Impulsion occurs in all gaits: the walk, the trot, and the canter and even the ambling gaits of gaited horses. Because the walk has no moment of suspension, it is a difficult gait to perform with impulsion. Impulsion at various gaits may not always appear the same. In the walk, it is seen when the hindquarters are engaged and the gait is "purposeful yet relaxed." The USEF describes impulsion at the piaffe as follows: "The piaffe must always be animated by a lively impulsion and characterized by a perfect balance. While giving the impression of being in place there may be a visible inclination to advance, this being displayed by the horse’s eager acceptance to move forward as soon as he