Neuromuscular differences between endurance-trained, power-trained, and sedentary subjects.

This study tested the hypothesis that neuromuscular characteristics of plantar flexor (PF) and knee extensor (KE) muscles explain differences of both performance in vertical jump and maximal voluntary isometric contraction (MVC) between endurance-trained (END, n = 9), power-trained (POW, n = 8), and sedentary subjects (SED, n = 8). Evoked twitch characteristics of PF and KE were measured. MVC, maximal voluntary activation (%VA) of KE, and performance in vertical jump were also measured. POW have higher maximal rate of twitch force development (MRFD) than SED and END for both PF (p < 0.05) and KE (p < 0.01); %VA and MVC were higher for POW and END than SED (p < 0.01). Higher performances were measured in vertical jump for POW compared with END and SED. Significant relationships were found between the squat jump performance and MRFD for both KE and PF (R = 0.71, p < 0.0001 and R = 0.55, p < 0.01, respectively). These findings show that low MRFD on lower limbs extensors does not limit expression of MVC on subjects with high levels of activation, whereas intrinsic muscular qualities have a direct influence on performance during the vertical jump.