Martin, Vera, authorGrandin, Temple, advisorHess, Tanja, committee memberKeller, Kayleigh, committee member2025-09-012025-09-012025https://hdl.handle.net/10217/241787https://doi.org/10.25675/3.02107While it is understood that horse-back riders have asymmetrical riding mechanics, there is a need for further investigation on the possible effects, this has on equine welfare. The current study aimed to provide preliminary insight into the impact of rider asymmetry on acute markers of equine welfare by evaluating the horses using the ridden horse pain ethogram (RHpE) and the change in the horses' neutrophil lymphocyte ratio (NLR). Horses (n = 6) and riders (n = 3) were randomly paired (HRP, n = 11) and rode a short pattern at the walk, trot, and canter on the right and left rein over two data collection days. Each rider was evaluated for trunk asymmetry in the frontal plane (tilt) while riding in a straight line. Behavioral markers of equine pain were evaluated using the RHpE, with ≥8/24 behaviors indicating likely presence of musculoskeletal pain. Physiological stress was measured through evaluation of the change in (NLR) in whole blood from samples taken before and after the session. When averaged across all HRP, rider tilt was in the direction opposite to the direction of travel for all gaits and directions (absolute value 1.88°±1.86° to 4.48°±1.48°). There was no significant effect of rider tilt on NLR (P > 0.05). The mean RHpE score was three out of 24 behaviors. Rider tilt was present across all gaits and directions. No association was found between rider tilt and physiological and behavioral markers of acute equine stress during a short, moderate intensity riding session.born digitalmasters thesesengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.biomechanicshorse-rider interactionasymmetryrider kinematicshorseText