The triceps have three heads, hence the prefix. The three heads are the lateral (outer), the medial (inner), and the long head. The long head originates on the lateral aspect of the scapula, while the medial and lateral heads originate on the humerus. All 3 heads insert on to the olecranon process.
Hard to visualise how this looks on a real life body?
Well this is the best description I’ve heard…
…“Ever see a guy from behind whose triceps look like Christmas hams sitting on the back of his arm? That’s great long and medial head development. Ever see a guy from the front whose triceps bulge out to the side giving his arm that awesome 3D look? That’s great lateral head development.”
Still struggling to picture it? Her’s a pic then (don’t say I don’t do things for you!)
The triceps function primarily as elbow extensors while the long head is a weak shoulder extensor and stabiliser.
During pressing movements the moment arm length of the triceps increases as the elbow reaches lock out so, exercises such as, bench lockouts, board presses and partial presses from pins are all likely to be highly effective at stimulating the triceps. These are exercises which are staples in the training of powerlifters to help drive up their bench press. It is no coincidence though that top powerlifters have FREAKY sized triceps.
The muscle activity of the long head is greatest when the shoulder is roughly 90o of shoulder flexion (e.g., bench press).
Possibly the best overall triceps exercise are close grip (approx. shoulder width or slightly narrower) bench presses. These create very high levels of muscle activity in the triceps. They are, however, a demanding compound exercise which also stimulate the chest and shoulders. As a result, if triceps hypertrophy is a priority isolation exercises like tripceps extensions with DBs or the EZ bar, rope and cable pressdowns are all good options to increase training volume without overly taxing the body’s ability to recover.
Like the biceps hand position can influence muscle activation amongst the various heads of the triceps. For example, having the elbows further apart than the hands stresses the lateral head to a greater degree. This is magnified if the elbows are turned out (e.g., close grip bench press with elbows flared out).
In contrast if the elbows are further apart than the hands then more stress is placed on the long and medial heads. A good example, would be a medium grip bench press with elbows tucked.
Supinating your hands (turning palms up) is another way to shift the focus on to the long and medial heads.
Changing your shoulder position during isolation exercises like extensions can also influence the muscle activation of the 3 heads. Having your arms overhead like in a French press places more tension on the often neglected long head. Doing conventional cable pressdowns or skullcrushers shifts the tension predominantly onto the medial head.
The medial head of the triceps showed high levels of EMG activity during weighted dips, rope and cable extensions making these great choices if that is a region of the triceps you want to develop.
The triceps are fast twitch fibre dominant. Given their fast-twitch nature they tend to recover more slowly than biceps. As such, training frequency should be lower for triceps (1-2 times a week for most). Generally, training with heavy loads, lower reps and fast reps speeds is best to train the triceps.
According to Dr. Mike Israetel weekly training volume for direct triceps work should be kept to 15-20 total sets per week. I would suggest you spread these over two sessions with an emphasis on close grip bench variations and dips in the 6-10 rep range. Then to add some volume do some higher rep (mostly 10-12 reps) isolation work.