Cochrane, K. C., Coburn, J. W., Brown, L. E., & Judelson, D. A. (2013). Effects of diverting activity on strength, electromyographic and mechanomyographic signals. Medicine & Science in Sports & Exercise, 45(5), Supplement abstract number 618.

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This study investigated the effects of different recovery interventions (passive, active, passive and diverting, active and diverting) on peak torque, electromyographic (EMG) activity, and mechanomyographic (MMG) measures. Recreationally trained college men (N = 10) performed four experimental recovery activities. Each experimental session consisted of two bouts of 50 maximal isokinetic leg extensions at 180/sec with the dominant leg. Between each bout of maximal exercise, two minutes of recovery involving one of the four interventions was completed. Passive recovery involved no movement of the involved limb with each S seated quietly in a chair. Active recovery involved unloaded leg extensions of the involved limb, passive diverting activity involved squeezing a 2-inch sponge while otherwise sitting quietly in a chair, and active diverting combined unloaded leg extensions with cadenced sponge squeezes. EMG and MMG measures were collected during pre-intervention and post-intervention maximal isokinetic strength tests.

Peak torque declined to a significantly greater degree during the post-intervention test in the passive condition than in the active, passive diverting, and active diverting conditions. EMG amplitude decreased on the post-intervention test, but did not differ between conditions. There was a significant two-way interaction for EMG mean power frequency between time and repetitions. There was a significant decrease in EMG mean power frequency from the first three to the last three repetitions for both the pre-intervention and post-intervention tests. The decrease in EMG mean power frequency from the initial to final repetitions was greater for the pre-intervention test than the post-intervention test. MMG amplitude significantly decreased from the initial to final repetitions regardless of time or condition.

Implication. Active, passive diverting and active diverting recovery strategies provide the same extent of recovery between maximal, fatiguing isokinetic leg extension tasks.

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