This is just a portion of the article but I would recommend reading the rest of it too. I added this to my abs routine this morning.
The 15-minute workout designed just for runners
Fortunately, quality core work doesn't require a lot of time or equipment-just a few key moves done correctly and consistently. This workout is designed by Greg McMillan, a running coach and exercise scientist in Flagstaff, Arizona, who has worked with many recreational runners and world-class athletes. The workout is devised to strengthen the specific muscles runners need for bounding up hills, sprinting to the finish, enduring long distances, and preventing common running injuries. Try doing two sets of these moves right before or after your run, three times a week.
Superman
What It Hits: transversus abdominis (deep abs) and erector spinae (lower back)
Start facedown on the floor, with your arms and legs extended out front. Raise your head, your left arm, and right leg about five inches off the floor. Hold for three counts, then lower. Repeat with your right arm and left leg. Do up to 10 reps on each side.
Keep It Honest: Don't raise your shoulders too much.
Make It Harder: Lift both arms and legs at the same time.
Bridge
What It Hits: glutes and hamstrings
Lie faceup on the floor, with your knees bent 90 degrees, your feet on the floor. Lift your hips and back off the floor until your body forms a straight line from your shoulders to your knees. Hold for five to 10 seconds. Lower to the floor and repeat 10 to 12 times.
Keep It Honest: Squeeze your glutes at the top of the movement, and don't let your spine sag.
Make It Harder: Straighten one leg once your hips are lifted.
Metronome
What It Hits: obliques
Lie faceup on the floor with your knees bent and raised over your hips, with your ankles parallel to the ground, your feet lifted, and your arms extended outward. Rotate your legs to the left side, bringing your knees as close to the floor as possible without touching.
Return to the center, then move your knees to the right side. Do 10 to 12 reps on each side.
Keep It Honest: Make sure not to swing your hips or use momentum; start the movement from your core and continue to move slowly from side to side.
Make It Harder: Keep your legs straight.
Plank Lift
What It Hits: transversus abdominis and lower back
Begin facedown on the floor, propped up on your forearms, with knees and feet together. With your elbows under your shoulders, lift your torso, legs, and hips in a straight line from head to heels. Hold for 10 seconds. Raise your right leg a few inches, keeping the rest of the body still. Lower and repeat with your left leg.
Keep It Honest: Pull in your belly and don't let your hips sag.
Make It Harder: Extend the time of the exercise. Each time you lift your leg, hold it for 15 to 20 seconds.
Side Plank
What It Hits: obliques, transversus abdominis, lower back, hips, and glutes
Lie on your right side, supporting your upper body on your right forearm, with your left arm at your left side. Lift your hips and, keeping your body weight supported on the forearm and the side of the right foot, extend your left arm above your shoulder. Hold this position for 10 to 30 seconds. Switch sides and repeat.
Keep It Honest: Keep your hips up; don't let them sag.
Make It Harder: Support your upper body with your right hand, instead of your forearm.