How much weight is safe?

I have a kickboxing tourney in one month, so of course I've been doing my usual, cardio/weights/class work. I'm starting to hit the weights a little harder now. I run track (sprint, discus, pole vault) so of course my legs had to be in super shape. My question is, how do I know when enough is enough? I usually max out with a few friends every Wednesday in the gym. I can hit 350 on the leg machine, 200 squat, 190 deadlift, 180 bench and so on (thats with reps), I tend to get really sore through my quads after I max out on the leg machine. Am I doing damage? Or am I just sore? thanks!!!!!!

You're just sore, almost certainly. If you can lift it with good form, it's not too heavy. If your form deteriorates or you can't lift it, it's too heavy.