A plank is a great exercise for your core. I much prefer it over crunches.
This video shows my preferred method for doing it as I do it on my forearms, too. Many do it with straight arms.
Listen to the proper form and alignment! It’s important.
Here is the modified version I have been doing since I need to stay off my toe:
- Plank Fest- Workout Wednesday (marshallcampusrec.wordpress.com)
- Marathon Plank Workout (toriteachesfitness.com)
- July Planking Challenge (carrotsandcardio.com)
- before-the-beach bodyweight workout (thefitchronicles.com)
- Bodyweight Plank Variations (fitnessandfeta.com)