Your max-support running bra might be hurting your back, new research says

For years, runners have been told that the best sports bras are the ones that lock things down—less bounce, less pain, right? But new research out of the University of Portsmouth, U.K., flips that logic on its head. A team from the school’s Research Group in Breast Health has discovered that ultra-supportive bras might reduce breast movement, while quietly increasing strain on your spine. Here’s what you need to know.

What the study found

Using a first-of-its-kind full-body female musculoskeletal model, a team simulated how different levels of breast support affect the body while running. Tools like 3D scanners, force plates and motion capture allowed them to estimate changes in spinal loading based on how much the breasts were free—or restricted—in their movement. The lab has tested more than 700 sports bras on over 8,000 women in the last decade, so they know their stuff.

Here’s the wild part: bras that eliminated nearly all bounce (100 per cent reduction) also increased the amount of torque on the spine. Your bra might be helping your chest, but making your back work harder.

Why it matters for runners

We already know runners can be prone to back pain, especially in the lumbar region. If a sports bra is putting extra strain on spinal muscles with every stride, that could eventually contribute to overuse injuries, particularly for long-distance runners logging high mileage. “Support is essential,” says Dr. Chris Mills, a professor at the University of Portsmouth and one of the head researchers on the team, “but too much can shift the load to your spine, increasing the risk of back pain.”

So…what should you do?

This doesn’t mean that you need to ditch your high-support bra and go for a jog in a bralette. But it does suggest that we need a smarter approach to support—one that balances bounce reduction with full-body biomechanics. Instead of treating bras like armour, we might need to treat them like running shoes: matched to your needs, your body and your movement style.

The takeaway for runners

According to Joanna Wakefield-Scurr, who leads the Research Group in Breast Health, the bra industry needs to evolve beyond bounce stats. “Maximum reduction may not be optimal,” she said. “There’s a cost to spinal health if we don’t get the design right.”

Your sports bra is gear, just like your shoes, shorts and watch. Choose one that feels good, supports you and doesn’t cause new problems. And maybe don’t assume that “no bounce” is always best. The perfect bra might be the one that moves with you, not just against gravity.