Accuracy and failure rate of the Yamax Digiwalker 651 Pedometer and Omron HG-112 Pedometer in two samples

Background. In this study the accuracy and failure rates of the commonly used pedometers and an accelerometer were determined for two groups of women that differ on the basis of waist circumference (WC) at different treadmill speeds and different positions.;Methods. Twenty-six women (16 with a WC ≤32 inches {WC 0} and 10 with a WC ≥38 inches {WC 1}) simultaneously wore one StepWatch Accelerometer, three Yamax Digiwalker 651 pedometers, and three Omron HJ-112 pedometers while completing nine walking trials, three each at 1mph, 3mph, and self-select speed. Pedometers were worn at the exterior hip, interior hip, and ankle, while the StepWatch Accelerometer was worn exclusively at the ankle. Accuracy was defined on the basis of comparison to hand tally counts.;Results. For the Digiwalker 651 at 1mph, accuracy for WC 0 and WC 1 was highest when worn at the ankle; at 3mph and self-select speeds it was superior when worn at the exterior and interior hip for WC 0 (p< 0.05), while for WC 1 the interior hip was best at 3mph (p< 0.05). No failures were observed when worn at the ankle at any speed for either waist group. Accuracy of the Omron in WC 1 at 3mph was most accurate when worn at the ankle (p< 0.05). For both WC groups, accuracy of the StepWatch was superior to either pedometer at 1mph (p< 0.05) and more accurate than the Digiwalker 651 at 3mph and at self-select speeds (p< 0.05).;Conclusions. The Digiwalker 651 offered relatively high accuracy for all individuals when it was worn at the ankle, regardless of waist circumference or speed of walking. However, the Omron HJ-112 pedometer provided more accurate steps counts than the Digiwalker for women of larger waist sizes, when worn at the interior or exterior hip, and when walking at speeds ≥ 2.5mph.