It seems to me that the piece of data always missing in these kinds of challenges is time. I think anyone probably can run a marathon given enough time to chang

It seems to me that the piece of data always missing in these kinds of challenges is time. I think anyone probably can run a marathon given enough time to change their lifestyle and build the appropriate strength and endurance. If that time is 10 years, then so be it for that person. The human body is designed to adapt to stressors and environmental conditions. The time it takes to adapt is where this genetic predisposition seems to come in to play.