Effects of diverting activity on strength, electromyographic, and mechanomyographic signals

The purpose of this study was to investigate the effects of different recovery interventions on peak torque, electromyographic (EMG), and mechanomyographic (MMG) measures. Ten (23.40 ± 1.00 years; 178.40 ± 5.03 cm; 84.80 ± 15.85 kg) recreationally trained college men performed 4 experimental visits consisting of 2 bouts of 50 maximal isokinetic leg extensions at 180°·s(-1). Between each bout of maximal exercise, 2 minutes of recovery involving one of the 4 interventions (passive, active, passive diverting, and active diverting) was completed. Electromyographic and MMG measures were collected during the preintervention and postintervention maximal isokinetic strength tests. Peak torque declined to a significantly greater degree during the postintervention test in the passive condition than the other interventions. Electromyographic amplitude decreased on the postintervention test but did not differ between conditions. There was a significant 2-way interaction for EMG mean power frequency (MPF) between time and repetitions. There was a significant decrease in EMG MPF from the first 3 to the last 3 repetitions for both the preintervention and postintervention tests. The decrease in EMG MPF from the initial to final repetitions was greater for the preintervention test than the postintervention test. Mechanomyographic amplitude significantly decreased from the initial to final repetitions regardless of time or condition. These findings suggest that active, passive diverting, and active diverting strategies provide the same extent of recovery between maximal, fatiguing isokinetic leg extension tasks, and that these strategies can be used by coaches and exercise professionals to select the most effective interset recovery strategy.