Gymnastic exercise refers to exercise performed without weights or outside resistance (bodyweight exercises). Gymnastic exercises vary in degree of difficulty from the relatively simple (jumping jacks) to the difficult and complex (iron cross, variations, etc). These are sometimes referred to as calisthenics and they help to promote general health and fitness. Examples of gymnastic exercises include pushups, air squats, and situps. It is not uncommon for entire training programs to be based solely on gymnastic exercise, such as Pilates, yoga, and even some military training.
Many systems incorporate gymnastics into strength and conditioning programs with great success.