Does air boxing build muscle

A repetitive movement using muscles will strengthen them. However, the key to building muscle more rapidly is to exercise against resistance to the motion. So, if you used elastic bands behind your back and held in your hands while 'Air boxing', the results would be better.

Isometric exercise is performed without using any equipment. In this case you use opposing muscles in your body to "strain against" and provide the resistance that is beneficial to the exercise.