[Erlich_Bachman]

> but did we think of looking intra-cell?

Yes, a lot of science has "thought of" at looking intra-cell. In fact, the explanation of "don't shake their cells enough" must be very fringe because I haven't heard it any one time before from any serious scientist or a health book etc. The human body is much more complicated, and the way we understand many of the functions of it, including healthy functions, are based on biochemistry, both intra-cell and throughout the body.

Also "shaking the cells" can't even be that important physically, when you compare the speeds at which the limbs move during running to the base speeds of molecules inside the cell due to basic heat-based brownian motion.