An equation was developed to estimate maximal oxygen uptake ([latin capital V with dot above]O2max, ml.kg-1.min-1) based on a single submaximal stage of a treadmill walking test. Subjects (67 males, 72 females) aged 20-59 yr completed 4-min stages at 0, 5, and 10% grades walking at a constant speed (2.0-4.5 mph) and then performed a [latin capital V with dot above]O2max test. Heart rate and respiratory gas exchange variables were measured during the test. Multiple regression analysis (N = 117) to estimate [latin capital V with dot above]O2max from the 4-min stage at 5% grade yielded the following model (R2 = 0.86; SEE = 4.85 ml.kg-1.min-1):
[latin capital V with dot above]O2max = 15.1 + 21.8*SPEED (mph)
-0.327*HEART RATE (bpm)
-0.263*SPEED*AGE(yr)
+0.00504*HEART RATE*AGE + 5.98*GENDER (0 = Female; 1 = Male).
The constant and all coefficients were highly significant (P < 0.01). To assess the accuracy of the model in a cross-validation group (N = 22), an estimated [latin capital V with dot above]O2max value was obtained using the above model. Estimated [latin capital V with dot above]O2max then was regressed on observed [latin capital V with dot above]O2max yielding the following equation (R2 = 0.92):
ESTIMATED [latin capital V with dot above]O2max = 0.15 + 1.03*OBSERVED [latin capital V with dot above]O2max.
The intercept and slope of this equation were not significantly different from 0 and 1, respectively. For 90.9% of the subjects in the cross-validation group, residual scores were within the range of +/- 5 ml.kg-1 [middle dot] min-1. In conclusion, this submaximal walking test based on a single stage of a treadmill protocol provides a valid and time-efficient method for estimating [latin capital V with dot above]O2max.
(C)1991The American College of Sports Medicine