If building a better pair of arms is your goal, triceps should be priority #1.

First of all, the triceps make up roughly 2/3 of your upper arm mass, compared to the biceps’ 1/3. In other words, you can’t have big arms without having big triceps, so don’t put all of your focus just on the biceps.

And then there are the indirect results: stronger triceps will lead to great gains in other important areas. Since the triceps are a “pushing” muscle, the stronger they are, the more you’ll be able to do on bench press, incline press and military (overhead) press. This will be crucial if building a bigger, stronger chest and shoulders is also a goal.

Before you start hitting those triceps hard, though, make sure you know what you’re doing and why you’re doing it. Arm training isn’t rocket science, but there is a science to it. Here’s a quick tutorial, plus a sample triceps workout to follow…

The back of the upper arm contains just one muscle, the triceps brachii, which is comprised of three separate heads: the lateral head, medial head, and long head. The long head originates at the scapula, while the other two heads arise from the humerus on either side. All three heads insert at the ulna (the forearm bone on the pinky side).

Fully developed triceps bulge out to the side (where the lateral head is prominent), are thick and defined in the inner portion (because of the medial head), and are the most massive up near the shoulder, which is where the long head resides.

If any of these areas is deficient, either the lateral, medial or long head can be targeted by altering the position of the arms. (However, keep in mind that any time the elbow is extended, all three heads of the triceps work together to initiate the movement; it’s virtually impossible to isolate any one head completely.)

The lateral head is targeted when doing close-grip bench press, while standard cable pressdowns also place slightly more emphasis on the lateral head than the other two. The medial head is emphasized when using a reverse grip, as when doing reverse-grip versions of pressdowns, bench press or lying extensions (aka “skull crushers”). Triceps exercises where the arms are overhead (all variations of overhead extensions) target the long head.

Here’s a more complete list of triceps exercises, organized by which of the three heads they emphasize:

Lateral Head: Close-grip bench press (all variations), decline bench lying triceps extension, cable pressdown (overhand grip), kickbacks (all variations), “diamond” push-ups (hands close together)

Medial Head: Reverse-grip bench press, reverse-grip cable pressdown

Long Head: Overhead extension (all variations)

Lateral + Long Heads: Lying triceps extension (aka “skull crushers”; all variations)

Lateral + Medial Heads: Dips (narrow grip), bench dips

*Note: “All variations” refers to the various types of equipment that can be used for the same movements. For example, close-grip bench press using either a free-weight barbell, dumbbells or Smith machine; kickbacks using either dumbbells or cables; overhead extensions using either a dumbbell, EZ-bar or cable; etc.

Use the below workout to thoroughly hit all three heads of the triceps. If you’re working biceps in the same workout, I recommend supersetting a biceps exercise with every triceps move.