Daily Step Target to Measure Adherence to Physical Activity Guidelines in Children

COLLEY, R. C., I. JANSSEN, and M. S. TREMBLAY. Daily Step Target to Measure Adherence to Physical Activity Guidelines in Children. Med. Sci. Sports Exerc., Vol. 44, No. 5, pp. 977-982, 2012. Purpose: There is a lack of robust evidence to support a daily step count target that equates to current physical activity guidelines in children and youth. This information would be useful to researchers and practitioners who are using pedometers to monitor physical activity. Methods: Accelerometer and pedometer data collected on children and youth age 6-19 yr in the Canadian Health Measures Survey were used in this analysis (n = 1613). Correlation analyses of daily step counts and minutes of moderate-to-vigorous physical activity (MVPA) by age and sex were completed. The daily step count equivalent to 60 min of MVPA was derived using linear regression by age and sex. Cross-validation, including receiver operating curve analysis, was completed to compare the new cut points to one currently used as a proxy estimate of 60 min of daily MVPA (13,500 steps per day) as well as a range of possible step count targets between 8000 and 15,000 steps per day. Results: Daily step counts were correlated with daily minutes of MVPA (r = 0.81, P < 0.0001). The step count equivalents to 60 min of MVPA ranged between 11,290 and 12,512 steps per day (R-2 range = 0.59-0.74). A step count target of 12,000 steps per day resulted in closer population estimates of meeting the physical activity guideline (as measured as minutes of MVPA by accelerometer) as well as improved balance between sensitivity and specificity when compared with any cut point between 8000 and 15,000 steps per day, including the currently used daily step count target of 13,500 steps per day. Conclusions: We propose that 12,000 steps per day be used as a target to determine whether children and youth age 6-19 yr are meeting the current physical activity guideline of 60 min of daily MVPA.