Examination of a Self-Selected Speed Graded Exercise Test using an Automated Treadmill as a Valid Means to Measure VO2max

The use of graded exercise tests for measuring maximal oxygen consumption (VO2max) is common practice in cardiopulmonary medicine. Limitations to VO2max are still being debated despite the concept being founded nearly a century ago. It has been suggested that measuring VO2max using traditional protocols (TP) does not allow for proper investigation of all theories of limitations to oxygen consumption, whereas allowing subjects to self-select their work rate does. Conflicting results exist in the literature for whether allowing subjects to self-select their work rate (SP) has resulted in a different VO2max compared to TP. Limitations to these studies include the use of a cycling modality and lack of well-trained subjects. Secondary criteria need to be investigated for their validity in discriminating VO2max from VO2peak in SP and TP. Purpose: The purpose of the study was to examine the validity of a self-selected work rate protocol (SP) using an automated treadmill for measuring cardiorespiratory fitness by A) determining whether it allowed individuals to choose their own pace to match a predetermined effort, and B) comparing VO2max from the SP to values obtained from a TP. Secondary criteria were evaluated for their ability to discriminate a VO2max from VO2peak in both SP and TP. Methods: Thirteen experienced endurance runners completed three maximal exercise tests to determine VO2max. Oxygen consumption was measured using a computerized system and averaged over 30 second time periods. SP was completed using an automated treadmill. The automated treadmill consisted of a sonar range finder, microcontroller, and customized computer software. Subject deviations from the middle of the treadmill belt resulted in rapid, graded increases or decreases in speed. Secondary criteria of VO2max were assessed using blood lactate (LA), respiratory exchange ratio (RER), and rating of perceived exertion (RPE). Results: Peak work rate achieved during SP was significantly greater than that achieved during TP by 1.2 METs, p < .05, d = .564. VO2 was significantly greater in TP (64.9 ± 8.2 ml*kg-1*min-1) than SP (63.4 ± 7.8 ml*kg-1*min-1), p < .005, d = .195. All secondary criteria were sensitive measures in both SP and TP; however, according to predictive values and likelihood ratios no criterion had values suggesting they were strongly linked to the condition. Conclusion: Although an automated treadmill allowed subjects to self-select their work rate, SP in combination with an automated treadmill is not yet a valid means of assessing cardiorespiratory fitness. The secondary criteria investigated here are not a suitable means of discriminating VO2max from VO2peak in SP or TP.

Name thesis:degree_name

Doctor of Philosophy

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

EDU Physical Activity and Educational Services

Grantor dc:publisher

The Ohio State University

Year dc:date

2013

Author dc:creator

• Scheadler, Cory Martin

Contributors dc:contributor

• Devor, Steven

• Kinesiology

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1365693122

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1365693122