These 21 day cycles are perfect for individuals who gained extra weight during the past 6 months, and need to drop just a little fat to get back to a more normal weight. 3 weeks. That's all the time you need to get in shape. It doesn't matter whether you haven't worked out in months or you're a gym rat looking to take your fitness to the next level. Follow our program and you'll emerge 21 days later stronger, faster, and more flexible. This 21 day Body Transformation app is designed to get you in the shape of your life in record time. Even better you don't have to leave your own home to do it. The 3-week fitness plan includes daily bodyweight workouts designed to target the most important muscle groups in your body. The workouts are easy to follow, with only 5 to 10 moves per day.