The triceps attach to the ulna, not the radius, so the position of your wrist/forearm (i.e., pronated, supinated or neutral) will have no bearing on whether you can accentuate one triceps*head more than another. The only way to differentiate between the three heads of the triceps is to change the humerus's position relative to the shoulder joint. For instance, if you move the humerus (upper arm) toward a more shoulder flexed position (≈ 90-180 ̊ ), you will put the long head on a stretch (since it crosses both the shoulder and elbow joints) increasing it's mechanical advantage over the medial and lateral heads (since they only cross the elbow joint). In contrast, if you move the humerus toward a neutral position (0 ̊ ) or beyond, the long head becomes actively insufficient, which allows the medial and lateral heads a greater opportunity to produce elbow extension compared to the long head.

__________________

Disclaimer: Hypermuscles.com does not promote the use of anabolic steroids without a doctor's prescription. The information we share is for entertainment and research purposes only.