(DONE) Lab #6 Prep Unit 13-16

Question 1

What are the 3 parts of a lever?

Answer 1

• force point
• resistance point
• fulcrum

Question 2

describe the force point

Answer 2

insertion point of a muscle of interest

Question 3

describe the resistance point

Answer 3

centre of gravity of moving body segment plus external weight

Question 4

describe the fulcrum

Answer 4

axis of motion

Question 5

First class levers

• define
• 2 examples (human body and real life)
• force or speed lever?

Answer 5

• fulcrum separates force and resistance point
• tricep muscles acting on elbow joint (fulcrum: elbow; force point: olecranon process; resistance point: center of gravity of forearm)
• seesaw
• can be force OR speed lever

Question 6

second class levers

• define
• 2 examples (human body and real life)
• force or speed lever?

Answer 6

• resistance point separates force and fulcrum
• controversial as to whether this exists in body; achilles tendon pushing/pulling across the heel of the foot (fulcrum: ball of foot)
• wheelbarrow or bottle opener
• strictly force lever

Question 7

third class lever

• define
• 2 examples (human body and real life)
• force or speed lever?

Answer 7

• force point separates resistance and fulcrum
• bicep muscle producing flexion at the elbow joint (elbow joint is fulcrum; force point: insertion of biceps on radial tuberosity; resistance point: the centre of gravity of forearm)
• broom
• strictly speed lever

Question 8

what defines a force lever

Answer 8

force arm is longer than resistance arm

Question 9

what defines a speed lever

Answer 9

resistance arm longer than force arm, optimising it for speed and range of motion

Question 10

give the equation for the principle of levers

Answer 10

Force x FA = Resistance x RA

Question 11

give the equation for the mechanical advantage of levers

Answer 11

• MA= FA/RA

Question 12

how is the centre of gravity defined in the human body? (3)

Answer 12

• Where 3 cardinal planes of body intersect
• Point of exact center where body may freely rotate in all directions
• Point where weight is equal on all opposite sides

Question 13

What is the reaction board method used for? How does it accomplish this?

Answer 13

• common method to determine centre of gravity

- subject lies on reaction board that is balanced ontop of scale and wooden block

Question 14

describe the stance phase and the 5 events

Answer 14

• phase where foot is on the ground
• heel strike
• foot flat
• midstance
• heel off
• toe off

Question 15

describe the swing phase and the 3 events

Answer 15

• same foot from stance phase is in the air swinging forward for next foot strike
• acceleration
• mid swing
• deceleration

Question 16

What is the stance:swing time during walking

Answer 16

60%:40%

Question 17

What 2 facts separate running from walking?

Answer 17

• There is a brief period where both feet are off the ground

- There is no period where both feet are touching the ground at the same time

Question 18

Give the equation for running velocity

Answer 18

• average stride length x average stride frequency

Question 19

What type of strength test is the levers experiment

Answer 19

isometric strength test

Question 20

What notable equipment is used for the lever experiment (1)

Answer 20

jackson strength evaluation system - model 32528

Question 21

What equipment is used for the COG experiment? (4)

Answer 21

• weight scale
• reaction board
• tape measure
• block of wood equal height as weigh scale

Question 22

When the subject lies on the reaction board in the COG experiment, what is it an example of?

Answer 22

• first class lever

Question 23

What is the segmental method of calculating COG?

Answer 23

Measure the COG of individual body parts to get the entire body’s COG