It’s wise to start with this exercise before beginning a heavy routine of resistance training.
Here’s how it’s done.
Get into a push-up position on the floor. Bend your elbows at a 90 degree angle 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 for two minutes straight.
The plank helps develop strength in the core, shoulders, arms, and glutes. You of course are not lifting or moving heavy weight but you have to constantly flex your abdominals to hold the position.