Eli5, Why can you lift more will both hands than each hand can lift combined

Question

Eli5, Why can you lift more will both hands than each hand can lift combined

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Answer 1

Studies have found the opposite of what you state.

In physiology, there is a concept called “bilateral deficit phenomenon” which basically means a single limb cannot generate as much force when it is being used alongside the other limb.

So, let’s say you can curl 50lbs max with your left arm and 50lbs max with your right arm. But, if you try to curls 50lbs with left and right arm at the same time, you would likely fail.

But notice, this is formulated differently than comparing 1 armed 50lb curls with dumbbells to 2 armed 100lb curls with a bar.

I am not ELI5ing well, but let me just say your question itself is more complicated than you are asking.

Btw, no one knows why Bilateral Deficit Phenomenom exists. It may be because your nervous system is overloaded, it may have to do with postural stability being overloaded, or it may be that people tend to train single limbs more and it’s just what subjects are used to… Or it could be something else.

Here’s an article (not telling you to read it, just as proof that I am not making stuff up):

https://pubmed.ncbi.nlm.nih.gov/27582260/