Comparação dos efeitos dos protocolos de progressão da sobrecarga do treinamento de força nos ganhos de força e hipertrofia muscular: um estudo uni-cego, randomizado, controlado intra-sujeito

Abstract

This was a single-blind, randomized, within-subject controlled study that aimed to compare the effects of overload progression protocols by intensity (progINT) and volume (progVOL) on muscle strength and muscle cross-sectional area (MCSA). Thirty-nine volunteers (20 men and 19 women) had their legs randomized to progINT and progVOL. Both training protocols were performed unilaterally on the knee extension machine, 2-3 times per week for 10 weeks. The progINT protocol consisted of using a previously determined maximal repetition zone (i.e., 9 to 12 repetitions), and load was adjusted only when the individual performed more or fewer repetitions than previously stipulated. For the progVOL, load was not altered, but repetitions were increased whenever the moment of concentric muscular failure was prolonged. The primary outcomes (muscle strength and MCSA) were evaluated before and after 23 training sessions. Muscle strength was evaluated through the one-repetition maximum test (1RM) on the knee extension machine, and lateral vastus MCSA was evaluated by ultrasound. To compare the volume load (i.e., sets x repetitions x weight [kg] [VL]) accumulated between the protocols, the sum of the VL of all training sessions was considered. To compare the VL progression between the protocols, the average VL of the first three and last three sessions of the experimental period was considered. Evaluators were blinded to the allocation of legs. A significance level of p < 0.05 was adopted. Both protocols promoted increases in 1RM values from pre (progINT: 52.90 ± 16.32 kg; progVOL: 51.67 ± 15.84 kg) to post (progINT: 69.05 ± 18.55 kg, progVOL: 66.82 ± 17.95 kg), with no difference between them (p > 0.05). Both protocols promoted increases in MCSA values from pre (progINT: 21.34 ± 4.71 cm²; progVOL: 21.08 ± 4.62 cm²) to post (progINT: 23.53 ± 5.41 cm², progVOL: 23.39 ± 5.19 cm²),8 with no difference between them (p > 0.05). There was no difference between protocols in accumulated VL (progINT: 53,703 ± 17,390 vs. progVOL: 52,528 ± 18,283 kg; p = 0.34) or in progression VL (progINT: 882 ± 491 kg vs. progVOL: 1,107 ± 586 kg; p = 0.084). We found no differences between overload progression protocols by intensity and volume in gains of strength and muscle hypertrophy in untrained individuals.