The only place I could find it was
here. As far as I can tell it is simply calculation of the rate constant of collagen degradation using the
Arrhenius equation.
However, the actual chemical reaction used for the collagen degradation seems to be hydrolysis. But since the collagen proteins involved are embedded in the calcium matrix of bone, I don't see how water would be present for such a reaction. The article also doesn't state the actual variables that were plugged into the Arrhenius equation, and I'm fairly useless at maths so don't know how valid their method was.