Muscles, explained · Lesson 5
Triceps: are overhead extensions better for growth?
Yes: with your arm overhead, your triceps grows more, even though you lift about a third less. In 21 adults, after 12 weeks of cable extensions, the long head grew one and a half times more on the overhead arm, and the other two heads about 1.4 times more. The reason: the long head runs behind your shoulder, so with your arm raised it’s pulled from both ends.
Is the triceps bigger than the biceps?
On its own, your triceps is as thick as all the muscles that bend your elbow combined. In 4 men scanned with MRI, its largest cross-section matched that of the biceps, brachialis and brachioradialis combined; its force-relevant cross-section, which accounts for fiber length, was even 1.9 times larger (Kawakami et al., 1994).
Across 10 donor arms, the triceps, all three heads combined, also had the largest force-relevant cross-section of the major elbow muscles: 14.9 cm², versus 1.2 cm² for the brachioradialis, the smallest (Murray et al., 2000).
What are the three heads of the triceps?
Triceps means three heads, at the back of your arm. Two start on your humerus, your upper arm bone. The third, the long head, runs up to your shoulder blade. And all three attach to the tip of your elbow: the end of your ulna, a forearm bone.
What does the triceps long head do?
Your triceps straightens your elbow: that’s elbow extension. But the long head runs behind your shoulder: it also brings your arm back, that’s shoulder extension.
With your arm by your side, the long head stays short; with your arm overhead, it’s pulled from both ends, lengthened more (Maeo et al., 2023).
Overhead or arm-by-your-side extensions?
21 adults did 12 weeks of cable extensions, from a right-angle elbow to a straight arm, one arm overhead, the other by their side, 5 sets of 10 reps at 70% of their max, twice a week. On MRI, the long head of the overhead arm grew 28.5% vs 19.6%, one and a half times more; the other two heads, which don’t cross the shoulder, 14.6% vs 10.5%; the whole triceps 19.9% vs 13.9% (Maeo et al., 2023).
Overhead loads were 34 to 39% lower throughout the study, yet maximal strength and training loads improved just as much on both sides, by 62 to 71% (Maeo et al., 2023).
Should you drop arm-by-your-side extensions?
Not necessarily: it’s a single cable study in adults, and it says nothing about other triceps exercises. Keep your arm-by-your-side extensions if you like them, just don’t only do those.
Your workout plan, built for your body.
In Tekio, your plan targets your triceps and you watch them progress on your body, week after week.
Sources
Studies checked in PubMed. Measured muscle activity isn’t growth: each fact keeps its study’s population and limits.
- Kawakami Y, Nakazawa K, Fujimoto T, et al. (1994). Specific tension of elbow flexor and extensor muscles based on magnetic resonance imaging. Eur J Appl Physiol Occup Physiol 68(2):139-47. PubMed · DOI
- Murray WM, Buchanan TS, Delp SL (2000). The isometric functional capacity of muscles that cross the elbow. J Biomech 33(8):943-52. PubMed · DOI
- Maeo S, Wu Y, Huang M, et al. (2023). Triceps brachii hypertrophy is substantially greater after elbow extension training performed in the overhead versus neutral arm position. Eur J Sport Sci 23(7):1240-1250. PubMed · DOI
These lessons inform; they don’t replace advice from a health professional.