The accuracy of the ACSM stair-stepping equation

Abstract

LATIN, R. W., K. BERG, K. KISSINGER, A. SINNETT, and L. PARKS. The accuracy of the ACSM stair-stepping equation. Med. Sci. Sports Exerc., Vol. 33, No. 10, 2001, pp. 1785–1788. Purpose: The purpose of this study was to determine the accuracy of the ACSM equation used to estimate the oxygen cost of stepping exercise. The equation appears as: V̇O2 (mL·kg−1·min−1) = 0.2 (steps·min−1) + (step height, m × steps·min−1 × 2.4) + 3.5. Methods: Subjects were 55 men and women between the ages of 19 and 35 yr. Steady-state V̇O2 was measured at six different combinations of step heights and step rates. Step heights were 0.1, 0.2, and 0.3 m (4, 8, and 12 in, respectively) and step rates were 20 and 25 steps·min−1. Predicted V̇O2 for each workload was derived from the ACSM equation. Results: Mean differences between actual and predicted V̇O2 values ranged from −0.2 to −1.1 mL·kg−1·min−1 and was −0.6 mL·kg−1·min−1 for all workloads combined. All differences except the lowest were significant (P ≤ 0.05). Total errors ranged from 1.3 to 2.5 mL·kg−1·min−1 and was 1.9 mL·kg−1·min−1 for all workloads combined. For all workloads combined, the correlation between actual and predicted V̇O2 was r = 0.95 with a SEE = 1.7 mL·kg−1·min−1. The statistics are comparable to other ACSM prediction equations. Conclusion: Although all of the mean differences except one were statistically significant, they were judged negligible from a practical standpoint. Therefore, it was concluded that the ACSM equation is an accurate predictor of the oxygen cost of stair-stepping exercise.