Defense Date

9-4-2009

Graduation Date

Fall 2009

Availability

Immediate Access

Submission Type

dissertation

Degree Name

PhD

Department

Rehabilitation Science

School

Rangos School of Health Sciences

Committee Chair

Christopher Carcia

Committee Member

Amy Phelps

Committee Member

RobRoy Martin

Committee Member

Anne Burrows

Keywords

ACL injury, female athlete, heel height, knee kinematics

Abstract

The purpose of this study was to determine if varying heel lift heights added to athletic shoe wear would alter sagittal plane knee kinematics when landing from jumping maneuvers. The hypothesis was that increased heel height would increase knee flexion at initial contact (KAIC), increase the peak knee flexion angle (KAPeak), and slow the rate of knee excursion (RKE). Fifty recreationally active, college-age females participated. Subjects performed two single-limb landing tasks: a forward hop and a jump-landing maneuver. Each participant performed five repetitions of each jump while wearing three different heel lifts placed on the under-side of a standardized athletic shoe: 0mm, 12mm, or 24mm lift heights. Dependent measures were KAIC, KAPeak, and RKE. Knee angle was measured using an electrogoniometer synchronized with a floor-mounted force plate. Raw data were acquired and filtered with a software acquisition and analysis system. Separate repeated measures ANOVAs were utilized to determine the influence of heel height on the dependent measures. Post hoc paired t-tests were performed when appropriate. All differences were considered to be statistically significant if p < 0.05; p < 0.017 with Bonferroni correction.

Forward hop task: Significant main effects were found for KAIC (p < .001), KAPeak (p=.014), and RKE (p=.019). KAIC increased from the 0mm lift condition to the 24mm lift(p < .001), but not the 12mm lift (p=.423). An increase was also noted between the 12mm and 24mm lift conditions (p=.003). KAPeak increased from the 0mm lift condition to the 24mm lift (p=.004), but not to the 12mm lift (p=.282). The RKE did not change from the 0mm to the 12 or 24mm lift conditions (p=.351 and p=.086, respectively). However, there was a significant increase from the 12mm to the 24mm lift (p=.004). Jump-landing task: The data demonstrated no significant changes in KAIC (p=.531), KAPeak (p=.741), or the RKE (p=.190) from 0mm to either the 12mm or 24mm heel lift conditions. The addition of a 24 mm heel lift to an athletic shoe significantly alters KAIC, KAPeak, and RKE as compared to baseline measures when performing a forward hop maneuver. However, a 12 mm lift did not alter these sagittal plane knee kinematics. There is no change noted from baseline when performing a jump landing maneuver with either a 12mm or 24mm lift.

Format

PDF

Language

English

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