Doing extra arm isolation exercises like bicep curls and triceps extensions doesn't help you get stronger or build more arm muscle than just doing big compound moves like bench presses and pull-downs — at least not for beginners after 10 weeks.

Scientific Claim

Adding single-joint exercises to a multi-joint resistance-training program does not result in greater increases in elbow flexor muscle thickness or peak torque in untrained young men after 10 weeks of training, compared to multi-joint exercises alone.

Original Statement

“There was a significant (p < 0.05) increase in MT (6.5% for MJ and 7.04% for MJ+SJ) and PT (10.40% for MJ and 12.85% for MJ+SJ) in both groups, but there were no between-group differences.”

From study:Effect of adding single-joint exercises to a multi-joint exercise resistance-training program on strength and hypertrophy in untrained subjects.

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

probability

Can suggest probability/likelihood

Assessment Explanation

The study is a randomized controlled trial, which supports causal inference, but blinding status is unknown, so definitive language is overly confident. Probabilistic language ('does not result in greater increases') better reflects the evidence.

More Accurate Statement

“Adding single-joint exercises to a multi-joint resistance-training program likely does not result in greater increases in elbow flexor muscle thickness or peak torque in untrained young men after 10 weeks of training, compared to multi-joint exercises alone.”

Evidence from Studies

Supporting (1)

Effect of adding single-joint exercises to a multi-joint exercise resistance-training program on strength and hypertrophy in untrained subjects.

Randomized Controlled Trial

Human

2013 Mar

Both groups got stronger and their arms got bigger, but the group that did extra arm curls didn’t get any bigger or stronger than the group that only did big compound exercises.

Contradicting (0)

No contradicting evidence found

Source Study

Effect of adding single-joint exercises to a multi-joint exercise resistance-training program on strength and hypertrophy in untrained subjects.

Score: 47

DOI: 10.1139/apnm-2012-0176

Similar Assertions

Doing extra arm exercises along with big compound lifts like squats and presses makes arms a little bigger, but doesn’t make you stronger than doing just the big lifts alone.

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If you're new to lifting, doing big lifts like presses and squats is just as good for getting stronger as doing those plus extra isolated arm exercises.

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After doing bicep curls 24 times over 12 weeks, women’s upper arm muscles got noticeably thicker, no matter which way they did the curls.

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For exercises that move just one joint—like bicep curls—lifting heavier weights leads to better strength gains than lifting lighter weights, even if both are done until exhaustion.

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When beginners do arm curls and triceps exercises with a little swing to lift heavier weights, their arms grow just as much as when they do the movements slowly and strictly—even though they lift way more total weight with the swing.

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