Pedometers and accelerometers can be a fantastic motivational and exercise-tracking tool. A 2001 study by Tudor-Locke et al. found that giving patients with type II diabetes a pedometer significantly increased their daily activity levels, lowered their blood pressure and decreased waist girth measurements, even two months after the study ended.
Selecting a Device
Step 1
Evaluate pedometers for sale at sporting goods stores or for sale online. Understanding how the device collects data will help you make your decision. A pedometer uses a pendulum that swings as you walk. With each step, the pendulum hits a sensor which registers one step. Accelerometers on the other hand, use high-tech microscopic crystals that register direction of movement and force. (This is the same technology used in Nintendo Wii and iPhones.) Because the crystals (called piezoelectric crystals) are so sensitive, accelerometers can estimate your stride length to calculate speed.
Step 2
Decide what you plan to use the device for and what features will help you reach your goal. Inexpensive pedometers may only count your steps, which is perfect if your goal is to reach a daily step minimum. More advanced products offer distance calculations, heart rate readings, calorie expenditure readouts, and even computer programs with GPS mapping and analysis of time spent at different intensities. Advanced features are useful to those using the device to train for an athletic event or as part of a weight-management program.
Step 3
Ask yourself how accurate you want the device to be. Pedometers can over- or underestimate step counts by as much as fifty percent, while accelerometers are usually accurate to within one percent. To avoid false readings while driving, or from shifting positions or sneezing, some models have electronic movement filters. Different models are more accurate at different speeds, with both accelerometers and pedometers losing accuracy below 3 miles per hour. A study by Foster et al. (see Resources) found that ankle pedometers that incorporate stopwatch technology are the most accurate when walking slower than 1.8 mph.
Step 4
Decide your budget. When it comes to pedometers and accelerometers, you get what you pay for in durability, accuracy, and extra features. Depending on your goals, you may not need all the bells and whistles of a top-of-the-line accelerometer. However, if you set your budget too low, you may wind up with buyer's remorse when you are forced to make due without the features that would have helped you reach your goal. Devices designed for walking may not be durable enough to keep up with the repeated impact of running.
Step 5
Compare specific models before making your decision. The materials and programming of competing brands can affect the devices' accuracy or longevity. If you have the luxury, do a field test on a measured course such as a high school track. Walk around the inside lane of the track (one quarter mile) and count your steps. When you have finished, compare the distance or step-count readings with your own data. If you can't test the product yourself before buying it, an internet search will give you information about the accuracy, durability and bugs that a product may have.
Things You'll Need
- Measured walking/running route (optional)
References
- Patient Education and Counseling: "Preliminary outcome evaluation of the First Step Program: a daily physical activity intervention for individuals with type 2 diabetes;" Tudor-Locke et al.; 2002
- Journal of Cardiac Failure: "Accelerometer-Based Quantification of 6-Minute Walk Test Performance in Patients With Chronic Heart Failure;" Jehn et al.; 2008
- Preventive Medicine: "Precision and accuracy of an ankle-worn accelerometer-based pedometer in step counting and energy expenditure;" Foster et al.; 2005
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