Strength Training

I went to the gym last night for the first time in months (maybe years) and did some strength training. I'm still undecided as to whether to join. I started with a bunch of core muscle exercises and push ups and then moved to the machines/weights. I did leg presses, hip abductions/adductions, and leg curls. I also did seated rows, chest presses, and arm curls. I have no idea whether any of this will benefit my running, but I assume that it cannot hurt it. I've got a weak upper body, hips, posterior muscles (anterior/posterior-muscle imbalance).