Doctor of Philosophy
School of Health Sciences
Bowles, Kelly-Ann, Sports bra design for active women, Doctor of Philosophy thesis, School of Health Sciences, University of Wollongong, 2012. http://ro.uow.edu.au/theses/3762
Background: Exercise induced breast motion and the associated breast pain, particularly in larger breasted women, can be severe enough to discourage some of these women from participating in sport and exercise. To ensure all females have the opportunity to comfortably participate in, and therefore reap the health benefits associated with regular physical exercise, it is imperative that we understand factors that enable sport bras to limit breast movement and associated pain, without negatively affecting physical performance or causing discomfort to the bra wearer.
Thesis Aim: The aim of this thesis was to identify factors that influence breast support choices made by Australian females when they participate in physical activity, and then systematically investigate the factors that may deter females from using sports bras in order to develop recommendations for improving sports bra usage.
Approach: A mail out survey was firstly used to analyse consumer usage of sports bras in a general Australian female population (Chapter 2), and to determine the deterrents to their use in this population (Chapter 3). Based on the survey results, two subsequent studies were designed to systematically investigate two factors that the survey respondents disliked about current sports bras: (i) the perceived tightness of sports bras around the wearer’s torso (Chapter 4); and (ii) perceived problems associated with sports bra shoulder straps digging into and/or slipping off the wearer’s shoulder (Chapter 5).
Results: The survey revealed that sports bras were not the most common breast support choice during physical activity, with only 41% of respondents indicating they currently wore a sports bra during physical activity (Chapter 2). Furthermore, the main sports bra features that respondents “extremely disliked” were the shoulder straps digging into the shoulder (34%) and the shoulder straps slipping off the shoulder (34%). From a design perspective, respondents also indicated that the perceived tightness of the sports bra around the chest was another disliked feature that deterred them from wearing a sports bra (Chapter 3).
When investigating the perceived tightness of sports bras around the wearer’s torso (Chapter 4), it was revealed that although the sports bra imparted significantly more pressure on the torsos of the females with smaller breasts, when compared with the fashion bra, this increased pressure did not significantly affect measured lung volumes or bra comfort scores. Bra size (or breast hypertrophy), however, affected maximal exercise ability, as well as some temporal measures of resting and submaximal respiration, whereby the participant’s with larger breasts displayed lower maximal exercise ability and faster rates of inspiration.
Investigating the effects of modifying bra shoulder strap orientation (Chapter 5) revealed that the cross-back strap orientation significantly reduced vertical breast displacement (VBD) compared to the no strap condition. However, there was no significant difference between the traditional and cross-back strap orientations in their ability to reduce VBD and both strap orientations successfully reduced breast pain compared to the no strap condition. Although the cross-back strap orientation resulted in some higher force and mean pressure values at the strap-shoulder interface compared to the traditional strap orientation, no significant difference was found between the two strap orientations. Unexpectedly, inserting a bra strap cushion under a bra strap was not effective in decreasing the pressure at the bra strap-shoulder interface due to design flaws that prevented the strap cushion from adequately increasing the strap-shoulder contact area.
Major Conclusions: Sports bras were not the most common breast support choice during physical activity, whereby factors such as perceived tightness around the chest and the shoulder straps digging into or slipping off the shoulder were identified as deterrents to the use of sports bras. However, no significant restriction to respiratory mechanics during exercise was found when participants wore a correctly fitted encapsulating sports bra, compared to other forms of breast support. In addition, if the bra is correctly fitted, using a cross-back strap orientation is a viable option to prevent shoulder straps from slipping off the shoulder of the wearer, without affecting vertical breast support. Further research is warranted to look at strategies to prevent sports bra straps digging into the shoulders of the bra wearer in order to improve sports bra usage when females participate in physical activity.