Review for Test 2
1. What is an Isometric contraction?
a. When the muscle develops tension but there’s no change in muscle length
2. What is an Isotonic contraction?
a. When tension develops and there’s muscle changes
3. What is a concentric isotonic contraction?
a. Muscle shortens while developing tension
b. Ex. Contracting bicep in a bicep curl
4. What is an eccentric isotonic contraction?
a. Muscle lengthens while developing tension
5. What is an Isokinetic contraction?
a. Muscular contraction at a fixed speed and with a fixed maximal load (done with a machine)
6. Give an example of a concentric contraction and an eccentric contraction?
7. What is a “muscle twitch”?
a. Contraction as the result of a single stimulus
8. What is the latent period of a muscle twitch, when does it happen, and how long does it last?
a. Is a gap/ waiting period at the beginning of twitch lasting for the first 5 miliseconds
9. What is the contraction phase of the muscle twitch, when does it start, and how long does it last?
a. When tension is developed, starts right after latent period and lasts 40 ms
10. When does relaxation start during a muscle twitch and how long it last?
a. Starts after the contraction phase and lasts 50ms
11. Is the speed of shortening greater or lower in fast fibers and why?
a. Is greater, because
i. SR (sarcoplastic reticulum) releases Ca at a faster rate
ii. Higher ATPase activity
12. Draw a graph of a muscle twitch
13. What are the 3 main types of muscle fiber and what are the shortening velocity? Slow, faster, fastest?
a. Type 1slow
b. Type IIa faster
c. Type IIx fastest
14. Draw a graph of contraction speed and developed tension
15. Fill out the following table
Characteristic Type IIx Type IIa Type I
# of Mitochondria L H/M H
Fatigue resistence L H/M H
Predominant Energy System Anaerobic Combination Aerobic
ATPase activity Highest...