Why lifting with both arms/legs at once is different
The effect of unilateral and bilateral strength training on the bilateral deficit and lean tissue mass in post-menopausal women
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When older women lifted weights with both arms or legs together, sometimes they weren’t as strong as when using one side at a time — but only for some exercises. Training with both sides together made them better at using both at once. Training one side at a time built muscle just as well, but didn’t fix the strength gap.
Surprising Findings
Knee extension showed NO bilateral deficit—even though leg press (a similar lower-body movement) did.
Both exercises use the quads, so scientists expected similar results. The fact that one shows BLD and the other doesn’t suggests neural coordination, not muscle size, is the key variable.
Practical Takeaways
If you’re over 50 and want to fight muscle loss: do any resistance training—unilateral or bilateral—2–3x/week, 2 sets per exercise.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
When older women lifted weights with both arms or legs together, sometimes they weren’t as strong as when using one side at a time — but only for some exercises. Training with both sides together made them better at using both at once. Training one side at a time built muscle just as well, but didn’t fix the strength gap.
Surprising Findings
Knee extension showed NO bilateral deficit—even though leg press (a similar lower-body movement) did.
Both exercises use the quads, so scientists expected similar results. The fact that one shows BLD and the other doesn’t suggests neural coordination, not muscle size, is the key variable.
Practical Takeaways
If you’re over 50 and want to fight muscle loss: do any resistance training—unilateral or bilateral—2–3x/week, 2 sets per exercise.
Publication
Journal
European Journal of Applied Physiology
Year
2006
Authors
C. L. Janzen, P. Chilibeck, K. Davison
Related Content
Claims (5)
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.
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.
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.
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.
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.