"in a strip mall karate class when I was six years old," he tells Men's Health. "I got my blue belt. But I forgot all of it before we started filming. It did not help at all." To get back into ...

Before his workouts, though, the Cobra Kai star always makes sure to get a solid warmup in. That typically includes some dynamic stretching. "You can't kick someone in the face if you're not flexible ...