By Rich Carroll
How would you like to drastically decrease your time working out while dramatically improving your results? That sounds like some too-good-to-be-true commercial, and you're thinking, "What's the catch". Actually, there is a catch. It is that these workouts are not easy. High intensity interval training (HIIT) has taken hold as a legitimate means of getting in shape and improving your health, and now studies are confirming their value. But unless you experience some pain
