Breast biomechanics, exercise induced breast pain (mastalgia), breast support condition and its impact on riding position in female equestrians

Breast biomechanics, exercise-induced breast pain (EIBP) and performance effects in female athletes are established. Wearing sports bras during exercise reduces breast movement and EIBP. Despite the prevalence of female equestrians, little investigation of breast movement during horse riding exists, yet excessive breast movement, embarrassment and EIBP are reported. Breast movement relative to the torso is linked to EIBP, associated with magnitude and direction of forces generated. Equestrians may experience novel breast and upper-body movement patterns in response to large vertical excursions of the horse. This study aimed to establish relative vertical breast displacement (RVBD), EIBP and positional changes in three support conditions: ‘no support’, ‘low support’ and ‘high support’. Thirty-eight female equestrians rode a Racewood™ Equine Simulator in each breast support condition in medium walk, medium trot (sitting) and medium canter. Trials were filmed and analysed using Quintic® Biomechanics V29. Significant reductions in RVBD (P<0.001) and EIBP (P<0.001) were identified with increased breast support in all gaits. In medium trot (sitting) a significant reduction in range of movement (ROM) of shoulder-elbow-wrist (P<0.001) was seen from low to high support. ROM of torso-vertical angles were reduced from no support to low support (P<0.001) and further by high support (P<0.001). This reduction in ROM was significantly greater in large breasted riders (cup size DD-FF) (n=21) (P<0.001) compared to small breasted (cup size AA-D) (n=17). These results suggest that appropriate breast support positively impacts EIBP and riding position in female riders possibly enhancing performance. As RVBD and reported EIBP were not wholly comparative with results in female runners, further research is warranted to establish breast movement in equestrianism in three dimensions.