From Tommy Thompson to Ronald McDonald™, everyone seems to be step counting these days. But what separates the tools from the trinkets? Let's look inside popular pedometers and find out.  
 
Pedometers can be broken down into a few basic pieces. Those pieces determine ACCURACY, RELIABILITY, and COST








   

A few years ago I got the idea that a pedometer would be a great way to measure my running routes, but was sorely disappointed by inaccurate devices. With all the different choices in pedometers now, it is easy to make a mistake. My goal is to share my findings with those that are interested in making an informed decision in hopes that the step counting movement is not squashed by the poor pedometer experiences found in an Adult Happy Meal and elsewhere.

Buying a pedometer is a lot like buying a watch. You're going to wear it all day, and several times a day, you'll get that mental itch that makes you want to check it to see how much you have been moving (or not moving). But, what if only a handful of watch manufacturers actually made an accurate watch? Let's face it, I sent in 4 cereal box tops a few months ago and got a free Spiderman watch in the mail, and even this free watch is going to keep reasonably the same time as a $10,000 Rolex.

But, other than aesthetics, how would your expectations differ between a vending machine watch and a Rolex? Hopefully, you would plan on keeping that Rolex for a lot longer than I will keep my new Spidey watch. Hopefully things like shock and rain and the occasional bump or drop wouldn't prompt you to throw that Rolex in the trash and get a new one.

So what about pedometers? Well, pedometers have been around since the days of Thomas Jefferson, and if you made the mistake of buying one five or ten years ago, you found out they were only slightly better than guessing how many steps you had taken. But good news! The digital age has brought us the digital pedometer and a certain amount of accuracy. We even have devices now that use 24 satellites circling the globe at around 8,000 mph just to tell you your morning jog was 3.492 miles, which if your friend asked over dinner was 'about 5 miles.'

But beware! Pedometers are not yet at the same point as watches. Many pedometers aren't even accurate counting steps in a controlled environment; some do as poorly as a 50% margin of error. A few of those that are accurate on a purposeful walk don't count well during normal daily movement like walking around the office, for example. Other accurate pedometers only last a month or two before the little pieces inside wear out and accuracy is lost.

The experts, like Dr. David Bassett Jr. at the University of Tennessee who has performed study after study on pedometer accuracy and reliability, separate the testing into phases. First, the basics: the pedometers are tested on a treadmill at a specific pace. The treadmill keeps the pacing and body movement stable. Most of the pedometers perform well here on a controlled treadmill test. Pedometers are then tested around a 400 meter track on different individuals with different stride lengths and different pacing. Lastly, the pedometers are worn during daily activities and tested against a criterion pedometer (typically this is the Yamax Digiwalker SW-200, which is considered to be the gold standard by most researchers.)

This website hopes to explain and illustrate the internal and external qualities that separate the accurate and reliable pedometers from those of lesser quality.

JSC Engineering LLC is an Electrical Engineering consultant group specializing in product design & performance testing.

© 2004 JSC Engineering, LLC. Direct reprint requests to webmaster@pedometers.com.