HOW CHAMPIONS DO IT
Researched, produced, and prepared by Brent S. Rushall,
INGE DE BRUIJN AT 25 m OF HER SILVER MEDAL 100 m FREESTYLE RACE AT THE 2004 ATHENS OLYMPIC GAMES
The time between each frame is .1 seconds. Inge de Bruijn's time for this 100-m race was 54.16, slower than her winning time of 53.83 four years earlier in Sydney. That Sydney time was also one one-hundredth of a second faster than Jodie Henry's winning time in Athens.
The purpose behind displaying a silver medal swim is to compare Inge de Bruijn's slower race techniques of Athens to the faster-time techniques of Sydney. It is generally known, that in Athens she displayed a rigid straight arm recovery whereas in Sydney her still-ballistic recovery incorporated a bent elbow.
A straight arm recovery emphasizes greater torque (twisting) along the body's longitudinal axis as well as demanding a different underwater technique. While many reasons could be offered, it is hypothesized that Inge de Bruijn's slower swimming in Athens was largely attributable to her changed propulsive actions, the changes resulting solely from emphasizing a straight arm recovery. Michael Klim's gradual performance decline and increased injuries spur this hypothesis since they occurred after he adopted a straight arm recovery.
This stroke analysis includes a moving sequence in real time, a moving sequence where each frame is displayed for .5 of a second, and still frames.
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The following image sequence shows each frame for half a second. It will play through 10 times and then stop. To repeat the sequence, click the browser's "refresh" or "reload" button.
At the end of the following narrative, each frame is illustrated in detail in a sequential collage.
Frame #1: The swimmer is very well streamlined and completing right arm propulsion. The left wrist begins to flex to initiate left arm pulling.
Frame #2: The left hand begins to press down on a rigid arm and flexed wrist. Judging by the distance between both feet, the kick could be construed as being excessive. However, if there is a powerful downward pressure from the left arm at the same time as the right arm begins its recovery, a very large counterbalancing force would be needed. That seems to be a reasonable explanation for the size of the kick illustrated in this frame. The right leg has completed its kick, is well outside the "shadow" of the torso, and is pointed down (creating a retarding drag force).
Frame #3: The left elbow bends and the upper arm appears to rotate medially, but only slightly. However, abduction has begun. Normally, one would expect abduction to wait until the arm's propelling surface was better positioned. The left foot kicks and the right foot rises preparatory kicking. The swimmer's shoulders are lowered on the left side in concert with the pull.
Frame #4: Abduction of the left arm is nearly complete and the arm is still at about 40 degrees to the horizontal plane. Normally, one would expect the lower arm and hand to be vertical at this stage of the pull. The path of the hand to this stage has been predominantly down. The shoulders start to rotate back to the other side. The head starts to rise. Streamline appears to be disrupted as the shoulders begin to rise.
Frame #5: The left elbow bends and leads the forearm. Adduction has pulled the arm through quite fast. What is noticeable here is the absence of noticeable drag force. The swimmer might be exerting considerable effort but it is not resulting in very effective propulsion. As the right arm approaches entry, the shoulders are almost flat. The head has lifted as part of the breathing action. Streamline is less than optimal as the head and shoulders have risen much higher than the hips. The right foot has kicked, probably to counterbalance the unusual forces created by the left arm.
Frame #6: Adduction of the left arm is complete. The left forearm/hand-propelling surface is vertical. The hand and forearm have risen relative to the previous frame when the fingers were at their deepest during this pull. Drag turbulence can be seen trailing the forearm. The right arm has entered. The head and shoulders are high. The left leg begins to kick.
Frame #7: The right arm/hand sweeps back and up. This completes the left arm pull. If the path of the fingers were traced over this series of frames, it would yield almost a semi-circle with no stage of horizontal movement, a feature that is necessary for a completely effective pull. This movement is partly similar to the paddle-wheel model that used to be displayed in swimming textbooks as something not to do in crawl stroke. [Because of that movement path, one is set to wonder if this semi-circle path is reflective of the semi-circle path of the hand on the rigid recovery arm. Physics would suggest that a long recovery arm would require a counterbalancing long pulling arm. It is possible that the rigid arm recovery forces poor underwater mechanics.] The left leg kicks and turns the hips to the left. The head and shoulder have returned into the water, which improves the swimmer's streamline.
Frame #8: The right arm presses down. The right leg kicks as the left arm rises in recovery. Inhalation begins.
Frame #9: The right arm continues to press down. The trailing drag turbulence demonstrates that this movement has no propulsive value. The right leg kick is complete and the hips begin to rotate back to the right. Inhalation continues.
Frame #10: The right arm continues to press down further while bending slightly at the elbow. Drag turbulence still shows no propulsion from this arm. Abduction is almost complete. The potential of abduction to create a powerful action has been wasted in this movement pattern. Inhalation is complete. The left leg begins to kick.
Frame #11: The right arm enters adduction. Considerable elbow flexion has occurred. The path of the fingers between this and the previous frame is horizontal. A drag pocket can be seen on the back of the hand and the forearm, but not the complete arm as in other swimmers. The elbow leads the forearm and upper arm being somewhat reminiscent of a "dropped-elbow". The head has returned and is oriented down and forward. The left leg completes its kick. The right leg prepares to kick.
Frame #12: The right arm continues to push straight back and retains a drag pocket that demonstrates its propulsive force. The left arm has entered. The right leg kicks.
Frame #13: A position similar to that displayed in Frame #1 is attained and the cycle commences again.
This stroke does not display the desirable features that were evident in the analyses of Inge de Bruijn's strokes at the Sydney Olympic Games. Her arms appear to go long and deep, only producing propulsive forces once adduction begins. Perhaps Ms. de Bruijn's high rate saves her somewhat. She does achieve a high frequency of small forces as opposed to a lower rate of larger forces produced by bent arm recoveries and effective underwater pulling patterns.
This writer suggests that readers heed the warnings given by James "Doc" Counsilman regarding recoveries. In his 1968 classic book, The Science of Swimming, he stated: "The mechanics of the recovery of the arms, . . . does have an effect upon the efficiency and speed of the swimmer" (p. 14). It is contended that the ballistic straight-arm recovery of swimming:
- reduces propulsive effectiveness,
- increases the degree of twisting in the swimmer (see Frame #4), and
- compromises the path of propulsive movements, introducing a large vertical component that mirrors the circular path of the recovering hand.
A good case is made for these technique flaws being somewhat responsible for Inge de Bruijn's slower times in her events in Athens when compared to her times in Sydney.
Counsilman, J. E. (1968). The science of swimming. Englewood Cliffs, NJ: Prentice-Hall.
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