I find his running ability quite remarkable. Of course the skiers do a lot of running in the summer and they have a huge engine from all their training hours. But skiers are also bigger in the upper and lower body than running specialists.
I like that guys like him (and Blummenfelt or Andy Vernon) show that you can run very fast without being built like a bird and that more power and a big engine can be helpful. I think when we talk about running prowess one often focuses too much on being ultra light and forgets the strength component.
(When I got into running at 17 I fell into this trap and kept my bodyweight unnaturally low. When I took up cycling I grew much more muscular and now, at my heaviest, I run faster than ever.)