the thing is, Pros doing quarter reps you see all the time....but doing quarter reps with that kind of weight that JJ and Branch use its a feature of a few...
Pros with perfect form always brag about their maximum poundages, but its very difficult to see any of that on video for example...(i just wonder why...hehe)
for now i can remember just the example of Kevin on M3, with very good form and heavy ass weights