Nonlinear Covariation Analysis (Müller & Sternad, 2003)

I have been working my way through some analyses that fall under the idea of the motor abundance hypothesis (Latash, 2012) - the idea that motor control does not work to produce a single, optimal movement trajectory, but rather works to produce a particular task goal, or outcome. Motor control preserves function, and not structure; it exhibits degeneracy. So far I have looked at uncontrolled manifold analysis here and here, and stochastic optimal control theory here. 

This post will review nonlinear covariation analysis developed by Müller & Sternad (2003). This purports to address several issues with UCM.