Chapter 4 - Biomechanics

Question 1

Sagittal

Answer 1

divides left and right

Question 2

frontal

Answer 2

divides front and back

Question 3

transverse

Answer 3

divides top and bottom

Question 4

linear momentum

Answer 4

mass x velocity

Question 5

angular momentum

Answer 5

inertia x angular velocity

Question 6

transfer of momentum

Answer 6

mechanism by which momentum is transferred from one body to another

Question 7

to change momentum

Answer 7

mechanical impulse must be applied

impulse = force x time

Question 8

torque

Answer 8

= force x moment arm (d)

Question 9

moment arm

Answer 9

the perpendicular distance from fulcrum to line of force action

Question 10

first class lever

Answer 10

fulcrum between 2 forces

Question 11

second class lever

Answer 11

resistance force between fulcrum and applied force

Question 12

third class lever

Answer 12

applied force between fulcrum and resistance force

Question 13

what kind of lever is primarily found in the body?

Answer 13

third-class

Question 14

what is mechanical advantage?

Answer 14

ratio of resistance to applied force
if it's 1 they are equal
<1 resistance force is greater
for first class, longer arm has advantage
second class, applied force always 
third class, resistance force always

Question 15

what is work?

Answer 15

force x distance

Question 16

what is power?

Answer 16

work / time
or
force x velocity

Question 17

what is linear kinetic energy?

Answer 17

.5 x mass x linear velocity squared

Question 18

what is angular kinetic energy?

Answer 18

.5 x moment of interia x angular velocity squared

Question 19

what is gravitational potential energy?

Answer 19

mass x acceleration x height

Question 20

what is deformational energy?

Answer 20

energy stored in a body when deformed

Question 21

how much energy in muscle activity goes toward performing mechanical work?

Answer 21

25%, the rest is lost to heat or recovery processes

Question 22

what contributes to inefficiency?

Answer 22

coactivation
jerky movements
excessive movements
isometric actions
excessive centre of gravity excursions

Question 23

four distinguishing muscle characteristics

Answer 23

excitability
contractibility
extensibility
elasticity

Question 24

what is pennation angle?

Answer 24

angle at which fibers are arranged
normally <30 degrees
fusiform - straight - biceps
multipennate - deltoid
radiate - pecs
longitudinal - abs
unipennate - tibialis posterior
bipennate - rectus femoris

Question 25

how long does max force take to develop?

Answer 25

0.5 seconds

Question 26

free weight resistance?

Answer 26

mass x acceleration + weight (when vertical)
mass x acceleration (other directions)
weight = 0 in all other directions but vertical

Question 27

buoyancy force?

Answer 27

50% at hips, 90% at neck

Question 28

in water what kind of force is always used?

Answer 28

concentric, to overcome the force because water acts in direction opposite to the movement