Step counts and energy expenditure as estimated by pedometry during treadmill walking at different stride frequencies.

ABSTRACT

BACKGROUND: The purposes of this study were to determine the accuracy and reliability of step counts and energy expenditure as estimated by a pedometer during treadmill walking and to clarify the relationship between step counts and current physical activity recommendations. METHODS: One hundred males (n = 50) and females (n = 50) walked at stride frequencies (SF) of 80, 90, 100, 110, and 120 steps/min, during which time step counts and energy expenditure were estimated with a Walk4Life Elite pedometer. RESULTS: The pedometer accurately measured step counts at SFs of 100, 110, and 120 steps/min, but not 80 and 90 steps/min. Compared with energy expenditure as measured by a metabolic cart, the pedometer significantly underestimated energy expenditure at 80 steps/min and significantly overestimated measured energy expenditure at 90, 100, 110, and 120 steps/min. CONCLUSIONS: The pedometers' inability to accurately estimate energy expenditure cannot be attributed to stride length entered into the pedometer or its ability to measure step counts. Males met 3 criteria and females met 2 criteria for moderate-intensity physical activity at SF of 110 to 120 steps/min. These results provide the basis for defining moderate-intensity physical activity based on energy expenditure and step counts and may lead to an appropriate steps/day recommendation.