Ran on the treadmill this morning with my 5x. As per usual the treadmill and watch were out and I normally just calibrate and save. This morning I tried this and for the 1st time I could not enter the correct distance. The watch would allow me to calibrate but not by very much. I had run 5km, the watch recorded 4.4km and the calibration would not let me enter anything higher than 4.6km