Comparação da amplitude do agachamento na ativação muscular de membros inferiores

Abstract

Introduction: Although the squat is one of the most common exercises in a strength training program for the lower limbs, there are still controversies regarding muscle activation in different squat amplitudes, especially with equalized loads. Women, when aiming to increase squat amplitude, perform greater knee flexion, which can modify muscle activation during this movement. Objective: To assess whether there is a difference in muscle activity in relation to the amplitude of the squat, in the rectus femoris (RF), vastus lateralis (VL), gluteus maximus (GM) and biceps femoris (BF) muscles in young women. Methods: This was a cross-sectional study, carried out with 35 women with a mean age of 32.9 ± 7.4 years, body mass of 64.5 ± 11.5 kg, height of 1.63 ± 0.1 m, BMI 24.2 ± 2.9 kg/m2, and percentage of fat of 24.9 ± 6.5%. The strength test was performed for 10 maximum repetitions (10RM) for the parallel squat (C1) and deep squat (C2). C1 and C2 were compared through an electromyographic analysis. For statistical analyses, data were presented as mean ± standard deviation and through ANOVA and post hoc Bonferroni. Results: For the RF in the concentric contraction there is no difference between the amplitudes of the squat, p = 0.097 while in the eccentric the value of p = 0.001. The VL showed a difference in muscle activation, in relation to amplitude, both for the concentric and eccentric phases, with values of p = 0.005 and p = 0.006 respectively. For the GM, the concentric and eccentric contractions were different in terms of the squat amplitude, with p = 0.02 and p = 0.022 respectively. And the BF there is no difference in the concentric contraction in relation to the amplitude, p = 0.551, however there is a difference in the eccentric contraction with p = 0.020. Conclusion: The biarticular muscles were not influenced by the squat amplitude during the concentric phase, only during the eccentric phase. While the uniarticular muscles were influenced by the amplitude of the squat in the two phases of the movement, so that the GM was more activated in C1, and for the VL, C2 it influenced a greater activation of the concentric phase, and C1 greater activation of the eccentric phase.