Doug Salomon
It's from Men's Health magazine, bit don't let that dissuade you from trying it. There's nothing exclusively "manly" about it.
제가 최근에 했던 꽤 괜찮은 30일 플랭크 챌린지입니다. https://www.menshealth.com/fitness/a35856218/30-day-plank-challenge/
처음에는 꽤 쉬운데, 결국은 꽤 어려워집니다.