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Week 7 Lecture 1
Muscle System Part 2
Question | Answer |
---|---|
What is motor unit recruitment? | The process of increasing the number of active motor units. |
When do sarcomeres produce maximal tension? | When thick and thin filaments overlap between about 100-120%. |
What happens if a sarcomere is stretched too far? | There will be insufficient overlap of the myofilaments and so the force produced will be reduced. |
What happens if muscle is over contracted? | The potential for further contraction is reduced which reduces the amount of force produced. |
What must force of contraction for the whole muscle account for? | Active (contractile) and passive (series and parallel elastic elements) components. |
How would you consider the passive force for lengths less than the normal resting length (l0)? | Negligible. |
What happens to the muscle in isometric contraction? | Muscle contracts but does not shorten -> no movement. |
Which direction would your arm move if your bicep was in concentric contraction? | Wrist moves towards shoulder. |
In which direction would your arm move if your bicep was in eccentric contraction? | Wrist moves away from shoulder. |
Is force greater during lengthening or shortening contractions? | Force is greater during lengthening (eccentric) than shortening (concentric) contractions. |
What affect does concentric velocity have on force? | The greater the concentric velocity, the smaller the force. |
When can the largest force be applied? | At the fastest eccentric motion. |
What muscle contraction is used most often for measuring muscle strength and why? | Isometric contractions are used most often because they are safe to conduct (no movement avoids potential collisions with objects in the vicinity). |