biomechanics

Question 1

biomechanical analysis

Answer 1

conducted both qualitatively and quantitatively.

Question 2

qualitative

Answer 2

non-numeric evaluation of motion based on direct observation.

Question 3

quantitative

Answer 3

numeric evaluation of motion based on data collected during the movement.

Question 4

kinematic of motion

Answer 4

description of motion from a spatial and temporal perspective,

linear or angular motion paths

Question 5

linear motion paths

Answer 5

movement occurs along a straight or curved pathway in which all points on a body or object move the same distance in the same amount of time.

Question 6

angular motion paths

Answer 6

motion around an axis so that different regions of the same object do not move through the same distance in a given amount of time.

Question 7

force

Answer 7

Forces cannot be seen, but effects of forces can be observed e.g. produce or stop motion; accelerate or change direction of an object/body.

Question 8

internal forces

Answer 8

Produced from structures located within the body.

active- generated by muscle contraction

passive- generated by tension in stretched tissue- ligamens stretch tendon stretch

Question 9

external force

Answer 9

Produced by forces acting from outside the body.

Gravity acting on mass of a body segment and its attachments, e.g. splints, casts,

External load acting on mass of a body segment, e.g. hand weight, manual resistance, weight bar or back pack

Friction which can provide stability if optimum, retard motion if excessive, or lead to instability if inadequate

Question 10

forces are characterised by

Answer 10

magnitude - weight on the limb

direction - which way muscles are pulling

point of application - where the weight is actually acting on

Question 11

what can forces do

Answer 11

translate a body segment

produce rotation- torque = when a segment is fixed or anchored at one or more points.

Question 12

torque and moment

Answer 12

dynamic rotatory effect of a force while moment is the static rotatory effect

Question 13

measure torque

Answer 13

Torque (T) = Force (F) x Moment arm (MA)

Question 14

composition

Answer 14

process of combining or adding two or more vector quantities (forces) together.

if 2 in the same direction will increase the magnitude

if in opposite direction will decrease the magnitude

Question 15

2 different muscle vectors result in

Answer 15

resultant force

Question 16

resolution of forces

Answer 16

perpendicular- force of the muscle

parallel- distraction of the elbow

parallel component will move- causing rotation

Question 17

distraction

Answer 17

pull apart a joint

Question 18

newton laws

Answer 18

1 Newton (N) is equal to the force needed to accelerate 1kg of mass at the rate of 1m/s² in the direction of the applied force.

Question 19

newtons first law

Answer 19

For a body to maintain a state of rest or static equilibrium there can be no unbalanced external forces acting on it. Therefore, the sum of all forces acting on a body must add to zero. ∑ F = 0

Question 20

newtons second law ( accel)

Answer 20

“A force applied to a body causes an acceleration of that body of a magnitude proportional to the force, in the direction of the force, and inversely proportional to the body’s mass.”

greater force applied to a ball- greater acceleration it will have

Question 21

newtons third law

Answer 21

“For every action, there is an equal and opposite reaction.”

Every time the foot impacts the ground during gait it produces a force against the ground. This results in the ground generating a force of equal magnitude back in the opposite direction.

Question 22

with a smaller moment arm we need to use

Answer 22

more force to produce same torque if we had a larger moment arm

Question 23

torque and lever system

Answer 23

bone acts a lever

weight of limb is resistance

joint acts as a fulcrum

muscle applies force

Question 24

mechanical advantage

Answer 24

force moment arm/ resistance moment arm

a greater mechanical advantage the less work is required

Question 25

ratio less then 1

Answer 25

momement arm of force is less then the resistance

then bicep will need to work harder to overcome resistance

Question 26

ratio greater then 1

Answer 26

moment arm is greater then the resistance so bicep will work less to overcome the force

Question 27

first class lever

Answer 27

force on one side

lever in the middle

resistance on the other

Question 28

second class lever

Answer 28

lever is on one side

resistance is in the middle

force is on the other in opposite direction to resistance

ankle usually

Question 29

third class lever

Answer 29

lever on one side

force in the middle

resistance on the other side agaianst the force

Question 30

direction

Answer 30

compression

e.g the effect of gravity

tension

e.g stretch or pull// due to muscle contraction placing force on bones

shear-
act parallel to the surface usually during squats

bending-
when asymetrical force is applied- compression on one side/ tension on other side reduces injury potential

torsion when a structure twist on longnitudal axis

Question 31

distribution

Answer 31

stress- force per unit of area it acts on

Question 32

magnitude and duration

Answer 32

acute load- single force of surficent magnitude to cause injury
macrotruama

repetitive load- repteated application/ use causing microtrauma

Question 33

magnitude stress vs strain

Answer 33

strain= deformation
change in shape due to force applied

load/ stress- structure goes back to original shape but if it goes beyond yeild point if load is removed it may not go back to original shape and deformation occurs

Question 34

bone components

Answer 34

spongy- trabeculae

compact- osteons

osteocytes- type 1 collagen fibre
bone isn’t hardest thing in the body that is dentin

brittle and weak

Question 35

deformation curve

Answer 35

elastic region- tempoary deformation due to increased load and stress

yield point- defromation becomes permenant

ultimate failure

plastic region= yield point/ ultimate failure

youngs modules- higher elastic region= stiff lower= flexible