Lecture 3 - BIOMECHANICS

Question 1

What are the 3 types of machines found in the body that produce movement?

Answer 1

1. Levers (most common)
2. Wheel-axis
3. Pulleys

Question 2

What are the three points of a lever that determine the type of lever?

Answer 2

1. Axis (A) = fulcrum, the point of rotation
2. Point (F) = of force application, usually muscle insertion
3. Point (R) = of resistance application, center of gravity of lever, or location of an external resistance

Question 3

What are the 3 classes of levers?

Answer 3

1st class lever = FAR 
2nd class lever = ARF 
3rd class lever = AFR

Question 4

What is a 1st class lever?

Answer 4

FAR

Example in body = Head balancing on neck in flexing/extending AND tricep in elbow extension

Question 5

What is a 2nd class lever?

Answer 5

ARF
**Good at producing force
Example in body = Standing on toes (gastrocnemius)

Question 6

What is a 3rd class lever?

Answer 6

AFR
**Most common example in the body
Example in body = Bicep brachii and hamstring

Question 7

What are the excessive tissue deformations? (due to mechanical loading)

Answer 7

1. Tension (stretching or strain)
2. Compression
3. Shear
4. Bending
5. Torque (twisting)