The effect of breast support on vertical breast displacement and breast pain in female riders across equine simulator gaits

The female breast has limited support. Loading of supporting structures through breast motion can result in breast pain. Female horse riders report exercise-induced breast pain while riding, constituting a participation barrier, and may negatively affect rider-horse interactions. Despite previous research in non-equestrian sports advocating sports bra use, their usage in riders is low. No research exists detailing breast biomechanics in riders where body movements are in response to excursions of the horse, suggesting unique breast motion. Twelve female riders UK bra size 32DD and 34D performed 1 minute walk, trot (sitting) and canter on a Racewood simulator in three breast support conditions: (a) no bra, (b) daily bra and (c) sports bra. Participants were filmed with a 50 Hz camera in the frontal plane at rider height; markers on the sternal notch and left and right nipple enabled relative vertical breast displacement (mm) to be calculated. Participants rated breast pain after each support condition and pace on a 10 cm Visual Analogue Scale. Mean (± SD) unsupported vertical breast displacement was highest during trot (45 ± 12) and was significantly reduced in a sports bra compared to the daily bra (T = -3.71, P < 0.01). Breast pain was significantly reduced in a sports bra compared to the daily bra during canter (Z = -2.95, P < 0.01) and trot (Z = -2.81, P < 0.01). Results may help develop specific equestrian bras and educate riders on breast support. Breast pain caused by inappropriate breast support may affect horse-rider interaction and warrants further investigation.