Morphological aspects of the quadriceps and their relationship with torque and power parameters in male soccer players at the beginning of the season

The aim of this study was to evaluate the relationship between the morphological characteristics of the quadriceps and torque parameters and anaerobic fitness in soccer players at the beginning of the season. Forty-eight (26.2 ± 3.6 years, 181±6 cm and 77.3 ± 7.9 kg) male soccer players participated in this study. The following morphological parameters of the quadriceps were evaluated using 2D ultrasound: pennation angle (PA_VL); muscle thickness (MT_VL); fascicle length (FL_VL); Echo-intensity (EI_VL) of Vastus Lateralis; Echo-intensity of Rectus Femoris (EI_RF); and muscular volume of quadriceps (MVQ). The torque parameters were: peak concentric torque (PTCon) and work (WConc) and peak eccentric torque (PTEcc) and work (WExc) of knee extensors. The anaerobic fitness parameters were obtained through a 30-s test of maximum continuous jumps (CJ30s). The following were evaluated: anaerobic power (PPO), anaerobic capacity ( Av _P), and fatigue index (FI). Only the MVQ presented a positive and significant relationship with all torque variables (PTConc p = 0.003; WConc p = 0.013; PTEcc p < 0.001; and WEcc p = 0.004). Furthermore, FL_VL and PA_VL were positively and significantly associated with PPO ( p = 0.003 and 0.030; respectively) and Av _P ( p = 0.002 and 0.011, respectively). It is concluded that MVQ is positively related to torque and concentric and eccentric work in knee extension. Furthermore, FL_VL and PA_VL showed positive relationships with PPO and Av _P during CJ30s.