The Walking Code: Why Do Your Arms Swing When You Walk
Chapter 4
Why Do the Arms Swing When You Walk
Ask yourself this "simple" question. Why do your arms swing when you walk? Even though it is a basic part of every day movement, it is a question most people probably never ask themselves. With a normal gait, the arms swing in opposition to the legs. The left arm swings forward with the right leg and the right arm swings forward with the left leg. The movement is automatic, not requiring any conscious effort, so the question is, why are they swinging?
If you have never asked yourself why your arms swing, don't feel bad. You are in good company. The textbook, Gait Analysis, Normal and Pathologic Function, the gold standard for the medical understanding of walking dedicates approximately 4 out of over 500 pages to describing the mechanics of arm motion in walking. Most of the research into this subject seeks to answer the question, is arm swinging necessary? That is a different question than that of why the arms are swinging.
The chapter on arm swing in the book begins with the following paragraph, which I will quote. It reflects a lot about the nature of the study of walking. "Reciprocal arm swing spontaneously occurs during walking. Eltman calculated the angular momentum of arm swing in the 3 functional planes and found the pattern was opposite to that of the rest of the body. He concluded that this allowed the lower legs to perform their necessary motion without imparting marked rotation of the body. The significance of this calculation was challenged by the results of energy cost analysis. Subjects walking with their arms free to swing and with them bound were tested and showed no difference in oxygen usage. These 2 findings suggest arm swing may be useful but that it is not an essential component of walking." Exerpt from Gait Analysis, Normal and Pathological Function. Jacquelin Perry, Judith Burnfield.
The preceding excerpt from the reference manual on walking technique demonstrates the approach to walking analysis taken by medical researchers. Very complex observational studies are used to come up with a conclusion that arm swing is not an essential component of walking. This appears to miss the obvious point that, if arm swinging is not necessary, why does everyone do it, and more importantly, why is it apparently automatic? Additional observations they made in the book were that EMG studies didn't indicate any significant active muscle contraction during flexion of the shoulder, or forward arm swing. This indicates that it is not something we do intentionally. So what is controlling it? The problem with the accepted analysis of walking technique is that it is presumed to be an activity of the legs, and the torso is just going along for the ride. But what we learn from Tai Chi, and what any dancer knows, is the torso is not along for the ride. In fact, it is the most important component of guiding walking, dancing, Tai Chi, or any other movement requiring locomotion or weight shifting.
A simple self analysis when walking will reveal a very clear fact, that the swinging of the arms has nothing to do with the arms or the shoulders. The arms and shoulders can remain completely relaxed when walking, yet the arms will swing in perfect rhythm with the step. If you run, the arms will naturally bend at the elbows as they swing forward and back. Just as with the arm swing when walking, the arm swing in running is automatic. You would have to make a conscious effort to prevent them from swinging. Clearly some unrelated force outside of the arms and shoulders is generating energy and the inertia required to swing the arms. So the relevant question is not whether arm swinging is necessary, it is whether the force that provides the inertia to the arms that makes them swing is necessary? And the answer to that question is a resounding, yes.
The arms swing because the waist is constantly rotating when we walk or run, and the inertia of the rotation of the waist drives the movement of the arms. The arm swing is not an optional part of walking because the waist rotation is not an optional part of walking. The waist in this context refers to the abdominal core muscles that flex and rotate the spine. Without the constant rotation of the torso generated by these muscles, there would be no arm swing, and there would be no walking.
When analyzing walking technique by observational means, it is easy for the waist rotation to go unnoticed because it is often not visible to the eye. The lack of visibility is not because the amount of rotation is insignificant, it is because the rotation of the upper abdomen and the rotation of the lower abdomen turn in opposite directions when we walk forward. The opposing rotations give the net appearance that the torso is simply facing straight forward when in fact it is engaged in constant torsion, first on one side then the other with each successive step. This torsional movement of the waist is what imparts the inertia to the arms that causes them to swing back and forth. Additionally, the torsional rotation must always follow the same pattern in order to produce the same direction of walking, which is why the left arm swings forward with the right leg and the right arm swings forward with the left leg when we walk forward in a straight line.
When walking, it is not required to swing your arms, rather your arms swing because you are walking. If someone is not swinging their arms properly when walking, it is not helpful to tell them to swing their arms because the fault is not in the arms, it is in the body. Actively trying to swing the arms does not engage the same muscles required of the natural arm swing associated with walking. Correcting the arm swing requires learning how to properly rotate the torso. It is insufficient or improper torso rotation that is the major contributor to reduced arm swing. It is also a cause of short shuffling gaits which are common as people age. When the arms do not swing correctly, it is a sign of incorrect walking technique. This can be an early warning sign for the development of a number of painful health conditions.