Muscular Movement vs Muscular Action

The Contrast between Muscular Movement and Muscular Action in Yoga

In the practice of yoga, we make a distinction between these two muscular activities. In a muscular movement, the muscles contract and are moved in a specific direction as is demonstrated below in

Warrior I pose when the arms raise overhead. In contrast, in a muscular action there is no or very little movement connected with the muscle contraction. The muscular action comes from the strong lift of the wrists and fingertips upward and the simultaneous descending of the shoulders and shoulder blades. It can appear that nothing is happening, however, the pose requires significant muscular action to give it its dynamic quality.

In terms of muscle contractions, muscular movement is an isotonic use of the muscles and muscular action is an isometric use of the muscles. The term isotonic contraction is used when a muscle changes in length against a constant load, for example, the raising and lowering of a book or raising the arms in Warrior I pose. In an isotonic contraction of the muscle, the length changes measurably when the load on the muscle is put into motion. If the length change is shortening then the movement is called concentric shortening. If the change is lengthening, the movement is said to be eccentric lengthening. In the case of an isometric contraction, the muscle length remains the same but the force changes. In this instance, holding the book still without raising it or letting it fall. Any and every yoga pose which we hold steadily with muscular energy is an isometric use of the muscles.

As we move in and out of yoga poses, various muscles progress through concentric and eccentric stages of isotonic contraction For instance, as we move into Warrior I pose from a starting position, the quadricep and hamstring muscles of the front leg lengthen eccentrically; the hamstring muscles of the back leg shorten concentrically; the rectus abdominis (abdominal muscle) lengthens eccentrically and the arm muscles facing the back shorten concentrically pulling the arms back. An eccentric contraction requires more power than a concentric contraction reinforcing the strength of the working muscle. In addition, as we hold still in Warrior I pose, the muscles throughout the body contract isometrically.

Contraindications: Cardiac Condition, High Blood Pressure

Avoid this pose unless you are practising under the supervision of an experienced teacher.