ELECTRICAL STIMULATION OF THE TRICEPS SURAE FOR MUSCULAR STRENGTH IMPROVEMENT IN VOLLEYBALL PLAYERS.

Abstract

INTRODUCTION Beside the studies carried out at "CentrO Scoliosi" of Istituto Ortopedico "Gaetano Pini" about idiopathic scoliosis pathogenesis (Dacquino et al., 1970) and its treatment using the electrical stimulation (Crivellini and Divieti, 1972, 1975; Crivellini et al., 1976, 1979; Divieti, 1979), an experiment was carried out to analyze the muscular strength increase, obtained by means of the same stimulation procedure for the scoliotic patients. The triceps surae muscle was chosen because of its size and accessibility. The electrical stimulation was performed on a group of subjects not involved in any sporting activity by Caiulo et al., 1980b. This study has shown that electrical stimulation increased the maximum spontaneous force (J 1.9%), the jumping index (23.7%) measured with the Abalakov method (Kots and Xvilon, 1971; Kots et al., 1971), and the maximum limb circumference (6%) measured near the belly of the stimulated muscle. Moreover this experience has shown that the stimulation of the whole gastrocnemius muscle, with well tolerable current values, causes not only the contraction of the triceps surae muscle but also the contraction of the posterior tibialis muscle, normally quite difficult to stimulate because it is deeply positioned under the soleus muscle. In this work the force of the triceps surae was transduced by means of a particular experimental device. The force of this muscle is measurable considering the action of the foot during the flexion movement. The same experiment was repeated on a group of athletes of a volleyball team in order to compare the results. It is important to note that the electrical stimulation first recruits the big superficial motor units that are the last activated in maximal voluntary contractions.