1. Mechanics of Movement

2. Muscle Structure Review Muscle fiber = muscle cell Muscle fiber = muscle cell Fibers lined up = direction of pull Fibers lined up = direction of pull Tendon attaches to bone Tendon attaches to bone Muscle pulls on bone Muscle pulls on bone

3. Muscle Origin and Insertion Origin Origin – Proximal – Fixed Insertion Insertion – Distal – Moves (usually!!) (usually!!)

4. What is the origin? Origin- is the point where the muscle attaches to a stationary bone.

5. What is the insertion? Insertion- is the point where the muscle attaches to the moving bone.

6. Muscle Physics Length of muscle is proportional to ability to shorten (strain) Length of muscle is proportional to ability to shorten (strain) – Number of sarcomeres in series gives shortening ability Short, fat muscles Short, fat muscles – Lots of force – Less shortening range Long, skinny muscles Long, skinny muscles – Less force – More shortening range

7. Muscular movement of bones Generally skeletal muscles are attached to one end of a bone, stretch across a joint, and are fastened to the end of another bone. Generally skeletal muscles are attached to one end of a bone, stretch across a joint, and are fastened to the end of another bone.

8. Muscular movement of bones Muscles are attached to bones to form lever systems to create movement Muscles are attached to bones to form lever systems to create movement

9. Types of fascicle arrangements Affects length and cross section of muscle Affects length and cross section of muscle Thus affects force and shortening properties of muscle Thus affects force and shortening properties of muscle

10. MUSCLES & LEVERS  LEVER – simple machine for making work easier Three factors influence a lever: Three factors influence a lever: 1. Load – to be moved 2. Effort – needed to move the load 3. Fulcrum – point of balance

11. Muscle movement across joints is like lever system

12. First-class lever

13. Second-class lever

14. Third-class lever

15. Muscles attach to bone by tough connective tissue called what?

16. Tendons Tendons

17. Movement of the limbs

18. Muscles work in pairs to move a limb Muscles work in pairs to move a limb 1) Agonist1) Agonist 2) Antagonist2) Antagonist

19. Agonist "prime movers" "prime movers" responsible for generating a specific movement through its own contraction responsible for generating a specific movement through its own contraction

20. Antagonist acts in opposition to the specific movement generated by the agonist acts in opposition to the specific movement generated by the agonist responsible for returning a limb to its initial position. responsible for returning a limb to its initial position.

21. Stabilization and Control Around Joint AgonistMain MoverE.g. biceps AntagonistOpposite motionE.g. triceps SynergistAids agonistE.g. brachialis  Antagonist often “fires” or contracts or is stimulated simultaneously with agonist to stabilize around joint during movement  NOTE: Muscle “contraction” or stimulus to “fire” does not always result in muscle shortening

22. Agonist/Antagonist