Front Squats

Wednesday night we did some front squats as the first part of the workout:
5 sets of 3 to 5 front squats, adding weight each set
I maxed out at 70 kilos, about what my past max front squat was. I felt as if I should have been able to go heavier by now.
Then, after a little rest:
10 kettlebell clean-front-squat-thruster complex (two 12-kg kettlebells)
Run to the stop sign and back
Three times through.
Before we started on the squats I didn’t warm up for some stupid reason, then ended up maxing out at 70 kilos on the squats. After completing the rest of the workout (8:30), I was still kind of cold, and since then I’ve had pain in my left kneecap. I knew I should warm up. I was being lazy and thinking I could get away with it. If I’d warmed up I might have been able to add a little more weight to the front squat and more importantly I probably wouldn’t have hurt my knee.