Purpose: The purpose of this study was to test the hypothesis that V˙O2peak is positively correlated with the regression coefficients of the curve-linear relationship between V˙O2 and speed during a protocol consisting of submaximal walking and running.
Methods: Nineteen healthy men (mean ± SD: age = 26.4 ± 6.4 yr, height = 179.9 ± 7.2 cm, weight = 77.7 ± 8.7 kg, % fat = 16.3 ± 7.3) and 21 healthy women (age = 25.6 ± 4.9 yr, height = 167.2 ± 5.4 cm, weight = 61.6 ± 7.7 kg, % fat = 24.0 ± 6.8) underwent an incremental treadmill test to determine V˙O2peak and on two separate days performed an exercise protocol consisting of treadmill walking on a level grade at 2.0 mph (54 m·min−1), 3.0 mph (80 m·min−1), and 4.0 mph (107 m·min−1) and running at 6.0 mph (161 m·min−1). Subjects exercised for 5 min at each velocity, with 3 min of rest in between each exercise bout. Pulmonary ventilation (V˙E) and gas exchange were measured breath-by-breath each minute. The average of V˙O2 values obtained during the last 2 min of exercise for both exercise sessions was used in polynomial random coefficient regression analysis.
Results: In the polynomial random coefficient regression analysis for walking speeds only, both linear (r = 0.31, P = 0.053) and quadratic (r = 0.35, P = 0.029) coefficients were modestly correlated with V˙O2peak. Steady-state V˙O2 during walking at 3.0 and 4.0 mph and running at 6.0 mph was also modestly correlated with V˙O2peak (r = 0.30-0.48).
Conclusions: The results confirm our hypothesis and suggest that, as walking speed increases, the increase in V˙O2 is positively correlated with the V˙O2peak. Our findings are consistent with the notion that cardiorespiratory fitness and exercise economy are inversely related.
1Department of Kinesiology, Point Loma Nazarene University, San Diego, CA and Healthy Lifestyles Research Center, Arizona State University, Mesa, AZ; 2Department of Human Services, University of Virginia, Charlottesville, VA; 3Endocrine Research Unit, Mayo Clinic College of Medicine, Rochester, MN; and 4Department of Public Health Sciences, University of Virginia, Charlottesville, VA
Address for correspondence: Brandon Sawyer, M.Ed., ATC, Arizona State University, 7350 E. Unity Avenue, Mesa, AZ 85212; E-mail: firstname.lastname@example.org.
Submitted for publication January 2010.
Accepted for publication March 2010.