How accurate are Omron X-HJ-304-E and Yamax SW-700/701 pedometers at different speeds and various inclinations?

AIM

The purpose of this study was to investigate step count and energy expenditure accuracy of the piezoelectric Omron (Walking Style X-HJ-304-E) and spring-levered Yamax (Digi-Walker-SW-700/701) pedometers at different speeds and various inclinations.

METHODS

Thirty subjects (15 females, aged: 24 ± 3 years) completed eleven 5-min trials at different treadmill speeds and inclinations (3.24 km∙h⁻¹ [inclination: 0, 9, 20%], 4.68 km∙h⁻¹ [0, 9, 20%], 6.48 km∙h⁻¹ [0, 9%], 9 km∙h⁻¹ [0%], 10.8 km∙h⁻¹ [0%], 12.6 km∙h⁻¹ [0%]). During each trial, an investigator recorded actual steps with a hand tally counter. Actual energy expenditure was measured using a portable indirect calorimeter.

RESULTS

The Omron pedometer revealed high step count accuracy for all speeds and inclinations when worn on the hip or a backpack (Mean % of actual steps: 99.6%; Range: 95.8-101.3%). The Yamax pedometer revealed high step count accuracy (Mean % of actual steps: 99.8%; Range: 96.2-103.3%) when worn on the left hip at 6.48-12.6 km∙h⁻¹ (0%), 4.68 km∙h⁻¹ (9%, 20%), 6.48 km∙h⁻¹ (9%) and on the right hip at 10.8 km∙h⁻¹ (0%) and 6.48 km∙h⁻¹ (9%). The accuracy of the Omron and Yamax determined energy expenditure was poor (57.9-59.7%) when compared to indirect calorimetry.

CONCLUSION

The Omron pedometer provides accurate step counts when worn on the hip and backpack at all tested speeds and inclinations. We therefore suggest an accurate application of this device for walking, hiking and running at moderate speeds. Both pedometers underestimated energy expenditure.