If you’re going for a PR on a lift, or just moving that new refrigerator into your house, don’t forget to use concurrent activation potentiation.
In other words, grit your teeth.
Scientists at Marquette University studied the concept that muscle contractions become stronger in one muscle when you contract a separate unrelated muscle at the same time. Researchers took a group of trained men and measured the load and level of contraction during a standard leg extension. When the subjects gritted their teeth, they were able to lift 10 percent more weight.
What’s more, when they also clenched their fists and contracted their stomach muscles, they became 15 percent stronger. (This is one of the reasons why powerlifters aggressively contract their core muscles before any big lift—and why you should, too.) While the strength boost doesn’t seem novel to gritting your teeth—feel free to clench other bodyparts — the jaw is one of the easiest muscles to activate when under a load. Just be careful of those chompers; the subjects in this experiment bit down on a mouthpiece.