Breast support – only the balls should bounce!

The breast has limited anatomical support and can move 15cm during running. Nicola Brown discusses the consequences of breast movement and provides guidance on obtaining the correct sports bra fit to help women exercise in greater comfort.

Introduction

The evolution of technology and sportswear aims to improve performance and prevent injuries. However, the sports industry regularly overlooks sports bras. The first sports bra was developed in 1977 and has undergone many advancements since then. However, currently, the use of a sports bra in physical activity remains relatively low despite women experiencing breast pain and bra fit issues⁽¹⁾. Additionally, while athletes may feel comfortable discussing their injuries, they may be hesitant about breast-related issues.

Researchers at the University of Wollongong in Australia found that although 58% of athletes reported suffering a contact breast injury during the season, with nearly half reporting an effect on their performance, the coaches and medical staff estimated fewer than 5% of players had sustained a breast injury⁽²⁾. Furthermore, at the 2020 Tokyo Olympic Games, it was the first time Team GB female athletes received bespoke breast support using innovative technology⁽³⁾. Therefore, a greater understanding of breast movement during exercise is needed to inform sports bra design and fit to allow women to perform optimally and comfortably.

Breast anatomy and movement

The breasts sit on top of the chest wall, with each weighing approximately 200g (A and B cups) to 1000g (≥ D cup)^(4,5). The breast does not contain any muscle tissue and is composed of adipose and specialized (glandular) tissue that produces milk (see figure 1). The only anatomical support is provided by the skin and fibrous tissue, referred to as ‘Cooper’s ligaments.’ The ‘Cooper’s ligaments’ are thin, paper-like tissues that weave throughout the breast and attach to the chest wall. As a result of the limited anatomical support, the breasts may move excessively over the chest wall during physical activity. The movement occurs in three dimensions, with breasts reported to move, on average, 4.2-9.9 cm in the vertical direction, 1.8-6.2 cm in the medial-lateral direction, and 3.0–5.9 cm in the anterior-posterior direction^(6,7,8). Thus, breast movement during physical activity may lead to several negative consequences.

 Figure 1: Anatomy of the breast

Negative consequences of breast movement

Up to 72% of general exercising females and 44% of athletes report pain during exercise^(9,10). The incidence of breast pain is relative to size, but is not exclusive to women with larger breasts⁽¹¹⁾. The etiology of breast pain is unknown but may be due to tension on the supporting structures during movement⁽¹²⁾. Furthermore, repeated loading may lead to irreparable damage, resulting in accelerated breast ptosis (sag), whereby the nipple migrates downwards below the inframammary fold⁽¹³⁾.

Changes in the level of breast support impact performance and result in biomechanical and physiological changes. For example, lower levels of support lead to increased ground reaction forces, which may have injury risk implications^(14,15). In addition, running economy is a crucial factor when assessing performance, and less economical upper body patterns are evident when participants run in low-level breast support⁽¹⁶⁾. This is an essential consideration for distance runners since breasts are estimated to bounce ~10,000 times during one hour of slow running⁽¹⁷⁾. Additionally, athletes may reduce their stride length to reduce breast movement, possibly adding an extra mile over a marathon⁽¹⁸⁾. Finally, the independent movement of the breast during activity can be embarrassing and reduce confidence levels, particularly in larger-breasted women⁽¹⁹⁾. These breast-related issues can create a barrier to physical activity participation, with 17% of adult females and 46% of schoolgirls avoiding physical activity because of their breasts^(20,21).

Sports bras

Wearing a well-fitted sports bra instead of an everyday bra can limit breast motion during exercise, reduce pain, and improve performance. There are currently three distinct sports bra designs on the market: compression, encapsulation, and combination (see figure 2). Compression bras are typically constructed from one piece of strong elastic material designed to flatten the breasts against the chest wall. Typically, they pull over the head and do not have cups. Encapsulation bras incorporate individual cups to surround and support each breast separately. Finally, combination sports bras encapsulate and compress the breasts to varying degrees, depending on specific design features. There is no consensus on whether one sports bra type is superior. However, compression bras may be more suitable for smaller-breasted women (< D cup), and encapsulation bras for larger-breasted women (≥ D cup)⁽⁵⁾.

Figure 2: Types of sports bras

It is common to see sports bras advertised as low, medium, or high-impact, referring to the level of support the bra provides during activities. However, evidence-based standards to inform these categories have yet to be established⁽²⁴⁾. In addition, there are specific design features that may influence the levels of support and comfort:

1. Sports bras with higher necklines, i.e., reach the upper boundary of the breast tissue, are considered more supportive⁽²²⁾.
2. Vertical, wide (4.5cm), and padded straps improve comfort⁽²³⁾. In addition, various shoulder strap configurations are available,g., vertical, cross-over, and racerback, but appear to have little impact on support levels, with the adjustability of straps considered more critical to accommodate varying torso lengths^(22,23).
3. To help maintain a comfortable breast temperature and avoid skin irritation, material that can wick sweat away from the body may be advantageous.

Getting the best fit

Selecting a well-fitting sports bra can be challenging. There is a wide choice of brands, styles, and sizes on the market and a lack of standardization of sizing^(25,26). Additionally, breasts can change size, shape, and position throughout the menstrual cycle and at different life stages⁽²⁷⁾. It is therefore unsurprising that approximately 85% of women wear ill-fitting bras⁽⁸⁾. Researchers at the University of Portsmouth found that the traditional tape measurement method is unreliable as it overestimates the underband size and underestimates the cup size⁽²⁶⁾. Instead, education on professional bra fitting criteria improves the ability to choose a well-fitted bra (see figure 3)^(25,26,28).

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Tips to ensure an optimal sports bra fit

1. When trying on sports bras, it is good to jump around in the fitting room to check it provides the support needed.

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Figure 3: Bra fitting criteria

Conclusion

The negative consequences of an ill-fitting bra impact physical activity participation and performance. The appropriate sports bra fit is essential to reduce breast pain, injury, and embarrassment. Unfortunately, many women wear inappropriate and ill-fitting breast support garments during exercise. Thus, education on breast support and bra selection are essential to reduce long-term health issues and performance impairments.

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