You want common sense? Take a look at this. Let's see how some of you idiots respond...
Here are the only 4 weightlifting exercises I would only focus on. All of them are specific to the sport:
1. Arms: Rowing or any exercise that involves a PULLING motion. Running involves the use of the arm where the resistance is in a pulling motion. The rowing or pulling exercise that is done should also be done to a set pace related to training development. In other words, you don't just start pulling. You pull to a certain pace or rhythm. For example, you might pull 50 pounds with both arms at a pace of 100 pulls per minute or 25 pounds with each arm alternating at a pace of 200 pulls per minute. You can always adjust the pace of rowing, the resistance, and length. Since arms recover faster than legs, I would do arm workouts the day prior to the workout and in relation. So if you were doing a 32x200 meter workout and your goal pace was 210 paces per minute (approximately 30 secs) with a minute rest inbetween each, I would do a 32x30 second rowing workout the day prior where I would do 220-230 pace per minute (alternating) with at a resistance level that would enable full recovery for the next day's workout. This is the only arm training I would do with weight training. Alternate forms could be pull-ups or swimming. Push-ups, curls, bench press, inclines, etc. have nothing to do with the running motion and should be avoided completely as they are counterproductive.
2. Legs: (A) Calf raises. The calf muscle is the muscle which pushes off the ground and has a large impact on how much extra distance is generated between the frequency of each stride length. This is that "bounce" that you see lost in many female distance strides when they mature because their calf development went unattended while they gained maturity weight, thus lack of strength in the push off enabling gravity to force the extra weighted runner to the ground sooner. Calf raises should be done with light weight and many reps and slightly faster at the desired training pace consistent with the rowing. Calf raises are very strenuous but recovery is very fast so it is the kind of workout where you would do reps for about 30-40 seconds with a minute recovery for about 5 times, and then take about 5-10 minutes rest before doing a couple of more sets. These should be done AFTER any type of easy running workout, never after a hard workout, and never before running. An alternative workout could entail the distance runner purposely pushing off the calf muscle as they run short distance workouts. Bicycling also helps the calf muslce but is counter-productive to hip flexor muscle development. Calf raises can be done on the stairs without additional weight but irregardless the athlete should lean forward since you want the push-off to be developed horizontally and not vertically.
3. Legs: (B) Hip flexors. These muscles mostly dictate the pace and length of stride and is the focus of "base" training. Resistance is on the leg or knee coming up to a 90% angle (straight to angle position). There are hip flexor machines but I strongly recommend distance runners run up and down a steep hill instead, forcing their knee up higher than normal as they go up the hill and running easy down the hill. The steeper the hill the more resistance but a sledding hill about 100 meters in length is about as long as you want it and no greater than a 22.5% incline. The hill run should be at an easy to moderate pace for runs of around 30 minutes or so. Periodically, interval workouts should be incorporated to develop base speed. The workout should always end on a fast note since hill training slows up the stride frequency. Either short sprints up the hill or a few 200-300 meter medium pace sprints on flat ground should do the trick. Stride frequency training can be incorporated in hill workouts but only on the uphill and at slower than race paces. Bicycling, leg squats, etc. involve opposite resistance since the motion is from the angled position to the straight position, and should be avoided.
Legs & Arms: (C) Flexibility. The final movement of the leg from the angled position involves the lower leg extending. Because this is more of a pendulum movement as opposed to a resistance movement, leg extension weight training should be completely avoided. The leg is already going to have additional weight from calf muscle so the best exercise to development this extension is flexibility. Flexibility exercises should also be done to help hip flexor and arm extensions so less effort has to be exerted to obtain an equal amount of extension.
4. Stomach: There's a great stomach exercise machine where you are in a sitting position (legs at 90 degree angle) and you PULL down with your ARMS the weight from over your head (ideally though, you'd want the arms lower by your sides pulling). Or you can lie down on the floor and bring your legs up into your chest as your bring your chest towards your knees. Whatever the case, stomach development should be done where the legs/knees are in the running resistance position and where the arms are in a pulling motion, preferably resistance where the arms end up going from the front of the stomach to the back area.
THERE ARE NO OTHER MAJOR WEIGHT TRAINING EXERCISES THAT SHOULD BE DONE. SQUATS, LEG PRESSES, BENCH PRESSING, INCLINES, FLYS, CURLS, PUSH-UPS, ETC, ARE ALL COUNTER-PRODUCTIVE!
IF IT IS NOT SPORT SPECIFIC IT IS COUNTER-PRODUCTIVE!