[Effect of stretching of the cat gastrocnemius muscle on its tetany, postcontraction hyperemia and energy metabolism indices]

Abstract

Longitudinal stretch of the muscle in the range E = 0.11-0.17 (111-117% of the initial length) is followed by increase in passive strength and in mechanical displays of the 15-sec isometric Blood flow in the muscle vessels decreases at rest in the longitudinal stretching whereas O2 extraction from the blood increases; O2 consumption and ration of arterio-venous differences in the lactate and pyruvate concentration do not change. Additional posttetanic blood supply in the muscle, posttetanic alteration of the O2 consumption in it and the lactate/pyruvate ratio in longitudinal stretch do not differ from the analogous parameters in the initial--length muscle. The data obtained are in accordance with the metabolic theory of the hyperemia mechanisms but can hardly be explained from the standpoint of the histomechanical theory.