The optional calibration of Polar s3 stride sensor W.I.N.D. / Polar s3+ stride sensor improves the accuracy of speed, pace, and distance measurements. We recommend that you calibrate the sensor:
a) before using it for the first time
b) if there are significant changes in your running style, or
c) if the position of the sensor on the shoe is dramatically changed (e.g. if you have new running shoes or if you switch the sensor from your right shoe to your left one).
Sensor calibration can be done by running a known distance or by setting the calibration factor manually. For more information on calibration, see here.
Each shoe setting (Shoes1/2/3) can be assigned its individual calibration factor. The training computer will automatically use the calibration factor you have determined for the shoes when you select the shoe setting at the beginning of the exercise.
If you have 3 pairs of shoes, one pair for road running, the second for track, and the third for off-track. Each set of shoes can have its own stride sensor, or you can use one stride sensor on all three. On the training computer you can, then, have the calibration factor for each set of shoes ready. Merely by selecting the shoe setting, the correct calibration factor will be used.
Calibration factor for each of the shoes can also be set in ProTrainer 5 through Tools → Edit Polar Product Settings.