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.

Scientific Claim

Both unilateral and bilateral strength training increase lean tissue mass in the lower body, upper body, and whole body of post-menopausal women compared to no training, but neither method is superior to the other for muscle gain.

Original Statement

“The unilateral-training group had a greater increase in lower-body LTM compared to the control group (P<0.05); however, there were no differences between unilateral and bilateral training groups. Both training groups had greater increases in LTM of the upper- and whole-body compared to the control group.”

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 design supports causal claims for muscle gain versus control, and the authors correctly avoid claiming superiority between methods, as no significant difference was found.

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

Both types of strength training — using both legs/arms at once or one at a time — helped post-menopausal women build more muscle than not training at all, and neither type was better than the other for muscle growth.

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

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.

88%

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.

77%

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.

75%

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.

74%

Doing leg extensions one leg at a time for 12 weeks makes each leg stronger and more active when tested alone, better than doing both legs together — even though both methods improve overall leg strength similarly.

70%