Understanding key performance indicators for breast support: An analysis of breast support effects on biomechanical, physiological and subjective measures during running

Breast-torso movement coordination during running in different breast support

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.

Clinical and exercise professional opinion of return-to-running readiness after childbirth: an international Delphi study and consensus statement

Female athletes have identified a lack of guidance as a barrier to successfully returning to running postpartum, and existing guidelines are vague. Our aim was to define the current practice of determining postpartum run-readiness through a consensus survey of international clinicians and exercise professionals in postpartum exercise to assist clinicians and inform sport policy changes.A three-round Delphi approach was used to gain international consensus from clinicians and exercise professionals on run-readiness postpartum. Professionals who work with postpartum runners participated in an online survey to answer open-ended questions about the following postpartum return-to-running topics: definitions (runner and postpartum), key biopsychosocial milestones that runners need to meet, recommended screening, timeline to initiate running, support items, education topics and factors that contribute to advising against running. Consensus was defined as ≥75% participant agreement.One hundred and eighteen professionals participated in round I, 107 participated in round II (response rate 90.6%) and 95 participated in round III (response rate 80.5%). Responses indicated that, following a minimum 3-week period of rest and recovery, an individualised timeline and gradual return to running progression can be considered. Screening for medical and psychological concerns, current physical capacity, and prior training history is recommended prior to a return to running.This study proposes recommendations for the initial guidance on return-to-running postpartum, framed in the context of current research and consensus from professionals. Future research is needed to strengthen and validate specific recommendations and develop guidelines for best practice when returning-to-running after childbirth.

Understanding experience, knowledge and perceived challenges related to bra fit for sports participation: a scoping review

The breasts are reported as the fourth largest barrier to participation in physical activity (PA). This scoping review provides a comprehensive understanding of experiences, knowledge and challenges relating to bra fit and sports participation. The search strategy was adopted by the Preferred Reporting Items for Scoping Reviews (PRISMA-ScR) guidelines and multiple databases were searched. All research was in English and within the last 20 years. Exclusion criteria excluded reviews, male participants and the inability to locate or access full-text articles. The JBI critical appraisal tool assessed methodological quality. Twenty-three studies were included. Key themes from the studies are breast motion during PA, sports bra design, perceived barriers to participation in PA and education/knowledge of breast support and bra fit. Increasing breast support reduces breast movement during PA yet breast motion and bra fit are still the most common breast concerns for females. This is likely influenced by poor breast knowledge, leading to poor breast support choices. Future research should explore to what extent breast motion, knowledge and bra fit influences sport participation, and this research should include a more diverse range of adult ages, cup sizes, ethnicities and PA levels to provide a wider understanding.

Increasing Breast Support is Associated With a Distal-to-Proximal Redistribution of Joint Negative Work During a Double-Limb Landing Task

Female athletes exhibit greater rates of anterior cruciate ligament injury compared with male athletes. Biomechanical factors are suggested to contribute to sex differences in injury rates. No previous investigation has evaluated the role of breast support on landing biomechanics. This study investigates the effect of breast support on joint negative work and joint contributions to total negative work during landing. Thirty-five female athletes performed 5 landing trials in 3 breast support conditions. Lower-extremity joint negative work and relative joint contributions to total negative work were calculated. Univariate analyses of variance were used to determine the effect of breast support on negative joint work values. Increasing levels of breast support were associated with lower ankle negative work (P < .001) and ankle relative contributions (P < .001) and increases in hip negative work (P = .008) and hip relative contributions (P < .001). No changes were observed in total negative work (P = .759), knee negative work (P = .059), or knee contributions to negative work (P = .094). These data demonstrate that the level of breast support affects lower-extremity biomechanics. The distal-to-proximal shift in negative joint work and relative joint contributions may be indicative of a more protective landing strategy for anterior cruciate ligament injuries.

A multi-stage intervention assessing, advising and customising sports bras for elite female British athletes

Appropriate breast support is recommended in sport; however, what constitutes appropriate support is complex, individual and often sports specific, particularly in elite sport given the wear duration. This intervention educated, assessed and advised elite British female athletes on breasts and bras; those with unresolved issues engaged in bespoke bra interventions. Following educational workshops (n = 80), breast/bra surveys (n = 60), individual bra assessments (n = 37); a rower, shooter, and hockey player participated in the bespoke bra intervention. Eighty-three per cent of athletes rated their breast/bra knowledge as ≤average. Fifty-one per cent experienced breast pain, affecting performance for 29%; seven used medication and one surgery to relieve symptoms. In individual bra assessments most wore ill-fitting, unsupportive bras and wanted bra advice. Bespoke bra interventions eliminated breast pain: for the rower, improved breast position and spine rotation; for the shooter, repositioned tissue and improved performance; and for the hockey player, accommodated smart devices. Whilst bespoke bra development is challenging, most elite athlete breast/bra issues are resolved via education, advice and fitting.

Increasing breast support is associated with altered knee joint stiffness and contributing knee joint biomechanics during treadmill running

Introduction

Greater breast support has been associated with improved running performance as measured by oxygen cost and running economy. Several candidate mechanisms have been proposed to underlie breast support-related improvements in running performance including increased knee joint stiffness. Greater knee joint stiffness has been associated with improved running performance (speed and metabolic cost), though the influence of breast support on knee joint stiffness has not been previously investigated. Therefore, the purpose of this study was to investigate the influence of increasing breast support on knee joint stiffness and its constituent components during treadmill running.

Methods

Thirteen recreational runners performed a 3-min running bout at their preferred running velocity in each of three breast support conditions: bare chested (CON), low support (LOW) and high support (HIGH) sports bras. Three-dimensional kinematics and ground reaction forces were collected simultaneously using a 10-camera motion capture system (240 Hz, Qualisys Inc.) and instrumented treadmill (1,200 Hz, Bertec Inc.). Visual3D (C-Motion Inc.) was used to calculate knee joint excursions, moments, powers and work while custom software (MATLAB) was used to calculate knee joint stiffness and breast displacements during the stance phase of running in each experimental condition. A series of 1 × 3 repeated measures analysis of covariance with post-hoc t-tests was used to evaluate the effect of breast support on knee joint biomechanics during treadmill running.

Results

Increasing levels of breast support were associated with greater knee joint stiffness (p = 0.002) as a result of smaller knee flexion excursions (p < 0.001). Increases in knee extension power (p = 0.010) were observed with increasing levels of breast support while no differences were observed in knee extension moments (p = 0.202) or work (p = 0.104).

Conclusion

Greater breast support is associated with increased knee joint stiffness resulting from smaller joint excursions. These findings may provide insight into the biomechanical mechanisms underlying previously reported improvements in running performance including reduced oxygen consumption and greater running economy.

A Systematic Analysis of 3D Deformation of Aging Breasts Based on Artificial Neural Networks

The measurement and prediction of breast skin deformation are key research directions in health-related research areas, such as cosmetic and reconstructive surgery and sports biomechanics. However, few studies have provided a systematic analysis on the deformations of aging breasts. Thus, this study has developed a model order reduction approach to predict the real-time strain of the breast skin of seniors during movement. Twenty-two women who are on average 62 years old participated in motion capture experiments, in which eight body variables were first extracted by using the gray relational method. Then, backpropagation artificial neural networks were built to predict the strain of the breast skin. After optimization, the R-value for the neural network model reached 0.99, which is within acceptable accuracy. The computer-aided system of this study is validated as a robust simulation approach for conducting biomechanical analyses and predicting breast deformation.

Greater Breast Support Is Associated With Reduced Oxygen Consumption and Greater Running Economy During a Treadmill Running Task

Introduction

Breast pain is a major barrier to running for women. While breast support through the use of sports bras reduces breast-related discomfort, the effect of breast support on running performance is less understood. Therefore, the purpose of the current study was to evaluate the effect of greater breast support on oxygen consumption and running economy during a treadmill running task.

Methods

Fifteen female recreational runners performed a 10-min treadmill running task at their preferred running speed in each of two sports bra conditions: low support and high support. Participants ran on an instrumented treadmill (1,200 Hz, Bertec) while indirect calorimetry was performed using a metabolic measurement system (100 Hz, TrueOne, ParvoMedics). Average VO₂ (absolute and relative) from the third to 10th minutes was used to evaluate oxygen consumption. Running economy was calculated as the distance traveled per liter of oxygen consumed. Paired samples t-tests were used to compare mean oxygen consumption and running economy values between breast support conditions. Correlation analysis was performed to evaluate the relationship between breast size and change in running performance.

Results

Greater breast support was associated with reductions in absolute (p < 0.001) and relative oxygen consumption (p < 0.001; LOW: 30.9 ± 7.1 ml/kg/min; HIGH: 28.7 ± 6.7 ml/kg/min). Greater breast support was associated with increases in running economy (p < 0.001; LOW: 88.6 ± 29.1 m/L O₂; HIGH: 95.2 ± 31.1 m/L O₂). No changes in temporospatial characteristics of running were observed including cadence (p = 0.149), step length (p = 0.300) or ground contact time (p = 0.151). Strong positive linear correlations were observed between the change in running performance metrics and breast size (Oxygen Consumption: p < 0.001, r = 0.770; Relative Oxygen Consumption: p < 0.001, r = 0769; Running Economy: p < 0.001, r = 0.807).

Conclusions

Greater breast support was associated with reduced oxygen consumption and increased running economy. These findings demonstrate that greater breast support is not only associated with improved comfort but also improved running performance.

Greater Breast Support Alters Trunk and Knee Joint Biomechanics Commonly Associated With Anterior Cruciate Ligament Injury

Objective

The female breast is a passive tissue with little intrinsic support. Therefore, women rely on external breast support (sports bras) to control breast motion during athletic tasks. Research has demonstrated that lower levels of breast support are associated with altered trunk and pelvis movement patterns during running, a common athletic task. However, no previous study has identified the effect of sports bra support on movement patterns during other athletic tasks including landing. Therefore, the purpose of this study was to examine the effects of breast support on trunk and knee joint biomechanics in female collegiate athletes during a double-leg landing task.

Methods

Fourteen female collegiate athletes completed five double-leg landing trials in each of three different sports bra conditions: no support, low support, and high support. A 10-camera motion capture system (250 Hz, Qualisys, Goteburg, Sweden) and two force platforms (1,250 Hz, AMTI, Watertown, MA, USA) were used to collect three-dimensional kinematics and ground reaction forces simultaneously. Visual 3D was used to calculate trunk segment and knee joint angles and moments. Custom software (MATLAB 2021a) was used to determine discrete values of dependent variables including vertical breast displacement, knee joint and trunk segment angles at initial contact and 100 ms post-initial contact, and peak knee joint moments. A repeated measures analysis of covariance with post-hoc paired samples t-tests were used to evaluate the effect of breast support on landing biomechanics.

Results

Increasing levels of breast support were associated with reductions in peak knee flexion (Right: p = 0.008; Left: p = 0.029) and peak knee valgus angles (Right: p = 0.011; Left: p = 0.003) as well as reductions in peak knee valgus moments (Right: p = 0.033; Left: p = 0.013). There were no changes in peak knee extension moments (Right: p = 0.216; Left: p = 0.261). Increasing levels of breast support were associated with greater trunk flexion angles at initial contact (p = 0.024) and greater peak trunk flexion angles (p = 0.002).

Conclusions

Lower levels of breast support are associated with knee joint and trunk biomechanical profiles suggested to increase ACL injury risk.

The impact of breast support garments on fit, support and posture of larger breasted women

Due to current measurement, sizing and fitting approaches, poor bra fit is prevalent amongst larger breasted women. The impact of improving bra fit hasn't yet been explored. This pre-clinical study aimed to explore immediate and short-term biomechanical responses to changing breast support garment. Asymptomatic participants (n=24) performed a static standing task, drop jumps and seated typing whilst kinematic data from the breasts and spine were recorded. Three breast support conditions were assessed: Usual, professionally fitted bra in the immediate term (PFB), and the same professionally fitted bra after four weeks wear (PFB₂₈). Bra fit assessments were included for both bras. All participants failed the bra fit assessment when wearing the Usual bra and 67% (n=16) failed when wearing the PFB. Less bra fit issues were present in the PFB, resulting in immediate biomechanical changes relating to breast support and spinal posture, yet nothing in the short term (PFB₂₈). This research sets the foundations for future work to investigate whether the implementation of better fitting breast support garments can influence musculoskeletal pain amongst larger breasted women, whilst attributing potential improvement of symptoms, objective measures of breast support and spinal posture.

The effect of washing and wearing on sports bra function

Sports bras provide support by restricting breast motion during exercise, which may prevent damage to breast structures. Laundering affects the mechanical properties of some sports bra materials. Bra function on the wearer after washing is unreported, meaning sports bra durability is unknown. This intervention study compared subjective and objective performance of sports bras that were washed, and worn/washed, to a control. Twenty-two females were assigned three identical sports bras; control, washed and worn/washed (washed after 60-min wear). Pre-intervention: breast position was recorded while standing and running in each bra. Comfort, fit and aesthetics were rated. Intervention: participants undertook their normal exercise in their worn/washed bra. Post-intervention: after 25 washes (n = 19), pre-intervention testing was repeated. Breast volume and control bra motion were consistent pre/post-intervention; however, post-intervention breast motion increased (20% mediolaterally, 16% superioinferiorly) in washed bras and (32% mediolaterally, 25% superioinferiorly) worn/washed bras. Post-intervention washed, and worn/washed bras were perceived as less supportive and washed bras less comfortable than worn/washed bras. Sports bra support reduced after 25 washes; this was compounded by wear. Participants detected reduced support, but comfort was sustained, suggesting replacement may not be considered. Guidelines on sports bra durability are recommended for breast health.

How the characteristics of sports bras affect their performance

Breast movement reduction (%) measures breast support and sports bra performance, however limited evidence exists on the sports bra characteristics which affect it. This study investigated breast movement reduction achieved by 98 sports bras, the categorisation of support levels, and the characteristics that contribute. Each bra was tested on ∼12 females (total n = 77). Relative breast position was recorded during sports bra and bare-breasted running, and breast movement reduction calculated; low, medium, high breast support tertiles were identified and compared to brand-classified support levels. Ten bra characteristics were identified, and regressions determined which characteristics contributed to performance. Breast movement reduction ranged from 36% to 74%; 69% of bras marketed as high support were in the high support tertile (>63%). Encapsulation style, padded cups, nylon, adjustable underband and high neck drop accounted for 37.1% of breast movement reduction variance. Findings facilitate high performance sports bra development and inform consumer choice. Practitioner summary: Little is known about the biomechanical breast support which sports bras actually provide. This original research facilitates high performance sports bra development, and helps inform consumer choice, by identifying the breast movement reduction of a large sample of sports bras, and the characteristics which impact sports bra performance. Abbreviations: A-P: anterior-posterior; BMI: body mass index; C7: 7th cervical vertebrae; LNIP: left nipple; M-L: medial-lateral; PX: xiphoid process; ROM: range of motion; S-I: superior-inferior; SD: standard deviation; STN: suprasternal notch; T8: 8th thoracic vertebrae.

Breast Biomechanics: What Do We Really Know?

Although half the world's population will develop breasts, there is limited research documenting breast structure or motion. Understanding breast structure and motion, however, is imperative for numerous applications, such as breast reconstruction, breast modeling to better diagnose and treat breast pathologies, and designing effective sports bras. To be impactful, future breast biomechanics research needs to fill gaps in our knowledge, particularly related to breast composition and density, and to improve methods to accurately measure the complexities of three-dimensional breast motion. These methods should then be used to investigate breast biomechanics while individuals, who represent the full spectrum of women in the population, participate in a broad range of activities of daily living and recreation.

Biomechanics of Breast Support for Active Women

More systematic breast biomechanics research and better translation of the research outcomes are necessary to provide information upon which to design better sports bras and to develop effective evidence-based strategies to alleviate exercise-induced breast pain for women who want to participate in physical activity in comfort.

Sports bra but not sports footwear decreases breast movement during walking and running

Running is a modality that has a large number of adepts, including women. Therefore, it is important to understand how sportswear can help women, with special attention to the breast movement. The aim of this study was to analyse the effect of different combinations of breast support and footwear on the breast movement during walking and running. Twenty women performed treadmill walking (5 km/h) and running (7 and 10 km/h) combining different footwear (barefoot, minimalist, and traditional) and breast support conditions (bare breast, everyday bra, and sports bra). Three-dimensional data from breast and trunk markers were tracked for 10 stride cycles. Relative breast displacement was calculated and derived for velocity. An interaction effect was observed between support, footwear, and speed conditions. The bare breast conditions presented differences from the other conditions in the majority of the kinematic variables, presenting higher breast displacement and velocity values. On the other hand, the sports bra conditions presented the lowest values for the kinematics variables. In the vertical component of breast displacement during running (10 km/h) we verified that the sports bra presented reductions of 56% and 43% in relation to the bare breast and everyday bra conditions, respectively. Despite this, no differences were found between footwear within each breast support condition. A sports bra is efficient to decrease breast movement. In addition, neither of the tested footwear was able to decrease these movements.

The relationship between breast size and aspects of health and psychological wellbeing in mature-aged women

OBJECTIVES

Increases in breast size with age are common but have not been widely examined as a factor that could affect the health and psychological wellbeing of mature-aged women. The purpose of this study was to examine the relationships between breast size and aspects of health and psychological wellbeing in mature-aged women.

METHODS

This was a cross-sectional study of mature-aged women (⩾40 years). Breast size (breast size score) was determined from self-reported bra size and was examined against health-related quality of life (Medical Outcomes Study Short-Form 36 and BREAST-Q), body satisfaction (numerical rating scale), breast satisfaction (BREAST-Q), physical activity levels (Human Activity Profile), the presence of upper back pain and breast and bra fit perceptions.

RESULTS

Two hundred sixty-nine women (40-85 years) with bra band sizes ranging from 8 to 26 and bra cup sizes from A to HH participated. The mean (standard deviation) breast size score of 7.7 (2.7) was equivalent to a bra size of 14DD. Increasing breast size was associated with significantly lower breast-related physical wellbeing (p < 0.001, R2 = 0.043) and lower ratings of body (p = 0.002, R2 = 0.024) and breast satisfaction (p < 0.001, R2 = 0.065). Women with larger breasts were more likely to be embarrassed by their breasts (odds ratio: 1.49, 95% confidence interval: 1.31 to 1.70); more likely to desire a change in their breasts (odds ratio: 1.55, 95% confidence interval: 1.37 to 1.75) and less likely to be satisfied with their bra fit (odds ratio: 0.84, 95% confidence interval: 0.76 to 0.92). Breast size in addition to age contributed to explaining upper back pain. For each one-size increase in breast size score, women were 13% more likely to report the presence of upper back pain.

CONCLUSION

Larger breast sizes have a small but significant negative relationship with breast-related physical wellbeing, body and breast satisfaction. Larger breasts are associated with a greater likelihood of upper back pain. Clinicians considering ways to improve the health and psychological wellbeing of mature-aged women should be aware of these relationships.