Date of Graduation

5-2016

Document Type

Thesis

Degree Name

Bachelor of Science

Degree Level

Undergraduate

Department

Health, Human Performance and Recreation

Advisor/Mentor

Kaitlin Gallagher

Committee Member/Reader

Michelle Gray

Committee Member/Second Reader

Tyrone Washington

Abstract

The purpose of this study was to look for changes in gluteus medius muscle activity during functional reaches and investigate whether or not anti-fatigue matting affects these changes. Fourteen participants (seven male & seven female) who did not meet any of the exclusion criteria completed forward and lateral reaches at hip and shoulder height on all four floor conditions for a total of sixteen reaches. Four floor types were tested: a control bare force platform, and a low, medium, and high stiffness anti-fatigue mat. Electromyography was applied bilaterally to the gluteus medius muscles, and maximum voluntary contractions were performed so that EMG data could be normalized to this value. Participants stood on two force platforms to get separate measurements under each foot and calculate percent of body weight on each foot. Reach profiles were divided into five phases: standing prior to reach, movement to peak reach, holding peak reach, return to standing, and standing post-reach. Forward reaches showed a main effect of time (p = .004) for peak EMG. Lateral reaches showed interactions between mat and time (p = .02) and height and time (p = .001) for peak EMG. Activity on the hard and medium mats was significantly lower than the soft and control mats at the R2 phase (p = .027). No main effects or interactions were found for percent of body weight shifted during reaches. Gluteus medius muscle activity increased during peak reach in both directions, but only lateral reaches were affected by floor condition and reach height. Future studies should investigate if gluteus medius muscle activity during functional reaches changes after a bout of prolonged standing or in an older population.

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