It's easy to understand why no-equipment-workouts are so popular. Being relatively easy to learn, they can be modified to suit any ability level, and they can be done just about anywhere. Plus, body weight exercises like planks, pushups and pull-ups are classic bodyweight moves.
There are plenty more to choose from-- squats and lunges just to name a few. However, there are downsides to these exercises. The wrists and shoulders are used a lot in these exercises and many people are prone to injuries in these joints if not done properly.
I also am a very competitive person so I understand if you do it in a group and find yourself trying to compete with the person next to you. That is a big no-no, and when an injury is likely to occur.
To avoid working above your ability, always have a training plan in place, and follow it diligently. Work at your own level and your own pace and remember-- consistency leads to results.
Workout Wednesday: Body Weight Training