Saturday, July 7, 2007

Paying the Price of a Cheap Pedometer

Wearing a pedometer can motivate adults and children alike to add more steps to their day and get in more exercise. However, a study suggests that using cheap, inaccurate pedometers could do more harm than good in giving people an inaccurate count.

The study tested a cheap Stepping Meter vs. the accurate Yamax Digiwalker SW-200 on 35 study subjects. Each subject wore 1 Yamax pedometer and 5 Stepping Meters all day and the step counts were recorded at the end of the day. Each subject tested 30 pedometers over the course of six days.

A 10% variation in the step counts was considered acceptable. Only a quarter of the inexpensive pedometers met this mark, while the resulting 74% overcounted or undercounted steps. The most inaccurate pedometers overcounted the steps - with a third of them overcounting them by 50%. The others undercounted steps. People who think they are walking 10,000 steps per day may only be walking 5,000 steps per day.

In a pilot test of pedometers with children, Peaceful Playgrounds tested an inexpensive ($5-10) pedometer against a more expensive ($15-20) pedometer. They found that the inexpensive pedometers resulted in inaccurate step counts, broke frequently, and frustrated children. Peaceful Playgrounds found that child proof pedometers must be durable, accurate, be able to withstand dropping, and shaking. "A safety strap is a must," according to Peaceful Playgrounds director, Dr. Melinda Bossenmeyer, author of the We Count Pedometer Walking Program. "We found that children were very competitive with their step counts and would challenge a friend to a specified distance and then both children would check their pedometers, " children found the inaccurrate pedometers frustrating and lost interest in their use.

Peaceful Playgrounds concluded that a target price for a pedometer for children is generally around $20. A price point in the $20 range seem to provide good quality pedometers that stand up to the use and abuse (dropping, shaking, etc) that is often typical use patterns for children.

For more information on pedometer studies: Crouter, Schneider, Karabulut and Bassett, "Pedometer Measures of Free-Living Physical Activity: Comparison of 13 Models." Medicine & Science in Sports & Exercise. 36(2):331-335, February 2004.