Chad F. Witt

Date of Award


Degree Name

Master of Arts


Human Performance and Health Education


Health, Physical Education & Recreation

First Advisor

Dr. Roger Zabik

Second Advisor

Dr. Mary Dawson

Third Advisor

Dr. Patricia Frye

Access Setting

Masters Thesis-Open Access


The purpose was to compare the effect of dietary supplementation using two different energy bars, the PRBar and the PowerBar, ingested 1 hour before exercise, on the exercise metabolism of endurance athletes. Four dependent variables were measured: respiratory exchange ratio (R), oxygen consumption (VO2), rating of perceived exertion (RPE), and blood glucose. Independent variables were bars (2), trials (2), and sample time. Sample times occurred at 5-min intervals for R, VO2, and RPE. Blood glucose was sampled before exercise, at 15 min and 25 min during exercise, and after exercise. Subjects completed four 35-min training runs, two after consuming each of the energy bars, in a random order on separate days. All testing was completed within 3 weeks. Subjects ran at an exercise intensity equal to 65% to 75% of their maximal oxygen consumption. Results indicated significant differences existed (a) between the energy bars for both R and RPE, (b) between sample times for all dependent variables, and (c) between trials for RPE. Also, a significant interaction effect, Bars x Trials, occurred for VO2. It was concluded that although the significant decrease in R and significant increase in RPE supported an increase in fat metabolism during exercise when subjects supplemented with the PRBar, the lack of significant changes in VO2 and blood glucose levels across training runs indicated a mixed result. Also, the practical significance of the changes in R and RPE was questioned.