In all cases in practicing expansion we should be careful that there is no increase in the curvature of the spine. The back should remain normal, or become more nearly normal if we find any perversions.
A hollow back, as is well known, is more difficult to correct than a hollow chest, though both of them are abnormal. A hollow back can best be corrected by the lifting of the feet, and the extension of the muscles of the back. If the hand is placed under the back where there is the greatest curvature there will be felt a normal action upon this curve of the spine.
One point which has been discussed is whether training can affect the bones, or only the muscles. The whole body can be affected by training if the right methods are used. In correcting something like a hollow back, which has been of long duration, not only the balance of the muscles but the very articulations and ligaments and even bones may be affected by patient and persevering practice.
If there is congestion in the region of the throat, the pivotal action of the head is important, but the hands can be made to do a great deal of work also during the pivotal actions. Such manipulation is one of the best remedies for sore throat, and also for dizziness, unless the dizziness is caused by a wrong condition of the stomach or liver, in which case the pivotal actions of the torso should be vigorously performed, with kneading by the hands, of the abdomen.
If one limb is weaker than its mate it should be given more practice until balance is restored.
If there is any muscle weak in any part of the body, we should find an exercise to strengthen it harmoniously.
It can hardly be emphasized too often that the central muscles should be stronger than the surface muscles. Whenever we find, for example, a weak diaphragm, we should use a greater number of exercises for it and be careful not to give too much attention to the arm muscles.
It is not mere strength to lift a heavy weight that measures the degree of vitality or indicates length of life, but rather the harmony of all parts working together. The muscles connected with breathing should be stronger in proportion than the superficial muscles of the arms or lower limbs.
People who perform one particular movement a great deal, such as a blacksmith in hammering, should study and use exercises for the parts that are habitually neglected.
A little thought can correct every abnormal condition, even stiff joints and headache. By practicing patiently such tendencies may be practically eliminated.