Having been a personal trainer I get asked the question, "What should I do to get in shape?". Well that or one of many variations. Often I focus on the philosophy and psychology of training over the physical act. Training doesn't require any specific exercise to be done right. In fact, what is right for one person may be wrong for another. Some people don't have the money for, or have enough discipline to train without, a gym. It can take some creativity, but bodyweight exercises are the easiest way for someone to start getting in shape. ...
Some well known body weight exercises are:
- Crunches / Sit ups
Going back to the psychology of working out, workouts are most successful when they are fun. Doing the above four exercises only is not going to be much fun in the long haul. So it takes some creativity and some times a little inspiration from others. Here is a video of some parkour enthusiasts showing their form of strength training, maybe it will inspire you.
So be creative, have some fun and move your body. That is what you can do to get into shape.