Health, Exercise, and Sports Sciences ETDs

Publication Date

Spring 5-13-2017

Abstract

Purpose: To investigate: 1) if a self-paced (SP) graded exercise testing protocol elicits similar and reliable maximal oxygen uptake (VO2max) responses compared to a ramp (RAMP) treadmill protocol; 2) the impact of SP on cardiac output (Q), stroke volume (SV), and arteriovenous oxygen difference (a-vO2diff); and 3) the metabolic response during SP through blood lactate (BLa-) accumulation and ventilatory threshold (VT) attainment. Methods: Sixteen recreationally trained men (23.7±3.0 yrs) completed two separate treadmill graded exercise testing protocols. SP consisted of five 2-min stages (10 min total) of increasing speed based on the Borg RPE6-20 scale. RAMP consisted of increases in speed by 0.16 km/hr every 15 s until volitional exhaustion. All tests were performed at 3% incline. VO2 was measured via indirect calorimetry, hemodynamic function was measured via thoracic impedance, and BLa- was measured via portable lactate analyzer. Differences between SP and RAMP protocols were analyzed as group means by using paired samples t-tests (R Core Team (2017)). Results: Maximal values for SP and RAMP were similar (p>0.05) for VO2max (47.1±3.4 vs. 47.4±3.4 mL•kg-1•min-1), heart rate(198±5 vs. 200±6 beat•min-1), ventilation(158.8±20.7 vs. 159.3±19.0 L•min-1), Q (26.9±5.5 vs. 27.9±4.2 L•min-1), SV (145.9±29.2 vs. 149.8±25.3 mL•beat-1), a-vO2diff (18.5±3.1 vs. 19.7±3.1 mL•dL-1), VT (78.2 ± 7.2 vs. 79.0 ± 7.6% VO2max), and peak BLa- (11.7±2.3 vs. 11.5±2.4 mM•L-1), respectively. Conclusions: SP elicits similar physiological responses in comparison to RAMP. These results support SP as a feasible GXT protocol. Electing to employ SP may benefit clinicians and researchers from a time-management perspective.

Keywords

RPE-clamped, stroke volume, cardiac output, VO2max

Document Type

Dissertation

Language

English

Degree Name

Physical Education, Sports and Exercise Science

Level of Degree

Doctoral

Department Name

Health, Exercise, and Sports Sciences

First Committee Member (Chair)

Dr. Len Kravitz

Second Committee Member

Dr. Fabiano Amorim

Third Committee Member

Dr. Ann Gibson

Fourth Committee Member

Dr. Christine Mermier

Fifth Committee Member

Dr. Jeffrey Janot

Comments

Sixth Committee Member : Dr. Lance Dalleck

Download

Share

COinS