Objective. To explain and underscore the use of principal component analysis in clinical
biomechanics as an expedient, unbiased means for reducing high-dimensional data sets to
a small number of modes or structures, as well as for teasing apart structural (invariant) and
variable components in such data sets. Design. The method is explained formally and then
applied to both simulated and real (kinematic and electromyographic) data for didactical
purposes, thus illustrating possible applications (and pitfalls) in the study of coordinated …