Extending Energy Optimization in Goal-Directed Aiming from Movement Kinematics to Joint Angles.
Energy optimization in goal-directed aiming has been demonstrated as an undershoot bias in primary movement endpoint locations, especially in conditions where corrections to target overshoots must be made against gravity. Two-component models of upper limb movement have not yet considered how joint angles are organized to deal with the energy constraints associated with moving the upper limb in goal-directed aiming tasks. To address this limitation, participants performed aiming movements to targets in the up and down directions with the index finger and two types of rod extensions attached to the index finger. The rod extensions were expected to invoke different energy optimizing strategies in the up and down directions by allowing the distal joints the opportunity to contribute to end effector displacement. Primary movements undershot the farthest target to a greater extent in the downward direction compared to the upward direction, showing that movement kinematics optimize energy expenditure in consideration of the effects of gravity. As rod length increased, shoulder elevation was optimized in movements to the far-up target and elbow flexion was optimally minimized in movements to the far-down target. The results suggest energy optimization in the control of joint angles independent of the force of gravity.
a Department of Kinesiology , McMaster University , Hamilton , Ontario , Canada.
James J
JJ
Burkitt
b University of Groningen , University Medical Center Groningen, Center for Human Movement Sciences , Groningen , The Netherlands.
Raoul M
RM
Bongers
a Department of Kinesiology , McMaster University , Hamilton , Ontario , Canada.|c School of Sport and Exercise Sciences , Liverpool John Moores University , Liverpool , England.
Digby
D
Elliott
d Schulich School of Education, Physical and Health Education , Nipissing University , North Bay , Ontario , Canada.
Steve
S
Hansen
a Department of Kinesiology , McMaster University , Hamilton , Ontario , Canada.
James L
JL
Lyons
D001696:Biomechanical Phenomena / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006040:Goals; D006112:Gravitation; D006801:Humans; D007596:Joints / Q000502:physiology*; D008297:Male; D009068:Movement / Q000502:physiology*; D011897:Random Allocation; D034941:Upper Extremity / Q000502:physiology*; D055815:Young Adult
energy optimization; goal-directed aiming; joint angles; tool use