Forearm muscles
Flexors and extensors of the forearm
// Structure & location
The forearm holds two large groups. The flexors on the inner (palm) side mostly arise from the inner bony bump of the humerus at the elbow. The extensors on the outer side mostly come from the outer bump. Most of these muscles end in long tendons that run into the fingers. The brachioradialis forms the bulge on the thumb side just below the elbow.
// Function
The flexors bend the wrist and fingers and provide grip strength. The extensors straighten them and stabilise the wrist while gripping. Some muscles rotate the forearm, and the brachioradialis helps bend the elbow, especially with the thumb up.
// For training & sport
- Grip strength grows with anything heavy you have to hold on to: deadlifts, rows, farmer's walks, hanging from a bar.
- Hammer curls and reverse curls (back of the hand up) train the brachioradialis.
- Wrist curls flex and extend the wrist directly.
// Good to know
The fingers themselves contain hardly any muscle. They are moved like puppets by tendons from the forearm; only the fine movements come from small muscles in the hand. Tennis elbow is an overload at the origin of the extensors on the outside of the elbow; golfer's elbow affects the flexors on the inside.