Decelerating from movement into a stable shooting position. The goal is to arrive balanced, with the gun up and ready, and to break the first shot as quickly as possible after stopping -- or even while still decelerating. Position entry is where the majority of time savings in practical shooting come from: not from running faster, but from shooting sooner after arriving.
Elite shooters explicitly do not listen to their body's proprioceptive feedback about stability. They listen to the SIGHT. If the sight picture shows the dot on the target, they press the trigger regardless of whether their body feels settled. The body will almost never feel fully settled during the first shots at a position -- but the sight picture may be perfectly acceptable 0.3-0.5s before the body "feels" ready.