caa a22 4500 463245628 CHVBK 20180405153325.0 cr unu---uuuuu 170326e20070201xx s 000 0 eng 10.1007/s00422-006-0109-1 doi (NATIONALLICENCE)springer-10.1007/s00422-006-0109-1 Dounskaia Natalia Movement Control and Biomechanics Lab, Department of Kinesiology, Arizona State University, P.O. Box 870404, 85287-0404, Tempe, AZ, USA aut Kinematic invariants during cyclical arm movements [Elektronische Daten] [Natalia Dounskaia] It has been observed that the motion of the arm end-point (the hand, fingertip or the tip of a pen) is characterized by a number of regularities (kinematic invariants). Trajectory is usually straight, and the velocity profile has a bell shape during point-to-point movements. During drawing movements, a two-thirds power law predicts the dependence of the end-point velocity on the trajectory curvature. Although various principles of movement organization have been discussed as possible origins of these kinematic invariants, the nature of these movement trajectory characteristics remains an open question. A kinematic model of cyclical arm movements derived in the present study analytically demonstrates that all three kinematic invariants can be predicted from a two-joint approximation of the kinematic structure of the arm and from sinusoidal joint motions. With this approach, explicit expressions for two kinematic invariants, the two-thirds power law during drawing movements and the velocity profile during point-to-point movements are obtained as functions of arm segment lengths and joint motion parameters. Additionally, less recognized kinematic invariants are also derived from the model. The obtained analytical expressions are further validated with experimental data. The high accuracy of the predictions confirms practical utility of the model, showing that the model is relevant to human performance over a wide range of movements. The results create a basis for the consolidation of various existing interpretations of kinematic invariants. In particular, optimal control is discussed as a plausible source of invariant characteristics of joint motions and movement trajectories. Springer-Verlag, 2006 Arm movement nationallicence Kinematics nationallicence Power law nationallicence Velocity profile nationallicence Trajectory nationallicence Curvature nationallicence Biological Cybernetics Springer-Verlag 96/2(2007-02-01), 147-163 0340-1200 96:2<147 2007 96 422 https://doi.org/10.1007/s00422-006-0109-1 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00422-006-0109-1 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Dounskaia Natalia Movement Control and Biomechanics Lab, Department of Kinesiology, Arizona State University, P.O. Box 870404, 85287-0404, Tempe, AZ, USA aut NATIONALLICENCE 773 0- Biological Cybernetics Springer-Verlag 96/2(2007-02-01), 147-163 0340-1200 96:2<147 2007 96 422 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer