Some people have asked me to tell that what a plank is..... well, its a great core builder.
I found all of the information at this link
Planks are good for you because they keep your spine in a neutral position, whereas when you are doing crunches your spine is in a flexed position.
There are many ways to do a plank. Resting on your forearms like the above picture, in a push up (arms straight) position and many more. All are great. The position resting on your forearms engages more of your abdominal muscles. To do the plank you simply get in this position and hold it as long as you can. Be sure to keep your back straight, your butt level with your spine and stomach "tight". It's that simple, yet very effective!
I love planks! I do them regularly during my power lift class. I joined #plankaday on twitter as a way to keep accountable, active and help with my fitness/running.
You should join in too! Twitter accounts are free!
P.S. I am going to do plank ladders this week. What is a plank ladder? It's a progression of planks with 30 second rests in between. The progression goes like this: 30 seconds, 40 seconds, 50 seconds, 60 seconds, 60 seconds, 50 seconds, 40 seconds, 30 seconds. Thats 8 planks with 30 second rests in between. So in 1 week I will do almost 2 months worth of planks!! Booyah! Crazy enough to join me??