Lecture 2 - Definitions

Question 1

Define Biomechanics

Answer 1

• Application of physics to the understanding of the motions and deformations of body segments, organs, structures, tissues, cells due to forces, pressures, torques, shears, etc.

Question 2

What is linked rigid body biomechanics?

Answer 2

• taking masses that have volume
• assuming its rigid (even thought it has slight movements because muscles change shapes)
• linked = at joints, segments between are “rigid”

Question 3

What are you measuring in linked rigid body biomechanics?

Answer 3

• the movement of the bones (the rigid segments)
• can use x-rays to see what bones are doing

Question 4

What is skeletal biomechanics?

Answer 4

• deformation of the skeleton after a hit etc.
• deformable-body = not rigid, how the bones move

Question 5

What is vascular biomechanics?

Answer 5

• deformation of the soft tissues (blood vessels etc.) as the blood flows
• what musculature is involved in making the blood flow

Question 6

what is cellular biomechanics?

Answer 6

• measuring forces with which cells interact with their surroundings
• how they adapt to applied forces

Question 7

what are the 3 assumptions of linked rigid body biomechanics?

Answer 7

1. body segments are rigid
2. segments connect at joints
3. joints have a well-defined number of ‘degrees of freedom’

Question 8

how many degrees of freedom are there?

Answer 8

• 6
• 3 rotational degrees of freedom
• 3 translational/linear degrees of freedom

Question 9

what is implied when a joint has more degrees of freedom?

Answer 9

• easier to dislocate/injure
• more movement

Question 10

define anthropometrics

Answer 10

• measurements of the physical characteristics of the human body

Question 11

what do larger moments of inertia entail?

Answer 11

• harder to rotate something
• vice versa with small moments of inertia

Question 12

what is mechanics?

Answer 12

• the physics of forces and motion, when applied to the human body it is ‘biomechanics’.
• there are 2 types; static and dynamic

Question 13

what is static mechanics?

Answer 13

• the study of bodies without acceleration
• does not mean no movement!!
• no inertia

Question 14

what is dynamic mechanics?

Answer 14

• the study of bodies with acceleration (what we mostly look at)
• the correct way to measure biomechanics

Question 15

what is acceleration?

Answer 15

• in m/s^2
• the time rate of change of velocity
• speeding up vs. slowing down

Question 16

what is velocity?

Answer 16

• in m/s
• the time rate of change of position
• movement

Question 17

what is position?

Answer 17

• in m
• aka length

Question 18

what is angular acceleration?

Answer 18

• in degrees/s^2
• the time rate of change of angular velocity
• are you speeding up or slowing down

Question 19

what is angular velocity?

Answer 19

• in degrees/s
• the time rate of change of angle
• how quickly are you going around

Question 20

what is angle?

Answer 20

• in degrees
• for rotational movements

Question 21

what is inertial force?

Answer 21

• your body want to keep going (even if you slam on the brakes) = linear
• when you are turning in a car and it causes you to fall = rotational

Question 22

define kinematics

Answer 22

• the study of geometry of motion
• position, velocity, acceleration
• angle, angular velocity, angular acceleration
• doesn’t care how you ar removing, jut that you are

Question 23

define kinetics

Answer 23

• study of the causes of motion
• force, pressure, torque, tension, shear, compression
• why you are moving, what is causing you to move

Question 24

what is inverse kinetics?

Answer 24

• measure the kinematics first, then work ‘backwards’ to figure out the kinetics that must have caused the motion you observed
• usually how you measure movement in the lab

Question 25

what is forward kinetics?

Answer 25

• measure the kinetics first, then try to figure out where the body is going to go
• hard to observe in the lab (but this is how you learned to walk/learn new movement patterns)