Comparação do efeito agudo do alongamento dos músculos posteriores da coxa nas variáveis biomecânicas e na primeira sensação de alongamento em adultos jovens treinados e não-treinados em flexibilidade

Abstract

Comparison of the muscle-tendon unit´s (MTU) stretching protocol response between subjects trained and untrained in flexibility shows distinct relationship. This way, one question is if volunteers trained and untrained in flexibility could show similar response to the same stretching protocol. The aim of the present study is compare the acute effects of flexibility training in biomechanics and first sensation of tightness (FST) responses between volunteers trained and untrained in flexibility in the hamstring muscles. Analysis were done through the following variables: maximal range of motion (ROMMax), value of relative torque to the same ROM pre and post test (torqueROM), value of ROM and torque when the volunteer noted FST (ROMFST and torqueFST respectively). Twenty three sedentary man (21,5 ± 0,60 years) in untrained group (UG) and twenty three dancers (27,5 ± 0,98 years) in trained group (TG) participated in the study. All subjects underwent one familiarization session and then were randomly directed to the experimental and control conditions with rest of 24 to 48 hours. An adapted litter was utilized to analyze the hamstring muscles during a passive knee extension. ROMMax was measured when the researcher perceived significative increase in stretching resistance in hamstring muscle, the value obtained, torqueMax, was used to maintain stretching intensity (constant torque CT). Six sets of 30s of stretch at 100% of torqueMax and an interval of approximately 30s were performed. Data were analyzed as difference between post and pre-test. A two way factorial ANOVA with Tukey post hoc was utilized. Significance level was set at =0,05 and data are presented as mean ± standard error. Both groups showed increase in ROMMax and decrease in torqueROM, however, the increase in ROMMax magnitude was bigger in TG. The sensorial response was different between groups, ROMFST and torqueROM showed opposite response between groups. FSTROM increase in UG but did not change in TG and FSTtorque decreased in TG but did not change in UG. Results showed that increase in ROMMax after training protocol seems to be related with both, biomechanical and sensorial response. ROMMax increase and torqueROM decrease were similar behavior between groups, however FSTROM and FSTtorque were different. The results in this study are in agreement with our expectation that different subjects have different training effects to same stimulus. This way, trained in flexibility population should need different stretching protocol.