Too much caffeine. And, my hips.

I learned today that drinking three cups of coffee before weightlifting is not a good idea. Having my heart rate shoot to 120 or so just from doing a couple of squats is, well, kinda scary. Also, sweating. Eiyich.

Question for weightlifting folks again, especially women: What do you think of those hip adductor/abductor machines? Probably my least favorite bits of myself are strengthened and toned by doing them, but I'm also doing wide-stance squats and sumo deadlifts, which seem to hit every part of the leg, and yoga, which often hits the difficult bits. Those two exercises seem sort of ineffectual and make my lower-body days take even more time.

Are these exercises necessary, or useful? By not doing them, am I creating an imbalance in my leg and hip strength?