Main Muscle Worked: Biceps
Other Muscles Worked: None
Equipment: Dumbbell
Concentration curl setup: Sit on the end of a flat bench with your legs apart and lean forward slightly. Grab a dumbbell in one hand with your palm facing upward and rest your elbow on the inside of your thigh letting the dumbbell hang.
Concentration curl execution: Slowly curl the dumbell up while keeping your elbow locked in place against your thigh. As you are curling, twist your wrist to the outside (i.e., supinate). Squeeze your bicep at the top of the movement for a one-count and then slowly return to the start position and repeat.
Tips: With concentration curls you will find that you can not lift as much weight as usual. This is because your bicep muscles are responsible for 100% of the work here! Start your concentration curl with a light weight and work up.
Don't rock your body too much during the concentration curl. You want to move the weight with your bicep muscle, not your shifting bodyweight. Focus on keeping your body still and flexing your bicep.
Try not to focus on how much weight you are lifting, buty focus on squeezing your bicep muscle hard at the top of the concentration curl and pausing before you lower the weight. You can get good strength and muacle gains on your bicep by only doing light concentration curl exercises.
source: www.ebicep.com
