Exercise Intermittent Isometric Handgrip Associated With Different Levels of External Vascular Compression: Acute Effects on Neuromuscular Response

Isometric handgrip exercises are used to explain the effects of fatigue on the strength and activation of the muscles involved. Blood flow available at the time of exercise can influence this fatigue process, as some studies demonstrate changes in the pattern of muscle recruitment and strength recovery when the exercise is performed in combination with an external total obstruction (through a pressure cuff or tourniquet ) blood flow. Low intensity exercises associated with external partial obstruction of blood flow has been widely used and studied, mainly due to its effect on increasing strength and muscle hypertrophy, often comparable to those observed in conventional exercises (ie, without external obstruction of blood flow) High intensity. Despite the vast literature on this method, some topics need to be better informed about the underlying neuromuscular physiology to such effects (strength and hypertrophy) and the process of fatigue during isometric exercises associated with partial obstruction of blood flow. The aim of this study is to evaluate the acute effects on neuromuscular response in healthy adults undergoing an intermittent isometric exercise protocol with different levels of external compression. In a study of the "crossover" male volunteers will be submitted to three intermittent isometric exercise protocols (with a load of 45% of maximum voluntary isometric strength) associated with three different levels of obstruction (held by a pressure cuff) blood flow (total obstruction, partial obstruction and free blood flow). The protocols will be performed on three different days (with a minimum of 48 hours between them). Will be considered as acute neuromuscular responses spending time to failure in the task, the electromyographic activity of the flexor muscles of the wrist and fingers, and the recovery curve of maximum voluntary isometric strength after exercise. The main hypothesis of this study is that exercise is performed when associated with partial obstruction of blood flow, the time spent until the failed job is similar to that seen when exercise is performed with free blood flow, and the recovery of strength and electromyographic activity will be similar to that observed in the exercise associated with total obstruction of blood flow.