I saw something similar the other day but a guy was doing it with squats had something really stupid like 5-600 and wasn't it even making it to 1/4 squats. The really odd part was after that he went back to like 250 and did proper full range squats.
Actually what he's probably doing is some sort of heavy isometric training (i dont know if that's the term) but the purpose of that is to 1) strengthen tendons/ligaments 2) stimulate CNS with weights MUCH heavier than one can handle so that when they go back to their regular weights, it feels lighter. Now i don't know if there is any scientific basis but i do implement this once a while on my recover days, and I THINK it actually helps.
P.S : Ya'll watch men too hard