Sorry to hear you got injured. Every time I go to the gym I say to myself "you are a cyclist, not a weight lifter", even though its obvious whenever I look in the mirror. On exercises like leg press where I can move large weights, I gradually work up to heavy weights rather than going for my max right off. If anything hurts, I stop that exercise for the day. When I come back after stopping for a while, I try to be careful not to get carried away.