The amateur video shot last summer shows a woman swimming all alone in a 50-meter pool. Her freestyle stroke is as distinctive as a fingerprint: stiff-armed, her head bobbing up and slightly forward before turning sideways to breathe. She looks more like she's lunging toward a life raft than racing the clock, but her biomechanics are still deadly efficient underwater. When she touches the wall after 800 meters, she has set a Masters world record for her age group.
That swimmer was quadruple ...
