Comparação dos efeitos da vibração de corpo inteiro e vibração localizada sobre o desempenho nos testes de IRM e CVM

Abstract

Several studies indicate that the application of mechanical vibrations may contribute to the increase of the maximum muscle strength. The objective of this study was to investigate the acute effect of the application of whole body vibration and localized vibration on the performance in the 1RM tests and MVC. The sample consisted of 15 male volunteers with a mean age of 25.6 + 3.96 years. All volunteers were inserted regularly in a strength training program for upper limbs for at least six consecutive months. All volunteers attend at least seven sessions, with a familiarization session and six test sessions. Each of the conditions (without vibration (WV) with whole body vibration (WBV) and localized vibration (LV)) was carried out in two subsequent sessions separated by an interval of 48 hours. The order of conditions in the test sessions was randomized from the Latin Squares procedure. In familiarization the volunteers performed a series of exercise of elbow flexion without the application of vibration, to estimate the value of 1RM. After a five minute break volunteers were submitted to a set of two repetitions with 95% of the estimated 1RM in each of the three conditions, on three minute intervals between sets. In the test sessions the volunteers initially performed the MVC test for normalization of electromyography data (MVCn), composed of three sets of six seconds and five minutes rest between sets. After a 10 minute interval was performed 1RM test in a study of the conditions, composed of a maximum of five attempts, with five minutes apart. At the end of the 1RM test, an interval of 30 minutes, was the CVM test conducted in one of the study conditions (WV, WBV or LV), for checking the mechanical vibration effect on the electromyography activity and the peak maximum strength during MVC. A range of at least 120 hours sessions between pairs of the same experimental condition was observed. The normalized EMGrms the biceps and brachioradialis during the 1RM tests and MVC was significantly higher (p <0.05) in LV condition in relation to the WBV and WV conditions, having the WBV condition presented significantly higher values (p < 0.05) compared to the WV condition. The weight shifted in the 1RM test in LV condition was significantly higher (p <0.05) compared to the WV condition. There was no difference between the conditions and WV, WBV and WBV and LV. The force values found in MVC test in LV condition were significantly higher compared to WV and WBV conditions, having the WBV condition presented significantly higher strength values compared to WV condition. Therefore, the application of LV affect performance in the 1RM test and CVM, while applying WBV only affect performance in MVC test.