Origin: At the upper two-thirds of the lateral supracondylar ridge of the humerus
Inserts: At the lateral styloid process of the radius
Function: Flexing the elbow when the hand is in a neutral position (as in a thumb-up “Hammer” curl). It shows little activity in slow, easy flexion and is more active in rapid flexion and extension.
MUSCLE: Extensor carpi radialis
Origin: At the distal third of the lateral supracondylar ridge of the humerus
Inserts: At the second metacarpal on the back of the hand
Function: Extension and abduction of the wrist and aids in flexion of the forearm
MUSCLE: Flexor carpi radialis
Origin: From the flexor tendon of the medial epicondyle of the humerus
Inserts: Into the second and third metacarpals of the hand
Function: Flexion and abduction of the wrist and aids in pronation of the forearm
Indications of Weakness:
The forearm may become weak in a number of ways:
1. Repetitive muscle trauma, causing the muscle to become shortened with adhesions (tennis elbow) and pain on the outer (lateral) side of the elbow joint
2. Pain on the inner (medial) side of the elbow joint indicates that the forearm flexor muscles are also shortened with adhesions
3. If the proximal radioulnar (elbow) joint has restrictions, the forearm may also become weak and hard to pronate and supinate when lifting weight
Optimal Training Principles:
Brachioradialis: Reverse grip E-Z bar curl. Use pronated or semipronated grip to put biceps at a mechanical disadvantage to increase stress on the brachialis and brachioradialis. Hammer curl is also excellent for these muscles and alleviates stress on the wrist.
Extensor carpi radialis: Dumbbell wrist extensions off a bench or the knee are an excellent way to develop strong wrist extensor muscles. The dumbbell wrist extension is preferred over the straight bar wrist extension since dumbbells allow for both radial and ulnar deviation to work different wrist extensor muscles as well as eliminate the excessive stress the straight bar puts on the wrist.
Flexor carpi radialis: Barbell or dumbbell wrist curls. Wrist flexor muscles use no pronation and therefore place little or no stress on the wrist. Barbells allow the use of heavier load during wrist curls. Deviate the wrist ulnarly or radially to work the various wrist flexors. Using a 45 degree angle on the preacher curl or resting the forearms on the thighs in a “Half-Squat” position allows you to increase stress on the wrist flexors at the top (end contraction position) of the wrist curl.
Dr. Jim Bell