We know fitness trackers are all the rage and help people get fit. Even just simple pedometers help motivate people to walk more and meet their fitness goals. But how do these clip-ons and fitness bands actually work? What is the science that makes these little trackers count your steps? We’ll break it down for you in easy to understand terms.
How do Step Counters Work?
Before the fitness tracker and smartwatch trend started, pedometers were mostly little digital clip-on devices worn at the waist. In the pre-Bluetooth days, using buttons and the digital display you could track steps throughout the day. Some models even had a built-in memory so you could store several days of stats and challenge yourself to beat your record. Now we have fancier fitness trackers that sync with our phones to give us step counts and under fitness data. You can even buy watches with built-in step counters or your phone may count steps for you. But how do all of these devices actually know how many steps you take?
It’s all based on movement. Early forms of pedometers used a mechanical switch to detect movement, which would then count as a step. Often this was done with a small metal ball that slides back and forth or a swinging pendulum. Modern pedometers and fitness trackers use data from MEMS inertial sensors analyzed by software to count steps. These use accelerometers to detect minute movements that translate into steps (or exercises in more advanced trackers).
If you’re using a fitness tracker or watch with GPS tracking activated, the GPS will track the route you run or walk and then translate that distance into steps. This is usually the most accurate way to record steps, but GPS is only available with expensive fitness trackers and requires cellular service.
Learn more about the history of pedometers on Wikipedia
How Accurate are Pedometers?
As time goes on and our technology improves, step counters become more and more accurate. However, there are many who debate the accuracy of these devices. Generally, for typical walking on flat surfaces, all pedometers will be reasonably accurate to the number of steps you take. Clip-on pedometers worn on the waist are generally more accurate since movements of the arms or wrist can register false movements for wrist-based trackers.
A study was done on this in 2017 by Hannah M. Husted and Tamra L. Llewellyn. They filmed students walking on a treadmill for five minutes at a fixed speed of 3.5 miles per hour to determine the accuracy of four different pedometers and fitness trackers (Fitbit Charge, Omron HJ-303, SmartHealth Walking FIT, and Sportline). After counting the steps recorded in the video, the determined the Sportline was the only device that was close to the accurate count, while the other three undercounted the steps. The Fitbit was the least accurate.
We have found from our own experience that most step counters are accurate enough to give a general idea of your activity levels on a given day. Plus, the extra motivation pedometers can give to stay fit and move more is a big plus that overshadows doubts about accuracy.
Want to add a pedometer to your workout routine? Check out the best pedometers and step counters. Looking for a fancier tracker? This fitness tracker comparison chart will give you a great overview on some of the best options.