There’s science behind it. This isn’t some clap-along “Because I’m Happy” riff. But it’s nearly that simple. If you tell yourself you’ll do it, you’re more likely to succeed; and, conversely, tell yourself you can’t, and failure is more of an option. Self-affirmation can make the difference between hitting a personal record or missing that PR and between getting 10 reps and struggling for eight. It’s an easy hack, too, once you know the most effective way of talking to yourself.

1. SAY IT OUT-LOUD.

You can keep your pep talk entirely in your head, but it’s better to let it out. This brings it closer to reality. Speak it, mouth it, or record it on your phone and play it back before and/or during your set. A recent trial positively used the latter method.

2. THERE IS NO TRY.

The great philosopher Yoda famously told Luke: “Do. Or do not. There is no try.” What was true in a galaxy far, far away is true in your gym. Say things like “Get six” or “I will deadlift this” and never “I’ll try to get six” or “I need to deadlift this.” Make it a command or a foregone conclusion and not merely an attempt or some target you’d like to hit.

3. VISUALIZE.

Back up your words by visualizing them becoming a reality. Research has demonstrated the success of this in strength athletes. While telling yourself you’re going to bench press a weight for three reps, picture yourself doing it. And make this picture as real as possible—the bench, the bar, your clothes, the spotter, the sounds and smells (sorry) of the gym.

4. NOD.

A unique study compared the effects of head nodding or head shaking while participants listened to their own (recorded) positive or negative self-statements before a vertical jump, one-rep squat, and one-rep deadlift. While head shaking combined with either positive or negative self-statements had little additional effect, head nodding significantly increased the performances of listeners to positive self-statements. It appears physically affirming verbal encouragement increases its efficacy. Nod if you agree.

5. THINK SMALL.

Focus your self-talk on only on your immediate realistic-but-challenging goal, not your long-term aspirations or even your targets for the rest of the workout. Go from A to B, and you’ll eventually make it to Z. Try to leap from A to F, and you’ll likely lose focus on the task at hand.

Ronnie Coleman leg pressing a “light weight,” August 2005, Metroflex Gym, Arlington, Texas / Kevin Horton

6. USE A MANTRA.

The most famous pre-set self-talk of all-time is the “Light weight!” or “Ain’t nothin’ but a peanut!” Ronnie Coleman barked before repping weights that were anything but light (800-lb. squats, 600-lb. T-bar rows…). You may also want to use a simple slogan, the briefer the better, that you can return to again and again just before the going gets tough to tell yourself it won’t be. Really, you got this. Light weight!