How do you develop piaffe from the ground in dressage?

Developing piaffe from the ground — using in-hand work with the trainer on foot alongside or in front of the horse — is the traditional approach used by classical trainers including those at the Spanish Riding School, the Portuguese School of Equestrian Art, and many contemporary classical practitioners who find ground work allows more precise communication and more careful development than mounted work during the earliest stages of piaffe training. The trainer works alongside the horse with a whip or cane used to tap rhythmically on the horse's hindquarters or hind legs, asking the horse to step up with its hind legs more actively while an assistant or a wall helps guide the horse's position. The initial ground work asks the horse to piaffe along the wall, which provides lateral support that helps the horse maintain straightness while the trainer develops the upward, carrying engagement of the hind legs. The rhythm of the trainer's tapping should correspond to the rhythm of the trot diagonal, creating a rhythmic request that the horse learns to follow with increasingly elevated steps. Classical in-hand work also includes the trainer positioning their hand on the horse's croup to feel the engagement of the hindquarters and to guide their lowering as collection increases. The transition from ground work to mounted piaffe is made gradually: first establishing the movement in hand, then asking for a few steps with a rider on board while the trainer continues the ground work, and gradually reducing the ground assistance as the horse becomes able to maintain the movement from mounted aids alone. Nuno Oliveira was particularly known for his in-hand work as a preparation for piaffe, describing the ground work as establishing the movement's physical pattern before the complexity of the mounted aids was introduced.