Researchers focused on the thigh muscle and used an MRI to measure its size in the women before and after the weight lifting. There is some good news - the 80+ year old ladies were able to lift 26% more after three months of training. This is probably because the nervous system got more effective in how the nervous system "ordered" the muscles to work.
So, bottom line, no gain in muscle mass; but from a purely functional point-of-view, a 26% gain in lifting ability.
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