Stacie Moore

Date of Award


Degree Name

Master of Arts


Human Performance and Health Education


Health, Physical Education & Recreation

First Advisor

Dr. Mary L. Dawson

Second Advisor

Dr. Roger Zabik

Third Advisor

Dr. Patricia Frye

Access Setting

Masters Thesis-Open Access


The problem of the study was to determine the effect of step height, speed, and choreography on ground reaction forces, electromyography of the knee extensors, and center of gravity displacement in step aerobics. Two step heights, 6 and 8 in.; two speeds, 126 and 132 bpm; and three steps, basic step, tum step, and hop step, were studied for a single subject across 5 trials. The muscles studied included the rectus femoris, vastus lateralis, and vastus medialis. Results indicated: (a) significant difference existed between the cadences as well as between the step heights for the sagittal plane center of gravity; (b) the 6-in. step height produced greater vertical impact forces than the 8-in. step, but not significantly for each step; (c) the step heights were significantly different across steps for the area under the curve for the three muscles studied; and (d) for vastus medialis, significant interactions were found for the higher step height, faster cadence, and higher impact step which were not seen for the other two muscles studied. The conclusions were: (a) the 6-in. step height produced greater vertical impact forces than the 8-in. step height; (b) the body does not have time to move through its full range of motion at the faster cadence or the higher step heights; (c) a greater EMG response was produced by the vastus lateralis, rectus femoris, and vastus medialis for the 8-in. step than for the 6-in. step; and (d) in a fatigued state a participant is less consistent at the faster cadences, higher step heights, and higher impact steps.