If sitting is the new smoking, then Robby Silk—a journalist who’s pioneering the sport of ‘extreme sitting’—has a pack-a-day habit. But in our hyper-connected, on-the-go, tech-addicted world, could simply sitting down be the most hardcore test of physical and mental endurance? James Shackell investigates.

Travel industry journalist Robby Silk has very specific rules about sitting down. 

Cell phones are not allowed. In fact, please remove any digital or battery-powered devices before commencing your sit (books are okay, for now). Standing and stretching are permitted, as is answering nature’s call. “I don’t recommend people soil themselves,” says Robby. You can drink water, but no other beverages. You can snack, but no proper meals. Sleeping is okay, too, but you have to doze while sitting upright. The prone position is considered cheating. Finally, you should leave behind all timepieces: watches, smartphones, etc. “Time can be estimated by the arc of the sun,” according to Robby. “This is the essence of sitting.”

As far as he can tell, Robby Silk invented ‘extreme chair sitting.’ Extreme sitting sounds a little paradoxical, like extreme napping or extreme crochet, but Robby’s version does have elements of painful endurance, stamina and adventure—all of which probably fall under the broad definition of ‘extreme.’