A triathlete’s “VO2max” number lends itself to strong leverage for bragging rights in the endurance sports arena. If you know this number, which defines your maximum aerobic capacity, you can talk trash while hanging at the pool edge, chatting in spin class warm-up, or stretching on the track. Conveniently, your true athletic superiority can be answered not by race results, lap splits, or age-group rankings, but instead by a simple number that easily defines aerobic dominance.