There have been numerous studies on the benefits of general movement and activity towards both physical improvements as well as cognitive improvements. Because the horse moves in a way that imitates human ambulation, clients on horseback receive that input affecting the clients hips and body almost as if they were walking. For able bodied individuals and individuals with disabilities, the movement of the horse is highly beneficial to humans across many areas, increasing circulation, respiration, challenging musculature, and affecting cognitive function.
So how can movement help cognition? The vestibular system gathers information and feedback of movement. That information travels between the cerebellum and the rest of the brain, including the visual system and sensory cortex. The vestibular system is modulated by the cerebellum and also activates the reticular activating system, a network of nerve pathways in the brain-stem that connect the spinal cord, cerebrum, and cerebellum. These areas are critical to our attentional system and learning areas as they help regulate incoming sensory data.
Simple biology supports the connection between movement and learning. Oxygen is essential for brain function, and increased blood flow augments the amount of oxygen the brain receives. Physical movement increases blood flow, and hence the amount of oxygen delivered to the brain. Even simple activities like stretching and walking are proven to increase your heart rate and blood flow. Further study shows exercise influences gene expression to improve learning and memory (Tong, Shen, Perreau, Balazs, & Cotman, 2001). "This improved pattern of gene expression enhances many factors that support the encoding and transfer of data, synaptic structure, and the activity and plasticity of neurons. All of these processes facilitate learning."
These are just a few ways that demonstrate how movement, and movement from the horse, influence our body and brain in fascinating, beneficial ways! For people who are unable to walk or ambulate with a consistent or regular gait pattern, the movement of the horse provides that input for them, thus triggering all the wonderful benefits and more discussed above.