Developing that kind of strength isn't as easy as doing squats or running a lot. You're using different muscle groups. If a person took the time to study human anatomy and recognized which muscle groups were most important in successfully executing a takedown. Then, experimented to figure out how to best target and develop those muscle groups to their full potential -- they could probably enjoy a big advantage over others who aren't willing to go to those lengths.
Are you saying that they are doing unconventional exercises? Bodyweight or kettlebells or both? The type of functional strength you get can only really come from bodyweight and kettlebells is what my friend told me.
I mean, what do you consider to be 'functional training'? You talk a big game but you haven't given me my workout routine that Rory does.