What is the role of the upper body in running?
In our earlier article, we discussed body lean and how it affects running. Arm swing is another important aspect of the upper body.
While walking, we keep our elbows straight and don’t bend our arms. While running, we change that pattern immediately. We bend our arms and move our elbows back and forth in sync with our feet. The faster we run, the faster we move our arms. In fact, GPS running watches, use the arm swing to measure running cadence. Why do we bend our arms while running, but not while walking?
Let us start by answering why we bend our arms while running. Bending the arm shortens its length, hence reduces the rotational inertia. As we swing our arms more vigorously and rapidly while running, bending the arms makes it more economical.
In our studio, we observed runners with different angles of bend at the elbow. We see runners with elbows extended (elbow angle far more than 90 degrees), and we also see runners with compact elbow angles (below 90 degrees). The picture below shows two runners one with an extended elbow (105 degrees), and the other with a compact elbow (70 degrees).
Elbow angles greater than 90 degrees have correlations with various running form issues. On the other hand, runners who have shorter elbow angles, often tend to have a better stride. Here are a few running form issues, correlated with higher elbow angles.
In the picture above you can see that the runner on the left has an extended elbow, and is landing with a straight knee. Incidentally, this runner also has low cadence as measured with foot pod.
We swing arms front to back to counter the leg movement. We also move & rotate arms side to side to stabilize at midstance. Excessive arm movement is an indicator of underlying running form issues. Here are some observations from our analysis at RunMechanics.
Here are two runners showing excessive elbow movement. The runner on the left is showing excessive elbow & shoulder roation to compensate for the lack of pelvic rotation. The runner on the right has the elbow flared out excessively, because of stability issues.
Changing the elbow angle or move the arms intentionally to fix the arm swing issues, doesn’t have significant effect on the underlying form issues. So the logical conclusion here is that arm swing is affected by lower body form issues such as overstriding, straight knee landing, pelvic drop, etc., and is not the other way around.
The arm swing and elbow angles are excellent indicators of running form issues.
How to do it?
Courtesy: Team Run Mechanics. This article was first published on runmechanics.in
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