Date of Award

2016

Degree Type

Thesis

Degree Name

M.H.K.

Department

Kinesiology

First Advisor

Cort, Joel

Second Advisor

Potvin, Jim

Keywords

Exercise Biomechanics, Fatigue, Knee, Maximal Jumping, Sport Performance

Rights

CC BY-NC-ND 4.0

Abstract

The purpose of the current study was to understand the effects of progressive muscle fatigue on the mechanical behavior of the knee joint throughout maximal double leg vertical jumping. A biomechanical methodology was utilized to examine 28 recreational athletes (14 male, 14 female) who completed continuous maximal vertical jumps in 5 s intervals (12 jumps/min) until fatigue. 3D motion capture was utilized to measure the changing kinematics of the participants trunk, hip, knee and ankle joint during jump landing. Two parallel force plates were utilized to record the ground reaction forces of the participants at jump landing. Finally electromyography was also employed to provide data from the muscular activity of 8 muscles on the participants’ dominant leg. Repeated measures ANOVA (p<0.05) with Tukey’s significant post hoc test were used on any significant main effect of time to fatigue, or interactions between time and sex. Analysis of the kinematic data revealed that as fatigue progresses, knee and ankle joint angle during jump landing significantly decreases in both males and females. Analysis of kinetic data revealed that peak landing impact force, normalized to body mass, significantly increases as participants’ fatigue, even though a significant decrease in jump height is observed. Finally, electromyography data showed that as fatigue progressed throughout the trial, activation actually decreased in both the pre-takeoff and pre-landing phases of the jump for both males and females. This work has helped to fill the current gap in understanding knee joint mechanics associated with progressive muscle fatigue, as well as changes in normalized landing force as fatigue progresses.

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