Working muscles: Core, shoulders and back.
Progression: Alternate lifting each leg six inches off the ground for eight counts. This also engages the glutes. Hold for 30 to 60 seconds.
“The planks is the perfect exercise for strengthening the entire core,” says Beth Shepard, owner and wellness coach at www.wellcoaches.com, adding that the core is often neglected by runners, but is essential for improving stride, form and speed. In a push-up position, with hands planted under the shoulders, align the body straight from the top of the head through the heels. Tighten up the abs while lifting through the chest to create as much space as possible in between the chest and the ground.