Hey, my knees are down here

3 minute read

A supportive bra can improve your running in an unexpected way.

Anyone with boobs above a certain mass knows that they get in the way of just about everything, especially running.  

What you may not know is that running with insufficiently cast-iron support can adversely affect the performance of your … *checks notes* … knees.  

“Greater knee joint stiffness has been associated with improved running performance (speed and metabolic cost), though the influence of breast support on knee joint stiffness has not been previously investigated,” the authors of a recent study published in Frontiers in Sports and Active Living noted.  

Well, whip us with an underwire and tickle us with a little satin bow – we at the Back Page had also never considered this association. We agree with the authors though that the problem is no laughing matter.  

“While running has many benefits, breast pain is a significant barrier to exercise, including running, for many women with up to 72% of women experiencing exercise-induced breast pain.” (Our levity is the wry, knowing, suffering sort.) 

Fortunately, now, someone is looking further into the whole thing. In aid of science, 13 runners (the just-for-fun types, not the I-would-rather-relieve-myself-roadside-than-lose-this-race cohort) each ran on a treadmill for three minutes at whatever speed they wanted. They did it three times, once without a bra, again with a low-support sports bra, and once more with the type of structural support some NSW residential builders might do well to emulate. 

Using heavy-duty tech for the elevated purpose it was surely designed for, researchers employed a 10-camera motion capture system and a fancy treadmill to collect “three-dimensional kinematics and ground reaction forces”, a biomechanics analysis tool to “calculate knee joint excursions, moments, powers and work” and customised software to “calculate knee joint stiffness and breast displacements during the stance phase of running in each experimental condition.”  

Compared to no bra, they found that a low-support sports bra was associated with a 2% increase in knee joint stiffness (as in stability, not soreness), and high support with a 5% increase. These improvements were related to the observed smaller knee flexion excursions and the increases in knee extension power.  

Knee joint stiffness is tied to economy when it comes to running.  

“It is postulated that the reduced knee flexion excursions observed with increasing breast support allow for greater energy storage within the passive, elastic tissues surrounding the ankle and knee joints which are returned during the propulsive portion of the stance phase,” the researchers said. 

On the downside, the sample size didn’t allow for conclusions about the effect of bra size on the whole knee-boob equation, but it wouldn’t be absolutely crazy for readers to draw some of their own (something about bigger load, maths, maths, maths, bigger effect size). 

The Back Page is, for once, pretty happy. It’s about time some (parts) of us got the kind of attention that’s actually useful for a change. Next on the agenda – bringing together a multidisciplinary dream team of biomechanics experts, active-wear designers and materials scientists (because there’s no room for underwire in this brave new world).  

Send applications to penny@medicalrepublic.com.au.    

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