Which Comes First, Cardio or Weights_ - Alex Hutchinson [20]
The idea that the position of your jaw can affect the rest of your body stretches back at least to ancient Greek athletes and Roman warriors biting down on leather straps; wounded U.S. Civil War soldiers “bit the bullet” to deal with pain. These days, top sprinters strive to relax their face—as you can see from their jiggling cheeks in slow-motion replays.
Nobody really knows why this should work. There are many theories, including that clenching may stimulate excessive production of the stress hormone cortisol, constrict airways, or interfere with nerve signals traveling from the brain to the rest of the body. Whatever the mechanism, Makkar Athletics reports immediate improvements in posture, flexibility, balance, and strength, and notes that its users report increased endurance and faster recovery. Under Armour makes similar claims and adds faster reaction time.
To back up these startling claims, Makkar funded an independent study at Rutgers University. In a double-blind study, researcher Shawn Arent tested 22 collegiate and professional athletes, all from contact sports where mouthpieces are already used to protect teeth. Each subject was fitted for a standard mouthguard and for one optimized with Makkar’s hour-long proprietary technique, and neither the athletes nor the researchers knew which one they were wearing. Arent—to his surprise, he admits—observed small but statistically significant improvements in vertical jump, in peak power produced in a 30-second cycling test, and in the average and peak powers produced during a sequence of 10-second bursts of cycling. The only test that didn’t show a significant change was the number of body-weight bench presses.
The research that Under Armour has made available so far is less convincing. For example, a series of 2008 studies conducted at the Citadel, a military college in South Carolina, compares subjects with mouthpieces to subjects with nothing in their mouths, taking no account of the placebo effect. And what’s described as “a definite trend for lower cortisol” turns out to mean that cortisol levels were lower in only 11 of the 21 cyclists in the study—barely more than half. A follow-up study of runners in 2009 also failed to find any statistically significant change in cortisol.
All these results are too preliminary to draw any firm conclusions about what different mouthpieces can and can’t do. Until more research is completed, anyone investing in these devices is making a leap of faith, not a scientific judgment. But there’s enough to suggest that the link between jaw position and physical performance isn’t just fantasy. “My sense is that it’s real and it could be important, for some sports more than others,” Arent says.
Is there any benefit to strengthening my breathing muscles?
It makes perfect sense: to avoid getting out of breath, you should improve your breathing muscles. When you inhale, you use the muscles of the chest wall and diaphragm to suck in air; you then relax those muscles to push air back out. After strenuous exercise, those muscles can fatigue. That’s the observation that spurred British researcher Alison McConnell of Brunel University in London to develop the Powerbreathe “inspiratory muscle trainer” in the 1990s, a portable device that looks like an oversized asthma inhaler, designed to strengthen the muscles you use to inhale, just as weights strengthen your arm muscles. Taking 30 breaths through the machine twice a day, and gradually increasing the resistance, is supposed to strengthen the muscles, increase endurance, and make you feel less out of breath.
There’s just one problem. Initial studies by a variety of researchers failed to find any benefits from inspiratory muscle training, though subjects