How to Do a Plank: A Single Move for Stronger Abs

It's hard to believe the plank could provide such a great workout—until you try it. Keith Scott, A.T.C., C.S.C.S., a strength coach in Medford, N.J., recommends conquering the plank before attempting any heavy weight exercise.

Get into pushup position on the floor. 
Now bend your elbows 90 degrees and rest your weight on your forearms. Your elbows should be directly beneath your shoulders, and your body should form a straight line from your head to your feet. Hold the position for as long as you can. Your goal should be to hold it for two minutes.
"The plank helps develop strength in the core, shoulders, arms, and glutes," 
says Scott, making it a great prerequisite for lifting heavy weights or playing intense sports. Even though you aren't moving or lifting weight, you have to constantly squeeze your abs to hold the position—most people can't last 30 seconds on their first attempt.
Ways to improve your plank time 
The longer you can hold the plank, the more resilient your lower back will be to injury, and the better your abs will look once you burn the fat off them. Follow these tips for longer plank times.

• Practice: Perform planks several times each day, trying to hold the position a little longer each time.

• Use body-weight exercises: Pushups and pullups will improve your core strength.

• Squat and deadlift: Guys who are strong in these specific lifts find planks are no problem.

HOLD IT 
If you don't have the core strength yet to do a regular plank, you can build up to it by doing a bent-knee plank. If you can hold a plank for more than two minutes with ease, you can move on to these tougher variations.

• Lift one leg up. By simply raising one leg in the air, you dramatically increase the demand on your core to fight your body's natural urge to rotate.

• Lift one arm up. Again, your body will want to fall to one side. Don't let it!

• Use a Swiss ball. Rest your forearms on the ball and you'll have to stabilize your body and stop the ball from rolling out from under you.