Not surprisingly, the competition effect has its limits. In another study, scientists had cyclists try to keep pace with avatars who were going 2 percent faster than their previous bests. As before, the researchers deceived the subjects, telling them that the avatars were going at the riders' previous fastest pace. But after keeping up for about half the race, the subjects gave up. All told, they performed no better than previous bests, and some did worse.
So it seems that the brain can trick the body only so much. After all, it's one thing to will yourself into finishing a 5k. But it's another to imagine that willpower alone would carry us to Olympic-quality times.
Interestingly, deception seems to play a key role in the competition effect. Because when researchers told cyclists that the avatars were riding 1 percent faster than they ever had, the riders made no attempt to keep pace; they simply matched their own previous bests.
Which brings us back to your question: Why did you run faster at the end of your race? Because you thought you could catch the competition. As any coach will tell you, that belief in yourself made all the difference.
Prescott, a physician and medical researcher, is president of the Oklahoma Medical Research Foundation. Cohen is a marathoner and OMRF's senior vice president and general counsel.