I agree with kungfu. I lift for a few reasons.
The main reason is that I enjoy it. I run a decent amount of miles, 70-80mpw. I am 5'11 and weigh 150lbs. I have some muscle, a lot if you compare me to "elite/sub elite" distance runners. I am not good enough to do anything really special with running. I just life improving, and how I feel when things are going well with my running. But I DO NOT want to be a scrawny distance runner. So I lift. Upper and lower body.
I lift based on strength building parameters, which usually involves less reps but more weight. ie; Squat 200lbs 5 reps 4 sets rather than 150lbs 10 reps 3 times.
I believe (Emphasis on believe, because I have no actual proof) that lifting this way for my lower body prevents injuries. I always feel better when I lift twice a week.
I do squats(weighted), calf raises (some sets weighted, some sets not), underhand and overhand pull ups, incline bench, Captains chair leg raises, side curls(obliques), push ups, leg kicks while lying on my back, hurdle drills once a week. I throw in other lifts and more core occasionally but these are my main lifts.
Summary: Does lifting help running? Maybe. Idk. It helps me, in my opinion. And I don't look like a tiny distance runner. Would I be faster if I cut out the upper body lifts? Theres a good chance I would be. But Its not worth losing muscle mass.