The Apple Watch is a wonderful device for fitness tracking. You don’t always have to wear it on your wrist to use it either. Take Twelve South’s ActionSleeve for Apple Watch for instance: it is a smartwatch armband that frees your wrist during yoga, cross-fit, and cycling workouts. It ensures tight skin contact for more accurate heart rate tracking.
This armband not only holds your watch but protects it from dings and damage. It fits arms up to 17 inches. You can find out more about it here.