Date of Award

2011

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology and Physical Education

Advisor

Robert A. Lehnhard

Second Committee Member

Stephen Butterfield

Third Committee Member

Craig Mason

Abstract

The purpose of this study was to determine the effect of load changes on angular accelerations of the ankle, knee and hip joints. Accelerations were measured in the squat (S), power clean (PC) and power hang clean (PHC), and compared to the accelerations in the push-off phase of the sprint start (SS). Methods: Nine female Division I college track athletes performed block sprint-starts, single-leg squat jumps (1S0) with 0% of 1RM, squats (jump) with 0, 25, 40% of 1RM, and PC and PHC with 30, 50, 75, 100% of 1RM. The fastest trial of each exercise was analyzed for minimum and maximum angular accelerations. A one-way, repeated measures ANOVA was used to determine any main effect among the variables between the exercises. Established effects were identified further using Least Square Difference post- hoc analysis. Results: Overall, angular accelerations differed mainly between groups of exercises (S vs. PC vs. PHC), less so within the groups (p < 0.05). Only for minimum angular knee joint acceleration in PHC and for minimum angular hip joint acceleration in S was change in acceleration significantly related to change in load. The ankle, knee and hip joint angular acceleration values in S, particularly the low-load S0, 1S0 and S25, were similar to the values measured in the SS. PC and PHC generally had smaller acceleration peaks, yet maximum angular knee and hip joint accelerations of all PCs and of PHC with 30% of 1RM approached the values of SS and S. Conclusion: Results suggest that light-load squat jumps emulate lower limb angular accelerations of the push-off phase in the sprint start much closer than medium- or heavy-load squats, or power cleans or power hang cleans. The lack of load dependency in PC and PHC should be studied further with athletes skilled in Olympic lifts.

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