Date of Award

Summer 2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Human Movement Sciences

Committee Director

Hunter J. Bennett

Committee Member

Joshua T. Weinhandl

Committee Member

Laura C. Hill

Committee Member

Patrick B. Wilson

Abstract

Increased hip forces are a proposed factor for osteoarthritis and femoroacetabular impingement. These forces can be estimated through musculoskeletal modeling using measured kinematics and kinetics. An understanding of hip joint loading during landing in a asymptomatic population will begin to elucidate what, if any, sex differences exist and how changes in landing condition alter hip mechanics. The overall purpose of this dissertation was to explore how sex and landing condition effect landing mechanics. Landing mechanics were quantified using ground reaction forces (GRF), hip joint forces (HJF), and lower extremity kinematics during unilateral drop landings from 30-cm, 40-cm, and 50-cm, as well as, a 40-cm land-and-cut task. The relationships between sex and limb side, sex and landing task, and sex and landing height on landing mechanics were assessed using three sub-studies.

Eighty-three, recreationally active, adult volunteers completed landing tasks (40 participants completed the land-and-cut task). For sex-limb side, bilateral differences (right versus left) were examined at 40-cm. No bilateral differences were identified. For sex-landing task, 40-cm drop landings were compared to land-and-cuts. Higher peak GRF (pGRF) and pGRF loading rates were identified for landing-only. Landing-only tasks were performed with less ankle dorsiflexion range of motion for landing (ROML) and impact (ROMI) phases. Landing-only tasks demonstrated more hip adduction ROML and more hip flexion ROMI. For sex-landing height, landings were compared between 30-cm and 50-cm. Increasing landing height resulted in increased pGRF, pHJF, pGRF loading rate, and pHJF loading rate. With increased height, larger 3-D hip and knee flexion ROMI and ROML were identified, as well as increased ankle dorsiflexion ROML.

There were no interaction effects between sex and landing condition. Sex differences across sub-studies demonstrated consistent trends. In all studies, females incurred larger pGRF compared to males, yet only the landing height analysis demonstrated increased pHJF. Females exhibited larger hip adduction and reduced hip rotation ROML. Females exhibited larger hip flexion, hip adduction, and knee flexion ROMI. The landing task analysis identified increased female ankle dorsiflexion ROMI.

Sex differences were identified between landing conditions, yet the lack of sex-landing condition interaction indicates both sexes may utilize similar modifications in response to changing landing conditions.

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DOI

10.25777/n05v-0776

ISBN

9780355409338

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Biomechanics Commons

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