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Thesis Format

Monograph

Degree

Master of Science

Program

Kinesiology

Supervisor

Belfry, Glen R.

Abstract

Introduction: The oxygen uptake (V̇O2) vs power output (PO) relationship from ramp incremental exercise (RAMP) is used to prescribe aerobic exercise. As PO increases, there is a delay in V̇O2 that contributes to a misalignment of V̇O2 from PO making precise prescription of exercise PO untenable. Three methods of determining Mean Response Time (exponential modeling (MRTEXP), linear modeling (MRTLIN), and the steady-state method (MRTSS)) were compared and evaluated for their accuracy at predicting the V̇O2 associated with two PO below estimated lactate threshold (qLT) and one above. Methods: Ten men performed a 30W·min−1 RAMP and three-30 min constant PO cycle ergometer trials at the aforementioned intensities. The measured steady-state V̇O2 was compared to the V̇O2 predicted after adjustment by each of the three MRTs. Results: For all three MRT methods, predicted V̇O2 was not different(P=1.000) from the measured, below qLT. Conclusion: All model predictions can be used for accurate exercise prescription provided the intensity is below qLT.

Summary for Lay Audience

Performing a ramp-incremental exercise test (RAMP) is of great benefit as it allows researchers to ascertain physiological variables to prescribe exercise accurately for constant load exercise intensities. The RAMP test also allows us to determine an individual’s lactate and respiratory compensation thresholds, which are important in determining their exercise intensity domains (moderate, heavy, severe), all of which are influenced by changes in metabolic pathways and the subsequent cardiorespiratory response to increases in energy demand. However, there is an inherent disconnect between oxygen use by the muscle and the oxygen that is measured through expired air, as blood takes time to reach the lungs and be exhaled at the mouth. This prevents the RAMP from being considered a precise foundation from which to prescribe exercise intensity. There have been three models that account for this delay in order to accurately determine the oxygen use and power output relationship derived from the RAMP test. We investigated these three models in an effort to determine which model is the most accurate at intensities below, slightly below, and slightly above the intensity of work that becomes more challenging. Comparisons were made between an individual’s model-adjusted oxygen uptake derived from the RAMP to the oxygen uptake associated with exercise at a known intensity and constant work rate. All three correction methods resulted in a more accurate oxygen uptake to power output relationship during exercise that was easy. However, these correction models were not as accurate at predicting the oxygen use at exercise intensities that were harder.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

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