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Thesis

Electromyographic activity in the gastrocnemius and tibialis anterior while pedalling a bicycle ergometer: Effects of foot positioning

1 May 1988

Abstract

This study was conducted in order to determine if electromyographic (EMG) activity of the gastrocnemius (GT) and tibialis anterior (TA) was altered following repositioning of the foot while subjects pedaled a bicycle ergometer (BE). The subjects were fifty healthy men (n=10) and women (n=31) who acted as their own controls. They pedaled a BE alternating a conventional foot placement (CFP) (the heels are placed flush with the posterior edge of the pedal). A pair of polyethelene heel cups secured the subject's feet in the FFP. Three 5 second integration periods were recorded for both the TA and GT in each foot position. The means of these trials were compared by foot position for each muscle for each subject. The difference of the means was summed and t-tests were performed on the sums of the difference of the means (p = 0.684 for GT, p = 0.374 for TA). During FFP the GT activity of eleven subjects decreased and TA activity increased as was hypothesized. In 27 cases only the activity of the GT conformed to expectations, while activity in the TA decreased or demonstrated no overall change. Twenty-five subjects had activity of the GT increase unexpectedly when using a FFP while TA activity increased as was expected. These results indicate that there is no significant change in GT or TA activity following repositioning of the foot while pedaling a BE.


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