My son started doing hippotherapy when we was 2 years old. I think the term comes from the latin word for horse which is hippo something? We live in Louisville, KY and are lucky enough to have a hippotherapy facility close to our home.
It has been wonderful for Brock plus it is a really fun activity. Kids can do PT, OT, and Speech therapy at our particular Hippotherapy Clinic. My son does PT there. We were doing PT in our home through our states early intervention program but by the time he was 2 our PT thought a clinic setting would be more helpful. We have also done aquatherapy at a different clinic.
Specifically, riding the horse helps SB kids with strengthening their core muscles and balance. They just don't ride around on a horse the regular way either. They put these kids on the horse backwards, forwards, and side ways. At his last session he was standing on all 4s while the horse was walking around the arena. It is amazing! He was saying to me, "look mommy I'm a circus rider!" They do all sorts of other activities and exercises as well. We currently go once a week for 1 hour. All the horses at our facility are very well trained and there is always a therapist on either side of him, holding onto him at all times.
My son has improved so much with is strength . . . he walks, runs, rides a regular tricycle (with foot straps) now. We are no longer a part of the early childhood program since he just turned 3 but our insurance (BCBS) thankfully will continue to pay for it!
You can check out this site to learn more and see if there is a therapist or facility in your area.
www.americanhippotherapyassociation.org 
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