Anyone who has performed a plank knows how deceivingly difficult they are.
How hard can it possibly be to lay forward with just your forearms and toes touching the ground? The answer is very and almost everybody has their legs shaking after just a few minutes.
However, if your name is Dana Glowacka, then we're not talking in minutes but hours.
The Montrealer set an astonishing new world-record in the women's plank this month, clocking an eye-watering time of 4 hours and 20 minutes at the First International Plank Training Conference.
It doesn't bear thinking about just how painful that would be, but Glowacka absolutely shattered the former record that stood at a comparatively paltry 3 hours and 30 minutes.
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New planking world record
That's pretty impressive going and footage of Glowacka during the attempt shows she was shaking far less than many of us would be after 30 seconds.
The fitness enthusiast has built up her core strength through activities like yoga and admits that her very first plank 'only' lasted four minutes.
Writing on Instagram after the event, she penned: "My brother surprised me with a literally 24 hours trip to just support me and push the button of starting and ending line of the new world record set for the Longest Abdominal Plank of 4hrs, 20min.
"Here he is...my brother, standing strong by my side like an Angel."
As far as the men's record is concerned, Mao Weidong of China raised the record to an unfathomable 8 hours and 1 minute during an event in May 2016.
How long do you think you could hold a plank for? Have your say in the comments section below.