Physical activity guidelines for youth and adults include recommendations for moderate intensity activity to attain health benefits. Indirect calorimetry studies have consistently reported a 100 ste·min−1 threshold for moderate intensity walking in adults. No indirect calorimetry studies have investigated step-rate thresholds in children and therefore the primary purpose of the study was to determine preliminary step-rate thresholds for moderate physical activity walking in children.
Oxygen consumption was measured at rest and used to determine 3 and 4 age-adjusted metabolic equivalents (A-AMETs) for 4 treadmill trials (self-selected, 2.5, 3.0, and 3.5 MPH). Two trained observers simultaneously counted children’s steps during each walking trial. Step-rate thresholds associated with moderate-intensity activity, defined as 3 and 4 A-AMETs, were determined using hierarchical linear modeling.
Regression analysis determined an overall step rate of 112 and 134 step·min-1 for 3 and 4 A-AMETs respectively. Body mass index (BMI) weight status and age were positively related to A-AMETs.
We suggest age and BMI weight status specific recommendations that range from a low of 100 step·min-1 threshold (3 A-AMETs) for overweight/obese 11- to 12-year-olds to a high of 140 step·min-1 threshold (4 A-AMETs) for healthy weight 9- to 10-year-old children.