What is the reason we bend out arms when we run, but hold them straight when we walk?
In: 28
We use our arms to produce torque (twisting force) to our bodies that counteract that produced by our feet. When we run, we need to move our arms faster in order to do that. With straight arms, we can choose to have them flapping around wildly (uncomfrotable), hold them stiff (strenuous), or lift them up (feels better).
When we walk, they won’t flap around since we’re moving them much more slowly, so using energy to hold them up is unnecessary.
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