Garmin's Forerunner series of fitness devices ordinarily rely on the company's well-proven expertise in GPS technology to track how far and how fast you've run in a given session. If you run indoors, in urban areas or in other locations where GPS is problematic, you might get more accurate results by using the optional foot pod sensor. Once paired with your watch, the foot pod tracks your steps and uses those to calculate distance. Garmin suggests calibrating the foot pod periodically for greater accuracy, and provides a choice of three methods.
Calibrate By GPS
Choose a portion of your normal running route with clear lines of sight, so the Forerunner can easily acquire and maintain a satellite signal while you run.
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Select "Mode" to bring up your Forerunner's menu. From the menu, choose "Settings," then "Run Settings," then "Foot Pod." Once you're in the Foot Pod section, select "Calibrate" and then choose "GPS" as your calibration method.
Choose "Continue," and then press "Start" to begin recording. Begin walking, running or jogging along your chosen course, at your ordinary pace. The Forerunner will inform you when you've traveled far enough for calibration, usually 1 kilometer.
Calibrate By Distance
Choose a location where you can easily run a verifiable distance, ideally of one-half mile or longer. The distance measurements on a treadmill are unreliable, so Garmin suggests using the inside lane of a standard track, which measures 400 meters per lap. Two laps, or 800 meters, is approximately one-half mile and will do nicely.
Select your calibration method. From the Forerunner's regular display, first press "Mode" to bring up the menu. Choose "Settings," then "Run Settings," then "Foot Pod," and finally "Calibrate."
Choose "Distance" as your calibration method, and select the 800 meter/one-half mile distance from the menu. Press "Continue" and then "Start" to begin the calibration.
Walk, jog or run two laps of the track. When you finish, press "Stop."
Select a known and verifiable distance, such as a dedicated running or hiking trail or a standard-sized track.
Walk, jog or run the distance. When you're finished, compare the actual distance you've traveled to the reported distance shown on your Forerunner. For example, your Forerunner might report a 4.5 mile run when you've actually traveled 5 miles.
Divide the actual distance you've run by the distance shown on the Forerunner. In this example, 5 miles divided by 4.5 miles equals 1.11. Write this number down.
Press "Mode" on your Forerunner to enter the menu. Select "Settings," then "Run Settings," "Foot Pod," and finally "Calibration Factor." The calibration factor is a number used to calculate the distance you've traveled.
Look up the number you'd gotten earlier, by dividing your real distance by the Forerunner's reported distance. Multiply that number by the current calibration factor shown on your Forerunner. For example, if the calibration factor were 90, you'd multiply it -- in this instance, by 1.11. That final number is your new calibration factor, which in this case works out to 100.
Enter the new calibration factor into your Forerunner, and select "OK."
(see reference 2 for calculation, reference 1 pg 25 for menu selections)