Just some more thoughts for those who insist on coaching arm swing changes.
"Whole-body coordination patterns may become partitioned in particular ways as a function of task requirements.”
Toddlers actively reorganize their whole body coordination to maintain walking stability while carrying an object. Hsu WH1, Miranda DL2, Chistolini TL3, Goldfield EC4. Gait Posture. 2016 Oct;50:75-81
Today we seem to be going back to dual-tasking again, in this case utilizing the arms as balance assistance devices, amongst their other functions. However, we all know that walking with a hand in a pocket, or carrying something alters our ability to maximize their ballast-like function. Balanced walking involves freely swinging the limbs in pendullar motion. Changes in arm swing will change gait economy and efficiency. We have all run with a water bottle or bag/briefcase and know how that changes the symmetry and fluidity of our gait.
Today's research piece discusses toddlers and their function as they carry objects. "children immediately begin to carry objects as soon as they can walk. One possibility for this early skill development is that whole body coordination during walking may be re-organized into loosely coupled collections of body parts, allowing children to use their arms to perform one function, while the legs perform another. Therefore, this study examines: 1) how carrying an object affects the coordination of the arms and legs during walking, and 2) if carrying an object influences stride length and width." -Hsu et al.In this study of 10 toddlers with 3-12 months of walking experience were recruited to walk barefoot while carrying or not carrying a small toy. "Stride length, width, speed, and continuous relative phase (CRP) of the hips and of the shoulders were compared between carrying conditions. While both arms and legs demonstrated destabilization and stabilization throughout the gait cycle, the arms showed a reduction in intra-subject coordination variability in response to carrying an object. Carrying an object may modify the function of the arms from swinging for balance to maintaining hold of an object. The observed period-dependent changes of the inter-limb coordination of the hips and of the shoulders also support this interpretation. Overall, these findings support the view that whole-body coordination patterns may become partitioned in particular ways as a function of task requirements." -Hsu et al.
So once again we will say it, if you are coaching the arm swing YOU want, because you do not like what you see in your client, or if you think you are helping your client get more out of their body in terms of speed, power, efficiency or anything of the sort, know that there is a higher, smarter program running the show. And that program in the client’s CNS is smarter than you when it comes to what they need for whole-body coordination pattern generation.