Plank is a simple but effective total-body exercise. This simple exercise tones and strengthens your core muscles along with those in your arms, thighs and calves. It’s a great full-body workout that you can do in under a minute to improve your health and fitness.
THE PLANKING CHALLENGE
You need to do the plank challenge for 4 weeks. At first, you simply start out in the plank position for 20 seconds. Easy, right? Slowly, you build up your stamina until you are planking for four minutes during the final days.