Author

Jordyn Naylon

Date of Award

5-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology

First Advisor

Kevin D. James, Ph.D.

Second Advisor

Larissa True, Ph.D.

Third Advisor

Mark Sutherlin, Ph.D.

Abstract

Previous research on lower body positive pressure (LBPP) treadmills have focused primarily on muscle activation (EMG), spatiotemporal variables, and metabolic differences from running on a standard treadmill. The current study aimed to establish the necessary accommodation time needed for runners to display reliable metabolic and neuromuscular responses on the LBPP treadmill. Fifteen habitually trained runners (11 males, 4 females, average± SD VO2Max=62.81 ± 5.43mL.kg-1.min-1) ran a total of 3, 15-minute trials on the AlterG® treadmill during a single testing session. For each trial, the AlterG® was set to support 30% of body weight at 70% of the speed at which the participant reached VO2Max on a standard treadmill. Oxygen consumption, the RMS EMG of the vastus medialis, and stance time were recorded every five minutes. A series of one-way ANOVAs with repeated measures were used to test whether dependent variables changed over time. Simple contrasts were made to compare each DV’s initial recording against all subsequent values. Significant differences in VO2were observed, with a 3.7% decrease from the first (31.37 mL.kg-1.min-1) to second (30.21 mL.kg-1.min-1) trial. RMS EMG of the vastus medialis also displayed significant changes over time, with~16% decrease in magnitude between trials one (0.13 mV) and two (0.11 mV). The third trial displayed similar magnitudes as trial two for each of these measures. Though not significant, there was an overall ~7% decrease in stance time from the first (0.200 s) to third (0.186 s) trials. Thus, approximately 20-minutes is necessary to observe stable metabolic and neuromuscular responses for running on an LBPP treadmill at 70% of bodyweight. Future research should provide sufficient accommodation time prior to collecting dependent variables and previous findings on these devices may need to be reconsidered.

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