To avoid jinxing herself, Canadian hurdler Angela Whyte never carries her podium clothes with her to the track at international competitions. But before the 100-metre hurdle final at last week's Commonwealth Games in New Delhi, Ms. Whyte faced a dilemma, because her roommate - whom she would usually ask to bring them - was gone for the day.
"I packed the podium clothes in a separate backpack, so they wouldn't touch the competition gear," she laughed, after sprinting to a silver medal. "It's a little psycho, but it worked!"
Ms. Whyte isn't alone in her faith in the power of superstition. Numerous studies have examined the prevalence of "magical thinking" among athletes, finding for example that the greater your interest in sports, the more superstitious you're likely to be.
There's a good reason for this, according to a forthcoming study in the journal Psychological Science: Superstitions work. Following a lucky ritual enhances your self-confidence, which leads you to set higher goals and be more persistent - and ultimately achieve greater success.
The lead author of the study, Lysann Damisch of the University of Cologne, is a diehard sports fan who was intrigued by stories about athletes such as Michael Jordan, who wore his old college shorts under his uniform throughout his professional career.
She and her colleagues started with a simple test: 28 volunteers tried to sink 10 golf putts. For half of them, the researcher said: "Here is your ball. So far it has turned out to be a lucky ball"; for the other half: "This is the ball everyone has used so far."
Sure enough, the "lucky" group hit 6.4 putts on average, while the control group hit just 4.8.
A second experiment elicited similar results when volunteers were told: "I press the thumbs for you" (the German equivalent of crossing fingers).
To figure out why the superstitions worked, the researcher then performed a pair of experiments in which volunteers completed memory tests and puzzles either with or without their lucky charm. (The subjects were led to believe that these performance tests were entirely unrelated to a survey on lucky charms - anyone who guessed the connection was excluded from the results.)
For example, when asked to form as many words as possible from a random list of eight letters, the subjects who had their lucky charms predicted that they would come up with a higher number of words, and spent longer searching for words before giving up - which, not surprisingly, translated to better results.
Not all athletic rituals work this way, Dr. Damisch points out. Routines such as bouncing a basketball exactly three times immediately before shooting a foul shot actually serve to focus attention and trigger well-learned motor sequences, rather than simply boosting confidence.
Other apparent superstitions may have more to do with creating a relaxed and positive mindset. Ms. Whyte, for example, always travels to competitions with a teddy bear named O.T. - but it's not because she believes O.T. brings her magical luck.
"I've had him since I was two years old," she explains, "so he reminds me of my home and family when I'm travelling. He's my security blanket."
This type of link between mindset and performance has shown up in a number of unexpected places. A study published earlier this year by Canadian researcher Kurt Gray, now at the University of Maryland, found that doing a good deed such as giving money to charity - or even imagining doing a good deed - enabled volunteers to hold up a five-pound weight for longer than they otherwise could. (Worryingly, they gained even more strength by imagining doing evil deeds like harming someone else.)
The effectiveness of superstitious rituals may explain why they have persisted across cultures and eras, Dr. Damisch points out. But there are limits to their power.
"It doesn't mean you win, because of course winning and losing is something else," she said in a statement. "Maybe the other person is stronger."
Alex Hutchinson blogs about research on exercise at sweatscience.com.