Still one of the best core exercises out there. One of the main functions of your core is to protect, stabilise your spine and maintain internal abdominal pressure. The plank activates the main muscle responsible for this, the transverse abdominis (TVA).
Perform the plank by laying face down on the floor supported by your forearms and on your toes. Form a straight line from heal to ear keeping your TVA squeezed (imagine you are bracing to take a punch) and gluteals (buttocks) squeezed to avoid lifting the bum in to the air (A framing) or sagging. Try not put your hands together to form a tripod as this makes it easier. Hold for as long as you can from 30 seconds up to a max of 2 minutes (you can start in 10 seconds blocks if you are new to it).
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