Rider fitness, balance, and body awareness directly affect horse welfare, with evidence that rider asymmetry and physical limitations cause biomechanical problems in ridden horses.
Rider fitness is a welfare issue for horses because poor balance, asymmetry, and excessive weight directly affect the horse's musculoskeletal welfare. Horses compensating for unbalanced or tense riders develop muscle asymmetry, back pain, and behavioral resistance. The welfare responsibility of riders extends to their own physical preparation for riding - maintaining appropriate fitness, developing an independent seat, and managing weight are welfare obligations toward the horses they ride. This is rarely framed as a welfare issue but evidence clearly supports the connection.