Strengthening Antagonistic Groups
Anyone who has made even a cursory study of this subject knows that there are hundreds of methods for relaxing, stretching, treating, toning, and strengthening muscles, almost all based on the assumption that if muscles are tight or weak, they can be stretched or strengthened by direct means. In fact, the subject of muscle tension is highly complex and involves a number of seemingly unrelated disciplines such as anatomy, biomechanics, neuroscience, and psychology. Simply practicing methods such as Pilates and stretching may give temporary relief, but it cannot address the question of how the human body works and how to restore it based on an understanding of how it becomes interfered with and what to do about this.
Methods for correcting muscular imbalances are based on several largely unquestioned theories and assumptions. The first theory is that muscle groups antagonistically balance each other, so that if one muscle group is weak, the opposing group needs to be strengthened or stretched. This concept has been invoked by exercise physiologists, proponents of corrective and postural techniques, and physical therapists for decades. If, for instance, the flexors of the arm are tight and shortened, it is believed that strengthening the opposing muscles (the extensors of the arms and shoulders) will help to restore balance. This technique is a commonly employed strategy in physical therapy and is also used in exercise methods such as Pilates, which seek to strengthen the abdominal muscles as a way of supporting and stabilizing the back and trunk.
The problem with this concept is that if your back is vulnerable or weak, strengthening the muscles in front -- while this might protect the back in a crude way -- will not establish a truly healthful condition of the back. A weak back is almost always connected with shortened muscles, and this shortening, which is in turn related to the body as a whole, cannot be addressed by strengthening opposing groups. In order for the back to function well, the entire trunk must have its full length, and exercising the abdominal muscles, which causes the trunk to stiffen, will only further imbalance the working of the back.
Excerpted from Neurodynamics