There are three heads to the triceps brachii muscle: the medial head (pictured at right in green), the lateral head (pictured at right in yellow), and the long head (pictured at right in red). The long head originates at the scapula whereas both the medial and lateral heads originate on the humerus. All three heads insert or attaches to/on the ulna (forearm).
All three heads act on the forearm by extending (increasing joint angle) at the elbow. This is essentially the primary function of the medial and lateral heads. The long head, however, since it originates on the scapula also helps the shoulder to:
- Adduct (moving arm towards body or midline)
By knowing and understanding exactly what the biceps do, you can then target them more effectively!
My Favourite Triceps Exercises
Although the long head is comprised of both main types of muscle fibers, the medial head is primarily made up of small type I fibers (“slow twitch” muscle fibers, which are used in lower intensity exercises. These fibers are involved in muscular endurance/high rep training), and the lateral head is predominantly made up of large type IIb fiber types (“fast twitch” muscle fibers, which are used during high intensity exercise. This fiber type is involved in high force, power, and speed generation).
Knowing this, to fully train your triceps, one should incorporate both low-rep, highly intense loads along with higher-rep, less intense loads. Because of the nature of the triceps, I believe that heavy loads should be handled only through compound movements such as pressing movements utilizing either the chest or shoulders (bench press, overhead press, etc.).