ES - Muscle Anatomy and Phys - Muscular dynamics involved during movement patterns

Question 1

Process of Sliding Filament Theory of muscle action (4)

Answer 1

1) States that actin filaments at each end of sacromere slide inward on myosin filaments, pulling Z-lines toward center of sacromere, thus shortening the muscle fiber.
2) As actin slides over myosin, both H-zone and I-band shrink.
3) The action of myosin cross-bridges pulling on actin is responsible for movement of actin.
4) B/c of very small displacement of action w/ each flexion of of myosin cross-bridge, very rapid, repeated flexions must occur in many cross-bridges throughout entire muscle for measurable movement to occur.

Question 2

What are the different types of muscle actions? (3)

Answer 2

Concentric
Eccentric
Isometric

Question 3

Discuss the difference in force production based on muscle action

https://www.youtube.com/watch?v=ERWQXiuwCFc

Answer 3

Concentric: as velocity increases, force decreases.
Eccentric: as velocity increases, force produced increases until plateau (doesn’t decrease).
Isometric: velocity is 0 b/c joint does not move, thus there is 0 force

you can lower more weighed eccentrically than you can push during concentric contraction.

Question 4

What factors affect the production of force within a muscle? (9) pages 30-33

Answer 4

Neural Control
Muscle Cross-Sectional Area
Arrangement of Muscle Fibers
Muscle Length
Joint Angle
Muscle Contraction Velocity
Joint Angular Velocity
Strength-to-Mass Ratio
Body Size