Related Experiment Videos
Organizing principles for single-joint movements. II. A speed-sensitive strategy.
D M Corcos1, G L Gottlieb, G C Agarwal
1Department of Physical Education, University of Illinois, Chicago 60680.
Journal of Neurophysiology
|August 1, 1989
Summary
Human movement control involves adjusting muscle activation rates to regulate joint torque and speed. This study reveals two distinct muscle activation strategies influencing movement dynamics and kinematics.
Area of Science:
- Neuroscience
- Biomechanics
- Motor Control
Background:
- Understanding how the nervous system controls voluntary movements is crucial for neuroscience and rehabilitation.
- Previous research has explored muscle activation patterns and kinematic variables during limb movements.
Purpose of the Study:
- To investigate the relationship between muscle activation, joint torque, and movement kinematics during elbow flexion.
- To identify the underlying control strategies governing human movement speed and accuracy.
Main Methods:
- Subjects performed elbow flexion movements to visually defined targets.
- Measured joint kinematics (angle, acceleration) and electromyograms (EMGs) from agonist and antagonist muscles.
- Manipulated movement speed via instructions and target width.
Main Results:
- Peak torques, accelerations, and integrated EMGs correlated significantly with movement speed.
- Inertial torque was identified as a key linking variable between EMG, kinematics, and task parameters.
- Two distinct muscle activation strategies (speed-insensitive and speed-sensitive) were identified, explaining movement variations.
Conclusions:
- Human single-joint movements are controlled by two primary strategies influencing muscle activation and torque development.
- A model based on controlling motoneuron pool excitation explains speed-sensitive movements.
- Muscle activation rules consistently explain observed kinematic changes across various movement conditions.