Dinamometria de preensão palmar e análise eletromiográfica em teste de 10 repetições máximas para flexão de cotovelo.

Abstract

Muscle fatigue is a limiting factor for both healthy and sick people and exercise can be beneficial. Ten RM tests give indicia of muscle strength and endurance and combining other analysis tools can provide valuable information. Therefore, the aim of this study was to analyze the effects of muscle fatigue on hand grip dynamometry along 30 seconds and on electromyographic activity in maximal voluntary isometric contractions (MVIC) and in dynamic actions along 10RM test for biceps braquialis in trained (TR) and untrained (NT) individuals and in dominant (DO) and non-dominant (ND) limbs. Eighteen young adult men, 9 untrained and 9 experienced in resistance training, participated in the study. The isometric handgrip dynamometry was assessed by grip dynamometer with precision load cell (Model G200, H500 Hand Kit - Biometrics®) in the position recommended by the ASHT. Electromyography (Miotool 400USB and software Miograph/Miotec®) from biceps braquialis isometry was collected in advance and subsequently the 10RM test and also from concentric actions during the test. Windows of 0.75 seconds from the center of the signal were analyzed. Significant difference in hand grip dynamometry between TR and NT was found for MIVC and average initial values for both DO and ND hemisides and also for initial values of endurance for ND. Significant difference between baseline and final values of each group was found only for MIVC in TR-DO and for average values within 30 s in TR-DO and TR-ND. In electromyography, only the TR-DO group showed significant reduction of FM during isometry between the initial and final values. Significant reduction in FM compared to the 1st contraction was observed from the 7th to NT and NT-DO and NT-ND and TR-ND, while the TR-DO was observed from the 6th. Significant increases in MVIC-normalized RMS were found in relation to the 1st contraction from the 3rd to TR-DO, TR-ND and NT-ND, while NT-DO increased significantly from the 2nd.It is concluded that it was possible to observe differences in the hand grip peak force and endurance due to resistance training before and after muscle fatigue, but no differences between hemisides. It was observed that TR can move larger loads and sustain longer the same mechanical performance than NT even in presence of fatigue signs, particularly for DO side. The NT group shows greater recruitment of new motor units before TR, in particular for ND side.