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

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.

Pedometer steps-per-minute, moderate intensity, and individual differences in 12- to 14-year-old youth.

BACKGROUND: Researchers have noted both the utility and limitations of using pedometers to measure physical activity (PA). While these unobtrusive devices are widely accepted for their ability to measure accumulated PA, they have been criticized for their inability to measure exercise intensity. However, recent steps-per-minute (SPM) research provides reasonably accurate measures of intensity allowing users to assess time spent at recommended PA levels. Therefore, the purpose of this study was to determine the SPM taken that are associated with moderate physical activity in 12- to 14-year-old youth. METHODS: Ninety-three participants (49 boys and 44 girls; ages 12 to 14) walked on a treadmill for 3 minutes at each of 4 different speeds while wearing a pedometer and a heart rate monitor. RESULTS: On average boys and girls reached their moderate activity intensity threshold at 122 SPM and 102 SPM, respectively. However, individual differences must be taken into account when determining appropriate SPM intensities for youth. CONCLUSIONS: The impact of individual differences underscores the need to address SPM for moderate intensity individually rather than with a single guideline for everyone at this age.