Abstract The lumbo-pelvic hip complex (LPHC) plays a pivotal role in equestrian sports, connecting the rider’s body to the horse’s back and influencing rider-horse interaction. Achieving an ideal ‘independence of seat’ characterised by balanced, elastic, and upright posture is representative of rider expertise. While previous studies have examined aspects of rider-horse coordination, the relationship between rider ankle range of motion (ROM) and shock attenuation at the LPHC remains mostly unexplored. Eight experienced dressage dyads participated, and their ankle ROM was measured using a goniometer while accelerometers recorded saddle and rider sacrum accelerations during 20 extended sitting trot strides. A strong positive correlation (r = 0.71, ) was observed between ankle ROM and saddle-rider’s sacrum increase in shock signal strength, indicating that greater ankle ROMs correlated to worse dampening capacities of experienced riders. Ankle ROM may have implications for the rider’s and horse welfare and performance. Understanding the role of ankle mobility provides valuable insights for coaching and training programs in equestrian sports.