The concentration curl is an old school move that can produce real results, but only if you’re ready to buy in and work with perfect form. You wont be able to mindlessly shift and swing your body to help to lift the dumbbells, like some people do during standard standing curls—so be prepared to be humbled by the weight if your form is sloppy. Top-level trainers like Men’s Health fitness director Ebenezer Samuel, C.S.C.S. and Don Saladino use the exercise to build major league biceps.
“The strength of the concentration curl is in how it helps eliminate any excess shifting at the shoulder joint during biceps curls,” says Samuel. “When you do standard biceps curls, it’s easy (and convenient) to let the elbow shift forward and stop keeping your upper arm perpendicular to the ground. That momentum takes the emphasis off the biceps very briefly, but just long enough you sometimes miss the sustained biceps contraction needed to really build your bis.”
You can’t even cheat during the concentration curl if you wanted to, due to the positioning. Instead of standing upright with your elbows free, you’ll bend at the torso and keep your arm at an angle perpendicular to the ground. You can do this the classic way, seated on a bench with your arm resting on your inner thigh, like Samuel and Saladino, or you can bend over and support yourself while you’re still on your feet, like The Rock. The important thing is that your arm only moves when you squeeze your bicep to lift the weight.
“You’re driving your upper arm into your inner thigh, and doing so will keep your upper arm perpendicular to the ground,” Samuel says. “That takes your shoulder out of play and lets you focus on squeezing your biceps. That also makes the very top of the concentration curl, which can become a position of rest if your elbow has shifted forward, into a position of work; squeeze the heck out of your biceps when you’re at the top.”
Samuel’s last tip is a subtle one, which is easy to do if you’re focusing as you should—but if you’re lazy, you’ll miss the benefit: “Make sure to supinate hard when you do concentration curls, turning your pinky toward the ceiling as much as possible,” he says.
Use concentration curls as your second or third exercise in a biceps training day. Try them for 3 sets of 10 to 12 reps. If you really want to get a pump, set a timer and do as many reps (with perfect form, of course) as possible for 30 seconds on one arm, then do the same on the other arm. Alternate back and forth for three sets.