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Reach-to-grasp movements during obstacle avoidance
M Saling1, J Alberts, G E Stelmach
1Arizona State University, Department of Exercise Science, Tempe 85287-0404, USA.
Experimental Brain Research
|April 18, 1998
Summary
Obstacle avoidance during reaching tasks significantly alters hand movement. This study reveals that changes in the transport component, like reaching over an obstacle, directly impact grip kinematics and timing.
Area of Science:
- Neuroscience
- Biomechanics
- Human motor control
Background:
- Prehensile movement involves coordinated transport and grip components.
- The precise timing and interdependency between reach and grasp remain incompletely understood.
Purpose of the Study:
- To investigate the interdependency of reach and grasp components under modified transport conditions.
- To examine how obstacle avoidance in the hand's path affects grip aperture kinematics.
Main Methods:
- Participants reached to grasp a dowel while navigating over obstacles of varying heights (9 cm and 11 cm).
- Kinematic data of hand transport and grip aperture were analyzed.
Main Results:
- Reaching over obstacles prolonged transport component time parameters and grip kinematics.
- Grip opening and closing velocities decreased, while relative time-to-peak closing velocity was maintained.
- Obstacle conditions led to smaller closure distances and maximum grip apertures, with reduced variability.
Conclusions:
- The organization of grip component parameterization is closely linked and interdependent with the transport component.
- Spatial localization of hand aperture is a crucial feature in prehensile movement control.
- Obstacle-induced changes in hand trajectory systematically influence grip kinematics.