Horse's have three basic gaits, walk, trot and canter.  The walk has 4 beats per stride because each of the horse's feet hit the ground consecutively. The trot has 2 beats per stride, as the feet hit the ground in diagonal pairs, and the canter has 3 beats.

 'Tempo' is the number of hoof beats per minute.  'Length of stride' is the length of each step.  Tempo and stride determine speed.  For example, a horse can travel at the speed of 10 miles per hour by taking short strides quickly (fast tempo) or by taking longer strides more slowly (moderate tempo).

Tempo and stride have to be balanced with overall speed because tempo and stride deal with how a horse's legs are moving, and overall speed deals with how his body is moving.  It's seems strange to think of legs and body separately but bodies move steadily forward, like an object rolling along, while legs swing back and forth, like pendulums.

Every horse has a natural tempo at which his legs will swing in a smooth motion and his body will appear to be rolling over them.  However, if the speed, tempo, stride and energy are not balanced, the motion looks rough and jerky.