If you cannot hold the full prone plank then begin with the half plank. Rather than having your forearms and toes contacting the ground, have your forearms and knees making the ground contact.
Where will I feel it?
You most likely will not feel your abdominal muscles because other areas may well be weaker at the beginning. Initially you may well feel your shoulders, arms or legs.
If you are feeling pain in your lower back you need to regress to the half prone plank.
Shaking during performing this exercise is common. Your longer-term objective is to hold your body straight and still enough so that a glass of water could be placed on your lower back without spilling.
How often and for how long?
Three times per week is optimal.
The amount of time you hold each plank for (10, 30, 45 seconds) depends on your technique. As soon as you cannot hold your body still and straight stop the exercise, rest and start again. Stopping this exercise for poor technique will help avoid injury.
