Abstract des Autors

To investigate training-induced changes in neuromuscular performance under voluntary and reflex contractions, 11 male subjects went through heavy resistance (high loads of 70-120 of one maximum repetition) and 10 male subjects through explosive type (low loads with high contraction velocities) strength training three times a week for 24 weeks. A large increase (13.9) in voluntary unilateral maximal knee extension strength with only slight and insignificant changes in time of isometric force production were observed during heavy resistance strength training. Explosive type strength training resulted in a small insignificant increase in maximal strength but in considerable shortening in the time of force production. A significant increase noted in the averaged maximal integrated electromyogram (IEMG) of the knee extensors during heavy resistance strength training correlated with the increase in maximal strength. No changes were noted during training in reflex time components, but significant decreases occurred in the peak-to-peak amplitudes of the reflex electromyograms (EMG) in both groups. The individual changes during training in the reflex EMG/force ratio were related to the respective changes in IEMG/force ratio in voluntary contraction. The present observations support the concept of specificity of training, and suggest that specific training-induced adaptations in the neuromuscular system may be responsible for these changes in performance.