I frequently have runners tell me that they have bad running form and I always think to myself, “Well, have you ever seen me run? I look like I’m about to tackle someone because my posture is tucked in”. Does ideal running form really exist and is what was ideal 40 years ago still the same as today? These are questions that are debated within the scientific community and I will probably crush some spirits in a future blog about foot striking patterns, but for now, I just want to write about why arm movement is equally important to performance and injury prevention.
When I first started marathon training, I was frequently told not to allow my arms to cross the midline of my torso so much. The more I tried not to, the more I was told to stop crossing over; in my mind, I was fixing it, but in reality it wasn’t happening. I think we all know that the movement of arms during running coordinate with the movement of the legs. Whichever leg is driving forward, the opposite arm is driving forward and hopefully all the energy to run is being used in forward propulsion. Unfortunately, we have a couple of things working against us. First, the arms are moving from the shoulder joint, which is the most unstable of all joints in the body. It sacrifices stability for mobility and we typically have strength imbalances, which I see time and time again when I do movement screenings on my runners.
Our second issue, which plays off the first issue are the postures we have developed thanks in part to modern conveniences. Have you ever heard the term “smartphone posture”? Even if you haven’t heard the term, I guarantee you see it every single day. In modern society, we commonly sit with a cell phone or tablet in front of us or on our lap with our arms extended (which is really the action of shoulder flexion), shoulders rolled in, and/or neck flexed. The posture I just explained is the position in which I have been sitting at work for the last 19 years. My body has learned to take the path of least resistance and I have a rounded shoulder posture and unfortunately, when I run, it makes my arms drive more across my body. This same posture is seen in video gamers, people that sit and work on a computer all day, people that spend a lot of time driving with their arms out in front of their body, and all of us that live life on our smartphone…a large portion of society today, but not of 40 years ago!
To be more efficient runners, we need arm drive to be turned on and this is accomplished by a balance between the muscles in the front and the back of the shoulder joint. As mentioned earlier, the shoulder joint is the most mobile of all joints so there are several muscles that contribute to movement about the joint but the prime movers for flexion (arm driving forward) are the pectoral muscles and the prime movers for extension (arm driving backward) are the latissimus dorsi and posterior deltoid muscles. Get these puppies in balance folks! In addition to decreasing the forward momentum of the body if the arms aren’t driving efficiently, it will also allow for more twisting through the torso and pelvis.
In a 2008 study by Pontzer and colleagues, control of arm swing during running was investigated in a passive arm swing model vs an active arm swing model. In the passive arm swing model, subjects were asked to fold their arms across their chest, which in turn also decreased the moment of inertia. It was noted in the passive arm swing model that there was a lot of upper body movement, but it was not from flexion and extension at the shoulder joint as observed in the active arm swing, but from rotation coming from the torso. In an active arm swing model, shoulder musculature drives arm swing, but equally important, the arms act as mass dampers, decreasing rotational movements of the torso. Low back pain anyone?
Not only can the extra rotation of the torso cause low back pain when arms are not flexing and extending during running, observational research has measured larger joint angles at the hip, knee, and ankle when arm swing during running is not efficient (Miller et al., 2009). Not only is this not energy efficient, it puts the distance runner at greater risk of strain injuries.
Check it out readers… I want you all to be the most efficient and injury free runners as possible. That is the point of my blog posts. That being said, I see a lot of runners taking part in group strength training programs/challenges and others that are also gym rats. Sometimes, what you do outside of running to enhance your fitness may impair your run performance. Keep that in mind and hopefully you are working with mindful trainers that can identify your imbalances before strength training already overactive muscles. If your primary goal is to improve your run performance, you must understand that it requires a balanced body from head to toe!
Oh, if you do in fact see me running down the road, you will see my rounded shoulder posture, rotating torso, and I may look like I’m about to tackle you. I promise I won’t, maybe just a high five. But seriously, the chances of having a perfect running form is slim in today’s day and age. I am far from perfect, but I do try to talk the talk and walk the walk and want to pass on the best available information on so that you, my readers, and running enthusiasts can make the best decisions for your body.
Runner Image: Becca Roane
Miller, R., Caldwell, G, & Van Emmerik, R. (2009). Ground reaction force and lower extremity kinematics when running with suppressed arm swing. Journal of Biomechanical Engineering, 131(12), 121-125.
Pontzer, H., Holloway IV, J. H., Raichen, D.A., & Lieberman, D. E. (2008). Control and function of arm swing in human walking and running. The Journal of Experimental Biology, 212, 523-534.