[Efeitos do pré-condicionamento isquêmico na força e no desempenho intermitente]

Abstract

In sports competitions, enhancement in the smallest details may cause a significant difference in the final performance. Thus, sports scientists and coaches are always seeking for lawful competition-day interventions that may improve performance. In this context, a maneuver called ischemic preconditioning (IPC) has emerged. The IPC consists in repeated bouts of muscular ischemia followed by reperfusion performed on the proximal limbs (i.e., arms or thigh) before an exercise event. Despite several studies testing the IPC-induced effects on exercise performance in different types of exercise, the beneficial effects of IPC are still debatable. Even meta-analyses show heterogeneous conclusions, showing that more studies are necessary. Therefore, the aim of our study was to evaluate the effect of IPC on: a) high-intensity intermittent exercise and (b) maximal strength. In the first study fifteen players (15.5 ± 0.5 yrs) attended four trials separated by seven days in a counterbalanced randomized cross-over design: IPC (4 × 5-min occlusion 220 mmHg/reperfusion 0 mmHg) in each thigh; SHAM (similar to the IPC protocol but "occlusion" at 20 mmHg); IPC-A and SHAM-A similar to the IPC and SHAM, but with a moderate aerobic activity (70% of HRmáx) on reperfusion phases. After 6-min of each trial, the players performed the YoYo Intermittent Endurance Test level 1 (YoYoIE1). In the second study, fifteen recreational weight-lifters participated in a randomized cross over design, involving two sessions (IPC and SHAM), consisted of three cycles of 5 minutes of occlusion at 170 mm Hg of pressure (IPC) or 20 mmHg (SHAM), alternated by 5 minutes of reperfusion at 0 mm Hg. Ten minutes after, participants performed an 1-RM test on bench press. Our data didn’t found any effect of IPC on intermittent exercise and a slightly increase (~2.4%) on maximal strength, suggesting that IPC can possibly be an ergogenic aid for strength athletes.