THE PLANK - "is the most awesome exercise in the world"
When you do a plank make sure to be stable on the palm of our hands, place them directly in line under your shoulders and make sure your elbows are not overstretched, slidely bend the elbows.
Try to look straight down and sligthly in front of you so you have a nice natural alinement in your neck, so you do not drop your head.
Relax in your shoulder and try not to point your shoulder blades and have a large gab in-between them or vise versa.
Active your entire core muscles including your pelvic floor and try to suck your belly button in towards your spine to engage your inner core muscles to make sure you do not curve to much in your spine. If you feel to much pressure in the lower back, widen you legs and try to tuck your bottom under you so you will have a more straight line in your back.
You can do the plank on your toes or knees. You can do it on or hands or elbows. Either way make sure to have a nice straight line from the top of your head, thru you neck and spine, hip, knees and all the way to your ankles.
Take care of your body and strengthen all your muscles - also the inner small muscles. Remember that if you do not strengthen your muscles - they all let weak.