Running...it seems like it should be the most natural thing in the world to do, but like all good things there is technique. What to do with your upper body can get confusing, since it is just riding on the legs that are doing all the work.
Here are some tips on running form:
- Your torso should be upright, with chest up and plenty of room for the diaphragm to work correctly. You're going to be breathing heavy so make it easier for your lungs and diaphragm to work.
- Do not lean forwards (aka bend at the waist or hips - I see lots of folks craning forward at their waist or hips), backwards or slouch, as all of these lazy postures can stress your lower back. Using your deep abs can help you keep upright and run properly.
- The shoulders should be relaxed with elbows bent to around 90 degrees and the motion should be from the shoulder not the forearms ( no floppy rag doll arms). Arms should swing freely with the action mostly front to back.
- The hands should be held with the palm facing inwards not down. If you prefer to hold your hands in a fist make it a loose fist with the thumb resting on the index finger.
Of course when you are running, it is always better to not over think the action. Do check in on your running form every few minutes until the habits become natural.