Response of Fast Muscle Fibres to Series of Impulses

The peak power at the beginning of an isotonic twitch is increased if it is initiated while a previous twitch is still in progress ; the effect is cumulative over the first few twitches of a series. The time taken to drop from peak power to zero power is not affected.

The power cycle in an isometric tetanus is considered and a possible method of predicting isometric tension, as a function of stimulus rate, from isotonic measurements, is explained. The steady component of tension is found to vary approximately with the logarithm of the stimulus rate in various fast muscles of the frog and dogfish.

The problem of incorporating the results of the present and previous papers in an empirical muscle model is reconsidered.