Breast Kinematics and Exercise Induced Breast Pain in Simulated Horse Riding

Introduction: Participation of women in sport has been reported at 58% (Audickas, 2017) and is often limited by excessive breast movement and exercise induced breast pain (EIBP) (Burbage & Cameron, 2017). Increased breast movement can lead to embarrassment, pain, and damage to delicate breast tissue (Cameron et al., 2022). Breast size and movement has also been linked to a decrease in participation across different sports (Burbage & Cameron, 2017). Limited research exists in the novel breast movement that may be present during equestrian activities and warrants further investigation.
Materials and Methods: Following institutional ethical approval, female equestrians were recruited (n=9), ranging in age from 20-29 all either students or faculty of Hartpury University, to ride a Racewood™ Event Simulator in four breast support conditions; everyday bra, riding bra, running bra and no support to establish the relative vertical, mediolateral, and anteroposterior breast displacement in sitting trot (medium). Retroreflective markers (12.5mm markers with a 35mm base from B&L engineering) were placed onto each participants left and right nipples, sternal notch, left and right anterior inferior aspect of the 10th ribs and 3rd and 7th vertebrae on the back. Range of motion across three directional planes – vertical, mediolateral and anteroposterior - were tracked using four optical motion capture cameras (240 Hz), then quantified in Qualisys Track Manager ™ Software (version 2023.3(build 12577)). Five full stride cycles were recorded for sufficient analysis. A 100mm Visual Analogue Scale (VAS) was used to assess perceived pain after each breast support condition, and a questionnaire was given to gather demographic information.
Results: Significant differences were found in relative breast displacement between support conditions. Vertical: (F=8.039, df=3, p<0.001), mediolateral: (F=1.132, df=3, p<0.001), anteroposterior: (F=4.588, df=5, P<0.001). Specifically seen between no support (B) and running bra (RB) (t= -4.136, p=0.003), B and riding bra (RD) (t= -3.860, p=0.005) and everyday bra (EB) and RD (t= -3.683, p=0.006) across the vertical axis. EB and RB (t= -2.873, p=0.021) mediolaterally, B and RB (t= -2.889, p=0.02); EB and RB (t= -3.397, p=0.009); RB and RD (t= 2.846, p=0.022) anteroposterior also showed significant differences. Correlations were also seen between the B, EB, and RB conditions and the VAS scores (p< 0.01, p<0.05, p<0.01). Relating the amount of movement produced to the pain scores, whereas no correlation was seen between the RD and VAS scores.