When a horse walks, trots or canters he moves his legs one or two at a time. When a horse moves a leg it is called a step. A stride is the distance a horse covers with all 4 legs, which is approx. 12 feet. Within each stride pattern there are different beats
The sequence in the animation, above, shows it to be:
There should be a distinct 4-beat rhythm to the walk. It is a sign of tension in the horse or restriction by the rider if the walk shows sign of becoming 2-beat; also known as ambling (diagonal pair moving together) or pacing (lateral pair moving together). The main cause is trying to collect the walk or make the horse work in the walk too early.