2-Week Plank Challenge: Build Up to a 5-Minute Plank
 

2-Week Plank Challenge: Build Up to a 5-Minute Plank
http://img.s-msn.com/tenant/amp/enti...6&q=60&o=f&l=fPlank is one of the most effective total-body moves, so here's a new challenge for you to conquer - a five-minute plank. Since holding a straight-up plank wouldn't be any fun (and could end up causing an injury), this challenge mixes up five basic variations to **t only tone your abs and arms, but to target the obliques, legs, and upper back as well. Here's an explanation of how to do each one, followed by the two-week plan.