I try and do weights once or twice a week. I used to do squats with higher reps and a lower weight eg 15 x 3 reps..ish, but I've found that my legs suffer for a couple of days after, especially my hams, so now I'm trying to do higher weights/lower reps, no more than 8 and I've found that the DOMS aren't as severe, although I'm not sure which is supposed to be more beneficial...
I also think that bounding, heel flicks,toe flicks, high knee drills etc are quite good and can just be done as part of a warm-up..