From a New York Times online article (Feb 27, 2020):
Mr. Hood, a former Marine and Drug Enforcement Administration agent, held the plank on Feb. 15 for more time than an average day’s work.
The plank is a feat of static, but strenuous, exercise. The torso is sustained in a horizontal position, anchored by the toes on one end and the forearms on the other. The abdominal and thigh, back and arm muscles are among those firing away, turning most of the human body into a gravity-defying platform.
George E. Hood, a 62-year-old retiree from Naperville, Ill., strapped a heart monitor band across his chest, attached a catheter to his body, climbed onto a custom-built table covered with a lambskin and dialed up a curated rock ’n’ roll playlist on his phone.
And then he raised himself into a plank — and held the position for eight hours, 15 minutes and 15 seconds to set a Guinness World Record.