Bra-breast forces generated in women with large breasts while standing and during treadmill running: Implications for sports bra design

Construction of multi-component finite element model to predict biomechanical behaviour of breasts during running and quantification of the stiffness impact of internal structure

This study aims to investigate the biomechanical behaviour and the stiffness impact of the breast internal components during running. To achieve this, a novel nonlinear multi-component dynamic finite element method (FEM) has been established, which uses experimental data obtained via 4D scanning technology and a motion capture system. The data are used to construct a geometric model that comprises the rigid body, layers of soft tissues, skin, pectoralis major muscle, fat, ligaments and glandular tissues. The traditional point-to-point method has a relative mean absolute error of less than 7.92% while the latest surface-to-surface method has an average Euclidean distance (d) of 7.05 mm, validating the simulated results. After simulating the motion of the different components of the breasts, the displacement analysis confirms that when the motion reaches the moment of largest displacement, the displacement of the breast components is proportional to their distance from the chest wall. A biomechanical analysis indicates that the stress sustained by the breast components in ascending order is the glandular tissues, pectoralis major muscle, adipose tissues, and ligaments. The ligaments provide the primary support during motion, followed by the pectoralis major muscle. In addition, specific stress points of the breast components are identified. The stiffness impact experiment indicates that compared with ligaments, the change of glandular tissue stiffness had a slightly more obvious effect on the breast surface. The findings serve as a valuable reference for the medical field and sports bra industry to enhance breast protection during motion.

Does an alternative breast support garment provide symptomatic relief for larger breasted women with chronic non-specific back pain?

BACKGROUND

Nonsurgical guidelines recommend implementing a correctly fitted bra when managing back pain among larger breasted women. Achieving this is challenging with current bra solutions, sizing principles, and fitting approaches. Persistent wearing of an ill-fitting bra can cause negative health implications, including non-specific back pain.

OBJECTIVES

This study investigated immediate and short-term biomechanical and pain responses to changing breast support garment among larger breasted women with non-specific back pain.

METHODS

Participants (n = 24) performed a standing task, drop jumps, and seated typing tasks while bra and spinal kinematic data were recorded. Five breast support conditions were assessed: participants' usual bra (control), a professionally fitted bra in the immediate term (standard) and after 4 weeks wear (standard28), and a bra with an alternative design, measurement, and fitting approach in both the immediate term (alternative) and after 4 weeks wear (alternative28). A bra fit assessment and clinical pain/disability questionnaires were included.

RESULTS

All participants failed the bra fit assessment in the control bra, compared with 87.5% (n = 21) in the standard and 4.2% (n = 1) in the alternative bras. The standard28 and alternative28 bras provided symptomatic relief, with the alternative28 bra improving a greater number of outcome measures. Reduced nipple-sternal-notch distance was observed only in the alternative28 bra condition.

CONCLUSIONS

Symptomatic relief may be associated with the resting position of the breast tissue on the anterior chest wall. The alternative bra may provide potential clinical benefit if implemented as part of a nonsurgical or conservative pain management strategy. Alternative breast support garments should be considered to provide solutions to the problems associated with traditional bras.

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.

Impact of implant-based breast reconstruction on bra fit

Comfortable and well-fitting bras are necessary for good quality of life but hard to find for women who undergo reconstruction after breast cancer treatment. This study aimed to provide data to inform bra designs for breast cancer survivors. We measured anatomical distances used in bra design on 3D clinical photographs of patients who underwent unilateral and bilateral implant-based reconstruction to quantify changes after reconstruction relative to the measured values before the person underwent surgery. We performed additional assessments of symmetry before surgery and after reconstruction, and we used regression analyses to identify associations between the measurements and patient characteristics, such as BMI. Overall, almost all measurements changed significantly in implant-based reconstructed breasts relative to native breasts. We highlight several aspects of ergonomic bra design that will be impacted by the changes in anatomical distances. Practitioner summary: Implant-based breast reconstruction surgery changes the breast so that off-the-rack bras are inadequate. This study provides designers with measurement data from women who underwent implant-based reconstruction to inform bra designs for this population. The key factor designers need to account for is the semi-spherical shape of the reconstructed breast.

Changes to breast structure and function across a woman's lifespan: Implications for managing and modeling female breast injuries

BACKGROUND

Female breasts change throughout a woman's life in response to fluctuating hormonal influences. Individuals managing active women and those modeling female breasts must understand these structural and functional changes across a female's lifespan because these changes affect breast injuries sustained by women.

METHODS

We initially review female breast structure and function and then describe how breast structure changes across a woman's lifespan. Key studies about direct contact and frictional breast injuries are then summarized. Limitations of current breast injury research, gaps in knowledge about breast injuries incurred by specific populations, and the lack of breast injury models are also highlighted.

FINDINGS

With minimal anatomical protection, it is unsurprising that breast injuries occur. Although research about breast injuries is scant, direct contact during blunt force trauma to the anterior chest wall and frictional breast injuries have been reported. There is a lack, however, of research documenting the incidence and severity of breast injuries incurred in occupational settings and in women's sports. Therefore, to design effective breast protective equipment, we recommend research to model and investigate the mechanisms and forces involved in breast injuries, particularly injuries sustained during sport.

INTERPRETATION

This unique review summarizes how female breasts change over a woman's life span, with implications for breast injuries sustained by females. Knowledge gaps about female breast injuries are highlighted. We conclude by recommending research required to develop evidence-based strategies to improve how we classify, prevent, and clinically manage breast injuries sustained by females.

SUMMARY

We review changes to the breast across a woman's lifespan, highlighting implications for managing and modeling female breast injuries.

Fundamental Research on the Invention of Breast Support Underwear with a Focus on Women's Comfort

The purpose of this study was to establish a system for measuring breast underling pressure, evaluate the degree of sustained underling pressure, and verify basic data on the breast lifting distance to improve it. We measured the lifting distance and force at which 24 adult women felt comfortable when their breasts were lifted with an uncovered cloth. The results revealed that the larger the breast size, the greater the pull-up distance and the wider the lifting distance perceived as comfortable. The validity of the measurement method in this study was determined to be useful for the measurement of breast ptosis pressure and breast ptosis position because the measurement was performed at least three times per participant, and the error was small. In the future, we would like to clarify the type of brassiere that supports the breast and gives women a sense of comfort.

Sports Bra Pressure: Effect on Body Skin Temperature and Wear Comfort

Sports bras are an essential apparel for active women, but may exert excessive pressure that negatively affects thermoregulation, thermal comfort and wear sensation. This study measures skin temperature changes during short durations of exercise on a treadmill with different bra pressures. The results based on 21 female subjects (age: 27.2 ± 4.5 years old) show that bras with more pressure at the underband or shoulder straps do not cause statistically significant skin temperature changes during exercise (p > 0.05). Nevertheless, compared to the optimal bra fit, significant differences in bra-breast skin temperature are found during running, cooling down and sitting when the bra pressure is increased (p < 0.05), particularly under bra cup (T1) in this study. The FLIR thermal images can visualize the skin temperature changes at abdomen throughout the four activity stages. Subjective sensations of bra thermal comfort, pressure and breast support are assessed. Despite the increased pressure on the shoulders and chest wall, perceptions towards thermal comfort remain unchanged. The perceived pressure comfort and support sensation amongst the 4 bra conditions are comparable. Interestingly, positive sensations of pressure comfort and breast support are perceived with a tight-fitting sports bra during treadmill exercise. High pressures induced by sports bras (>4 kPa) that habitually considered harmful to the human body may not lead to wear discomfort but enhance bra support sensation and a sense of security to the wearers.

Maximizing Recovery in the Postpartum Period: A Timeline for Rehabilitation from Pregnancy through Return to Sport

Increased participation and duration in sport has become commonplace for women with their involvement often including the transition to motherhood in the peak of their athletic careers. No rehabilitation models that assess the full spectrum of pregnancy to postpartum have been developed for women to assist in safe exercise progressions that reduce postpartum symptoms and optimize performance during the return to full activity. Referral to physical therapy both in the prenatal and postnatal period is currently not considered standard of care to reduce prevalence of symptoms such as musculoskeletal pain, diastasis recti, and pelvic floor dysfunction which may ultimately interfere with physical activity and performance. This commentary presents a timeline and suggested progression for exercise participation to improve awareness of the musculoskeletal changes that occur after labor and delivery. The concepts covered may increase the understanding of how to manage pregnant and postpartum athletes from a musculoskeletal perspective and serve as a starting point for establishing appropriate and guided rehabilitation for safe return to sport after childbirth.

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.

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.

Breast biomechanics, exercise induced breast pain (mastalgia), breast support condition and its impact on riding position in female equestrians

Breast biomechanics, exercise-induced breast pain (EIBP) and performance effects in female athletes are established. Wearing sports bras during exercise reduces breast movement and EIBP. Despite the prevalence of female equestrians, little investigation of breast movement during horse riding exists, yet excessive breast movement, embarrassment and EIBP are reported. Breast movement relative to the torso is linked to EIBP, associated with magnitude and direction of forces generated. Equestrians may experience novel breast and upper-body movement patterns in response to large vertical excursions of the horse. This study aimed to establish relative vertical breast displacement (RVBD), EIBP and positional changes in three support conditions: ‘no support’, ‘low support’ and ‘high support’. Thirty-eight female equestrians rode a Racewood™ Equine Simulator in each breast support condition in medium walk, medium trot (sitting) and medium canter. Trials were filmed and analysed using Quintic® Biomechanics V29. Significant reductions in RVBD (P<0.001) and EIBP (P<0.001) were identified with increased breast support in all gaits. In medium trot (sitting) a significant reduction in range of movement (ROM) of shoulder-elbow-wrist (P<0.001) was seen from low to high support. ROM of torso-vertical angles were reduced from no support to low support (P<0.001) and further by high support (P<0.001). This reduction in ROM was significantly greater in large breasted riders (cup size DD-FF) (n=21) (P<0.001) compared to small breasted (cup size AA-D) (n=17). These results suggest that appropriate breast support positively impacts EIBP and riding position in female riders possibly enhancing performance. As RVBD and reported EIBP were not wholly comparative with results in female runners, further research is warranted to establish breast movement in equestrianism in three dimensions.

Sports Bra Preferences by Age and Impact of Breast Size on Physical Activity among American Females

For many females, sports bras are an essential piece of equipment for participation in sports and physical activity. Breast pain or discomfort from lack of support may be a contributing factor to the noted gender disparity in physical activity of females compared to males. Our objective was to evaluate sports bra usage and characterize sports bra preferences of an active female cohort. This multicenter cross-sectional survey study was conducted at five geographically distinct academic centers. Our measure was administered during outpatient sports medicine clinic visits to females aged 11–64 years old. Chi-square tests were used to compare characteristics across subgroups. Our analysis consisted of 438 respondents, with a mean age of 22 ± 12.2 years. More than a quarter (27.4%) reported lack of breast support prevented them from being active or exercising. Age (p = 0.03), breast size (p < 0.0001), and household income (p = 0.01) were significantly associated with greater frequency of physical activity being limited by lack of breast support. Lack of breast support may be an important barrier for young females of specific populations to meeting physical activity recommendations. Further research is needed to improve the understanding of this important piece of sporting equipment for women.

Bra-body armour integration, breast discomfort and breast injury associated with wearing body armour

This study investigated whether female soldiers experience bra integration or breast discomfort/injuries related to body armour use and whether these issues were associated with breast size. Ninety-seven Australian Defence Force female soldiers completed a questionnaire and had their breast volume assessed (range: 91-919 ml/breast) using three-dimensional scanning. Twenty-two percent (n = 21) of participants reported integration issues between their bra and body armour, 63% (n = 61) reported breast discomfort while wearing body armour and 27% (n = 26) reported experiencing a breast injury related to wearing body armour. Although bra-body armour integration was not dependent upon breast size, female soldiers with medium-large breasts reported significantly more breast discomfort and injuries when using body armour compared to participants with small breasts. These findings highlight the importance of developing body armour systems that cater to the range of breast sizes of female soldiers in order to improve bra-body armour integration and reduce breast discomfort and injury. Practitioner summary: This exploratory research provides evidence of bra integration issues, breast discomfort and breast injury experienced by female soldiers when wearing body armour. Given the growing representation of women in military organisations, strategies to alleviate these issues for female users of body armour, particularly those with larger breast sizes, are required.

Multi-study randomised controlled trial to develop, implement and evaluate bra prescription to reduce breast pain and improve quality of life

BACKGROUND

and Purpose: Breast pain is a common condition presented at breast care clinics and bras are often recommended to reduce symptoms, although criteria and pathways for obtaining appropriate bras are limited. This multi-study, randomised controlled trial (RCT) aimed to establish criteria and performance variables to prescribe bras for breast pain patients, to implement this bra prescription, and evaluate whether, compared to standard care alone, the bra prescription improves breast pain and quality of life (QoL).

MATERIALS AND METHODS

Eighteen breast pain patients from a UK hospital were assigned to standard care or bra prescription groups and completed the study. Bra prescription patients were prescribed a bra to wear every day for eight weeks. Patient Global Impression of Change (PGIC), breast pain intensity, QoL, and adherence were assessed.

RESULTS

Between-groups there were no differences in baseline breast pain or QoL and no differences in PGIC or breast pain following the intervention. Within-groups, improvements in QoL within bra prescription patients were identified.

CONCLUSION

This study developed a framework for bra prescription for breast pain patients and the intervention demonstrated improvements in QoL.

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.

Body Scan Processing, Generative Design, and Multiobjective Evaluation of Sports Bras

Sports bras are critical to the comfort and performance of female athletes, yet mechanical models of sports bras are generally not used to guide their design. Typically, assessing any sports bra’s performance requires time-consuming and expensive biomechanical testing, which limits the number of designs considered. To more broadly advance knowledge on how different design properties of sports bras affect their performance, this paper presents a new design framework to explore and evaluate the sports bra design space. The framework incorporates methods for body scan analysis, fast simulation, design generation, and performance evaluation. Using these methods together enables the rapid exploration of hundreds, or thousands, of designs—each one having been evaluated on key metrics related to sports bra performance, namely, range of motion and average pressure. With this framework, designers can potentially discover a diverse set of new, high-performing sports bra concepts, as well as gain insights into how design decisions affect performance.

Use and perception of breast protective equipment by female contact football players

OBJECTIVES

Female contact football players sustain contact breast injuries that can negatively affect their sporting performance. This study investigated what female contact football players wear on their breasts during training and competition, and their perceptions on the protection provided by these garments against contact breast injury.

DESIGN

A custom-designed survey about breast injuries and prevention strategies was distributed via an online link to coaches and team staff of contact football teams throughout Australia. The fit and features of breast support and/or protection that players wore during training and competition were also directly assessed.

METHODS

207 female Australian Football League (AFL), Rugby League, Rugby Union (XVs) and Rugby 7s players completed the survey. The breast support of 112 of these players was also assessed.

RESULTS

Only 17% (n=35) of players reported using breast protective equipment, of which 66% (n=23) perceived it provided protection against contact breast injuries. Reasons reported for not using protective equipment included not knowing it existed (n=79, 53%), it was too uncomfortable/hot (n=50, 24%) and that it did not fit or was restrictive (n=33, 22%). Although most players (n=97, 87%) reported to wear a sports bra, 52% (n=58) wore an ill-fitted bra and only 31% (n=63) perceived it provided any protection against contact breast injuries.

CONCLUSIONS

Breast protective equipment is not commonly worn by female contact football players reportedly due to a lack of awareness of its existence, discomfort or poor fit. Although most female contact football players usually wore a sports bra, most players perceived these bras did not provide breast protection.

Validity and Reliability of Three Commercially Available Smart Sports Bras during Treadmill Walking and Running

A variety of wearable technology devices report heart rate. Heart rate sensing smart bras are manufactured for females who participate in activity, however accuracy has not been determined. The purpose was to determine the validity of heart rate measures in three commercially available sports bras during walking and running. Twenty-four healthy females completed bouts of treadmill exercise. The Adidas Smart sports bra, Berlei sports bra, and Sensoria Fitness biometric sports bra were tested. Participant perception of each garment was obtained immediately after the participant divested the sports bra. The Adidas Smart sports bra was valid only during rest (Intraclass correlation Coefficient [ICC] = 0.79, mean absolute percentage error [MAPE] = 4.5%, Limits of Agreement [LoA]=−8 to 8). The Berlei sports bra was valid across all conditions (ICC = 0.99, MAPE = 0.66%, LoA = −19 to 19), and the Sensoria biometric bra was valid during rest and walking (ICC = 0.96, MAPE = 1.9%, LoA = −15 to 12). Perception of the smart sports bras was higher for the Adidas Smart sports bra and Sensoria Fitness sports bra, and lower for the Berlei sports bra. Sports bra manufacturers designing wearable technology garments must consider the ability of returning accurate biometric data while providing necessary function and comfort to females engaging in physical activity.

Effects of obesity on breast size, thoracic spine structure and function, upper torso musculoskeletal pain and physical activity in women

PURPOSE

This study investigated the effects of obesity on breast size, thoracic spine structure and function, upper torso musculoskeletal pain and physical activity participation in women living independently in the community.

METHODS

A total of 378 women were divided into 3 groups (Not Overweight: body mass index (BMI) = 22.5 ± 0.2 kg/m² (mean ± SE); Overweight: BMI = 27.4 ± 0.3 kg/m²; Obese: BMI = 35.4 ± 0.3 kg/m²). Outcome variables of breast volume (mL), thoracic flexion torque (N·m), thoracic kyphosis (degrees), upper torso musculoskeletal pain (score) and time spent in physical activity (min) were calculated and compared among the 3 groups, adjusting for between-group differences in age.

RESULTS

There was a significant main effect of BMI on all outcome variables. Participants classified as Obese displayed significantly larger breasts, had greater thoracic flexion torques and reported less time participating in physical activity relative to the participants who were classified as Not Overweight and Overweight. Participants in the Obese group also displayed significantly more thoracic kyphosis and reported significantly more upper torso musculoskeletal pain compared to their counterparts who were classified as Not Overweight.

CONCLUSION

This study is the first to demonstrate that increased obesity levels were associated with compromised kyphosis and loading of the thoracic spine, as well as increased symptoms of upper torso musculoskeletal pain and reduced time spent in physical activity in women living in the community. We recommend further research to determine whether evidence-based interventions designed to reduce the flexion torque generated on the thoracic spine can improve these symptoms of upper torso musculoskeletal pain and the ability of women with obesity to participate in physical activity.

Effect of external breast prosthesis mass on bra strap loading and discomfort in women with a unilateral mastectomy

BACKGROUND

A common complaint of women who wear external breast prostheses following mastectomy is that they are too heavy. This study aimed to investigate the effect of external breast prosthesis mass on bra strap loading, discomfort and perceived pressure in women with a unilateral mastectomy.

METHODS

Pressures exerted at the bra strap-shoulder interface and ratings of discomfort and perceived pressure (visual analogue scales; 0-12 cm) were recorded for 17 women (mean 68 (SD 5.7) years) who had a unilateral mastectomy. Data were collected during standing and walking while the women wore a Lightweight prosthesis and Standard-weight prosthesis. Pressure, discomfort and perceived pressure between the two prosthesis conditions were compared using Wilcoxon Signed Ranks and the sum of the pressure values during walking and standing were correlated with discomfort and perceived pressure scores using Spearman's Rho tests.

FINDINGS

Mean peak bra strap pressures were significantly less when the participants wore the Lightweight prosthesis compared to the Control prosthesis during walking (0.28 (SD 0.14) N/cm² versus 0.35 (SD 0.20) N/cm²; P < 0.05) but not during standing. No significant main effect of prosthesis mass on the participants' ratings of discomfort or perceived pressure were found, which were highly variable.

INTERPRETATION

Reducing external breast prosthesis mass decreased mean peak bra strap pressures during walking but this was not accompanied with reductions in bra strap-shoulder discomfort or perceived pressure. Treatment strategies to decrease bra strap-shoulder interface loading due to external breast prostheses mass could assist women who complain of prosthesis heaviness during physical activity.

Upper back pain in postmenopausal women and associated physical characteristics

The physical characteristics of postmenopausal women that are associated with upper back pain are not well-understood. The aim of this cross-sectional study was to identify the physical characteristics associated with presence and severity of upper back pain in healthy postmenopausal women. Self-reported upper back pain presence (within the previous month) and severity (numerical rating scale) were examined against the physical characteristics: height; weight; body mass index; breast size; breast ptosis; upper back extensor muscle endurance (isometric chest raise test); head, shoulder and upper back posture (photogrammetry); thoracic extension mobility (photogrammetry); bone mineral density (dual-energy x-ray absorptiometry (DXA)); body composition (DXA); and thoracic kyphosis, thoracic osteoarthritis and thoracic vertebral fracture (all radiography). A multivariable logistic regression model, adjusted for age, was built using physical characteristics with a significant univariate association with upper back pain. Censored Tobit regression, adjusted for age, was used to examine each physical characteristic against upper back pain severity. Postmenopausal women (n = 119) with a mean (SD) age of 61.4 (7.0) years participated in the study. After adjusting for age, the physical characteristics independently associated with upper back pain were: height (OR: 0.50, 95% CI: 0.31–0.79); and upper back extensor muscle endurance (OR: 0.46, 95%CI: 0.28–0.75). This model explained 31% of the variance in upper back pain (p<0.001). After adjusting for age, being taller and having better upper back extensor muscle endurance were associated with lower odds for upper back pain. After adjusting for age, differences in upper back pain severity were explained by upper back extensor muscle endurance (p = <0.001) and lean mass (p = 0.01). Conclusion: As a modifiable physical characteristic of postmenopausal women with upper back pain, upper back extensor muscle endurance is worth considering clinically.

A Comprehensive Method to Measure 3-Dimensional Bra Motion During Physical Activity

Breast and bra motion research aims to understand how the breasts/bra move to aid development of apparel that minimizes motion. Most previously published research has tracked nipple motion to represent bra motion. However, this method does not provide information regarding regional tissue motion. A more comprehensive approach might facilitate understanding how the entire soft-tissue mass moves during physical activities. This study developed and tested an objective method to comprehensively measure 3-dimensional bra motion, including regional displacement and velocity, displacement phasing, and surface stretch. To test the method, 6 females were fitted with a minimally supportive, seamless bra (small bra n = 3; large bra n = 3). Data were collected as participants ran on a treadmill. Results indicated marker displacement, velocity, link stretch, and link stretch velocities reached as high as 52.6 (6.8) mm, 504.8 (88.7) mm/s, 29.5% (7.1%) of minimum length, and 3.8 (1.0) mm/s/mm, respectively, with the large bra having greater motions compared with the small. Most bra motion occurred above/below the nipple region and at the bra’s strap–body interface, independent of bra size. Importantly, maximum marker displacement and velocity did not occur at the nipple. Measurements obtained from this new method may be important for designing innovative clothing that minimizes bra motion during physical activity.

Effects of age and body mass index on breast characteristics: a cluster analysis

Limited research has quantified variation in the characteristics of the breasts among women and determined how these breast characteristics are influenced by age and body mass. The aim of this study was to classify the breasts of women in the community into different categories based on comprehensive and objective measurements of the characteristics of their breasts and torsos, and to determine the effect of age and body mass index on the prevalence of these breast categories. Four breast characteristic clusters were identified (X-Large, Very-ptotic & Splayed; Large, Ptotic & Splayed; Medium & Mildly-ptotic; and Small & Non-ptotic), with age and BMI shown to significantly affect the breast characteristic clusters. These results highlight the difference in breast characteristics exhibited among women and how these clusters are affected by age and BMI. The breast characteristic clusters identified in this study could be used as a basis for future bra designs and sizing systems in order to improve bra fit for women. Practitioner summary: This original research provides evidence for bra designers and manufacturers on the diverse breast characteristics exhibited by women within the population and the significant effect that both body mass index and age have on the breast characteristic clusters. Future bra designs should consider the variation in breast characteristics among women.

ABBREVIATIONS

BMI: Body Mass Index; UBCC: Under-bust chest circumference.

Can breast characteristics predict upper torso musculoskeletal pain?

BACKGROUND

Several studies have associated a large breast size with an increased prevalence and severity of musculoskeletal pain, particularly pain in the upper torso. Despite this evidence, no research has explored whether breast size or related characteristics are risk factors for upper torso musculoskeletal pain.

METHODS

A backward multiple regression analysis was performed to identify whether characteristics of the breasts and upper torso, as well as physical factors known to be associated with musculoskeletal pain, could predict musculoskeletal pain among a cohort of 378 Australian women aged 18 years and over who had a wide range of breast sizes.

FINDINGS

The model identified that breast volume, age and nipple-to-nipple distance predicted 23% of the variance in upper torso musculoskeletal pain reported by the participants.

INTERPRETATION

Women with a larger breast volume, lower age and a greater nipple-to-nipple distance were predicted to report a higher upper torso musculoskeletal pain score.

An investigation of bra concerns and barriers to participation in horse riding

Horse riding is a female-dominated sport where participation levels are declining. The influence of the breast on participation levels and current satisfaction with bras for this activity is unknown. This study aimed to investigate bra concerns and breast-related barriers to participation in horse riding. A 6-part, 32 question online survey was completed by 1,324 females who participated in horse riding. Descriptive and chi-squared analyses were utilised; inductive content analysis was completed to analyse qualitative responses. At least one breast-related barrier was reported by 25% of all participants. Larger-breasted riders were less satisfied (P<0.001) with their bras. 70% of riders stated that improvements needed to be made in bras to help reduce breast health issues, with support, style and fit the most common reasons cited. This study highlights the importance of addressing breast-related barriers and provides rationale for the development of equestrian-specific breast support garments and educational initiatives.

Upper torso pain and musculoskeletal structure and function in women with and without large breasts: A cross sectional study

BACKGROUND

Women with large breasts frequently experience upper torso pain secondary to their breast size. Evidence is lacking on the underlying causes of this pain. This study investigated whether upper torso pain and musculoskeletal structure and function differed between women with large breasts and women with small breasts.

METHODS

A linear regression, adjusting for body mass, compared the upper torso pain, thoracic flexion torque due to breast mass, thoracic kyphosis, shoulder active range-of-motion, and scapular retraction muscle strength of 27 women with large breasts (bilateral breast volume>1200ml, age 45.9y SD 9.9y, BMI 29.0kg/m² SD 3.8kg/m²) and 26 women with small breasts (bilateral breast volume <800ml, age 43.8y SD10.9y, BMI 23.3kg/m² SD 2.9kg/m²).

FINDINGS

Women with large breasts reported a higher upper torso pain score (46.6, 95%CI 33.3-58.0 versus 24.1, 95%CI 12.5-37.8), accompanied by a larger flexion torque (5.9Nm, 95%CI 4.5-5.8Nm versus 0.9Nm, 95%CI 0.8-2.4Nm), greater thoracic kyphosis (34°, 95%CI 31-38° versus 27°, 95% CI 24-31°), decreased shoulder elevation range-of-motion (160°, 95%CI 158-163° versus 169°, 95%CI 166-172°), and decreased scapular retraction endurance-strength (511.4s, 95%CI 362.2-691.3s versus 875.8s, 95%CI 691.5-1028.4s) compared to the women with small breasts.

INTERPRETATION

Differences in the upper torso posture, range-of-motion, and muscle strength of women with large breasts provides insight into underlying causes of their musculoskeletal pain. This information can be used to develop evidence-based assessment and treatment strategies to relieve and prevent symptom progression.

The Bionic Bra: Using electromaterials to sense and modify breast support to enhance active living

BACKGROUND

Although the most supportive sports bras can control breast motion and associated breast pain, they are frequently deemed uncomfortable to wear and, as a result, many women report exercise bra discomfort. Given that exercise bra discomfort is associated with decreased levels of physical activity, there is a pertinent need to develop innovative solutions to address this problem.

OBJECTIVES

This research aimed to evaluate the use of electromaterial sensors and artificial muscle technology to create a bra that was capable of detecting increases in breast motion and then responding with increased breast support to enhance active living.

METHODS

The research involved two phases: (i) evaluating sensors suitable for monitoring and providing feedback on changes in the amplitude and frequency of breast motion, and (ii) evaluating an actuator capable of changing breast support provided by a bra during activity.

RESULTS

When assessed in isolation, the developed technologies were capable of sensing breast motion and actuating to provide some additional breast support.

CONCLUSIONS

The challenge now lies in integrating both technologies into a functional sports bra prototype, and assessing this prototype in a controlled biomechanical analysis to provide a breast support solution that will enable women to enjoy active living in comfort.

Breast volume is affected by body mass index but not age

BACKGROUND

This study aimed to establish normative breast volume data for women of varying ages, body masses and breast sizes, and to determine the effect of age and body mass index (BMI) on breast volume.

METHODS

The breast volume of 356 women (age range: 18.1-83.7 years; BMI range: 18.4-54.5 kg/m²) was measured using three-dimensional scanning in a prone position.

RESULTS

Breast volumes ranged from 48 to 3100 mL. Although breast volume was not significantly affected by age, it was significantly affected by BMI, with the breast volume of overweight and obese women being two-to-three times greater than women with normal BMI's.

CONCLUSION

It is recommended that bra cups must be designed to support the wide range and increasing magnitude of breast volumes exhibited by women. Practitioner summary: This original research provides evidence for bra designers and manufacturers on the range of breast volumes of women and the significant effect of BMI on breast volume. Bra cups need to be designed to support the wide range and increasing magnitude of breast volumes exhibited by women.

Three-dimensional scanning in women with large, ptotic breasts: implications for bra cup sizing and design

BACKGROUND

This study aimed to compare breast volume calculated from scanning large, ptotic breasts of women while they were standing upright relative to when lying prone in order to identify the error associated with breast volume calculations.

METHODS

Breast volume and visualisation were compared in 50 women with large breasts (D⁺ bra cup size) while they were scanned in three different positions.

RESULTS

Full visualisation of both breasts occurred in 100% of participants in the prone position and only 5% of participants in either standing position. Breast volume was significantly greater (p < 0.01) in the prone position, with the percentage of underestimation in the standing position increasing as breast volume increased.

CONCLUSION

Breast volume measured by three-dimensional scanning in the standing position will be underestimated by 7-10% in large, ptotic breasts. Consideration of these inaccuracies in breast volume relative to breast size can assist bra manufacturers when designing bras. Practitioner Summary: Errors have been reported when measuring the breast volume of women with large, ptotic breasts using three-dimensional scanning. This original research provides evidence for bra designers and manufacturers on the degree of error associated with this measurement. These errors should be accounted for in future bra designs.

Bra strap orientations and designs to minimise bra strap discomfort and pressure during sport and exercise in women with large breasts

Background

Bra straps are a primary source of discomfort during sport and exercise, particularly for women with large breasts. This study aimed to investigate the effects of altering bra strap orientation and design on bra strap comfort, pressure and breast support in women with large breasts. This is a descriptive laboratory study.

Methods

Bra strap discomfort (visual analogue scale, 0 to 10), pressure (custom-designed 10 mm² calibrated pressure sensor, 0.5 to 24 kPa range, 50 Hz, S2011, Novel GmbH, Munich, Germany, placed under the right bra strap at the crest of each participant’s shoulder), preference ranking and vertical breast displacement (VBD; Optotrak Certus® motion capture system, 200 Hz, Northern Digital, Ontario, Canada) data during dynamic treadmill running and static upright standing (pressure only) were collected for 23 active women with large breasts (D+ cup size) while they wore an encapsulation sports bra with six different bra strap conditions (two bra strap orientations: vertical and cross-back; three bra strap designs: standard width, wide and gel).

Results

Bra strap discomfort was significantly less (p ≤ 0.001) in the vertical compared to the cross-back strap orientation, which was the most preferred orientation despite no significant difference in strap pressure. The wide strap design had the lowest discomfort scores, significantly lower strap pressure compared to the standard width and gel strap designs (p < 0.001), and was equally the most preferred design with the gel straps. There was no significant difference in VBD among the six strap conditions.

Conclusions

Bra straps that are vertically orientated and wide (approximately 4.5 cm in width) are preferable for women with large breasts during sport and exercise to minimise bra strap pressure and discomfort. The addition of gel pads under bra straps may also decrease discomfort and prevent straps slipping off the shoulders, although this notion warrants further investigation.