As a runner who primarily uses their legs to propel themselves forward, I don't need to train my upper body, right?
While the legs are, of course, arguably the most significant body part in running, a weak upper body can cause problems. Have you ever seen someone run with their arms at their sides? Not only does it look super awkward, their torso tends to rotate quite a bit to make up for the lack of arm movement, expending much more energy than necessary. It's also not uncommon to see runners lean back or hunch forward while they run, both of which are unproductive. The runner who leans back is effectively braking the entire time, and the runner who hunches forward is interfering with their lungs' expansion and asserting their momentum down rather than forward.
Thus, yea, upper body strength is rather important!
Some examples of exercises to improve upper body running mechanics include shoulder press, pull-ups, push-ups, narrow and wide rows, back extension, chest flys AND back flys, and hammer curls.
For questions about these or other exercises, please email me at firstname.lastname@example.org or fill out the contact form.