Even if you have no intention of doing so, it’s easy to cheat in the gym. At the end of a tough set, you often find you recruit less fatigued muscles to shift the weight to the detriment of your form, or you can take advantage of momentum just to get through those final few reps.
This is definitely something that’s true of the biceps curl, where a little sway can go a long way in building momentum. But if you’re doing curls, it’s natural to assume you’re shooting for bigger biceps, so stop cheating yourself and add the concentration curl to your repertoire.
The position of this exercise more or less eliminates your ability to cheat with your curls, and since you’ll be working each arm individually it also stops your weaker side (if you have one) from letting your stronger side do more than its fair share when curling a barbell or EZ-bar.
In addition, the slow and steady pace of the exercise makes for greater time under tension which helps you to really put the squeeze on your biceps. You might find that you need to use lighter dumbbells than you expect because of this, or do fewer reps, but that doesn’t matter – the key is that you’re putting your biceps to work properly, and the results will follow in the shape of sleeve-busting upper arms.
How To Do The Concentration Curl
Sit on a bench that’s set at a height so your knees are bent at 90° with your feet flat on the floor. Pick up a dumbbell in your right hand and place the back of your upper right arm on the inner part of your right thigh. Your arm should be extended holding the weight off the floor.
Slowly curl the weight up, only moving your forearms – the position of your upper arm on your thigh will help you keep it still during the exercise. At the top of the move, pause for a beat and squeeze your biceps, then slowly lower the weight back to the start. Do all your reps on one arm, then switch to the other.