Harris, C., Dolny, D., Browder, K., Adams, K. J., & DeBeliso, M. (2004). The effect of prior contractile activity on power output. Medicine and Science in Sports and Exercise, 36(5), Supplement abstract 2379.

This study attempted to determine if power output could be enhanced from previous contractile activity and the time course of the possible power enhancement effect. Physically active males (N = 9) performed a 3 RM leg press movement on an Omnikinetic dynamometer (OMK). On the next four laboratory visits, power output tests were conducted using a load of 53% of measured 3 RM. Average and peak power were determined via five repetitions (each leg) of bilateral recumbent stepping on the OMK. Of the four power output testing sessions, one was done with no prior contractile activity (session 1). In sessions 2-4, the power test was performed as described for session 1, however, prior contractile activity consisting of three sets of five reps (each leg) of stepping on the dynamometer at intensities and order of 80%, 27%, and 53% of 3 RM were employed. Ss were instructed to step as fast as possible in the no prior contractile activity and prior contractile activity sets. In session 2, the power output test was performed 5, 10, and 15 minutes after the prior contractile sets. In session 3, power tests were performed 10 minutes after the prior contractile sets, and in session 4, power tests were performed 15 minutes after the prior contractile sets. The order of sessions 1-4 was randomized and at least 24 hours was provided between testing sessions.

No significant increase in either average or peak power following the prior contractile sets was observed.

Implication. Prior contractile activity ranging from 27% to 80% of 3 RM had no effect of increasing subsequent power output at 53% of 3 RM at 5,10 and 15 minutes following the contractile activity.

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