Award Date

August 2016

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology and Nutrition Sciences

First Committee Member

John A. Mercer

Second Committee Member

Julia Freedman-Silvernail

Third Committee Member

James Navalta

Fourth Committee Member

Jennifer Pharr

Number of Pages

64

Abstract

The purpose of this study was to determine if body weight support or speed influences specific physiological and biomechanical parameters while running at a preferred pace, or variations of preferred pace. Nine participants (age: 28.56 ± 7.88 years, height: 1.68 ± 0.08 cm, mass: 65.70 ± 7.64 kg) who were running a minimum of 10 miles per week (14.67 ± 4.92 miles) were recruited for participation. Participants were asked to sign an institutionally approved informed consent form upon arrival to the lab. After determining preferred running speed at each body weight support condition (no support, 10%, and 20% support), participants were instrumented with four Delsys EMG leads, a PCB one-dimensional accelerometer, and a K4B2 portable metabolic gas analysis system to measure muscle activity, tibial acceleration, and metabolic variables at various points throughout each running condition. Muscle activity was recorded for the rectus femoris, semitendinosus, tibialis anterior, and medial gastrocnemius muscles. Participants were asked to run a total of nine conditions, running with no body weight support, 10% support, and 20% support at a preferred running pace, as well as +10% and -10% of that preferred speed. Average muscle activity, average tibial acceleration, and average VO2 and VCO2 values were determined for each condition. None of the dependent variables were influenced by the interaction of speed and body weight support (p>0.05). EMG of the four lower extremity muscles was not influenced independently by body weight support (p>0.05) or speed (p>0.05). VO2 was influenced by body weight support (p<0.001), reporting VO2 during running at 0% support was significantly higher than VO2 at both 10% body weight support (p<0.05) and 20% body weight support (p<0.05). Tibial acceleration was not influenced by body weight support (p>0.05) but was influenced by speed (p<0.05). Specifically, tibial acceleration was significantly higher during the +10% of preferred speed condition compared with both the preferred speed condition (p<0.05) and the -10% of preferred speed condition (p<0.05). It is concluded that oxygen consumption was affected by both body weight support and speed; yet, lower extremity muscle activity was not. It should be understood that although it may be possible to achieve similar levels of muscle activation while running at 10% and 20% support, the metabolic demand is continually less and less as body weight support is added.

Keywords

body weight support; leg acceleration; metabolic; muscle activity; running

Disciplines

Kinesiology

File Format

pdf

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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