I am about to start training for my third marathon and I have chose a program that peaks at around 65 miles a week. There is also some speed work during the week. My goal is to run the race in about 2:46 (rather ambitious for me). I have heard mixed reviews about weight training helping with distance running and have decided to give it a shot. I was wondering if anyone knew if it was a good idea to lift 4 times a week (upper and lower body workouts) while running at least 6 days a week, or if I would just tear my body down too much. Thank you for any help/suggestions.
I think it would be a good idea to talk with a personal trainer at your gym so that you can best develop a weight-lifting program that is personally structured and best fits in with your overall marathon training. (There are many variations, intensity levels, recommendations and so on).
I have really benefited from weight lifting, especially regarding the importance of upper-body strength for longer distances. It was very helpful to work with a trainer initially to develop a plan that was specifically designed for the goal of improving running. Depending on your schedule and expected outcomes, lifting 2 to 3 times per week might be of great assistance. I think it would improve your performance (over an extended period of time, provided you were following a plan that compliments your marathon training).
I have been lifting for several years now and it does make a difference with the right combination of other elements.