"Efeitos do Pré-Condicionamento Isquêmico (PCI) Sobre composição corporal, variáveis neuromusculares e bioquímicas em atletas paralímpicos em período de destreinamento"

Abstract

Introduction: Studies have indicated that imposing ischemia on skeletal muscles before or during exercise induces acute and chronic adaptations that enhance physical performance. Ischemic preconditioning (IPC) is one of the ways to impose this ischemia, alternating complete vascular occlusion and reperfusion before exercise, in order to precondition varied physiological functions. In the sports context, there are times when athletes interrupt their physical activities, with a consequent reduction in strength and muscle mass. Therefore, the hypothesis arises that the IPC cold reduces these effects of detraining, accelerating the process of the athlete returning to their sports activities. Objective: To evaluate the effects of IPC on neuromuscular (strength, trophism, and EMG) and biochemical (CK, MDA, and TAC) variables in Paralympic athletes undergoing periods of discontinuity in training loads. Materials and Methods: The sample consisted of 19 young adult athletes (29.4±7.9 years of age, 1.7±0.1 m, 79.4±14.2 kg and BMI of 27.0±5.2 kg/m2), of both sexes, who compete in competitions at national level and international level, in their modalities, being randomly divided into 2 groups: IPC group (IPCG group: n = 9) and control (CG: n = 10). The IPCG spent two weeks of IPC twice a day (20 sessions) and both groups were evaluated pre and post intervention regarding: body composition, knee flexor and extensor strength, explosive strength (vertical jump), EMG and biochemical markers (CK, MDA and CT scan). Data were analyzed using the Statistical Package for the Social Science (SPSS – 20.0). Initially, normality (Shapiro-Wilk test) and homogeneity of variances (Levene's test) were checked, followed by the t Student (paired) or Wilcoxon tests to analyze the pre- and post-intervention effects and the Student t tests (independent) or Mann-Whitney for intergroup analysis, adopting a significance level of P ≤ 0.05 in all analyses. Results: There was a decrease in total fat mass (MGT) in IPGC in body composition (fat mass and lean mass), pre versus postintervention. In the explosive strength of the lower limbs, significant increases (P<0.05) were observed in the extension movement of the left knee in both groups. For electromyographic variables, when comparing pre and post, an increase in the amplitude of the EMG signal was observed in the left hamstring muscles in both groups, in addition to a decrease in EMG activity in the right quadriceps muscle, in the control group. The correlations were moderate to weak (knees versus explosive strength of the lower limbs) and knee extensor and flexor strength versus EMG. In the analysis, pre versus post intervention, no significant differences were observed (P>0.05), both in the experimental group and in the control group, in any of the biochemical variables analyzed (CK, MDA, TAC). Conclusion: In general, the ICP protocol used had no effect on the detraining period, assessed by explosive strength (vertical jump), isometric strength and electromyographic (EMG) signal of knee extensors and flexors, in Paralympic athletes.