I saw this going around on FB and figured why not. I started tonight but I was able to hold for 60 seconds. You just have to remember to hold your body straight, not dipping down or up. No cheating. 
I just copy/paste from FB:
The 30 Day Plank Challenge. All you have to do is HOLD this position, nothing else! It looks pretty easy, but it isn't!
Day 1 - 20 seconds
Day 2 - 20 seconds
Day 3 - 30 seconds
Day 4 - 30 seconds
Day 5 - 40 seconds
Day 6 - REST
Day 7 - 45 seconds
Day 8 - 45 seconds
Day 9 - 60 seconds
Day 10 - 60 seconds
Day 11 - 60 seconds
Day 12 - 90 seconds
Day 13 - REST
Day 14 - 90 seconds
Day 15 - 90 seconds
Day 16 - 120 seconds
Day 17 - 120 seconds
Day 18 - 150 seconds
Day 19 - REST
Day 20 - 150 seconds
Day 21 - 150 seconds
Day 22 - 180 seconds
Day 23 - 180 seconds
Day 24 - 210 seconds
Day 25 - 210 seconds
Day 26 - REST
Day 27 - 240 seconds
Day 28 - 240 seconds
Day 29 - 270 seconds
Day 30 - PLANK FOR AS LONG AS POSSIBLE!!
Benefits of Plank Exercise:
*It strengthens your lower back
*It develops your core muscles – which include the abs, back, hips and the butt.
*Helps you to avoid injuries and encourage good posture
*Can be done anywhere
*Develops your abdominals by targeting the rectus abdominis
This is a beginner routine.. everyone starts somewhere!
