Fig. 9. (A) A least-squares regression of muscle force versus electromyogram (EMG) amplitude within one individual across speeds. (B) A least-squares regression of muscle shortening velocity during downstroke versus EMG amplitude within the same individual across speeds. EMG amplitude was quantified as the integrated rectified EMG signal, divided by its duration. We performed the regression against mean values for amplitude, force and shortening velocity at each speed to give a balanced data set. However, we plotted all points included in the mean values as small `x' symbols to show the full range of variation; the mean values used in the regression analyses are shown as large diamonds. Table 4 reports additional analyses of EMG amplitude with respect to muscle force.

Return to article