For people new to weight training, lifting weights with one arm or both arms at the same time leads to similar muscle growth, suggesting that the total amount of weight lifted matters more than...
Mechanism
Synthesis from 1 study
Your muscles grow based on how much total weight they lift, not whether you lift it with one arm or two. As long as the total effort is the same, the chemical signals telling your muscles to grow are just as strong.
Most probable mechanism
When you lift weights, the tension on your muscle fibers triggers chemical signals that tell the muscle to build more protein. Whether you use one arm or two, as long as the total weight lifted is the same, the total tension on the muscle fibers is similar, so the muscle grows the same amount.
Mechanical tension from muscle contraction activates mechanosensitive pathways, including mTORC1 signaling, which increases the rate of muscle protein synthesis.
Total mechanical load over time determines the cumulative activation of protein synthesis pathways, regardless of whether the load is distributed unilaterally or bilaterally.
Evidence from Studies
Supporting (1)
Community contributions welcome
Small muscle mass exercise enhances muscular adaptations? Effects of unilateral and bilateral biceps curl on maximum strength and muscle size changes.
Contradicting (0)
Community contributions welcome
Gold Standard Evidence Needed
According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.