IKMF competition rule. Marathon & Extended Formats category.
For extreme marathon events of 2 hours and up, additional allowances ensure athlete safety: the athlete may rest in a static hang position, perform low-amplitude swings between reps, place the kettlebell on the shoulder, and use 2 hands on the kettlebell while resting elbows on the knees in all disciplines. It is however still forbidden to place the kettlebell on the ground during the event.
See the interactive comparison on KETTLEBELL MONSTER™ for filterable views and more detail.