Is this way too throw leading uppercuts?

[BCBUD]

https://m.youtube.com/watch?v=egIfayF05Gg
here's a video clip of a very hard hitting fighter throwing what looks to be leaving uppercuts is it thrown from the back foot,and how does he do it is he rolling his shoulders and then putting out? @0:09 he turns his thumbs in, something that scrap is taking about.