Does pectus actually give certain athletes a physical advantage?

The old swimming adage is that breaststrokers are born, not made. You often can look at a swimmer standing still and tell whether they are a natural fit for the most esoteric of the four strokes.

Start from the ground up: Most successful breaststrokers have duck feet that point outward, making it all the easier to perform the frog kick that goes with the stroke. Flexible ankles are a plus. So is a long torso.

Tierney pointed out that he, like many swimmers and particularly breaststrokers, has poor posture. His shoulders come forward and chest is down, a common physical trait in swimmers due to greater muscle mass on the front of the torso – it essentially pulls the shoulder into a slouch. That’s also a common posture profile of someone with pectus excavatum. “That’s what breaststroke pull is,” Tierney said. “Your shoulders are coming forward while your chest is in.”

But what if there is one other rare physical trait that lends itself to excellence in breaststroke? And what if that trait is a birth defect?

It sounds crazy, and it might be nothing more than coincidence. But two of the three American Olympic breaststrokers here were born with a chest wall deformity, and a third elite American breaststroker has the same physical abnormality.