Pedometers (stepometers, step counters) are used to help lose weight or improve fitness. One popular program is to walk 10,000 steps a day. A study titled "A Meta-Analysis of Pedometer-Based Walking Interventions and Weight Loss" (Caroline R. Richardson, MD, Tiffany L. Newton, BS, Jobby J. Abraham, MBBS, Ananda Sen, PhD, Masahito Jimbo, MD, PhD, MPH and Ann M. Swartz, PhD) concludes that "Pedometer-based walking programs result in a modest amount of weight loss. Longer programs lead to more weight loss than shorter programs."
Pedometers can also be used:
- by runners who want to run a fixed distance, but without being constrained by a sports field track or a fixed trail in a park
- as a rangefinder for general information (How far to the mall?) or outdoors navigation (with a map and compass)
Prices range from $5 to over $50. Popular brands include Omron (HJ 112), Sportline, Silva, Oregon Scientific, Yamax (Digiwalker), SportBrain, Bodytronics, Walk4Life, Kenz and Accusplit.
GPS pedometers have certain advantages but don't work when their satellite signals are blocked (forests, tall buildings, indoors). They are more accurate in measuring distance, but don't count steps. They will not be covered in this article.
Some of the information in this article is based on user reviews of pedometers on the Amazon.com website.
How Pedometers Work
Mechanical pedometers use a swinging pendulum or a weight on a spring, to count steps taken. This is counted up on a digital display (like an automobile tripmeter) or a dial (like a clock, for example the Accusplit AL3010). Some pedometers (such as the ULTRAK 220) display distance walked instead of steps, with a mechanical slider to adjust for stride length. Mechanical pedometers are now difficult to find because of the increasing popularity of electronic pedometers.
Advantages
- no battery required
- inherently waterproof
Disadvantages
- usually no sensitivity adjustment provided; can be too sensitive and overcount steps, or too insensitive and undercount
- no electronic intelligence to filter out non-walking movements
- pendulum and mechanism makes ticking noise with each step
- usually displays either steps or distance, not both
Electro-mechanical pedometers still use a mechanical pendulum, though the pendulum is usually smaller and quieter. Electronics are used to count and display the steps. Distance and calories burned (estimated) are calculated from the stride length and weight entered by the user. Many are clamshell designs.
They theoretically can have the same advanced features as accelerometers. However, many are older designs and don't have the necessary electronics.
Advantages
- small
- light
- quieter than mechanical pedometers, but they still tick
- sensitivity adjustment sometimes provided
- can display steps, distance and calories burned
Disadvantages
- battery required; the cost of a new coin or button cell battery every few months (or a year), quickly adds up
- some are water-resistant; however, the battery compartment's rubber gasket can't be relied on after the battery has been changed (just like a digital watch). Waterproofing is important because it is easy to forget to unclip the pedometer, and throw it into the washing machine.
Fully electronic pedometers are sometimes called accelerometers. Instead of a mechanical pendulum counting steps, an electronic device (an accelerometer) is used to measure acceleration. These are usually newer designs and have more features. This is the type used in watches.
The accelerometer provides more information (the magnitude and duration of the acceleration, not just a on/off click from the pendulum) to the electronics. This explains why many models don't have a sensitivity setting, yet are as or more accurate than electro-mechanical pedometers that have a sensitivity adjustment.
Advantages
- small
- light
- quiet or noiseless
- smart electronics are able to filter out false signals (moving when sitting in a chair, standing in a train) by ignoring short bursts of movement
- no moving parts, theoretically providing longer lifespan
- Some models have two or three accelerometers (axis or dimensions), allowing them to count accurately in more than one position. They don't need to be kept vertical and can be slipped into a pocket or backpack.
- Some models automatically zero the counters at midnight, and keep seven days of counter readings. The built-in clock means that a watch is not needed.
- Some models can upload daily statistics to a PC through a USB cable.
- Some models can differentiate between light and moderate ("aerobic") exercise, and provide separate counters.
- Some models can store different stride lengths. For walking, jogging and running (selected manually or automatically).
Disadvantages
- battery required
- Some are water-resistant, however the battery compartment's rubber gasket can't be relied on after the battery has been changed.
Pedometer Accuracy and How to Improve It
The accuracy of the step counter depends on:
- the sensitivity of the pedometer. If too insensitive, strapping the pedometer to an ankle might help, though it's probably better to upgrade to a higher quality unit.
- its ability to filter out false signals. Accelerometers have an advantage here.
- the user keeping the pedometer upright. Two-axis (2D) pedometers can be tilted sideways, but can't be placed flat (horizontal). Three-axis (3D) models can work properly in any position.
- the user wearing the pedometer in the correct position. Experimenting with different placements can help: left hip, right hip, front left, rear left, front right, rear right, shirt pocket. Wearing it as a pendant might also work.
- the size of the walking or running impact. Shock-absorbing shoes or soft ground will reduce the impact and can cause an undercount. Running generates a larger impact. Less sensitive pedometers might work for running but not for walking.
Omron claims a five percent step count error rate for many of its accelerometer models. This is probably conservative, as users have reported errors of less than one percent in actual usage. Other brands of accelerometers should have similar accuracies.
The accuracy of the distance calculation depends on:
- the accuracy of the step counter
- the accuracy of the stride length entered. The stride length should be settable in steps of one inch or one centimeter. Some older models are set in steps of four inches, which limits their accuracy.
- the consistency of the user's stride length. This will vary depending on the terrain and how quickly the user runs or walks.
Even with these constraints, users report error rates of one to ten percent for the distance, at least for the better pedometers. Lower quality pedometers can be much worse.
To check the accuracy of the pedometer, the step counter should be compared against a manual count of steps. The distance display should not be used, as many of the contributing factors are not under the pedometer's control and depend on the user.
Pedometer Watches or Wrist Pedometers
Pedometers are now available in sports watches, often combined with a digital compass, barometer, or heart rate monitor. Prices start below $100. Brands include Casio, Sportline, Silva, Polar, New Balance, Highgear, Eureka and Tech4o.
Advantages
- easy to wear the whole day; less likely to be forgotten
- more secure, less likely to be dropped and lost; pocket pedometers should have a safety leash in case the belt clip fails.
- easy to read the display while on the run. Information such as speed (miles per hour) and pace (steps per minute) are therefore more likely to be provided, compared to pocket models that are usually checked only at the end of a run.
Disadvantage
- relatively new; few models and brands to choose from
The Best Pedometer
Based on user reviews, accelerometer pedometers are the most accurate, especially 2 or 3-axis models. They usually have the most features as well. However, a simple and cheap step-counter-only electro-mechanical model can be better for those who just need a rough gauge of their level of activity, to help motivate them to exercise more.
Pedometer applications for the iPhone and other smartphones, should also be considered.
Yuen Kit Mun - Kit Mun is a self-confessed information junkie, reading an average of a book a week over the past two decades. His growing Internet ...
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