Training one arm or leg at a time helps older women build muscle just as well as training both at once—but it doesn’t help them use both sides together any better.

Scientific Claim

Unilateral strength training has minimal impact on reducing the bilateral deficit in post-menopausal women, despite increasing lean tissue mass similarly to bilateral training.

Original Statement

“Bilateral training decreased the BLD; whereas unilateral training had minimal effect on the BLD.”

From study:The effect of unilateral and bilateral strength training on the bilateral deficit and lean tissue mass in post-menopausal women

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

definitive

Can make definitive causal claims

Assessment Explanation

The study directly compared unilateral and bilateral training effects on BLD and found no significant change with unilateral training, supporting a definitive conclusion.

Evidence from Studies

Supporting (1)

The effect of unilateral and bilateral strength training on the bilateral deficit and lean tissue mass in post-menopausal women

Randomized Controlled Trial

Human

2006 Jun

Doing one arm or leg at a time didn’t help post-menopausal women overcome the weakness that happens when using both sides together, but it still built muscle just as well as using both sides at once.

Contradicting (0)

No contradicting evidence found

Source Study

The effect of unilateral and bilateral strength training on the bilateral deficit and lean tissue mass in post-menopausal women

Score: 47

DOI: 10.1007/s00421-006-0165-1

Similar Assertions

Whether older women train one arm or leg at a time or both together, they both gain muscle—just as much as each other—and both are better than not training at all.

88%

When older women train by pushing or pulling with both arms or legs at the same time, they get better at using both sides together, making their strength more efficient.

81%

Older women who lift weights—even just one arm or leg at a time—gain muscle and fight off the natural muscle loss that comes with aging.

81%

If you train one leg at a time, that leg gets much stronger than the other when tested alone — but if you train both legs together, both legs get stronger at the same rate, with no one leg getting ahead.

77%

When older women try to push with both legs at once on a leg press or pull with both arms on a lat machine, they’re weaker than when using each side separately—but this doesn’t happen when they extend their knees.

72%