title: Effects of a combined inversion and plantarflexion surface on knee and hip kinematics during landing.
abstract: Although landing in a plantarflexion and inversion position is a well-known characteristic of lateral ankle sprains, the associated kinematics of the knee and hip is largely unknown. Therefore, the purpose of this study was to examine the changes in knee and hip kinematics during landings on an altered landing surface of combined plantarflexion and inversion. Participants performed five drop landings from 30 cm onto a trapdoor platform in three different conditions: flat landing surface, 25° inversion, or a combined 25° plantarflexion and 25° inversion. Kinematic data were collected using a seven camera motion capture system. A 2 × 3 (leg × surface) repeated measures ANOVA was used for statistical analysis. The combined surface showed decreased knee and hip flexion range of motion (ROM) and increased knee abduction ROM (p < 0.05). The altered landing surface creates a stiff landing pattern where reductions in sagittal plane motion are transferred to the frontal plane, resulting in increased knee abduction. A stiff landing pattern is frequently related to increased risk of anterior cruciate ligament injury. It may be beneficial for athletes at risk to train for alternate methods of increasing their sagittal plane motion of the knee and hip with active knee or trunk flexion.
authors.affiliation: a Biomechanics/Sports Medicine Lab, Department of Kinesiology, Recreation, and Sports Studies, College of Education, Health, and Human Sciences , University of Tennessee , Knoxville , TN , USA.
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Valenzuela
authors.affiliation: b Department of Physical Medicine and Rehabilitation , University of Minnesota, Twin Cities , Minneapolis , MN , USA.
authors.forename: Divya
authors.initials: D
authors.lastname: Bhaskaran
authors.affiliation: a Biomechanics/Sports Medicine Lab, Department of Kinesiology, Recreation, and Sports Studies, College of Education, Health, and Human Sciences , University of Tennessee , Knoxville , TN , USA.
authors.forename: Cicily
authors.initials: C
authors.lastname: Hummer
authors.affiliation: a Biomechanics/Sports Medicine Lab, Department of Kinesiology, Recreation, and Sports Studies, College of Education, Health, and Human Sciences , University of Tennessee , Knoxville , TN , USA.
authors.forename: Antonio
authors.initials: A
authors.lastname: Schefano
authors.affiliation: a Biomechanics/Sports Medicine Lab, Department of Kinesiology, Recreation, and Sports Studies, College of Education, Health, and Human Sciences , University of Tennessee , Knoxville , TN , USA.
authors.forename: Songning
authors.initials: S
authors.lastname: Zhang
mesh_terms: D016512:Ankle Injuries / Q000503:physiopathology / Q000517:prevention & control; D000070598:Anterior Cruciate Ligament Injuries / Q000503:physiopathology / Q000517:prevention & control; D001696:Biomechanical Phenomena; D005260:Female; D006615:Hip / Q000502:physiology*; D006801:Humans; D007717:Knee / Q000502:physiology*; D008297:Male; D059385:Plyometric Exercise; D011187:Posture / Q000502:physiology; D016059:Range of Motion, Articular; D012307:Risk Factors; D013180:Sprains and Strains / Q000503:physiopathology / Q000517:prevention & control; D013996:Time and Motion Studies; D055815:Young Adult
keywords: Drop landing; ankle sprain; knee abduction