Lower Limb Coordination and Stiffness During Landing from Volleyball Block Jumps

Abstract

Abstract.The aim of the study was to investigate lower limb coordination and stiffness in five male and five female university volleyball players performing block jump landings. Coordination was assessed using angle -angle plots of the hip -knee, knee -ankle and hip -ankle joint couplings and discrete relative phase (DRP) of right -left joint couplings (i.e. left knee coupled with right knee). Leg stiffness was calculated as the ratio of the change in vertical ground reaction force (GRF) to the change in vertical displacement of the centre of gravity between ground contact and maximum vertical GRF. Knee stiffness was calculated as the ratio of the change in knee joint moment to the change in knee flexion angular displacement between ground contact and maximum knee joint moment. Comparison of the DRP angles between left and right legs indicated reduced symmetry between the left and right legs in females compared to males which may indicate greater likelihood of ligament strain in females compared to males. Furthermore, females exhibited reduced stability in the coordination between the left and right knee joints than males. Males exhibited significantly greater absolute and normalised leg stiffness and significantly greater absolute and normalised knee joint stiffness during landing compared to females. In conjunction with the coordination data, this may indicate reduced dynamic stability of the leg in females compared to males which may contribute to the greater incidence of ACL injury in females compared to males.

Lower Extremity Kinematics and Kinetics When Landing From Unloaded and Loaded Jumps

“…In a previous volleyball block jump task, leg stiffness during landing from a volleyball block jump was reported as 15.02 kN/m (Hughes & Watkins, 2008), which is similar to the values observed in the current study (13.62 kN/m). These similarities in leg stiffness values may be due to the similar task involved.…”

“…Dynamic stability of the leg is determined by the coordination between the ankle, knee, and hip joints during landing and is reflected in the stiffness of the leg (Hughes & Watkins, 2008). In a previous volleyball block jump task, leg stiffness during landing from a volleyball block jump was reported as 15.02 kN/m (Hughes & Watkins, 2008), which is similar to the values observed in the current study (13.62 kN/m).…”

“…In this investigation, we have reported only sagittal plane kinetics; however, frontal plane moments have been implicated with increased injury risk (Hughes & Watkins, 2008) and further research should investigate frontal plane moments for the lower extremity joints during unloaded and loaded jump landings. Nevertheless, outcomes from this study will assist sports scientists by providing an objective measure for prescribing loaded block jump training as a modality to improve jumping performance.…”

“…Leg stiffness provides an indication of the dynamic stability and may reveal whether landing with increased load alters the dynamic stability of the leg (Granata, Padua, & Wilson, 2002). Leg stiffness (k leg ) was calculated as the ratio of the change in vGRF to the change in vertical displacement of the CG between IC and the maximum vGRF (∆z) (Hughes & Watkins, 2008):…”

Sex differences in lower extremity stiffness and kinematics alterations during double-legged drop landings with changes in drop height

“…Nevertheless, research concerning the alteration of stiffness that also includes both sexes during landing is limited. Granata, Padua, and Wilson (2002) and Hughes and Watkins (2008) found that females have less stiffness than males during hopping and volleyball block jumps, which may be associated with the greater risk of ACL injury in females.…”