The Joints Involved in a Dumbbell Curl

Unless you've got one of Popeye's energizing spinach cans handy, you've got to do strength-training exercises to develop big arms. Though the well-known biceps curl and the lesser-used wrist curl are relatively simple to do, you've got to move the joints involved in those exercises in specific ways to achieve the best results. Learn how the correct joints should move -- and which joints shouldn't move -- to help you perform dumbbell curls correctly.

  1. Bend Your Elbow for Biceps Curls

    • The elbow is the only joint that should bend when you perform dumbbell biceps curls. Your front upper-arm muscles -- the biceps brachii, brachialis and brachioradialis -- all contract as you lift the dumbbell. The upper-arm contraction flexes your elbow joint and provides the power you need to raise the weight toward your shoulder. The elbow then extends as you lower the weight. Keep your elbow close to your side and your upper arm still throughout the exercise. Your elbow can move forward very slightly as your hand approaches your shoulder, but keep the movement to a minimum.

    Keep Your Wrist Neutral

    • Don't cheat by curling your wrist up as you raise the dumbbell. Also avoid flexing your wrist as the weight descends. Your wrist should remain firm and in neutral position from start to finish. If you do twisting curls – starting the exercise with your palm facing your body, then turning your palm to face your shoulder as you lift the dumbbell – rotate your forearm to change your wrist's orientation; don't twist your wrists.

    Shoulder Involvement is Minimal

    • You should not have any visible shoulder movement when you perform dumbbell biceps curls. The anterior deltoid muscle at the front of each shoulder is activated as a stabilizer when you perform biceps curls, but that's the limit of your shoulder's involvement.

    Flex Your Wrist for Wrist Curls

    • Dumbbell wrist curls target your forearm muscles. Standard wrist curls work your wrist flexors while reverse curls target the wrist extensors. Begin standard curls with your arm stabilized on your thigh while sitting. The palm is up and the wrist is extended. Then flex your wrist upward so your palm moves toward your forearm. Do reverse curls with your palm down and your wrist flexed, and then move your palm away from your forearm and up toward the ceiling. Either way, your wrist is the only joint that moves. The target muscles contract as you raise the dumbbell.