Only the arm you actually train gets a boost in its muscle cells' ability to sustain signals from the brain—your other arm doesn’t get this change.

37

Pro

0

Against

Evidence from Studies

Supporting (1)

37

Community contributions welcome

38

Neural determinants of the increase in muscle strength and force steadiness of the untrained limb following a 4 week unilateral training

Cohort Study

Human

2025 Jun

Only the arm that did the workouts got stronger at the nerve level due to a special electrical boost called persistent inward currents — the other arm got stronger too, but for different reasons.

Contradicting (0)

0

Community contributions welcome

No contradicting evidence found

Source Study

Neural determinants of the increase in muscle strength and force steadiness of the untrained limb following a 4 week unilateral training

Score: 37

DOI: 10.1113/JP288954

Similar Assertions

Working out one arm can make the other arm stronger and more steady, even if you didn't touch it—your brain is learning to control it better.

37

0

71%