The Ultimate Plank Test

How long can you continuously hold yourself in a lowered push-up position (see challenge photo for example). Your arms must be in a position where your forearm is at 90 degrees from your bicep. Your body must be straight / horizontal with no arching of the back or bum. Sound easy? - you won't be saying that when your whole body is shaking! One tip before we get started: post video evidence if you want to be taken seriously and avoid the wrath of your fellow competitors.