Resumen de Effects of Two Days of Isokinetic Training on Strength and Electromyographic Amplitude in the Agonist and Antagonist Muscles

Travis W. Beck, Terry J. Housh, Glen O. Johnson, Joseph P. Weir, Joel T. Cramer, Jared W. Coburn, Moh H. Malek, Michelle Mielke

• The purpose of this study was to examine the effects of 2 days of isokinetic training of the forearm flexors and extensors on strength and electro- myographic (EMG) amplitude for the agonist and antagonist muscles. Seventeen men (mean +/- SD age = 21.9 +/- 2.8 years) were randomly assigned to 1 of 2 groups: (a) a training group (TRN; n = 8), or (b) a control group (CTL; n = 9). The subjects in the TRN group were tested for maximal isometric and concentric isokinetic (randomly ordered velocities of 60, 180, and 300[degrees][middle dot]s-1) torque of the dominant forearm flexors and extensors before (pretest) and after (posttest) 2 days of isokinetic strength training. Each training session involved 6 sets of 10 maximal concentric isokinetic muscle actions of the forearm flexors and extensors at a velocity of 180[degrees][middle dot]s-1. The subjects in the CTL group were also tested for strength but did not perform any training. Surface EMG signals were detected from the biceps brachii and triceps brachii muscles during the strength testing. The results indicated that there were no significant (p > 0.05) pre- to post- test changes in forearm flexion and extension torque or EMG amplitude for the agonist and antagonist muscles. Thus, unlike previous studies of the quadriceps femoris muscles, these findings for the forearm flexors and extensors suggested that 2 days of isokinetic training may not be sufficient to elicit significant increases in strength. These results may have implications for the number of visits that are required for rehabilitation after injury, surgery, or both