Efeitos de Diferentes Protocolos de Aquecimento na Performance Motora e na Função Neuromuscular

Abstract

Post-activation potentiation (PAP) can be defined as an increase in muscle performance after a conditioned contraction (CC) (Xenofondos et al., 2010) and can be observed after muscle contractions induced by electrical stimulus or on a voluntary basis (Jubeau et al., 2010). The mechanisms responsible for PAP are phosphorylation of myosin light chains (Sale, 2002), increased excitability of a-motoneurons (Aagaard, 2003) and changes in the angle of penation (Tillin & Bishop, 2009). PAP is influenced by the individual characteristics of the subjects, the characteristics of the conditioned contraction and the recovery interval between CC and the subsequent exercise (Tillin & Bishop, 2009). The objective of this study was to analyze the effects of four different warm-up protocols on the occurrence of PAP in 6 trained male athletes, comparing the athlete's performance in countermovement jump (CMJ) and the variations of Hoffman's reflex (H-reflex) and the motor response wave (M-wave) of greater amplitude (M-Max) before and after the respective warm-up protocol. The warm-up protocols consisted of: Protocol 1 - performing 2 sets of 3 half squat (½ Ag) with 91% of a maximum repetition (1RM) with 4 minutes interval; Protocol 2 - performing 2 sets of 3 repetitions of ½ Ag with 91% of 1RM with 8 minutes interval; Protocol 3 - performing 4 sets of 5 drop jumps with 4 minutes interval; Protocol 4 - performing 4 sets of 5 drop jumps with 8 minutes interval. The recovery time after CC (warm-up protocol 1, 2, 3 or 4) was 8 minutes. In the analysis of the results no statistically significant differences were found in the three variables analyzed: height of CMJ, normalized H-reflex and amplitude of M-Max. Thus, it was not possible to conclude whether protocols of a plyometric nature induce improvements in motor performance similar, superior or inferior to protocols based on squatting exercise. Neither in what way the neural changes can contribute to the performance changes observed after application of the different protocols. These results can be justified by the small sample size, the athletes' performance changes induced by the confinement imposed by the SARS-CoV-2 pandemic and the high interindividual variability in the response to PAP.