The athlete’s anaerobic threshold, the point at which the body’s muscles have exhausted their oxygen store and start burning other fuel. For regular folks, reaching that threshold is quitting time; anaerobic work is 19 times harder than aerobic work. But rowing is all about harder. Elite rowers fire off the start at sprint speed — 53 strokes per minute. With 95 pounds of force on the blade end, each stroke is a weightlifter’s power clean. Rowers cross their anaerobic threshold with that first stroke. Then there are 225 more to the finish line.