I strength train almost everyday and unless you lift far too much weight or don't use proper form, you're probably more likely to get an injury from running than strength training.  Strength training should actually help prevent injury and help to provide more stability to joints.  Start out with small amount of weight or use your own body weight and work your way up.  Always keep good form, if you are having difficulty doing that then you are using too much weight. For legs- squats, leg presses and lunges are good. Working on your chest, shoulders, abs, and back will help you maintain proper posture while running.  Don't forget to stretch. You may be sore initially because you body is not use to strength training but you should not be in pain.

If you are looking to bulk up then lift heavier weights with less repetitions.  If you are looking to tone your muscles without adding lots of extra bulk, use lighter weights in high repetition.  I do the light weights with lots of repetition and notice a big difference in the way I look and feel.  Just keep in mind that the more muscle you add, the more weight you will have to carry around while you're running.  Have fun!

Malori

I have been running marathons since 1978 and lifting since 1979.  I have generally been able to avoid adding bulky pounds because of the mileage I (average 35 a week, more in the months prior to the marathon).  Some of my most sucessful marathons were run with a 3 day a week lifting routine.  My last workout of the week was done immediately after my 20 mile Saturday run.  I would first do freeweights for the upper body and then go through the Nautilus routine, which included the leg machines.  During the free weight routine, I would stretch between sets. These stretches included hamstrings, calf muscles, back, quads, and groin.  After several weeks of this routine, the marathon always seemed like a walk in the park.

Injury Prevention :Injury Prevention 

Build A Solid Foundation

Strength-training your legs helps you run strong and stay injury-free.

By Jim and Phil Wharton

Here is the REAL secret to marathon success: Devote some of your precious training time to lower-body strength training. All the pavement pounding isn't building the muscles in balance, says New York City musculoskeletal therapist Jim Wharton, and you're asking for trouble when you overtax weaker muscles. I strength trained once a week--and then a hamstring imbalance sidelined me for three full weeks. Only then did I do three days a week of lower-body work, which helped me get to the starting line. The Whartons prescribed these six exercises, which anyone can do with a basic set of ankle weights. Do two sets of 15 repetitions on each leg for each exercise. (For the Whartons' full program, go to runnersworld.com/wpm.)

Knee Extensors: Sit on a chair with a rolled-up towel under the knee of the exercising leg. Angle the toes in slightly and extend the leg straight out. Lock the knee and hold for a three-count; this exercises the medial head of the vastus medialus, the knee's shock absorber. Slowly lower the leg.

Hip Flexors: Lie on the floor, with the exercising leg straight out, and the nonexercising leg bent with your foot on the floor. Lift the exercising leg from the hip, ending at a 90-degree angle with the heel pointing toward the ceiling. Slowly lower. Repeat with foot angled to the outside, then to the inside.

Hamstring Curl: Lie facedown on a flat surface and, bending at the knee, bring the exercising foot up toward your buttocks; slowly lower the leg. Turn the foot toward the outside and repeat; then turn the foot toward the inside and repeat.

Hip Extensors: Lie facedown over a table or bed, pelvis at the edge, feet on the floor. Relax your nonexercising leg to a 90-degree angle at the knee; it should stabilize you but not support you. Keep the exercising leg straight and turn it in at the hip. Lift the leg up to the point where it is parallel with your back. Slowly lower.

Hip Abductors: Lie on your side on the floor, the exercising leg on top. Bend the nonexercising leg 90 degrees at the hip and knee. Rotate the foot of the exercising leg down (inward) to isolate the outside hip muscle. Keep the leg straight (it will feel like it's behind you) and raise it as high as possible. Slowly lower.

Hip Adductors: Lie on your side on the floor, the exercising leg on bottom. Place your upper (nonexercising) leg on a chair or table at a height of about 20 inches off the floor. (Your leg should be at about a 45-degree angle to the floor.) Slowly bring your exercising leg up to meet the other leg. Slowly lower.

I got this off of the runner's world website.

Jen Johnston

Try this plan, I use it for triathlons & marathons.

Day 1.

Lat Pulldowns

Leg Extensions

Leg curls

Bench press

Squats

Shoulder shrugs

DB Pullovers

Seated row

Lunges

Side lateral raises

Biceps

Triceps

Calf raises

Sit ups

Day 2.

Lat Pulldowns

Leg Extensions

Leg curls

Bench press

Squats

Shoulder shrugs

DB Pullovers

Seated row

Lunges

Side lateral raises

Biceps

Triceps

Calf raises

Sit ups

15 Reps hold for 4 seconds

Increase weight 5% per week upper body

Increase weight 10% per week lower body

Adaption phase weeks 1 - 3

High rep, low weight

Endurance phase weeks 4 - 10

(used during off season)

Power Phase weeks 11 - 14 (Exercises indicated by *)

The key is core exercises that are split into 2 groups

1.  Lats & triceps

2.  Legs, chest & biceps

Increase power by adding additional 20% - 30% to load over that of endurance phase by doing 10 reps, 8 reps, then 6 reps going to failure on final rep of each set.

Allow 3 - 4 mins recovery between power exercises.

Chisel phase weeks 16 - 16

Return to lighter weights (same as start of endurance phase).

Hold for 2 seconds, fast but NOT sloppy.

Use HR monitor - when below 60% of max HR start next set.

Add 5 hard mins of abs exercises to every session.

This program is to be completed only twice a week in conjunction with other training.

If you follow the plan with your usual run workouts, don't worry you won't gain weight, I have done this for sometime and I am still 175lbs with no weight gain.

Don't forget to eat & drink right.

Have fun.

Some great insights above gang.  The key to the "right answer" is in identifying your true goal of the marathon.  Many people want to finish the marathon and use it as a (fantastic) way to get in shape at the same time.  They're concerned about overall health first...finish time second.  For this individual, an overall strength training program (not too dis-similar to the one mentioned above) is perfect.

But other people are focused on finish time and PR.  For those folks, you want to remember that every extra pound (as long as you're eating well!) will cost you 2 seconds or more.  Doesn't sound like a lot?  Do the math.  I'm 40 and gunning for a sub-2:35 at the R & R.  I'm down 7 lbs from a year ago, and that 14 sec/mile gives me a 6-7 min advantage.  That's big!

That doesn't mean you don't need "Strength Training," but it does mean you don't need weights.  Core stabilization was mentioned several times above - GREAT advice (Pilates would be excellent example).  The key is to balance what you do with your running, which is 100% forward motion.  One simple idea I just wrote about in the USAT Magazine last month was to add an "S" pattern to a few minutes of your running a few times/wk (snaking back and forth during your warm-up/warm-down rather than just straight ahead).  This develops some of the lateral hip muscles such as the gluteus medius that are so important to keeping runners healthy.

I'm getting lengthy, so if you have questions, feel free to contact me through www.FullSpectrumCoaching.Net

All the best!

Brad Cooper, MSPT, MTC, ATC

www.FullSpectrumCoaching.Net

Consider trail running early in the season - it works to build the 'little' muscles as you weave your way through obstacles along the course! You'll also likely avoid injuries from "pounding the pavement" but be aware of the potential for ankle and knee injury if you have weakness in these areas.  A good pair of trail running shoes is a plus!