Impact Of Limb And Total Body Composition On Drop Vertical Jump Landing Kinematics

Abstract

Lower limbs containing elevated levels of adipose tissue exhibit diminished quadricep strength and power. Deficits in quadriceps function negatively influence sagittal knee mechanics during drop vertical jumping (DVJ) maneuvers. It is poorly understood how measures of limb and systemic composition impact landing performance and injury risk. PURPOSE: Determine the relationship between composition and sagittal knee kinematics during landing from a DVJ. METHODS: Thirty-six female (171.0 ± 7.6 cm; 66.5 ± 7.6 kg; 22.7 ± 1.8BMI) collegiate volleyball and soccer athletes participated in this study. Biomechanical variables of interest include sagittal knee angle (KA) obtained at two different points during landing using 3-dimensional marker-less motion capture during DVJ maneuvers. These two points were initial contact (IC) and the ending of the landing phase, defined where the center of gravity was at its lowest point (MIN). Higher negative sagittal angle values are indicative of greater knee flexion. Dual x-ray absorptiometry (DXA) was used to compute total body fat percentage (BF%) and bilateral limb lean mass (LLM). LLM was normalized to the total mass of the limb. Associations between landing biomechanics and compositional measures were analyzed via Pearson Product Moment correlations. RESULTS: KA at MIN in the left (-92.8 ± 8.9°) and right leg (-92.4 ± 9.5°) were associated with BF% (27.5 ± 4.3%) (Right: r = 0.430, p = 0.009; Left: r = 0.432, p = 0.008) and LLM (Right: 64.3 ± 4.3% limb mass; Left: 64.0 ± 4.6% limb mass) (Right: r = -0.416, p = 0.012; Left: r = -0.410, p = 0.013). At IC, right leg (-23.7 ± 8.4°) KA had a weak relationship to BF% (r = 0.390, p = 0.019) and LLM (r = -0.364, p = 0.029). Relationships between KA at IC in the left leg (-26.5 ± 8.3°) and BF% (r = 0.289, p = 0.088) and LLM (r = -0.311, p = 0.065) were not significant. CONCLUSIONS: The relationship between BF% and LLM and sagittal KA during DVJ landing indicate that greater LLM and lower BF% may be better for injury risk and performance. Lesser knee flexion range of motion during landing may be caused by inhibited capacity to attenuate landing forces during sport performance. Greater adipose tissue within the limb and systemically may negatively influence injury risk by reducing the ability to adequately absorb forces when landing during an athletic task.