Is arm swing more to keep your momentum moving forward or is it to counteract the rotation caused by your stride?
If one arm is swinging back at the same time another is swinging forward, is there really a momentum gain?
does it matter if your arms come across your body if arm swing is just to offset rotational forces?
The arms swing to add leverage for your body (through the legs) to drive force to the ground and to offset rotational forces. This goes back to Newton's third law: equal and opposite reaction . . .
The arms, by themselves, do not gain momentum by swinging. They are only one part of the system.
The arms swinging in front of the body actually helps to offset rotational forces. Each stride applies a rotational force in planar view (looking down) because the force vector of the stride is not perfectly aligned with the center of mass. It is slightly to the outside. To illustrate, a stride with the right foot will push the right side of the body a little more forward than the left side of the body. Without anything else going on, this will cause the body to rotate to the left. But we can keep the overall body stable if we swing our arms to the left, because that will cause the body to rotate to the right. Adding the legs and arms together, the body stays neutral.
Keeping the arm swing tidy and in straight line down the track is more efficient. Only towards the end of a distance (800 and up) race when a runner is trying to keep the knees moving and turnover fast does it ever come much of a noticeable factor based upon my observations.
I am not a sprinter but am sure arm movement is more important to them than to a long distance racer. Keeping all motions tidy and moving straight down the track or road is what I would consider the most important way to move the arms.
Maybe some of you have some advice on how to use arm swing to run better races. I only pump my arms really hard at the end of a 800 or 1600 or maybe kicking in a 5k. The rest of the time, I keep it all nice and tidy.
By the way, in these parts, a real man takes his kid running, hunting, hiking, canoeing and fishing instead of sitting around watching tv or playing on his computer. My 14 year old teases me that he is finally better at all of the above activities than I am. But, I tell him that someday my grandkids will be better than both of us. Ha,ha! We haven't caught suppper yet so we better get going. Time to be a real man!
Not sure what this has to do with arm swing!!
Wow, for a moment I felt like this thread was trapped in an M.C. Escher etching.
I thought arm swing sets the tempo for your feet and helps with balance.
Arms great for tempo.
Have never seen a great runner saw logs with their arms.
Seen plenty pinwheel their arms like crazy.
Arm work may be the quickest easiest fix on beginner runners
& one of the best ways to get them toward the forefoot.
Arm analysis way underappreciated.
Mrs. M, you summed it up in just a few, well thought out words. Great job! I can see you going up, or maybe down the stairs just off to my right, or maybe my left. How did M.C ever get us both in here at the same time. If we keep swinging our arms and maintaining our tempo and balance, surely one or both of us will find a way out of this place!!