In order to investigate the effect of exercise modality and bra type on vertical breast displacement, seven participants with similar ages and body types were selected to take part in this study. Three-dimensional motion capture system (NDI Optotrak Certus) was used to collect the data of vertical breast displacement when participants were walking at the speed of 5 km/h, jogging at the speed of 7.5 km/h, running at the speed of 10 km/h on a treadmill, and rope skipping at the frequency of twice per second. It was found that there was no significant difference in vertical breast displacement between rope skipping, jogging and running. And the vertical breast displacement when wearing sports bra is significantly less than everyday bra in four exercise modalities. The results of this study might be useful for designing special sports bra for rope skipping modality.

The aim of this study was to determine whether exercise-induced vertical breast motion and discomfort in women with large breasts decrease when an underwired bra is used compared with when an underwire-free bra is worn. Vertical breast displacement was assessed in nine women (C cup size) who exercised on a treadmill in two bra conditions: underwired bra and underwire-free bra. Perceived breast motion and discomfort were reported by each participant using the visual analogue scale after each bra condition trial. Vertical breast displacement and perceived breast motion and discomfort were compared between the two bra conditions. Vertical breast displacement (p < 0.05) and perceived breast motion (p = 0.007) and discomfort (p = 0.025) were significantly lower in the underwired bra condition than in the underwire-free bra condition. The bra design feature of containing an underwire was effective in decreasing exercise-induced vertical breast motion and discomfort among the women with large breasts. The current research is the first study to explore the effects of including a bra underwire on the change in breast motion and discomfort.

Asian women have smaller breast sizes and greater breast density, which suggests specific research on their breast kinematics and biomechanics. To investigate vertical breast displacement of Asian women among exercise modalities (rope skipping, walking, jogging, running) in different support conditions (wearing everyday bra or sports bra), and assess the motion between different parts of the breast, seven participants were selected to participate in this study. Five infrared markers were placed on each of their left breasts, and a three-dimensional motion capture system (NDI Optotrak Investigator) was used to collect the data on vertical breast displacement during walking (5 km/h), jogging (7.5 km/h), running (10 km/h) and rope skipping (2 Hz). No significant difference was found in the vertical displacement of different parts of the breast in the two bra conditions. Also, there was significant difference in vertical breast displacement among rope skipping, jogging and running. Breast size did not significantly affect its vertical displacement. The smaller, denser breast appears to reach a threshold of vertical displacement that is similar at high severities of dynamic exercises (jogging, running and rope skipping). The results might be useful for designing special sports bras for Asian women with small breasts or rope skipping participants to improve the shock absorption function.