title: Lower extremity variability changes with drop-landing height manipulations.
abstract: Landing is a common lower extremity injury mechanism in sport, with potential connections to movement control accessed through variability measures. We investigated intra-subject lower extremity variability changes following drop-landing height manipulations using standard deviation (SD) and coefficient of variation (CV) among lower extremity peak sagittal joint angles and moments. Fourteen healthy participants completed five drop-landing trials from five heights 20%, 60%, 100%, 140% and 180% maximum vertical jump height (MVJH). Peak joint angles and moments increased with greater landing height (p < 0.001), highlighting inter-joint differences (Flexion: Knee > Hip > Ankle, p < 0.001; Extensor Moment: Hip > Knee > Ankle, in excess of 60% MVJH, p < 0.05). Kinematic and kinetic SD increased with variable magnitudes, while CV decreased at greater landing heights (p ≤ 0.016). Decreased relative variability under greater task demands may underscore non-contact injury mechanisms from repetitive loading of identical structures.
authors.affiliation: a School of Kinesiology , University of Michigan , Ann Arbor , MI , USA.
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Nordin
authors.affiliation: b Department of Kinesiology and Nutrition Sciences , University of Nevada , Las Vegas , NV , USA.
authors.forename: Janet S
authors.initials: JS
authors.lastname: Dufek
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000843:Ankle Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D007719:Knee Joint / Q000502:physiology*; D035002:Lower Extremity / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D055815:Young Adult
keywords: Intra-subject; joint angle; joint moment; sagittal