I've always done squats with my feet about shoulder-width apart, toes pointed out. A couple weeks ago I started to change things and started doing squats with my feet quite a bit farther apart than I used to. I wasn't able to squat as much this way. Today I went back to shoulder-width and was able to do weight/reps closer to what I'd been doing before the switch. I've always heard the farther apart your feet are, the more weight/reps you can squat. What's going on?