Effects of maximal power and the force-velocity profile on sprint acceleration performance according to maturity status and sex.

Abstract

This study aimed to determine whether maturational and sex-related differences in sprint times were accompanied by changes in relative maximal power (P_max), force-velocity profiles (S_FV) and optimal sprint distances (x_opt). Sprint times and continuous velocity-time data were collected using a radar. Inverse dynamics applied to the centre of mass provided accurate estimations of force-velocity relationship parameters (P_max, F₀, v₀, S_FV, x_opt) and technical variables (RF_max, D_RF). Somatic maturity was determined from peak height velocity (PHV). Performance increased with maturation in girls and boys (p < 0.001, d = 0.86‒2.78) accompanied by increases in relative P_max from pre to post-PHV (p < 0.011‒0.001, d = 0.98‒5.20). Increases in relative P_max were predominantly due to more velocity-oriented profiles (p < 0.007‒0.001, d = 0.76‒1.41). x_opt, RF_max and D_RF also increased with maturation (p < 0.030‒0.001, d = 0.87‒3.40). P_max increases in girls and boys throughout maturation enabling them to reduce sprint times. Both girls and boys increased P_max through a shift to more velocity-oriented profiles. However, plateaus in F₀ and RF_max were present from pre-PHV in girls, while boys had slower development from mid-PHV. Improving P_max through increases in F₀ and RF_max, while maintaining a velocity-oriented profile, will likely benefit youth sprint performance. A specific focus on these parameters is necessary from pre-PHV onwards in girls and from mid-PHV in boys.