Outstanding arms can only be great if they are developed from shoulder to fingertips. This means that you cannot ignore the forearm muscles.

Just about every exercise that causes you to grip a bar requires activation of the forearm muscles. Thus, it is natural to ask why should you need direct forearm work. However, if you use a lot of machines rather than free weights, you may not be achieving as much forearm stimulation as you might think. Furthermore, people with weak grip strength will often shy away from heavy rowing, deadlifts or shrugs and therefore miss the radical changes that can occur in whole-body strength and muscle mass with theses exercises. Think about it. With stronger wrists and forearms, you could use heavier weights on the lat pulldown bar or in dumbbell rowing and see new improvements in your back that you would miss with subpar forearm and wrist strength. Thus, direct forearm work can have beneficial carryover effects for other body parts, especially if you use a bar. Furthermore, stronger wrists and forearms will improve your performance in activities such as racquetball and rock climbing, or increase the speed of your wrist shot if you are gearing up for the hockey season. Whatever your goal may be, you will quickly find that the wrist curl will be a simple, but very effective tool for activating, strengthening and thickening the anterior forearm muscles and improving your overall grip, wrist and forearm strength.

The forearm has an anterior (flexor) compartment and a posterior (extensor) compartment. The muscles in the anterior compartment are responsible for most of your hand grip and wrist strength. The muscles of the anterior compartment of the forearm are layered into superficial, intermediate and deep muscles. Only the superficial layers of the forearm muscles are visible, but that does not mean the deeper muscles are not important. The deeper muscles are mostly finger flexors and they will not be discussed here. The more superficial forearm muscles are named by their anatomical location and function.

For example, the flexor carpi radialis longus muscle is a long (hence the “longus” name), narrow muscle that lies medial (toward the little finger) in the forearm over the radius bone (hence the “radialis” name). It is anchored on the medial epicondyle of the humerus at the elbow (a large “bump” on the inside of the humerus bone just above the elbow joint) and inserts into the base of the third finger (third metacarpal bone; hence the “carpi” part of its name). This muscle flexes the wrist joint (hence the “flexor” name). The flexor carpi ulnaris muscle lies over the ulna bone and it is the most medial superficial flexor forearm muscle. One head of this muscle begins on the medial epicondyle of the humerus (just like the flexor carpi radialis longus). The other head begins on the medial edge of the ulna bone of the forearm, near the elbow joint. It inserts on several small carpal bones on the medial part of the hand and into the base of the little finger. The flexor carpi ulnaris muscle flexes the wrist and adducts the hand (moves the little finger on the medial side of the hand toward the midline of the body, when the palms are facing forward and away from the body).

The pronator teres muscle fills in a thick segment on the medial portion of the anterior forearm, just below and medial to the insertion of the tendon of the biceps muscle. It has one origin on the medial epicondyle of the humerus bone and another on the ulna bone of the forearm. This muscle inserts into the radius bone of the forearm and partly wraps around the radius bone when the hand is supinated. After it is activated to contract, it unwraps around the radius and in doing so it pronates the forearm (turns the palm of the hand toward the floor). It also functions as a weak flexor of the elbow joint.

The palmaris longus muscle is positioned in the very center of the anterior forearm. It is actually absent in about 20 percent of people. Although its function is not missed in normal activities, persons without this muscle are at a distinct disadvantage when forearm strength is needed (e.g., heavy deadlifts, rowing or any heavy pulling movement). The palmaris longus muscle begins on the medial epicondyle of the humerus and inserts into the palmar aponeurosis, which is a sheet of connective tissue on the palm of the hand just deep to the skin. The only function of this muscle is to flex the wrist.

Although the very large flexor digitorum superficialis muscle is classified anatomically as an intermediate muscle, it could be easily classified as a superficial muscle. The flexor digitorium superficialis takes its origin from the medial epicondyle of the humerus, and also the ulna and the radius bones of the forearm. It inserts into the palmar side of the middle four digits. This muscle flexes the wrist joint and the middle four fingers. It is therefore critically important in conveying a crushing grip strength to the hand.

Wrist Curls

It is important to achieve a full range of motion on each repetition.

1. Select a straight barbell and sit on the edge of a bench. Place the posterior side of each forearm on the top of each corresponding thigh, but let your wrists hang beyond your knees. Alternatively, you can kneel down so that your forearms are resting on a bench. With either position, only your hands should be hanging over the edge of the bench or your knees.

2. Grip the bar with your hands about four inches apart and with your palms supinated (palms facing the ceiling).

3. Next, curl your fingers as you tighten your grip on the bar. With the bar firmly in the palms of the hands, flex the wrist joint by bringing the knuckles of the hands toward the anterior (front) part of the forearm. This results in lifting the bar upward and should be completed in about 2 seconds. Do not “jam” your wrist upward, but firmly bring your hands upward as far as possible. Hold the highest position for 3 seconds.

4. While maintaining the forearms on your thighs, lower the bar toward the floor, over a very slow count of four. The long muscle bellies of the anterior forearm muscles should heave and slither like a sack full of snakes writhing with each contraction. Loosen your grip on the bar, and let it roll down to the end of the fingers. This will increase the stretch that occurs across the muscles of the anterior forearm. Stretch against tension is an excellent stimulus for muscle growth. Do not lose control of the bar or it will roll right off of your fingers and onto the floor (or your foot).

5. Finally, tighten your grip on the bar and roll it back to the palms of your hand. Begin the lift upward again by repeating the sequence until the set is complete. As you fatigue, you will have the tendency to reduce the range of motion in each set, or lift the forearms from your thighs; make every effort to avoid these errors.

6. Four sets of heavy wrist curls should be enough for one workout. Rather than stopping prematurely on the last 2 sets, you should enlist the help of a training partner or someone in the gym to help you complete another 3-4 forced repetitions on the last 2 sets of your session. If you choose to add forced repetitions, you should lower the weight about twice as slow as usual (i.e., 8 seconds). As you will be getting very fatigued, be careful not to let go of the bar on the way down with forced reps.

You should not need to do more than 2 sets of forced repetitions, and only do these after you have a several weeks of direct forearm training under your belt. If you prefer to train alone, you can work up to 5 to 10 partial repetitions on the final 2 sets of each workout. However, make sure that you only do these partial repetitions after you are unable to complete any more full repetitions. Either approach will instill a burn so deep in your oxygen-starved muscles that you will gladly welcome the blood back to your hands and forearms between sets.

Outstanding arms can only be great if they are developed from shoulder to fingertips. This means that you cannot ignore the forearm muscles. Wrist curls are guaranteed to thicken and strengthen the muscle bellies of the anterior forearm. Your newly acquired forearm strength will also help you to better hang on to heavier weights in your normal workouts. Your new wrist and grip strength will also be recognized and appreciated by your associates, especially when they unravel their hands from your newly developed crushing handshake.

References:

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Oksa J, Ducharme MB and Rintamaki H. Combined effect of repetitive work and cold on muscle function and fatigue. J Appl Physiol,92: 354-361, 2002.

Segal RL, Catlin PA, Krauss EW, Merick KA and Robilotto JB. Anatomical partitioning of three human forearm muscles. Cells Tissues Organs, 170: 183-197, 2002.

Soller BR, Hagan RD, Shear M, Walz JM, Landry M, Anunciacion D, Orquiola A and Heard SO. Comparison of intramuscular and venous blood pH, PCO(2) and PO(2) during rhythmic handgrip exercise. Physiol Meas, 28: 639-649, 2007.

Vigouroux L and Quaine F. Fingertip force and electromyography of finger flexor muscles during a prolonged intermittent exercise in elite climbers and sedentary individuals. J Sports Sci, 24: 181-186, 2006.