Eight hours is a long time spent doing anything, especially with your face hovering 20cm away from the floor of a gym, but the benefits of a good plank go a very long way. “The plank is excellent because it’s all about stability,” says Chris Magee, the head of yoga at Psycle London, and a former personal trainer, rugby player and martial artist. “That’s key to an active, healthy lifestyle. You want to feel – when you’re walking around, running around or even sitting down – that your spine is strong and protected.”

Source: Core blimey: how a 62-year-old man planked for eight hours – The Guardian