GymKit has been one of Apple Watch’s smartest fitness features since it launched in 2017. Tap your watch to compatible gym equipment, and Apple Watch shares your heart rate while the machine sends back metrics like distance, incline, pace, and calories. With iOS 27, Apple is expanding that idea beyond Apple Watch. I tested the new GymKit on iPhone and AirPods Pro 3 ($179, reg. $249) experience with a GymKit-compatible treadmill. It basically gives you the Apple Watch GymKit workout tracking experience, just without the watch. This could be useful in a lot of scenarios. GymKit, no Apple Watch required The setup is simple. I tapped my iPhone to the treadmill, picked Indoor Walk (Indoor Run is also offered), and started the workout from the treadmill. With GymKit, workout data is stored privately on iPhone and removed from the equipment. Once the workout started, the treadmill received heart-rate data from AirPods Pro 3.…