That's lifting pretty heavy. Too heavy. RJ said Dorian lifted no heavier that any average bodybuilder.
If you tear a muscle off the bone then by definition its too heavy for you
If you watch his Blood and guts he didnt shift any real big poundages for his size
3 plates on incline bench, looked like 60lb dumbels for flys
Also most muscle tears are when the muscle is at full extension under a load (deadlift bicep tears/ tricep skull crushers/ pecs bottom of a press)