Pravilo is a device in which the person is suspended horizontally of feet and hands and at certain angles. This arrangement allows the body to be in a complex state of tension and relaxation that is not easy to achieve in other circumstances. Pravilo can help a person, through proper tension and relaxation training, strengthening the tendons and ligaments will make it reach a greater development of its own strength. It will make a person with the ability to increase their strength by 5% per week, developing internal muscles and increasing their muscular endurance and elasticity. It is a method of physical and mental training based on ancient techniques.