SWIMMING MOVEMENT PATTERNS ARE VELOCITY SPECIFIC
Rouard, A.H., Billat, R.P., Deschodt, V., & Clarys, J.P. (1977). Muscular activations during repetitions of sculling movements up to exhaustion in swimming. Archives of Physiological Biochemistry, 105(7), 655-662.
The purpose of this study was to examine the influence of the repetition of sculling movements of the upper limb on muscular electrical activities during an exhaustive test in front crawl.
The activity of six upper limb muscles in nine swimmers were recorded via a telemetric EMG data acquisition system using active surface electrodes, during a 4 x 100 m front crawl test conducted to exhaustion. The pattern of the movement was analyzed from views obtained by two underwater cameras. Four phases in the stroke were identified from the hand coordinates in the frontal plane (down-sweep, insweep, outsweep and recovery). Raw EMG data were rectified, integrated (IEMG) and normalized for each subject and for each muscle with respect to the highest IEMG obtained during the strokes and the phases.
Results indicated that the repetition of the stroke up to exhaustion was not associated with an increase in IEMG for the total stroke and its phases except for the most activated muscle. The different sculling movements appeared to be clearly identified by the EMG approach whatever the trial. The contribution of the different muscles remained the same through the different repetitions up to exhaustion. Larger muscular recruitments were observed during the insweep phase when important antagonist activities were activated. It would be interesting to observe the EMG in a next 100 m repetition when the swimmer could not sustain the same velocity.
Implication. In swimming to exhaustion at a constant velocity the pattern of muscular movements remains relatively constant. However, within-stroke phases can be identified by distinct patterns of muscular activation. Thus, within a constant technique at a constant velocity there are distinctive phases of muscular patterning suggesting acute specificity of sequencing and timing factors for velocity dependent techniques. Swimming movement patterns are velocity specific.
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