Efeito da superfície instável na ativação eletromiográfica e percepção subjetiva do esforço durante o exercício meio agachamento

Abstract

Unstable platforms (UP) have been widely used in resistance training programs with different objectives, in which the neuromuscular system is believed to be more required than in the stable platform (SP). Thus, the objectives of the study were to verify the electromyographic response of the vastus lateralis (VL), rectus abdominis (RA), external oblique (EO) and spinal erector (SE) muscles in men, during exercise half squatting on a stable and unstable platform, and to identify and compare the Rating of Perceived Exertion (RPE) during UP and SP testing. The sample consisted of 15 trained adult males (25.0 ± 2.7 years, 77.7 ± 6.8 kg, 174.6 ± 7.3 cm, 25.5 ± 1.5 kg / m² and 14, 4 ± 2.6% fat). The experimental protocol consisted of the evaluation of the electromyographic activation of the VL, RA, EO and SE muscles during the half squat exercise in UP with random loads of 50, 60 and 70% of 1-RM and in the UP with loads of 40, 50 and 60 % Of 1-RM, also randomized. After 15 repetitions in each load, the volunteers responded to the OMNI-RES scale and remained at rest for the next load. A minimum of 48 hours between the tests was observed. The Root Mean Square (RMS) of the muscles VL, RA, EO and SE, and RPE were compared between each experimental condition (50% 1-RM, 60% 1-RM and 70% 1-RM in SP, 40% 1-RM and 60% 1-RM in the UP), through the analysis of repeated measurements (ANOVA), using the mixed model technique. The statistical significance was 5%. In case of significance, matched post hoc comparisons were made using the Bonferroni correction. In the post hoc analysis, no significant differences were observed in the electromyographic activation between SP and UP loads. The RPE was higher in the 50% 1-RM UP condition compared to 50% 1-RM in SP (5.2 ± 2.3 vs. 3.8 ± 1.6, p = 0.04, TE = 0, 72) and higher RPE in the condition 60% 1-RM in UP compared to 60% 1RM in SP (6.1 ± 2.1 vs. 4.7 ± 1.8; p = 0.04; TE = 0, 72). The UP produced a similar electromyographic activity in relation to the SP using a lower load and, for loads of 50% and 60% of 1-RM, the RPE was significantly higher in the UP.