Popsugar Fitness Workouts Core-Strengthening Exercises For Runners 5-Minute Core-Strengthening Workout For Runners August 28, 2018 by Anna Renderer View On One Page Photo 1 of 5 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 1 Plank With Side Step Start in an elbow plank. Extend your left leg out to the side, gently tapping your toes on the ground. Bring your foot back into a plank. Repeat the same movement with your right leg. Continue alternating legs for one minute. Previous Next Start Slideshow WorkoutsRunningMarathon TrainingMarathonsCore Exercises