Due to their location on the anterior chest wall, limited anatomical support and lack of musculoskeletal protection, female breasts are vulnerable to injury, particularly from direct blows during contact sports (Greydanus et al., 1998; Jiang and Ni, 2013; Loud and Micheli, 2001). The extensive superficial capillary networks within breasts also increase the likelihood of contusions and haematomas from direct contact (Haycock, 1987; Holschen, 2004). Despite this vulnerability to injury, there is a paucity of published research investigating breast injuries sustained during sport. One of the few published studies in this field was a survey completed by athletic training staff of injuries sustained by female collegiate athletes in 1975, which revealed that breast injuries were the least common injury for this cohort (Gillette, 1975). Possibly because breast injuries were not considered problematic in this study, injuries to the breast or chest have seldom since been included in research that has documented injuries sustained by female athletes (Hagglund et al., 2009; Hilibrand et al., 2015; Langeveld et al., 2012; McCarthy et al., 2013; Peck et al., 2013; Zelisko et al., 1982).
In sports injury research, investigators traditionally record injuries that have been reported by athletes to coaches or athletic trainers (Donmez et al., 2018; Gillette, 1975; Schiff et al., 2010) or that have been diagnosed by team physiotherapists or physicians (Giza et al., 2005; Peck et al., 2013; Wik et al., 2019). These methods of recording sports injuries, however, are unlikely to capture reliable information on breast injuries because female athletes are often reluctant to report injuries they sustain to their breasts or chests (Smith et al., 2018), particularly to male athletic staff (Drummond et al., 2007). Furthermore, there is no widely accepted medical classification for breast injuries sustained during sport and no information about breast injuries was included in the most recent iteration of the Team Physician Consensus Statement on Female Athlete Issues, a publication specifically designed to educate team doctors about injuries which female athletes might sustain (Team Physician Consensus Statement, 2018). As such, the most reliable method of recording these sensitive and unclassified breast injuries is through a direct survey of female athletes.
Most sports injury researchers also use a narrow definition of injury (Clarsen and Bahr, 2014), recording only injuries that result in time-loss from training or matches (Donmez et al., 2018; Engstrom et al., 1991; Schick et al., 2008) or that necessitate medical attention (Giza et al., 2005; Holland et al., 2018; Peck et al., 2013). It is unknown, however, whether breast injuries are severe enough to remove an athlete from sport or require medical attention, or whether female athletes seek medical attention for their breast injuries. It is therefore possible that a narrow definition of a sports injury might systematically exclude breast injuries from being recorded, even though these injuries could negatively affect athletic performance. To better understand the scope of breast injuries sustained in sport and whether these injuries affect performance, it is necessary to adopt an "any physical complaint" injury definition (Clarsen and Bahr, 2014) and record all occurrences of breast injuries during sport, irrespective of severity.
In a direct survey of female collegiate athletes, the authors of a 2018 study found that breast injuries affected nearly 48% of collegiate basketball, soccer, softball and volleyball athletes in America (Smith et al., 2018). Only 10% of female athletes in this study reported their breast injuries to medical personnel (Smith et al., 2018), which supports the notion that breast injuries are likely to have been under-represented in previous sports injury research. This study also broadly classified breasts injuries as any trauma to the breast including contusions, bruising, hematomas, oedema and pain (Smith et al., 2018), irrespective of time-loss or medical attention, which might explain the higher prevalence of injuries recorded in this study compared to the 1975 survey (Gillette, 1975). Although this 2018 study revealed that nearly half of the female athletes had sustained a breast injury during sport, the participants only included college-aged basketball, soccer, softball and volleyball players. Given the wide variety of sports that female athletes participate in (Brisbine et al., 2019a) and the growing popularity of contact sport (Huxley, 2016; Navaratnam, 2017; Roberts, 2017; Rubgy Australia, 2018), there is a need to investigate the occurrence, causes and perceived performance effects of breast injuries sustained across a greater diversity of sports.
In addition to the breasts being vulnerable to trauma, skin around the upper torso and breast is also sensitive to potential injury from repetitive contact with an athlete's sports bra or uniform, which might result in chafing or lacerations from rigid bra components (Haycock, 1987; Loud & Micheli, 2001). "Runner's nipple" (also known as "jogger's nipple") is a chafing injury that has been extensively reported in both female and male runners, the occurrence of which has been associated with running distance (Purim and Leite, 2014), body mass index (BMI) (Helm et al., 2012) and infrequent sports bra use in female athletes (Mailler and Adams, 2004). It is therefore possible that female athletes who train for several hours, have a higher BMI or use a sports bra less frequently might be susceptible to frictional breast injuries. Larger breast size might also contribute to frictional breast injuries in female athletes, because overweight men have been found to sustain frequent chafing injuries due to increased "jiggling" of breast tissue and a resultant increase in friction between the breast and their shirt (Helm et al., 2012). Although numerous studies have investigated chafing injuries in runners (Adams, 2002; Loud and Micheli, 2001; Mailler and Adams, 2004; Mailler-Savage and Adams, 2006), no research was located that specifically investigated frictional breast injuries across a range of sports or how these injuries might affect sporting performance.
This study aimed to investigate, through a direct survey and the use of a broad injury definition, the occurrence and causes of breast injuries reported by elite female athletes from a wide range of sports and whether the athletes perceived these breast injuries to affect their sporting performance. These aims address the crucial first phase of the Team-sport Injury Prevention framework by evaluating the current breast injury situation in sports (O'Brien et al., 2019). This exploratory research is necessary to inform future specific breast injury research and the development and implementation of evidence-based breast injury prevention strategies. It was hypothesised that: H1: elite female athletes would experience breast injuries during sport;
H2: breast injuries would be caused by direct contact or friction between breast skin and an athlete's bra or uniform during sport; and
H3: elite female athletes would perceive that breast injuries negatively affected their sporting performance.
Survey design and implementation
Although sports injury research traditionally relies on surveillance by coaches or medical staff, the sensitive nature of breast injuries, the absence of standardised breast injury definitions and the lack of breast injury reporting necessitated a survey to directly ask female athletes about the occurrence, causes and performance effects of breast injuries. An anonymous 42-question survey was therefore designed to gather data on breast issues sustained by female athletes, aged 18 years or older, currently competing nationally or internationally (i.e. representing their state or country) in any sport. Full details of how the survey was developed and implemented are described in a previous publication (Brisbine et al., 2019a); in brief, the survey was initially developed using focus groups comprised of female athletes from a range of sports. The survey was then distributed as an electronic link or a hard copy to sporting organisations, coaches, medical professionals and sports teams throughout Australia via email, social media, standard mail and in-person. The survey was presented in four sections: About You, About Your Bra, Your Breast Pain and Your Breast Injuries. Only relevant data from each section was reported in this paper. The University of Wollongong Human Research Ethics Committee (HREC 2017/009) and the Australian Institute of Sport Ethics Committee (20170610) approved the survey design and implementation procedures.
Age: Participants recorded their date of birth, which was then used to calculate their age at the date they completed the survey. Age was recorded as a continuous numerical variable.
Breast size: Participants were asked to...