September 14, 2004 – The error rate of a pedometer – the small, belt-worn device used to count steps – increases when the walker’s pace is very slow, according to the results of a study published in Preventive Medicine1.
The study found that pedometers fail to count all the steps of a walker whose stride speed is less than three miles per hour (4.82 km / h). The study also shows that, depending on the counting mechanism they are equipped with, some pedometers may fail to correctly calculate all the steps at a slow pace.
First, 259 people aged 19 to 85 walked at their own pace on a motorized treadmill. Beyond three miles per hour, the reliability of all pedometers tested was at least 96%. At speeds of less than two miles per hour (3.22 km / h), reliability dropped to 71%.
Second, we compared the reliability of two mechanisms with which pedometers on the market are equipped. At preset slow speeds of 1.8 miles (2.89 km / h) to 2 miles per hour, 32 individuals aged 19 to 51 marched on the same treadmill. The piezoelectric pedometer has proven to be fairer than the pedometer with lever and spring. A piezoelectric pedometer counts the steps when an electrical signal is produced under the action of mechanical stress. The spring-loaded pedometer contains a lever that moves under the impulse of hip movement, making contact with a sensor that registers the step.
Should we make a great deal of pedometers that underestimate the number of our steps since after all, that means that we exercise more than we think? The authors of the study explain that the lack of accuracy of pedometers when walking slowly is significant enough that it may discourage some individuals from reaching their fitness goals. Such a consequence would run directly counter to the primary purpose of the use of this instrument.
An individual can take 4,000 to 13,000 steps per day, depending on their level of physical activity. Several awareness campaigns suggest that a goal of 10,000 steps per day can contribute to better physical condition.
Marie france Coutu – PasseportSanté.net
According to Science Direct
1. Melanson E, Knoll JR, et al, Commercially availaible pedometers: considerations for accurate counting, Preventive Medicine, August 2004, Vol. 39, No 2, 361-8.
