If you want to run as well as you possibly can, you need outstanding strength in your “core” muscles – the sinews attached to your pelvic girdle and spine which stabilize your upper body.  Without such strength, you can have the best-planned training program in the world, with all the right intervals, hill repeats, and lactate-threshold sessions, but you still won’t reach your true potential as a runner.

To become maximally strong and stable in your core area while you are actually running, you need to include specific training which mimics fairly precisely what your core muscles do when you run.  Just as running fast intervals is better than playing badminton for improving your 10-K time, forcing your core muscles to work almost exactly as they do while you are running is usually better for running-related core strength than performing exercises while you are lying down or when you have put your body into various other non-running-specific positions.

Since running is an activity which one performs in a standing posture, with full body weight supported by one leg at a time, specific core exercises for runners are almost always performed on one leg in a standing position.  The basic starting position for the core exercises is as follows:

Stand upright with full body weight supported by one leg only (the other leg is flexed slightly at the knee so that the foot is off the ground); the foot of the support leg should be pointed straight ahead.  Then, perform a posterior pelvic tilt by tightening your buttocks, contracting your abdominal muscles, and curling your pelvis “under” (this is sometimes referred to as “tucking your tail”; you can think of it as moving the bottom of your pelvis forward and the top of your pelvis slightly backwards).  Lean backwards with your shoulders slightly so that your abdominal muscles are in a state of constant tension (you can test the effectiveness of this position by placing the index fingers of each hand on either side of your belly button; your tummy should be tight).  Your head and neck should be in a neutral position and aligned with your upper body, such that your face is looking straight ahead.  It is important to maintain this basic position with your pelvic girdle, shoulders, and head during the exercises in order to derive the maximum benefit from them and minimize your risk of injury.  If you initially have trouble balancing on one leg, you may carry out the exercises on two legs until you are ready for the one-leg version.

          Here are the exercises:

          (1) Carry out 10 one-leg, overhead dumbbell presses with 15-lb dumbbells, using an alternating arm action, standing on left foot only with a running-specific posture (flex right knee so that right shin is parallel with the ground and flex right hip slightly, so that thigh is slightly in front of body).  Rest for a moment, and then perform 10 presses while standing on your right foot.

          (2) Single-leg arm dumbbell press: 15 reps per arm on each leg.  To do these correctly, begin with a standing-tall alignment on one foot, with your shoulders relaxed, and fairly light dumbbells in your hands.  Initiate a powerful alternate-arm action, mimicking the movements of your arms and shoulders during running.  Utilize a large range of motion, with your elbows held high.  Although your arms are moving fast, your upper body must be held very still; twisting of the trunk is minimized.  This exercise improves core strength in a running-specific manner, upgrades the strength of the shoulders, enhances range of motion of arms during gait (for those with too-limited arm action), advances arm-pumping rate (facilitating faster stride rates), and enhances economy.  Things to avoid: Lifting of shoulders, punching or pounding actions with arms (must mimic natural arm swing associated with running), using dumbbells so heavy that they change natural form.

          (3) Side-to-Side Arm Swings with Light Dumbbells: While holding light dumbbells in hands, move your arms from side to side in front of your body – parallel to the floor – with both arms moving in synchrony without pauses.  Don’t let your upper body and shoulders rotate as you do this; only your arms should be in motion (both arms swing together to the left and then to the right).  Repeat this movement continuously for 20 seconds at a rhythm of approximately one cycle every two seconds.  Over time, progress to heavier dumbbells or a medicine ball.

          (4) Strong medicine - One-leg stability-balance exercises with throws (five ways): Please begin in a running-specific position, and try to maintain standing-tall alignment at all times.  Start with a light ball (about eight to 10 pounds), throwing ball to a wall with good speed and catching it without losing body control on the throw or catch.  Use six chest passes, six overhead (soccer) throws, six low-to-high (underhand) tosses, 10 twist-to-the-left throws, and 10 twist-to-the-right tosses.  For the side tosses (twist-to-the-left and twist-to-the-right) do rotate your torso significantly as you throw (don’t rely completely on your arms).  To complete each side toss, you will first rotate your upper body away from the wall with the ball in your hands and your arms extended straight out and then rotate your body toward the wall, releasing the ball at the appropriate time.  Things to avoid: Using a ball so heavy that it causes you to lose your standing-tall alignment, not rotating your torso with the ball on side throws

          (5) Single-leg chop shops:  Squat on one foot, angling (with straight arms) a medicine ball down to the side of the support leg.  Return to a standing position while keeping back straight, extending arms across body up and diagonally until the ball is high above the shoulder on the non-support-leg side of the body.  Keep back extended – not rounded – during overall movement (including the squat and the movement of the ball down to the side).  Things to avoid: Not keeping arms straight, not squatting low enough (not enough knee bend), rounding the back, not lifting the ball high on the ascent, using so much weight that stability is lost.  12 reps on left leg, then 12 reps on right

          (6) Bicycle Sit-Ups: 60 touches per knee.  From the classic sit-up position (lying on back), contract abs and sit up while twisting trunk so that right elbow touches left knee (left hip will be flexed to permit this).  Return to down position and then sit up and touch left elbow to right knee (right hip will be flexed).  That’s one rep!  Continue until each knee has been touched 60 times.

          (7) Torso Extensions from the Floor. To do these, simply lie in a prone position on the floor with your head raised, looking straight ahead, with your arms extended forward and slightly off the floor.  Then, raise your upper body off the floor (i. e., extend your torso) while simultaneously raising your arms and legs as high as possible.  Hold this contraction for three seconds before returning to the starting position.  Two sets of 20 reps are a great beginning (progress to three sets of 20); this is a terrific exercise for the spinal erector muscles in your lumbar region.

          (8) Crunches on a Bench.To perform this exercise, simply sit on the edge of a bench with your hands resting on each side of your buttocks, with your feet off the floor.  Then, inhale and bring your knees up to your chest (a concentric or shortening action for the key rectus abdominis muscle in the center of your abdomen), while rounding your back at the same time.  Now the key part: Hold the knees-up position for three seconds, producing a great isometric action for your rectus abdominis.  Then return to the beginning position while exhaling, and start another rep (about two sets of 20 reps are fine for your first few stabs at this exertion; progress to three sets of 30 repetitions).

          Regular "crunches on a bench" don't do much for your oblique abdominal muscles, but you can easily activate them by making a slight change in the movement.  For example, if you move your knees aggressively to the right before you raise them toward your chest, you will get some nice eccentric work for your left obliques.  Move your knees to the left, and you will put eccentric pressure on your right obliques.  All three movements can produce a nice "burn" - and can dramatically improve overall ab strength.