adduction. (The muscles used to pop the balloon) After the balloon is popped any extra effort to effect propulsion would necessitate the use of the smaller muscles of the arm and forearm. This action would add to the expenditure of energy at an inopportune time in the stroke and with inefficient muscles.
The illustration of the popping balloon underscores the concept of swimming with the body’s core and emphasis of the major muscles used to adduct the shoulder. In order to pop the balloon, it is the major muscles of the body’s core that are used to accomplish the task. The athlete can envision and feel the importance of adduction and the power of that movement. It is also easy to see the futility and ineffective nature of S curves and sweeping actions that use the smaller muscles of the arm and forearm to accomplish the task. A sweep or S curve stroke is not an effective way to pop the balloon. After the balloon is popped, effort to continue propulsion is ineffective because the major muscles of shoulder adduction are no longer involved. The so named ‘long’ stroke is the result of the completion of adduction that is set up by an early and efficient catch. Descriptions of long strokes that emphasize a push at the end of the propulsive phase and a finish with the hand past the hip risk the use of inefficient muscles of the arm and forearm and precarious shoulder mechanics.
The Economy of an Effective Propulsive Phase The beauty of world-class swimming performance can be found in the economy of the movements the athletes exhibit. Extraneous and wasteful effort and movement are minimized. While the under lying mechanisms, physiology, and fluid dynamics are complex, the expression of the activity at the world-class level appears to be effortless and easy. Identifying the major propulsive muscles and demonstrating when they are most effective is a key step to efficient swimming. Prioritizing the focus reduces the complexity of a movement to a manageable state for conscience creativity.
Prioritizing the adduction movement is a key element in any stroke because the adduction of the shoulder is the most efficient movement of the shoulder during the propulsive phase. Adduction also sets up the other phases of the stroke by generating momentum that can be carried inertially through to the other phases. Stroke descriptions that emphasize movement that distract from the power of shoulder adduction and movements that occur at times in the stroke that occur during the non-propulsive phase are not helpful. Illustrations of such descriptions include sweeps, hip roll, and balance (to some degree). Body balance could be used to improve streamlining and resistance, but is a fine tuning event that follows well behind the mechanics of propulsion as a teaching priority. Hip roll is a result of an inertial, free-swinging stroke, but not an important focal point for propulsion. All strokes require vigorous adduction of the shoulder during the propulsive phases of the stroke and only two of the competitive strokes involve rotation around the long axis of the body (crawl stroke and backstroke). The lack of rotation of the hips along the long axis in the butterfly and breaststrokes does not compromise the effective adduction movement of the shoulder during the propulsive phases of these strokes.
The peculiarities of technique exhibited by world record holder and Olympic gold medallist Tom Dolan in the 400 IM in Sydney 2000 punctuate the importance of arm action over any other propulsive effort in his butterfly and backstroke legs of his performance.. Dolan took only one kick per arm cycle during his butterfly leg of this swim and used a two beat kick throughout his backstroke leg. Clearly, the arm action is the key part of Dolan’s propulsive effort in these two strokes.
Mechanical Risks of Shoulder Rotation The strength and efficiency of adduction of the shoulder in swimming is not without its risks even in the most proficient of strokes. The vigorous adduction and shoulder rotation of the swimming movement can put the shoulder into a precarious position at the completion of the stroke and at the beginning of the stroke. As mentioned previously, the shoulder and the arm comprise a third class lever that is noted for its wide range of motion, not for its strength. Precarious positions that can result in injury can easily be assumed in the fast and repetitive motions of swimming.
The most notable precarious position of the shoulder during the crawl stroke is assumed during the hand entry. An impingement can occur in the front of the shoulder when the arm enters the water with the shoulder fully abducted, flexed and humerus internally rotated. From this hand entry position, if the swimmer’s first action is to push down, the result is a bracing action that is non-propulsive and serves to lift the body out of the eater. If the body is rotated on its long axis at the same time the hand enters the water, the result is an increase in the potential for impingement of the long head of the biceps and supraspinatus tendons. The result of this repetitive action is inflammation and pain as well as stroke inefficiency. The world-class swimmers that use a straight elbow entry reduce both the bracing downward push upon hand entry and shoulder impingement problems by internally rotating the humerus while flexing their elbows before any vigorous effort is exerted against the resistance of the water (adduction of the shoulder).
Another common trait of the straight elbow entry is the loping or catch-up nature of these strokes. The opposing and recovering arm is allowed to inertially catch up to the other arm as time is taken to position the propulsive arm. This catch-up action reduces the amount of body rotation on the long axis and further refutes the need to emphasize the perceived power of hip roll. The result of this action is a shallower stroke with the elbow of the propulsive hand remaining relatively close to the surface of the water even as the trunk of the body rotates on the long axis. The catch-up stroke forces less trunk rotation along the body’s long axis and negates the rotation of the body that would further aggravate the shoulder impingement upon hand entry.
Other precarious should positions occur in the stroke and illustrate the fragile nature of should rotation throughout the stroke. A swimmer who does not externally rotate the humerus during the recovery will limit the recovery due to the impingement of the greater tuberosity of the humerus with the coraco-acromial arch of the shoulder. Complete adduction of the shoulder at the end of the propulsive phase will wring out the long head of the biceps and the supraspinatus tendons. Vigorous extension of the elbow at the end of adduction forces the palm up and faces the palm away from the body during recovery. This action will result in prolonging the wringing out of the long biceps and supraspinatus tendons. While not effecting propulsion, these actions will ultimately impact the shoulder in a negative manner. The wringing out of the supraspinatus and biceps tendons creates an avascular situation in these tendons that Rathburn and Macnab have postulated overtime causes tendon degeneration (14). Couple the wringing out of these muscles at the end of the stroke and the impingement at the beginning of the stroke and it is no wonder that the syndrome of swimmer’s shoulder has been reported to be very common among competitive swimmers. It is for these reasons that a straight elbow recovery is fraught with danger. World-class crawl stroke swimmers have been very successful using straight elbow recovery techniques, but so have others been successful using the bent elbow recovery. The true key to propulsive success is in the completion of shoulder adduction that allows for a free-swinging and inertial recovery regardless of the position of the elbows during non-propulsive phases. The risk of a straight elbow recovery comes from the position in which the shoulder is subjected as recovery continues as well as extending the time the shoulder remains fully adducted at the finish of the propulsive phase.
Efficient butterfly stroke recovery demands a straight elbow recovery because being of the elbows require the shoulders to be lifted out of the water so the hands can clear the water. Freestyle allows for both a straight elbow and a bent elbow recovery due to the rotation of the body along its long axis. In both straight elbow techniques, (fly and crawl) risks to the shoulder come at the end of adduction of the shoulder that result in the ringing out of the supraspinatus and bicep tendons, and the shoulder impingement that will occur if the palms remain up as recovery continues. The success of bent elbow swimmers points to the frivolous nature of the push at the end of strokes. All actions at the end of the adduction phase of the stroke that promote a free-swinging and inertial (least muscular) recovery will have success. Muscular actions that promote the use of smaller muscles of the arm and forearm will have a negative impact on efficiency. Obviously, both the straight and the bent arm recoveries can be performed with minimal effort. An inertial straight elbow recovery requires a release of muscular tension at the end of the vigorous adduction phase and not an added push with the small muscles of the arm. An inertial flexed elbow recovery is initiated by releasing the grip on the water by supinating the hand and forearm while maintaining the flexed elbow of the propulsive phase this technique facilitates external rotation of the humerus by keeping the palm of the hand facing the body during recovery. Thus, the ringing out of the supraspinatus and biceps tendons is minimized to the extent that is possible at the end of shoulder adduction, and shoulder impingement during recovery is avoided.
The common threads of successful technique revolve around the ability of the athlete to exploit his power. This power is found in effective mechanics that emphasize the use of the shoulder adductors during the propulsive phase regardless of the stroke. Within these effective technique parameters are movements that are fraught with danger to the integrity of the shoulder. It is the understanding of these dangers that will allow for adjustments to individual techniques and continued exploration of the potential of human swimming. The future of swimming technique has been exposed in the recent performances that have broken the mold. The limits of performance have been moved into new territory and the exposure of the principles involved will allow for more athletes to experience the ‘sweet spot’ of outstanding performance.
Selected Bibliography 1. Adams, Marshall E.; Thoughts on the Crawl Stroke. Swimming Technique. 17-23. July/Sept 2000. 2. Carew, John., Distance Freestyle. American Swimming Magazine. 10-13. Aug/Sept 1993. 3. Counsilman, James E., The Complete Book of Swimming. IDG Books Worldwide. 1979. 4. Counsilman, James E. and Counsilman, Brian E., The New Science of Swimming. Prentice Hall Publishing Company. 1994. 5. Cureton, Thomas K., Jr., Factors Governing Success in Competitive Swimming. Spalding’s Intercollegiate Swimming Guide. 48-62, 1934; also, Swimming Pool Data and Reference Annual. 49-55, 1936. 6. Cureton, Thomas K., Jr., How to Teach Swimming and Diving. Association Press 1934. 7. Hannula, Dick., What’s New & What’s Not. The National Interscholastic Swimming Coaches Association Journal. November/0ecember 1999. 8. Johnson, Jeffrey E., Sim Franklin H., Scott, Steven G., Musculoskeletal Injuries in Competitive Swimmers. Mayo Clinic Proceedings. 62:289-304. 1987. 9. Kendall, Henry 0., Kendall, Florence P., Wadsworth, Gladys E., Muscles Testing and Function., Williams and Wilkins Company. 1971 10. Kennedy, John C. and Hawkins, R. J., Swimmer’s Shoulder. The Physician and Sports Medicine. Vol. 2 No, 4 April 1974. 11. Kennedy, John C., Hawkins R. J. and Krissoff W.B. Orthopaedic Manifestations of swimming. The American Journal of Sports Medicine. Vol. 6 No. 6. 1978. 12. Maglischo, Ernest W., Response To “Speculation” ‘ vs. Science. American Swimming. 12-17 Vol. 1999 Issue 4., also 10-17 Vol. 1999 Issue 5. 13. Maglischo, Ernest W., Swimming Faster: a comprehensive guide to the science of swimming. Mayfield Publishing Company. 1982. 14. Maglischo, Ernest W., Swimming Even Faster: a comprehensive guide to the science of swimming. Mayfield Publishing Company. 1993. 15. Rathbun, J.B., and Macnab, I., The Microvascular pattern of the Rotator Cuff., Journal of Bone and Joint Surgery. 52:540-553. 1970. 16. Richardson, Allen B., Jobe, Frank W., and Collins, H. Royer., The shoulder in competitive swimming. The American Journal of Sports Medicine. Vol. 8, No. 3. 1980. 17. Rushall, Brent S., Springings, Eric J., Holt, Larry E., Cappaert, Jane M., Forces in Swimming – A Re-Evaluation of Current Status., Journal of Swimming Research, 6-30. 10-1993. 18. Rushall, Brent S., How Champions Do It., Internet page http://www.rohan.sdsu.edu/dept/coachsci/swimming/champion/table.htm 19. Silvia, Charles E., Manual and Lesson Plans for Basic Swimming, Water Stunts, Life Saving, Springboard Diving, Skin and Scuba Diving. Privately Published by Author, Springfield Massachusetts. 1970 20. Smith, Charles J., and Reardon Edward., Springboard Diving Fundamentals. Springfield MA.: Springfield College 1978. 21. Springings, E.J., and Koehler, J.A., The Choice between Bernoulli’s or Newton’s Model in predicting dynamic lift. International Journal of Sports and Biomechanics. 235-245 6-1990.