William C. Shiel Jr., MD, FACP, FACR
Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.
In this Article
- What are the benefits of stepping out with pedometers?
- What's a pedometer used for?
- How do pedometers work?
- Are pedometers accurate?
- Which type of pedometer is best for me: piezoelectric or spring-levered?
- Are pedometers accurate for measuring distance and calories?
- How many steps should I take?
- Which pedometer is accurate?
- How do I position my pedometer on my body?
- How do I know if my pedometer is accurate?
- How do I go about getting started with my first pedometer?
- How far am I walking? How many steps are there in a mile?
- How do I increase my daily steps?
- Where can I purchase a pedometer?
What's a pedometer used for?
A pedometer is a small, beeper-sized device you wear on your waist that counts the number of steps you take.
How do pedometers work?
There are two types of pedometers, spring-levered and piezoelectric. Spring-levered pedometers use a spring-suspended horizontal lever arm that moves up and down in response to the movement (vertical accelerations) of your hips as you walk or run. The movement opens and closes an electrical circuit, and as the lever arm makes contact, a step is registered. Spring-levered pedometers must be placed in a vertical plane, perpendicular to the ground, in order for them to work. They don't work if they tip forward to a horizontal plane.
Piezoelectric is a material that generates an electric charge when it is mechanically deformed. Piezoelectric pedometers use a horizontal cantilevered beam with a weight on the end that compresses a piezoelectric crystal when subjected to movement like walking (acceleration). This generates a voltage proportional to the acceleration and the voltage oscillations are used to record steps. Got that?
Pedometers work when you dance, climb stairs, or walk outdoors or on a treadmill, but they don't work if you're biking, skiing, rowing, or swimming.
Are pedometers accurate?
The accuracy of pedometers has been carefully studied because they are frequently used in studies and researchers demand to know if they are reliable and accurate. Research shows that pedometers tend to count steps more accurately at speeds greater than 3 miles per hour (mph) than at slower speeds. Accuracy can exceed 96% when speeds exceed 3 mph, whereas the accuracy drops to between 74% and 91% at speeds from 2 mph to 3 mph, and it drops even further to between 60% and 71% at speeds below 2 mph. The error has to do with the insensitivity of pedometers to detect steps when people shuffle or drag their feet at slow speeds. Detectable vertical movement of the hips is necessary for pedometers to work well.
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