Comparison of interdevice measurement difference of pedometers in younger and older adults

Objectives: In this study, the relationship between inter-instrument differences in regard to the daily number of steps with the intensity distribution of daily physical activity in younger and older adults was examined. Methods: 17 younger individuals and 28 older individuals wore two pedometers (Lifecorder (LC) and EC-200 (YM)) simultaneously for 7 days, in order to determine the number of steps each took. Furthermore, LC determined the time spent in light, moderate and vigorous physical activity, corresponding to <3 metabolic equivalent (METs), 3 to 6 METs and >6 METs, respectively. Results: The LC detected a significantly larger number of steps than YM (p < 0.001), yet there was a strong relationship between the two measurements (r = 0.962, p < 0.001). The interdevice difference with the number of steps significantly decreased in inactive older individuals compared with the active older and younger individuals, and it was also significantly negatively correlated with the time spent in light-intensity physical activity (LPA) (r = 0.523, p < 0.01). Conclusion: This study showed that the interdevice difference with the number of steps significantly increased in older participants due to the greater length of time spent in LPAs.