The biomechanics of riding addresses the position, muscle tone, stabilization and symmetry of the rider and how those things affect the horse's way of going.
Each rider starts off from a different place and needs to make different corrections to achieve proper alignment and application of the aids. Contrary to what happens when a "cookie cutter" approach is taken to teach riding, the application of biomechanical principles makes it possible to teach any rider to ride as well as the talented rider or professional rider.
The biomechanical approach breaks down skills, such as sitting in alignment, engaging the seat or riding with a correct contact, into bite-size chunks and describes them in ways that any rider can understand.
Biomechanically sound riding not only produces better results from the horse. It produces safer riders with better seats and fewer repetitive strain injuries, and horses free from the soundness issues associated with unbalanced and asymmetrical riding.