> If I took a random population and made them train for grip strength. Then I compared that groups lifespan to the overall lifespan of people I didn't make train for grip strength and I find that there is a correlation with longer life span for people who trained for grip strength...
Well I've just verified causation. There is literally no other conclusion.
What if the people you trained for grip strength also started taking care of their health in general (eg. eating better and moving more often), after starting your grip strengthening exercises?
What if the people you trained for grip strength also started taking care of their health in general (eg. eating better and moving more often), after starting your grip strengthening exercises?