The Science of Training: Triceps

by Josh Bryant and Joe Giandonato

IFBB Pro Cory Mathews had the biggest back arms in prison, now from behind the pulpit.

In “bro” bodybuilding circles, many claim, faster than Grant went through Richmond, to possess 20-inch arms.

In reality, these inches are about as realistic as the skirt-chasing Lothario’s claims at the local mobile home turned kick n’ stab bar. 

According to the late Arthur Jones, of Nautilus fame, when he measured Sergio Olivia’s arms, they were 20 1/8” cold. Arnold’s were 19 7/8” slightly pumped and Bill Pearl’s fell just shy of 19 inches when measured in 1960.

Gym bros consider arm measurements the measuring stick of succes, yet spend at least two thirds of their time training biceps, when the triceps make up two thirds of their arm size!
And, generally, those that place an appropriate focus on “back arms”, as the triceps are called behind bars, do it all wrong.

Because, veteran lifters — both competitively and recreationally — are obsessed with blowing up their arm size and bench press numbers, we are binging you the science and application of how to properly train the triceps.

Josh Bryant helping Texas bodybuilding legend, Tyrus Hughes, build massive triceps.

Understanding the Triceps

The triceps brachii consists of three distinct aspects—the long head, the lateral head, and the medial head.  It is the muscle principally responsible for extension of the elbow joint, or straightening of the arm, while its long head assists with shoulder extension.

  • The long head starts at the back of the scapula close to the glenoid fossa (the socket where the humerus is fitted into, a.k.a. the “shoulder” or “arm bone”). This is the only muscle of the triceps that spans across two joints (elbow and shoulder) maintaining the longest moment arm in both shoulder and extension.
  • The medial head of your triceps begins at the back of the humerus.
  • The lateral head originates on the posterior surface of the humerus.

All three heads insert around the area of the olecranon process of the ulna or the back of the elbow. The long head is the largest portion of your triceps, the lateral head is the smallest, and the medial portion is partially sheathed by the long and lateral heads. 

And since all three heads of the triceps join at a common tendon, it impossible to completely isolate one head of the triceps.


With some ingenuity and manipulating body position and your upper arm in relation to your torso, and gravity, you can redistribute the role of each head.  

Specific Application

Below are the specifics applied for size and strength, much of what we learned from the late Charles Poliquin, and how to specifically target and place emphasis on each head of the triceps.

The Long Head 

The further your arms are away from your belly button, the greater the recruitment of the long head.  

The Lateral Head

Executing triceps extensions on a flat bench will increase the contribution of the lateral head, while also hitting the long head.  

The Medial Head

When your arms get closer to your torso, for example, exercises performed on a decline bench, recruitment of the medial head increases. 

Force potential of the triceps is greatest beyond 90 degrees of elbow flexion since all heads are lengthened, likely why many bodybuilders are observed drawing their forearms upward — further increasing their elbows during the eccentric portion of cable press down movements.

MRI Researxch

Target Bodybuilding,an iconic classic by Per Tesch, used MRI scans on bodybuilders to see which exercises placed greater stress on different heads of the triceps. Two “X”s denoted heavy muscle use, one “X” equated to moderate muscle use and no “X” s signified no use during the exercise, here were the results.

Exercise NameLateral HeadLong HeadMedial head
French Press with EZ BarXXXX
French Press with EZ Bar (On Decline Bench)XXXXXX
Supine Triceps Extension with Dumbbells and Neutral GripXXXX
Overhead Triceps Extension with dumbbell and neutral gripXXXXXX
Overhead Triceps Extension with dumbbell and neutral grip and RotationXXXXXX
Overhead Triceps Extension with reverse gripXXXX
Standing French Press with Straight BarXXXXX
Triceps Pushdown with Straight Bar and Narrow GripXXXXX
Triceps Pushdown with RopeXXXXXX
Triceps Pushdown with Angled BarXXXXXX
One-Arm Triceps PushdownXXXXX
One-Arm Triceps Pushdown with Reverse GripXXXXXX
Overhead Triceps Extension with RopeXXXX
Bench Press with Narrow GripXXXXX
Parallel Bar DipXXXXXX
Pullover with EZ Bar and Narrow GripXXXX
Behind the Neck PressXX
Standing Dumbbell Press with elbows inX

Fiber Composition 

Don’t drink the Jim Jones-like Kool-Aid and believe the YMCA intramural bodybuilding champion and his pump-worshipping cronies!

The triceps respond best to heavy weight and longer rest periods of one to three minutes. Why?  The triceps are predominantly a fast-twitch muscle fiber group. In fact, 50 to 65 percent of triceps fibers are fast-twitch!


You still can’t just train with compound movements, eat like a bodybuilder and expect to have stage-ready triceps, unless, of course, you are assembling one as you take breaks to scan its instructions perched on your dad bod paunch.

The triceps still have 35 to 50 percent slow-twitch muscle fibers, which respond better to higher reps, more time under tension, and reduced rest periods. Interestingly, the triceps can have different fiber composition between individual heads, reinforcing the importance of using a variety of exercises, tempos, rep ranges, rest periods time under tension, and even blood flow restricted training to develop triceps that will gain respect on the yard and give you the power to stiff arm petulant coworkers as you charge toward the time clock to punch out for a work shift. 

Breaking it down even further, the lateral head of the triceps is very predominantly fast-twitch type IIX muscle fibers, the medial head is made up of more slow-twitch type I fibers, and the long head is mixed.  Overall, the triceps are a mixed-fiber type with a slight fast-twitch bias, explaining why the heads fatigue at different rates, though they team up like weak-willed millennial NBA stars, working in unison once exhausted, meaning all cylinders should be firing during banded finishers performed to failure.

Big Jack preaching on heavy pig iron and triceps extensions

Final Thoughts

If we had to pick one exercise for the triceps for a perfectly healthy trainee, it would be weighted dips with eight reps or fewer.

But, the reality is, the best “back arms” are built with heavy and light weights, fast and slow tempos, and a variety of rep ranges.

Triceps require a holistic approach to maximize muscular development. 

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Hussain, J., Sundaraj, K., Subramaniam, I.D., & Lam, C.K. (2019). Analysis of fatigue in the three heads of the triceps brachii during isometric contractions at various effort levels. Journal of Musculoskeletal and Neuronal Interactions, 19 (3), 276-285.

Jones, A. (n.d.). The Ultimate Physique–Nautilus Bulletin #2. Retrieved from

Kholinne, E., Zulkarnain, R.F., Sun, Y.C., Lim, S., Chun, J., & Jeon, I. (2018). The different role of each head of the triceps brachii muscle in elbow extension. Acta Orthopaedica et Traumatologica Turcica, 52 (3), 201-205.

Lucas-Osma, A. M., & Collazos-Castro, J. E. (2009). Compartmentalization in the triceps brachii motoneuron nucleus and its relation to muscle architecture. The Journal of Comparative Neurology516 (3), 226–239. 

Poliquin, C. (2015). Ultimate Guide to Arm Size. Strength Sensei.

Srinivasan, R., Lungren, M., Langenderfer, J., & Hughes, R. (2007). Fiber type composition and maximum shortening velocity of muscles crossing the human shoulder. Clinical Anatomy20 (2), 144–149. 

Tesch, P. (1999). Target bodybuilding. Champaign, IL: Human Kinetics