Heavy metal drummer Jon Dette recently finished filling in for ANTHRAX's Charlie Benante and SLAYER's Dave Lombardo for both bands' Australian shows. In an interesting twist, Dette played back-to-back headline sets with both legendary thrash groups on February 25 in a true test of endurance.Late last year, Dette posted to Facebook a picture of himself doing double-unders as a warm-up before hitting the skins, and it turns out the native of Carlsbad, California, trains at CrossFit San Elijo. He's been a CrossFit athlete since 2010. "CrossFit, it really pushes your intensity like nothing else, and since I'm continually pushing my intensity onstage, it was the perfect training ... tool," he says. Dette, of course, isn't delicately caressing a snare drum with brushes while a seated singer-songwriter soulfully plucks an acoustic guitar. Instead, he's crushing tempos well above 200 beats per minute while "tattooed Satanists" scream about geysers of blood and masks made of skin. That requires fitness, and a firm commitment to evil. "When I'm onstage, I'll actually push my energy level like I'm doing a WOD. ... I'll just sit there and I'll just beat the shit out of those things," he says. He adds: "What I love bout the style of music I play ... is that it's so compatible with CrossFit." The video below was shot by Jordan Gravatt.