People who rely on inexpensive pedometers to record the number of steps taken per day may actually be taking fewer or more steps than they think they are taking, according to the results of a new study. The findings also suggest that cheap pedometers should not be used in public health programs since they are often inaccurate.
"Researchers, the merchandising industry and possible buyers of inexpensive step counters should be aware of the considerable validity problems of some pedometer brands," study co-author Dr. Katrien De Cocker, of Ghent University in Belgium, told Reuters Health.
Ghent's public health campaign has urged people to take 10,000 steps per day and many have begun using pedometers. Some experts considered distributing pedometers, in particular, the inexpensive Stepping Meter, for free to help more people meet this physical activity goal. However, this pedometer, which sells for about 1 euro (US $1.20), has not been evaluated to determine its accuracy.
De Cocker and colleagues recruited 35 healthy volunteers, between 20 and 60 years old, to test 973 of these pedometers. Each volunteer tested 30 Stepping Meters, over a course of six days, along with the Yamax Digiwalker SW-200, a pedometer known to give highly accurate readings.
Overall, 26 percent of the Stepping Meters displayed readings that fell within the acceptable range, which was a 10 percent or less variation from the Digiwalker reading. The remaining 74 percent either overestimated or underestimated the numbers of steps taken by more than 10 percent, the researchers report in the British Journal of Sports Medicine.
More than one in three of the faulty step counters diverged from the Digiwalker by more than 50 percent. In most cases, the pedometers displayed a reading that was greater than the number of steps actually taken, the report indicates.
De Cocker concludes that the Stepping Meter pedometers have "no merit in promoting physical activity because of the low validity."