Cause: Researchers at the University of Portsmouth in England have found that during high-impact activities like running, breasts move not just up and down, but also in a repetitive figure-8 pattern that is barely controlled by most standard sports bras. It sounds perverse, feels miserable and leads to chafing, discomfort, weakened breast tissue and even an unstable stride, found the researchers.
Solution: The sports bra company Shock Absorber commissioned a portion of the breast-health research from the University of Portsmouth. Its Run bra top encapsulates and lifts the breasts in soft, molded cups that control vertical and lateral sway, has seam-free inner elastics to reduce chafing, and stays put thanks to wide straps. When running on a treadmill, a typical sports bra might reduce bounce by about half; tests show that the Shock Absorber reduces it by 78 percent. Panache, a U.K. lingerie company, was inspired by the University of Portsmouth research to do its own tests. Last October, Panache released a sports bra that reduces bounce by 83 percent.