What's the move? Basically, it's a barbell biceps curl broken down into three phases, so it's a mix of partial and full reps. Packing all that work into a single set and using serious resistance ignites plenty of biceps growth, and teaches you to master your full curling range of motion, too.
How do you do it? Simple.
- Start with 7 reps from the top position of a curl going only halfway down. It's smart to start with the top phase when you're fresh because that range of motion is the most challenging phase for your biceps, forcing them to work without any assistance from your forearms.
- Do 7 reps from the bottom with your arms straight going only halfway up to your waist.
- Finish by doing 7 full reps, from the bottom with your arms extended, curling the barbell up to your shoulders.
Johnson noted that, "Pushing past your pain threshold to squeeze out a few more extra reps is where success and magic happens." If you've done a hard arms workout and have a challenging weight on the bar, your guns will be on fire those last seven repetitions.
Because he's The Rock and because Instagram, there was lots of good-natured trolling.
One man noted he was doing those in high school.
Another observed that using 25-pound plates for 21s (which added up to a fierce 95 total pounds that the Rock was moving) was burly.
Another critiqued The Rock's form, commenting that he was rocking back and forth.
And another said The Rock's biceps and triceps still need work. LOL.
While many people do 21s using a barbell, you can also do it using dumbbells. And you can apply the same rep and range of motion scheme to many other exercises , including squats, pushups, and even pullups.