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To reduce breast motion with a bra, we need to understand what drives the motion of the breasts, and what variables change as support increases. Quantifying breast-torso coordination and movement complexity across the gait cycle may offer deeper insights than previously reported discrete time lag. We aimed to compare breast-torso coordination and mutual influence across breast support conditions during running. Twelve female participants ran on a treadmill at 10 km h−1 with an encapsulation and compression sports bra, and in no bra. Nipple and torso position was recorded. Vector coding, granger causality and transfer entropy were calculated within gait cycles. In both bra conditions, a greater percentage of gait cycles was spent with the breast and torso in-phase (> 90%) compared to no bra running (~ 66%, p < 0.001), with most time spent in-phase in the encapsulation versus compression bra (p = 0.006). There was a main effect of breast support condition on Granger causality (p < 0.001), both from breast to torso and torso to breast. Transfer of information was highest from torso to breast, compared to breast to torso in all conditions. Overall, these results provide novel insight into the mutual and complex interaction between the breast and the torso while running in different bra conditions. The approaches presented allow for a greater understanding of bra support conditions than existing discrete measures, which may relate to comfort and performance. Therefore, measures of coupling, predictability and transfer of complexity should be employed in future work examining these features. [ABSTRACT FROM AUTHOR]

Current mastalgia assessment diaries are effective in reporting severity and frequency; however, literature suggests that timing and location should also be considered when assessing mastalgia alongside severity and frequency. This study aimed to assess validity, reliability, acceptability and minimal detectable change (MDC) of an improved mastalgia diary. Twenty premenopausal females who self-reported pre-menstrual mastalgia completed the diary once a day using paper, email or mobile formats, over one menstrual cycle. Predictive validity was assessed comparing pain pre- and post-menstruation. Test-retest and internal consistency established reliability. Acceptability was assessed using evaluation questions. MDC was calculated using a previously established method using the SEM to a 95% confidence interval. Results showed pre-menstrual mastalgia was significantly higher than post-menstrual, demonstrating diary validity. Reliability tests determined high test-retest reliability (ICC > 0.90) and internal consistency (α = 0.89). The diary was acceptable for >90% of participants. MDC-determined change of 1 on each question would be greater than measurement error and therefore representing 'real' change. This improved mastalgia diary is a more comprehensive, valid, reliable and acceptable tool for assessing mastalgia. [ABSTRACT FROM AUTHOR]