Both Bosa's seem to be injury prone. Joey has missed quite a few games, and Nick has had at least 2 significant injuries.
They're both hard working, dedicated, and intense, and maybe they need to back off trying to be Superman a bit. Too much bulk can cause health problems as bones can only take so much stress and torque.
I hope they're not genetically predisposed to lower body injuries, but some people are just built stronger, like Marshawn Lynch, John Riggins, and Brett Favre. Kam Chancellor laid some violent hits, but he said "I never got a concussion." Some people are more susceptible, like Luke Keuchly and Wes Welker.
Remember Bo Jackson? He put on so much thigh muscle, that the power in his legs caused his hip to pop out. His legs were like tree trunks. And they muscles just wore the bone out until it came apart.
Joey and Nick need to find a good trainer and doctor to help them find their best playing weight and build.