Principal components in three-ball cascade juggling

To uncover the underlying control structure of three-ball cascade juggling, we studied its spatiotemporal properties in detail. Juggling patterns, per formed at fast and preferred speeds, were recorded in the frontal plane and subsequently analyzed using principal component analysis and serial correl ation techniques. As was expected on theoretical grounds, the principal com ponent analysis revealed that maximally four instead of the original six di mensions (3 balls x 2 planar coordinates) are sufficient for describing the juggling dynamics. Juggling speed was shown to affect the number of dimens ions (four for the fast condition, two for the preferred condition) as well as the smoothness of the time evolution of the eigenvectors of the princip al component analysis? particularly around the catches. Contrary to the thr ows and the zeniths, and regardless of juggling speed, consecutive catches of the same hand showed a markedly negative lag-one serial correlation, sug gesting that the catches are timed so as to preserve the temporal integrity of the juggling act.