L01. Intro to Muscle and Joint Mechanics

Question 1

What are the main 2 joint classifications?

Answer 1

Structural and Functional

Question 2

Define: Functional Joint

Answer 2

Based on type and degree of movement permitted

Question 3

Define: Structure Joint

Answer 3

Based on type of tissue involved in formation

Question 4

What are the main 3 structural classifications of joints?

Answer 4

Fibrous, cartilaginous, and synovial

• in order of least to most movement allowed

Question 5

What are the 5 main synovial joint movements?

Answer 5

1. Abduction (away from midline)
2. Adduction (towards midline)
3. Extension (open/straighten)
4. Flexion (close/bend)
5. Rotation (circular about a point)

Question 6

What are the types of synovial joints? Hint: 6 of them

Answer 6

1. Gliding/Plane
2. Hinge
3. Pivot
4. Condyloid
5. Saddle
6. Ball and socket

Question 7

What 2 bones make up the shoulder joint? Type of joint?

Answer 7

Scapula - Humerus
Ball & Socket Joint

Question 8

What 2 bones make up the elbow joint? Type of joint?

Answer 8

Humerus - Radius/Ulna
Hinge Joint

Question 9

What 2 bones make up the radio-ulnar joint? Type of joint?

Answer 9

Radius - Ulna
Pivot Joint

Question 10

What 2 bones make up the wrist joint? Type of joint?

Answer 10

Radius/Ulna - Carpals/Metacarpals
Plane Joint

Question 11

What 2 bones make up the Hip joint? Type of joint?

Answer 11

Acetabulum (Pelvis) - Femur
Ball and Socket Joint

Question 12

What 2 bones make up the Knee joint? Type of joint?

Answer 12

Femur - Tibia
Hinge Joint

Question 13

Define: Agonist vs Antagonist Muscle

Answer 13

Agonist: Prime Mover
Antagonist: Acts Opposing Agonists

Question 14

How are muscle fibers, fascicles, and muscles related?

Answer 14

Fascicles are bundled to form individual muscles. Muscle fibers are bundled together in fascicles.

(fibers –> fascicles –> muscles)

Question 15

How are muscle fibers, myofibrils, and sarcomeres related?

Answer 15

Bundles of myofibrils make of muscle fibrils. Myofibrils are bundles of protein filaments that are arranged in repeating units called sarcomeres.

(sarcomeres –> protein filament –> myofibril –> muscle fiber)

Question 16

How are physiologic cross sectional area and force related?

Answer 16

They are proportional

• Sarcomeres are in parallel

Question 17

How are fiber length and velocity related?

Answer 17

They are proportional

• Sarcomeres are in series

Question 18

What are the names of the 4 skeletal muscle anatomical arrangements?

Answer 18

1. Parallel
2. Circular
3. Pennate
4. Convergent

Question 19

What muscle architecture is best suited for force production?

Answer 19

Large pennation angle and large PSCA

Question 20

What muscle architecture is best suited for velocity?

Answer 20

Smaller pennation angles and intermediate PSCA

Question 21

What is the muscle length-tension relationship?

Answer 21

Muscle force varies with muscle length due to changes in cross-bridge overlap with thin filaments

• maximal force at resting length (all or most cross bridges effective)

Question 22

What is the muscle force-velocity property?

Answer 22

Muscle force varies with velocity of contraction. Inverse relationship between force and velocity

Question 23

Define: Concentric contraction

Answer 23

Length of muscle shortens

• the faster the muscle contracts, the shorter time that a given active site is close enough to a crossbridge to attach therefore producing little force

Question 24

Define: Eccentric contraction

Answer 24

Length of muscle lengthens

• When crossbridge attaches, its power stroke takes some time. If an external load pulls on an attached crossbridge, it resists like a spring with a force that adds to its normal power stroke (produce large force)