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Vertical stiffness asymmetries during drop jumping are related to ankle stiffness asymmetries
Author(s) -
Maloney S. J.,
Richards J.,
Nixon D. G. D.,
Harvey L. J.,
Fletcher I. M.
Publication year - 2017
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12682
Subject(s) - stiffness , ankle , medicine , asymmetry , jumping , joint stiffness , drop (telecommunication) , jump , orthodontics , materials science , physics , anatomy , composite material , physiology , telecommunications , quantum mechanics , computer science
Asymmetry in vertical stiffness has been associated with increased injury incidence and impaired performance. The determinants of vertical stiffness asymmetry have not been previously investigated. Eighteen healthy men performed three unilateral drop jumps during which vertical stiffness and joint stiffness of the ankle and knee were calculated. Reactive strength index was also determined during the jumps using the ratio of flight time to ground contact time. “Moderate” differences in vertical stiffness ( t 17 = 5.49; P < 0.001), “small” differences in center of mass displacement ( t 17 = −2.19; P = 0.043), and “trivial” differences in ankle stiffness ( t 17 = 2.68; P = 0.016) were observed between stiff and compliant limbs. A model including ankle stiffness and reactive strength index symmetry angles explained 79% of the variance in vertical stiffness asymmetry ( R 2 = 0.79; P < 0.001). None of the symmetry angles were correlated to jump height or reactive strength index. Results suggest that asymmetries in ankle stiffness may play an important role in modulating vertical stiffness asymmetry in recreationally trained men.