What does a planted pivot foot mean in reining?

A planted pivot foot means the horse keeps its inside hind foot in place or very near the same spot while the front end turns around it, creating a fixed axis for the spin rather than moving all four feet equally through the turn. In practice, the inside hind foot may step slightly or shuffle in a small area as the horse maintains its balance and generates the rotation — true rigidity in the pivot foot is not the goal and not what judges expect. The goal is a hind end that stays anchored and low while the front end moves freely and quickly around it, so the horse appears to be spinning in place rather than drifting or traveling during the spin. The mechanics that produce a good pivot foot are hindquarter engagement and correct body position: the horse must be balanced over its hind end and driving its energy upward and sideways through the shoulders rather than pushing forward from behind in a way that causes the hind end to travel. A horse that understands the pivot will naturally keep its hind end quieter as its front end speeds up, because the hindquarters are serving as the base of the rotation rather than contributing to forward movement. Horses that lose the pivot foot — whose inside hind begins to travel during the spin — are either being ridden too forward, lack the balance and strength to maintain the position at speed, or have not yet developed the body awareness to hold the hind end in place while the front end moves quickly. Building the pivot foot response begins at a slow walk-pace turnaround where the horse can be corrected precisely, and speed is added only after the pivot is consistent and the body alignment is correct at the slower pace.