The patent goes on to describe a handful of tensioner systems that might be employed in order to cause a strap to constrict and loosen. It further posits that sensors might be utilized to make the tightening and loosening of the strap a seamless, automatic feature requiring little in the way of active input from a wearer.

By the way, it bears mentioning that our own Jack Forster seems to have anticipated this feature set when he wrote his review of Apple Watch Series 2: