Abstract des Autors

The present study was performed on 20 women of the Austrian national ski team and analyzes changes in the myoelectrical activity of thigh muscles at two isokinetic work loads (Cybex 2+). EMG data were recorded from m. vastus medialis, m. vastus lateralis, m. semimenbranosus, and m. biceps femoris with Ag/AgCI electrodes. Test 1 (5 reps 60ø/s): Isokinetic work per repetition decreases whereas iEMG and iEMG/work values increase. Test 2 (25 reps 240ø/s): Isokinetic work shows a linear decrease to 50% (extension) and 70% (flexion). iMG increases continuously up to the fifteenth repetition whereas values stay on a plateau level (levelling off) in the course of the following repetitions (16th-25th rep). The levelling off phenomenon in the iEMG and iEMG/work curve is regarded as the point of maximal neurophysiological activation, i.e. a decrease of torque beyond this point can no longer be compensated by additional recruitment of muscle fibers. Verf.-Referat