How do you teach a horse to change leads on a straight line rather than only through a turn?

Lead changes through a turn are taught first because the turn provides a natural physical cue — the change of direction — that helps the horse understand what is being asked. Lead changes on a straight line are more advanced because they require the horse to change leads based entirely on the rider's aids without any directional change as a prompt, which demands a more confirmed understanding of the change signal. Clinton Anderson develops the straight-line change progressively from the turn-based change. Once the horse is executing clean, willing changes through the figure eight consistently, he begins asking for changes on a diagonal line across the arena rather than at the center of a circle. The slight angle of travel still provides some directional context for the change but begins to reduce the horse's reliance on the turn as the cue. From diagonals, the change is moved to a genuinely straight line. On a straight line, the aids must be very clear because the horse has no directional cue to help it understand the request. Anderson uses a deliberate weight shift — sitting deeper to the new inside, moving his new inside shoulder slightly back — combined with the leg position change and a very subtle opening of the new inside rein. The cleaner and more deliberate the rider's position change, the more clearly the horse can read the change signal without a turn to help interpret it. The horse that has understood the change aid through turns and diagonals typically makes the transition to straight-line changes relatively quickly, because the aid itself is what the horse has been learning to read — the turn was just a context that made the aid easier to understand initially. The progression from turn to diagonal to straight line should happen over weeks or months rather than days, confirming each stage before moving to the next.