A crash workout is not the best way to get in shape. Eating well and exercising daily over a long period is a much healthier – and easier – approach to getting a body you can live with. But if it's a matter of vanity, not long-term well-being, you can turn your body around fast. "Three weeks may seem last minute," says Ron Mathews, a Hollywood trainer who specializes in high-intensity circuit routines and who designed this 21-day workout for us. "But you just need to maximize caloric output and minimize calorie input while activating as many muscles as possible."
Simple. Grueling. Effective. Here's your plan.
Day 13: Extra Flexing
Practice flexing each muscle group in between sets. This will help add shape and density to your muscles. It also keeps constant tension on them, elevating the intensity.
*For examples of back and leg exercises see our Summer Fit Workout cheat sheet.
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