LE3 .A278 2011

2011

Landry, Scott

Acadia University

Bachelor of Kinesiology

Honours

Kinesiology

Kinesiology

Purpose: To investigate muscle pattern differences as described through the use of surface electromyography (EMG) between 2 different surfaces (treadmill and overground) and inclines (level and uphill at 6°) in a physically active female older adult population. Methods: Healthy active female older adults (n= 20; 56.4±4 yrs; 68.7 ± 14.3 kg; 162.9 ± 5.8 cm ) performed a walking protocol that involved overground and treadmill walking at 2 inclines while surface EMG was used to measure activity patterns of the medial and lateral gastrocnemii, medial and lateral hamstrings, and vastus lateralis and medialis. EMG data were normalized using maximum voluntary isometric contractions (MVICs) and principal component analysis (PCA) was used on the waveforms, with PC scores being statistically analyzed using a two way repeated analysis of variance. Results: Greater muscle activity magnitudes due to both surface and incline effects were demonstrated for all muscles during stance except for the vastus medialis. The vastus medialis did, however, demonstrate a trend towards greater activity magnitude. Phase shifts were also identified for the gastrocnemii and vastii muscles during stance. For the swing phase, the only significant difference was a greater activity magnitude due to incline for the medial hamstrings. Discussion and Conclusions: This study is the first study to identify differences between overground and treadmill surfaces while walking for both a level and uphill condition. Uphill walking and overground walking utilize higher levels of muscle activity, and are greater stressors of the locomotor system. These findings have important implications for future research and exercise programs aiming to use incline as a locomotive stressor.

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https://scholar.acadiau.ca/islandora/object/theses:826