The Common Threads of Successful Swimming Technique
By Marshall Adams
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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.
=========================================
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