If you've read other stories of mine but think this one is better, here's why: I'm writing it while wearing a high-performance mouth guard.
I recently spent two weeks doing everything, aside from sleeping and eating, with a thin piece of plastic and two large yellow bite pads snapped over my lower teeth. Mouth guards are common in football, hockey and boxing, but a growing number of pros in noncontact sports have been wooed by claims that jaw-positioning retainers can improve strength, power and accuracy as well as help them think more clearly under pressure. Derek Jeter wears one. So does Shaq.
I tested a $495 model made by Bite Tech, a Minneapolis company that began selling its patented technology in September through the sports brand Under Armour. Canadian firm Makkar sells a similar device for $695. Both products require a trip to the dentist to have a mold of your teeth made. But starting in January, Under Armour plans to sell a Bite Tech model for $60 that can be fitted at home. Boil the mouthpiece, bite down for 30 seconds and your jump shots will start dropping like the Dow.
Or so the theory goes. Clenching your teeth pinches the nerves that run through the temporomandibular (jaw) joint, causing the body to produce the hormone cortisol, which increases your heart rate and blood pressure and can trigger a fight-or-flight response. That's good when you're actually in danger but distracting when you're playing softball. Bite Tech aims to improve your physical and mental performance by preventing you from clenching. It also moves your lower jaw forward. The combination opens the throat, improving breathing. (Some dentists recommend the gear for night grinders too.)
I noticed a slight difference. On a stationary bike, I typically go 6.3 miles (10.1 km) in 30 minutes. With the mouthpiece, I easily made 6.6 miles (10.6 km). My golf score dropped a few strokes, but my wife still beat me at Scrabble. I called golfer Hunter Mahan to find out how long it took him to see results. Turns out Mahan, whose picture and testimonials about Bite Tech take up most of the company's home page, wears the mouthpiece when he practices but not during tournaments. Maybe he doesn't want to lisp in public?
Studies that Bite Tech funded show a small improvement less than 10 milliseconds in subjects' response times. Shawn Arent, director of exercise science at Rutgers University, got similar results when he tested 22 athletes wearing a Makkar mouthpiece vs. a generic $20 protector. The athletes were able to jump higher with the Makkar, by one inch. That's not a heck of a lot, but Arent concedes, "For top athletes, that little bit extra might matter." So, uh, can I take this thing out now?
This article originally appeared in the Aug. 9, 2010, issue of TIME.