"Push your finger as hard as you can against the surface. Now as hard as you can but move it slowly – follow the ticking clock. Now faster. Now faster."
These were the commands for volunteers in a simple experiment that casts doubt on old ideas about mechanisms to control hand muscles. Complete understanding of the result may help explain why manual dexterity is so vulnerable to aging and disease, and even help design more versatile robotic graspers.
A research team led by Francisco Valero-Cuevas of the University of Southern California reports the paradoxical result in the Journal of Neuroscience.