6 Questions
What is the purpose of the hierarchic recruitment pattern used by the nervous system?
To conserve energy by activating the fewest muscles possible for a given joint action
Which muscles control activities that require lower level extensor torque?
Anconeus and medial head of the triceps
Which triceps muscle is selected for more dynamic or highly resisted extensor torque?
Long head
What is the position of elbow extension that increases the moment arm for the triceps?
60-70 degrees
What determines peak elbow extension torque?
Muscle length
What type of muscles are recruited for tasks with low-level force demands?
One-joint muscles
Study Notes
- The nervous system uses a hierarchic recruitment pattern to modulate levels of extensor torque.
- The law of parsimony states that the nervous system activates the fewest muscles or muscle fibers possible for a given joint action.
- The anconeus and medial head of the triceps control activities that require lower level extensor torque.
- The larger, polyarticular long head of the triceps is selected for more dynamic or highly resisted extensor torque.
- The position of elbow extension increases the moment arm for the triceps.
- Peak elbow extensor torque occurs at about 80-90 degrees of flexion.
- Muscle length may be more influential than moment arm in determining peak elbow extension torque.
- The hierarchic pattern of muscle recruitment makes practical sense from an energy perspective.
- Tasks with low-level force demands are often accomplished by one-joint muscles.
- As force demands increase, larger polyarticular muscles are recruited, along with necessary neutralizer muscles.
Test your knowledge of the nervous system's control of elbow extension with this quiz. Discover the hierarchic recruitment pattern, the law of parsimony, and which muscles are selected for different levels of extensor torque. Learn about the role of muscle length and moment arm in determining peak torque, and understand the practical implications of the hierarchy of muscle recruitment. Test your understanding of these concepts and more with this informative quiz.
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