Acurácia de equações generalizadas para estimar a carga relativa no agachamento com pesos livres para homens e mulheres

Abstract

The study aimed to determine the accuracy of the generalized equations for estimating the relative load in the free-weight squat for men and women. Twenty-one men (24.45 ± 4.35 years; 1.77 ± 0.07 meters; 80.26 ± 8.35 kg; practice time: 3.40 ± 3.10 years) and 21 women participated in the study (25.22 ± 3.06 years; 1.64 ± 0.05 meters; 64.27 ± 7.49 kg; time of practice: 3.49 ± 2.32 years). The study was conducted in 2 days, with an interval of ~72h. Familiarization with the squat with free weights exercise occurred on the 1st day and, on the second day, was performed an incremental test in the proposed exercise to assess the 1RM load. The mean propulsive velocity (MPV) was measured during the test using a linear transducer coupled to the bar and a smartphone app. The prediction of 1RM was performed using generalized equations: general (based on the study sample) and proposed by Pareja-Blanco et al., (2020), and based on MPVs relative to ~ 50% and ~ 80% of 1RM. Data were analyzed using descriptive statistics. The load-velocity relationship was tested using linear (L) and polynomial (P) regression. Differences between sex were evaluated through t- test and effect size, and to compare the real 1RM and the predicted values, repeated measures ANOVA and Bonferroni post hoc were used. The level of agreement between the real and predicted 1RM was tested using the intra-class correlation coefficient (ICC) and Bland-Altman. A strong inverse load-velocity relationship was observed for men (L: R2 = 0.9628; EPE = 0.0553 m / s; P: R2 = 0.9630; EPE = 0.0553 m / s) and women (linear: R2 = 0.9327; EPE = 0.0595 m / s; R2 = 0.9328; EPE = 0.0595 m / s). There was no significant difference between the real and predicted 1RM by general equations (related velocity ~50% and ~80% of 1RM), regardless of the regression model used. However, results for the Pareja-Blanco equations underestimated the 1RM of men and women. There was agreement and low bias (<5%) of prediction from the general linear equations, using an MPV relative to ~ 80% of 1RM. The general linear equations predicted from ~80% 1RM velocity added greater accuracy in predicting 1RM in free weights squat for men and women.