Movements
Trot
The trot is a two-beat gait with a second of suspension between each step, meaning that two legs are always off the ground. While trotting, the legs move in diagonal pairs.
Ideally, a good trot should be regular and energetic. It should be elastic, meaning that the horse has a bounce or swing in its step. The horse should be free in its shoulders, and the hocks (the main joint on a horse's two hind legs; the equivalent of a knee) should be active and flexing.
In the trot, the rider may sit (maintaining contact with the saddle at all times) or post (rising a small amount out of the saddle during each stride).
This video animation illustrates the trot.