Dumbbell concentration curl

Sit on a bench with your legs spread apart and a dumbbell in one hand, resting your elbow on the inside of your thigh. Fully extend your arm and hold the dumbbell with an underhand grip. Keeping your upper arm stationary, exhale and curl the weight up towards your shoulder while contracting your biceps. Continue to raise the dumbbell until your biceps are fully contracted and the dumbbell is at shoulder level. Hold the contracted position for a brief pause as you squeeze your biceps. Inhale and slowly lower the dumbbell back to the starting position. Repeat for the desired number of repetitions, then switch arms.