Dumbbell Concentration Curl

Sit on a bench with your legs spread and feet flat on the floor.

Hold a dumbbell in one hand with an underhand grip.

Keep your upper arm stationary; only your forearm should move.

Focus on squeezing your biceps at the top of each curl for maximum contraction.

Swinging the dumbbell or lifting the elbow off the thigh to finish the curl.

Dropping the weight quickly instead of controlling the lowering phase.