Predicting V̇O_2max with an objectively measured physical activity in Japanese Women

PURPOSE: To investigate the use of the accelerometer-determined physical activity (PA) intensity variables as the objective PA variables for estimating V̇O_2max in Japanese adult women. METHODS: The subjects of this study were 148 Japanese women aged 20 to 69 yr. Maximal oxygen uptake (V̇O_2max) was measured with a maximal incremental test on a bicycle ergometer. Daily step counts (SC) and the amount spent in moderate to vigorous PA (MVPA) and vigorous PA (VPA) were measured using accelerometer-based activity monitors for 7 consecutive days. Using data of age, SC, MVPA, or VPA, and either body mass index (BMI) or waist circumference (WC), the nonexercise V̇O_2max prediction models were derived as BMI models, WC models, BMI models, and WC models, and cross-validated by using two separate cross-validation procedures. RESULTS: SC, MVPA, and VPA were significantly related to V̇O2max (r = 0.43, r = 0.52, and r = 0.58, respectively). The multiple correlation coefficients for the BMI and WC models were 0.83 and 0.85, respectively, and for the BMI and WC models, they were 0.85 and 0.86, respectively. The SEE was 3.3 and 3.1 mL•kg•min for the BMI and WC models, respectively, and it was 3.1 and 3.0 mL•kg•min for the BMI and WC models, respectively. All regression models demonstrated a high level of cross-validity supported by the minor shrinkage of the coefficient of determination and the increment of SEE in the predicted residual sum of squares procedure, and by small constant errors for the subgroups of age, SC, and V̇O_2max between 25 and 35 mL•kg•min. CONCLUSIONS: This study demonstrated that multiple regression models using data of MVPA or VPA were useful in predicting V̇O_2max for Japanese adult women.