Sports bra support – How too much restriction may harm back health

[WORLD] While tight-fitting sports bras are often seen as a go-to for support during physical activity, new research suggests that maximum restriction might do more harm than good—particularly to back health.

A British study published in the European Journal of Sport Science challenges long-held assumptions about the benefits of high-support sports bras. The findings indicate that bras designed to minimize breast movement during exercise could, over time, contribute to back pain.

Advances in biomechanics have shed new light on the body’s intricate response to physical stress. The spine, in particular, relies on a coordinated system of muscles, ligaments, and bones to absorb shock. Researchers have found that when breast motion is overly restricted, this natural system is disrupted, forcing the lower back to absorb more impact—an overlooked factor in traditional bra design.

For decades, sports bra manufacturers have emphasized “maximum support” as key to both comfort and performance. However, scientists at the University of Portsmouth have uncovered a surprising mechanism: controlled breast movement during running actually plays a role in shock absorption, functioning as a natural buffer for the spine.

Their research, which used sophisticated computer modeling of the female body in motion, suggests it may be time to rethink current design standards. The team developed an innovative musculoskeletal model, incorporating sliding joints between the breasts and torso, to better simulate real-life movement and test various levels of support.

The study is part of a broader shift toward personalized ergonomics in sports science. As awareness grows around how individual anatomical traits—such as breast size, density, and torso structure—affect physical performance, researchers are advocating for more adaptable solutions. Future designs could feature adjustable support mechanisms tailored to activity type and body shape.

In a key experiment, a volunteer with a 34DD bra size was fitted with 59 motion-tracking markers and ran on force-sensitive platforms under four conditions: braless, wearing a standard bra, a sports bra, and a simulated ultra-supportive model that entirely eliminated breast movement.

The results were telling. When breast motion was fully suppressed, stress on the lower spine rose sharply. Researchers observed spinal loading exceeding 0.05 Newton metre per kilogram—a level already linked in scientific literature to the development of back pain.

Experts say these findings reflect the lived experience of many female athletes, including long-distance runners and gymnasts, who have reported persistent back discomfort despite using high-support sports bras. Some companies have begun exploring hybrid designs, integrating compressive elements with more flexible, adaptive fabrics. However, widespread commercial use of these next-generation bras remains in early stages.

Another noteworthy discovery was the effect of support on posture. The study found that participants stood about four degrees straighter when wearing a sports bra compared to no support at all—a small but significant improvement, as posture plays a key role in injury prevention.

Importantly, researchers are not dismissing the value of sports bras. Rather, they are urging a more nuanced approach to support design. While limiting breast movement can improve comfort and reduce immediate strain, excessive restriction may inadvertently shift pressure to the spine.

“Supportive sports bras are vital for physical activity,” said Dr. Chris Mills, senior lecturer in sport and exercise science at the University of Portsmouth. “But when they overly reduce movement, they may also increase load on spinal muscles, heightening the risk of back pain.”

With female participation in sports continuing to rise globally, demand is growing for performance gear rooted in scientific research. The authors emphasize the need for further studies, particularly on how age, fitness level, and hormonal changes may influence the relationship between breast movement and spinal health.

For women with larger breasts—who often experience exercise-related discomfort—finding a bra that offers both shock absorption and mobility may be the key to long-term comfort and performance.

This evolving understanding could lead to a new generation of sports bras, offering smarter support that adapts to the individual rather than enforcing a one-size-fits-all approach.