Hardware of apple watch Sports Edition: Waterproof is OK, but there is no built-in GPS, so it is accurate to measure the running distance with IPHONE during long-distance running, but badminton only consumes calories. Because the distance is indoors, the IPHONE doesn't need to be carried around, but the short-range GPS is not accurate.

There are two situations as follows:

1. When you only have an apple watch without an IPHONE, you must rely on the IPHONE to measure the distance, but only the apple watch can't.

(1) The running data is inaccurate or even useless.

(2) However, when playing badminton, the watch has built-in accelerometers, gyroscopes and optical heart rate sensors. These configurations are very common in mainstream sports monitoring equipment, so badminton sports can be simulated with these configurations, and the calculation of energy consumption and heartbeat is accurate.

2. If you bring apple watch and IPHONE at the same time, you can calculate the distance of long-distance running: GPS must rely on GPS satellite positioning when moving, so the long-distance running will accurately measure a large range, but the badminton court is a small venue, so the GPS measurement method is inaccurate.

(1) Long-distance running is the accumulation of distance, which is relatively long. The GPS chip has the function of calibration, so it will be correct.

(2) The movement distance of badminton is within the range of indoor court, and it is easily disturbed indoors, so GPS is often unavailable, and satellite GPS is not allowed to be relied on for short distance.

Supplement: the accuracy of heart rate monitoring of apple watch, because apple watch can also be connected to a third-party heart rate monitoring wristband, such as Wahoo TickR, and the heart rate reading will be displayed immediately, so it is as accurate as general medical instruments.