Dois diferentes protocolos de pré-condicionamento isquêmico para membros inferiores e suas respostas no desempenho do exercício resistido

Abstract

The ischemic preconditioning (IPC) is characterized by a restrictive maneuver of blood flow in the limb for short periods of time, followed by consecutive reperfusion. Of simple and practical application, this technique has aroused interest in the sporting context, considered as a possible modern ergogenic strategy applicable at the moment before the beginning of the exercise. Currently, its results are still controversial, with a lack of conformity on several methodological issues and evidence of induction of placebo effect on subjects. Tested under predominantly aerobic and anaerobic conditions, little has been known about its effects on resistance exercise (RE) being dominant cycling and running in this direction. In this sense, the present study had aim to evaluate the effect of two different IPC protocols on performance of resistance exercise in recreationally trained adults. The sample consisted of 30 men with at least one year of experience with RE and involved in regular training at least three days a week. For this study two different experimental protocols were carried out with the purpose of evaluating: 1) the effects of a 5-day IPC application, and 2) the effect of an acute simultaneous application of IPC and SHAM. For both protocols were performed, 1RM test and retest, isometric test and 3 maximal sets of unilateral leg extension after 3 cycles of blood occlusion and reperfusion (IPC, SHAM or Control, when appropriate). Were also evaluated, fatigue index, total load and subjective scales. The IPC session consisted of 3 cycles of 5 minutes of occlusion at 50 mmHg above systolic blood pressure alternated with 5 minutes of reperfusion at 0 mmHg of pressure. The SHAM session consisted of 3 cycles of 5 minutes cuff administration at 20 mmHg of pressure alternated with 5 minutes of reperfusion at 0 mmHg. Both experimental conditions totaled 30 minutes of intervention. For Control, no cuff was used, with the volunteers remaining in the supine position passively for 30 minutes. The results showed that the number of repetitions increased significantly for the IPC (approximately between 5 and 8 repetitions) and SHAM (approximately between 7 and 8 repetitions) conditions, when compared to their baseline condition. Similarly, the total load increased significantly only for the IPC (p=0.0274) and SHAM (p=0.0052) conditions for the delta of the first day of evaluations. Lastly, both isometric force and fatigue index were similar for the experimental conditions. In conclusion, according to the results of the present study, the application of IPC does not promote ergogenic effects that surpass the SHAM on RE in moderately trained individuals.