There is a plethora of research that demonstrates pedometers’ ability to promote increases in ambulatory activity. Efforts have been made to make pedometers more user friendly, such as reducing the user’s need to frequently record daily steps. Uploadable pedometers aim to achieve such capabilities, and also have the potential to provide the user with continual and individualized feedback. There is limited research on the accuracy of such pedometers, and this lack of knowledge resonates more so in the older adult population. The results of the current study showed that the OM and LC were increasingly accurate in their ability to quantify steps in both participant age groups as both treadmill walking speed and overground walking speed increased. The LC significantly underestimated steps during the 53.6 m/min stage for the younger adult group, and during the 53.6, 67.0, and 80.4 m/min stages for the older adult group. The LC also significantly underestimated steps for the younger adult group during the less than normal walking speed in the overground walking trial. During the 24 hr observation period, the OM pedometer significantly underestimated steps for both young and older adult groups.
Similar to previously published research, the OM pedometer generally became increasingly more accurate as walking speed increased on the treadmill. Using the same treadmill speeds as the current study, the Omron HJ-105 has been shown to have the largest percent error in measuring steps at 2.0 mph, with increasing accuracy as treadmill speed increased . A study by Foster et al. showed the Omron HF-100 to be accurate (>98%) in quantifying steps at speeds greater than 2.0 mph . Likewise, studies examining the validity of the Omron HJ-122, Omron HJ-720ITC, and Omron HJ-113 have demonstrated the pedometers’ high accuracy for quantifying steps at increasing speeds above 2.0 mph [18, 19]. These results, collectively with those of the current study, indicate that Omron pedometers become increasingly accurate in assessing ambulatory activity above slow walking speeds. One study, however, indicates otherwise. Crouter and colleagues showed the Omron HJ-105 to significantly overestimate steps at treadmill walking speeds at 4.0 mph (the fastest speed of the protocol) . The trend for increasing accuracy of the Kenz Lifecorder during increasing treadmill speeds resonates that of previous research, which shows the slowest walking speeds to have the largest mean error [6, 20]. Current study results also show significant underestimations at the 2.0 mph stage, but were much more evident in older adults. Although two additional walking speeds significantly underestimated steps in older adults in the current study, the corresponding percent errors were similar to previously reported results in younger adults . Overall, both the Omron HJ-720ITC and Kenz Lifecorder examined in the present study represent suitable options for walking behaviors assessed via treadmill, with minor decrements in accuracy at slower walking speeds.
The results of the current study for overground trials provides further credence that the pedometers examined in the current study are generally accurate in their measurements of walking activity. The OM of the current study reported more accurate step measurements than that of reported by Schneider et al., who reported an underestimation of 19.0 steps over a distance nearly identical to that of the current study . Even at the slowest walking cadence of the present protocol, the largest mean error was an overestimation of 4.7 steps (for the young adult group). These results are similar with those presented by Holbrook et al. . They assessed the validity of two Omron brand pedometers over 100 m walking trials, reporting absolute percent errors less than 2% for the HJ-151 for their slow, moderate, fast, and self-selected speed trials, and less than or equal to 2% for the HJ-720ITC for the same trials. The OM in the current study had percent errors less than 2% for the < normal walking speed, and less than 1% for the normal and > normal walking speeds. Currently, there exists limited research on the validity of the Kenz Lifecorder during overground walking. We are aware of one study that assessed such during self-selected walking paces on a track, which showed a less than 1% error in steps , which are very similar to the normal walking speed results of the current study. Overall, the OM and LC pedometers exhibited increasing accuracy during faster walking cadences during the OG protocol, a trend similar to that of the TM protocol.
The OM pedometer recorded less steps compared with the NL standard of care comparison in both the young age group and the older age group during the 24 hr observation period. Silcott et al. also examined the Omron HJ-720ITC pedometer during day long observation periods in a sample of adults aged similar (mean 31.3-46.2 years) to that of the young adult category in the present study (20–49 years), and showed the pedometer to significantly underestimate steps . Collectively, their results are likely due to the hardware of the Omron pedometer, as they only quantify steps after movement of four seconds or more. The magnitude of difference in error was approximately 13% for the young age group and 7% for the older age group in the current study. Although such differences are marginal, it highlights that a degree of caution is needed when comparing daily values of accrued steps across different pedometer brands.
There are several limitations of the current study that warrant mention. The populations used were all generally healthy, so it may not be appropriate to extend the results previously stated to diseased, those with gait impairments, or obese populations. Due to feasibility, the NL was used as the comparison variable for comparing OM and LC measured steps during the observation period rather than employing a manually tallied count. The current study does, however, fill an important void in the literature, by examining the validity of uploadable pedometers in both young and old age groups across laboratory, overground, and free-living activities.