Abstract

Twelve experienced male weight lifters of varying ability completed two bench press lifts at 95 of maximum. These lifts were a rebound bench press and a bench press performed without prior stretch. Force, electromyographic (EMG) and cinematographic data were collected during each lift. A significantly greater level of muscular activity was recorded from the deltoid and triceps brachii muscle groups during the concentric phase of the rebound bench press lift as compared to the non-rebound lift. However, the level of muscular activity recorded from the pectoralis muscle group was similar between movement conditions and for all muscle groups monitored neither the concentric nor the eccentric EMG were related to the performance augmentation derived from prior stretch. Further the stretching stimulus did not alter the firing characteristics of motor units, as quantified by the median frequency of the Fourier transformed power spectrum. Based on the above results and recent observations of strong relationships between mechanical variables and prior stretch performance augmentation it is suggested that the benefits associated with the performance of maximal stretch shorten cycle movements by experienced subjects are primarily sustained through the utilisation of elastic strain energy and that the neuromuscular contribution is of minor significance. Verf.-Referat