Sprinting comprises 3 very important structures: Posture, Leg Action, and Arm Action. I listed these in the level of importance. We know leg action, and arm action get the most attention when someone is teaching or being taught speed mechanics.
We’ve all seen ample drills that help with arm swings, and by no means am I saying these do not have a place. Arm swings can’t make you faster, but they can make you slower if they aren’t being done properly. As a matter of fact arm swings rank the lowest on our mechanic checklist. Again, I am not saying they aren’t important, they just aren’t the most important.
Posture is king when it comes to sprinting. This goes for acceleration and absolute speed. The projection of posture varies in angles from the acceleration phase to the absolute speed phase but the point we are trying to make is the overall importance of being in proper posture alignment. Posture is the anchor points for the legs and arms to move around. If we are lacking the proper posture lines we lose the efficiency our limbs.
When you are sprinting, be aware of your posture before you worry about knee drive and arms swings. If the anchor, the limbs will clean up. Sprinting is about angular force production and without good posture, we lose the necessary angles.