Data from: Increasing cognitive load attenuates right arm swing in healthy human walking

Human arm swing looks and feels highly automated, yet it is increasingly
apparent that higher centres, including the cortex, are involved in many
aspects of locomotor control. The addition of a cognitive task increases
arm swing asymmetry during walking, but the characteristics and mechanism
of this asymmetry are unclear. We hypothesized that this effect is
lateralized and a Stroop word-colour naming task—primarily involving left
hemisphere structures—would reduce right arm swing only. We recorded gait
in 83 healthy subjects aged 18–80 walking normally on a treadmill and
while performing a congruent and incongruent Stroop task. The primary
measure of arm swing asymmetry—an index based on both three-dimensional
wrist trajectories in which positive values indicate proportionally
smaller movements on the right—increased significantly under dual-task
conditions in those aged 40–59 and further still in the over-60s, driven
by reduced right arm flexion. Right arm swing attenuation appears to be
the norm in humans performing a locomotor-cognitive dual-task, confirming
a prominent role of the brain in locomotor behaviour. Women under 60 are
surprisingly resistant to this effect, revealing unexpected gender
differences atop the hierarchical chain of locomotor control.