Análise de um protocolo de treinamento resistido baseado na carga ótima de potência e no tempo sob tensão sobre variáveis mecânicas e fadiga no desempenho do salto vertical de indivíduos treinados

Abstract

Resistance training (RT) is widely used to enhance the maximal dynamic power of the lower limbs, which is essential for actions such as vertical jumping that rely on the interaction between force and movement velocity. Although RT prescription has traditionally been based on one-repetition maximum (1RM), the use of optimum power load (OPL) has been proposed, as it may allow for greater power output with reduced neuromuscular fatigue. Furthermore, prescribing RT based on time under tension (TUT) can enable adjustments in the duration of movement phases, potentially providing a more targeted stimulus for the development of muscular strength and power. Objective: To analyze the effects of a RT protocol based on the OPL and TUT on mechanical variables and fatigue in the vertical jump performance of trained individuals. Methods: Two systematic reviews and one experimental study were conducted to understand TUT as a training prescription variable, in association with the OPL method, and its relationship with mechanical variables involved in muscular power output. Results: The behavior of TUT in different RT methods has shown that increased muscular power output is associated with lower TUT and higher movement execution velocity. The effects of RT with OPL on vertical jump performance have demonstrated positive outcomes for neuromuscular power output. However, the effects of RT combining OPL and TUT on vertical jump performance revealed reductions in the results of vertical jump tests (countermovement jump and squat jump) in terms of flight time, height, absolute and relative power (p<0.05). Regarding the mechanical variables, TUT was lower in set 5 (S5) compared to sets 1 (S1), 2 (S2), and 4 (S4) (p = 0.001; p = 0.004; p = 0.044). Velocity was lower in S5 compared to S1, S2, set 3 (S3), and S4 (p<0.001; p = 0.005; p = 0.016; p = 0.048). Power was higher in S1 compared to S4 and S5 (p = 0.035; p = 0.013). Relative power was higher in S1 compared to S5 (p = 0.031). Force was lower in S4 compared to S1, S2, and S3 (p = 0.029; p = 0.030; p = 0.030). Mechanical work was significantly lower in S5 compared to S1, S2, S3, and S4 (p = 0.009; p = 0.001; p = 0.014; p = 0.036). RPE was lower in S1 compared to S2, S3, S4, and S5 (p<0.001 for all comparisons). No significant changes were observed in the number of repetitions or in the acceleration variable. Conclusion: The RT protocol based on OPL and TUT led to reductions in mechanical variables over the course of the 5 sets of 20 seconds each, especially from S4 onwards. These reductions reflected the progressive accumulation of fatigue, evidenced by decreased vertical jump performance and increased subjective perception of effort. Additionally, the average of 19 valid repetitions per set may provide a relevant parameter for prescribing training aimed at muscular power development using OPL in the half-squat exercise