title: Increased external hip-rotation strength relates to reduced dynamic knee control in females: paradox or adaptation?
abstract: The purpose of the present study was to examine the relationship between hip muscle strength (abduction and external rotation) and frontal-plane knee control during drop jumping in recreational female athletes. Thirty-three healthy young recreational female athletes were included. Maximal isometric hip abduction and external rotation torque were measured using hand-held dynamometry, and frontal-plane knee control during drop jumping was assessed using three-dimensional motion analysis. Frontal-plane knee control during drop jumping was expressed as the absolute (cm) and relative (cm/cm body height) change in distance between lateral knee markers from foot-ground contact to the time of minimal marker distance during the contact phase of the jump. Greater maximal external hip-rotation torque correlated significantly with greater absolute (r=0.48, P=0.005) and relative (r=0.43, P=0.012) change in knee marker distance during drop jumping. Maximal hip-abduction torque did not correlate with the absolute (r=0.18, P=0.31) or relative (r=0.19, P=0.29) change in knee marker distance during drop jumping. Contrary to our expectations, greater maximal external hip-rotation torque was related to greater change in knee marker distance during drop jumping (reduced frontal-plane knee control) in recreational female athletes.
authors.affiliation: Clinical Research Centre (Section 136), Copenhagen University Hospital at Hvidovre, Copenhagen, Denmark. thomas.bandholm@hvh.regionh.dk
authors.forename: T
authors.initials: T
authors.lastname: Bandholm
authors.forename: K
authors.initials: K
authors.lastname: Thorborg
authors.forename: E
authors.initials: E
authors.lastname: Andersson
authors.forename: T
authors.initials: T
authors.lastname: Larsen
authors.forename: M
authors.initials: M
authors.lastname: Toftdahl
authors.forename: J
authors.initials: J
authors.lastname: Bencke
authors.forename: P
authors.initials: P
authors.lastname: Hölmich
mesh_terms: D000222:Adaptation, Physiological; D056352:Athletes; D001696:Biomechanical Phenomena; D003718:Denmark; D005260:Female; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D012399:Rotation; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult