Arm swing and Gait Stability

"When discussing the effects of arm swing on gait stability, it is
necessary to start with a definition of gait stability. In steady-state gait, infinitesimally small perturbations are ever present, and the system’s response to such perturbations may be called local stability. When gait is externally perturbed, global stability can be assessed by quantifying the response to such a perturbation. Following Bruijn et al. [12], in human gait, this response may be divided into two phases: an initial phase, which is dependent upon both the steady state of the system (as it was before the perturbation) and the system’s intrinsic mechanical properties (e.g. inertia, stiffness), and a second, reactive phase (‘recovery’), which is mainly dependent on active control and reflexes." - P. Meyns et al. / Gait & Posture 38 (2013) 555–562

*The how and why of arm swing during human walking
Pieter Meyns a,1 , Sjoerd M. Bruijn a,b,1, Jacques Duysens a,c,