No pain, no gain, right? Well, that philosophy is definitely on target if we're talking about strength training and athelete caliber workouts. As the world has seen the last couple of weeks, star soccer players at the FIFA World Cup have some of the best bodies in the world (which they gratefully show off at the end of the game by ripping their shirts off), but they didn't get it just lounging around by the pool sipping gin and tonics.
If getting a full six pack is your goal then you need to commit yourself to an extensive and, yes, difficult workout routine. Watch this episode of the Diesel Crew to learn an extremely challenging core exercise integrating kettleballs, situps, and presses.