Are you referencing the actual study? The article states, “The study involved restricting mice from using their hind legs, but not their front legs, over a period of 28 days.”
They also didn't control for other muscles so who's to say that it is specific to leg exercise, or even, sedentary life, living life at a 45 degree incline, too much blood flowing to the brain, or any other factor.
I'm all for barbell squats and deadlifts, but I have to point out that there's a difference between saying "leg exercise is critical to brain and nervous system health" and "mice restricted from using their hind legs exhibit lower numbers of neural stem cells".
You’re not wrong; the full write up (and the researcher’s quote in particular) makes a much more nuanced statement than the title does. I do wonder if these conclusions are ill-founded, though. Otherwise wouldn’t people who lose a limb or use thereof suffer from extreme neurodegeneration?
My non scientific opinion is that the way they made the mice not be able to use their rear limbs (suspension of the mice by the tail attached to fixure on ceiling of cage) might have only shown measureable stress levels via blood sample in 6 percent of mice studied but that had to have some other psychological impact on all the mice - if we did that to humans at least we could tell human subjects what was going to happen, I am not arguing that mice have the same cognitive abilities as humans.
I've read that our lymphatic system needs muscle movement to properly circulate. Is it possible that leg movement has a positive lymphatic response? Could it be that better lymphatic systems == better nervous system health?
"Leg exercise is critical to brain and nervous system health" is the title but what they actually did is hang a mouse by it's tail for a month.
I guess doing strange things to rodents and measuring the outcomes is useful, but going so far as to turn it into health advice for humans is absurd.