Tempo, long rest, tempo

I’ll be brief, but where is the literature that says a “lactic environment” (perhaps a definition of this might make things more clear) destroys mitochondria within muscle cells? Without some context and basis, this statement kinda detracts substantially from the rest of your post. I am not going to argue about whether or not we want or don’t want lactic in tempo, but to say it destroys mitochondria?