biomechanics intro

Question 1

kinematics

Answer 1

the study of movement without regard for the forces that cause that movement

Question 2

kinetics

Answer 2

the study of forces causing movement

Question 3

world frame meaning

Answer 3

earth’s horizontal and vertical axes; is relative to the segmental angle

Question 4

joint angle

Answer 4

the angular position of a body part relative to another body part; ex. the angular position of the tibia bone with respect to the femur bone is described as the knee joint angle; can be open or closed chain

Question 5

reference frame meaning

Answer 5

the definition of what directions or rotations are considered positive or negative

Question 6

force meaning

Answer 6

a push or pull applied on an object

Question 7

sum of linear force formula

Answer 7

F = ma

Question 8

moment arm

Answer 8

the perpendicular distance between the line of action of a force and the axis of rotation of the object

Question 9

moment other name

Answer 9

torque

Question 10

moment meaning

Answer 10

the angular equivalent force which describes the amount of turning force that tends to create angular motion about a specific axis of rotation

Question 11

moment formula

Answer 11

M = d x F; d is the moment arm

Question 12

moment of inertial

Answer 12

a measure of the distribution of mass in an object relative to a specific axis of rotation; if the mass is more concentrated further away from the axis of rotation, the moment of inertia will be larger

Question 13

angular motion formula

Answer 13

M = Ia; I is the moment of inertia and a is angular acceleration

Question 14

internal forces

Answer 14

forces generated by tissues of our body; can be active (muscles) or passive (ligaments, fascia, bone, etc.)

Question 15

external forces

Answer 15

forces from outside our body that act on our body; are determined by the point of application, the direction, and the magnitude of force

Question 16

law of inertia

Answer 16

an object will remain at rest or in constant motion unless acted upon by an external force; this is newton’s first law

Question 17

law of acceleration

Answer 17

linear acceleration is inversely proportional to the object’s mass (or moment) and directly proportional to its force; this is newton’s second law

Question 18

law of reaction

Answer 18

every action has an equal and opposite reaction; this is newton’s third law

Question 19

common mechanism of ACL injury

Answer 19

femoral adduction, ankle eversion, and valgus knee

Question 20

biomechanics definition

Answer 20

the use of mathematical and physical principles to study and understand movement

Question 21

is increased knee valgus kinematics or kinetics?

Answer 21

kinematics

Question 22

is increased force of medial rotation kinematics or kinetics?

Answer 22

kinetics

Question 23

osteokinematics

Answer 23

movements between bones and describes what position/angle is a bone in at a certain point in time

Question 24

two ways to describe the motion we can see

Answer 24

segment or joint angle

Question 25

two ways to describe knee flexion

Answer 25

proximal end fixed with distal end moving (open chain) or distal end fixed and proximal end moving (closed chain)

Question 26

axis of sagittal plane

Answer 26

mediolateral

Question 27

types of movements allowed through sagittal plane

Answer 27

flexion and extension

Question 28

transverse plane axis

Answer 28

inferosuperior or longitudinal

Question 29

types of movements allowed with transverse plane

Answer 29

rotation along the longitudinal axis, ex. internal and external rotation

Question 30

frontal/coronal plane axis

Answer 30

anteroposterior

Question 31

what types of movements does the frontal/coronal plane allow?

Answer 31

abduction and adduction

Question 32

segmental angle

Answer 32

angle of a segmental angle like a bone relative to horizontal or vertical plane (relative to a 'world frame')

Question 33

3 ways that we can describe movements in biomechanics

Answer 33

position/distance/displacement, velocity, and acceleration

Question 34

linear kinematics

Answer 34

describes motion along a straight line or path

Question 35

angular kinematics

Answer 35

describes rotational motion around an axis

Question 36

distance vs displacement

Answer 36

distance is the total distance traveled whereas displacement is the overall change in position from point A to B; distance is not displacement

Question 37

linear force unit

Answer 37

newtons

Question 38

angular moment units

Answer 38

newton-metres

Question 39

moment arm relationship to force

Answer 39

is perpendicular

Question 40

what internal force control the body during eccentric loading?

Answer 40

passive forces like ligaments, the muscles are not active and are being stretched

Question 41

what creates a larger moment of inertia?

Answer 41

more mass concentrated at a greater distance from the center of rotation

Question 42

inertia meaning

Answer 42

the natural tendency of an object to resist any change in its state of motion; it is the rotational equivalent of mass

Question 43

inertia relationship to mass

Answer 43

more mass = greater inertia

Question 44

isometric contraction relationship to internal and external forces (formula)

Answer 44

Mm = Mg; Mm = Fm x dm; Mg = Fg x dm; (g is gravity, external forces, and m is internal forces)

Question 45

what is the optimal length of actin and myosin relative to?

Answer 45

the maximum amount of force production

Question 46

how does anatomy help with force generation?

Answer 46

due to structures like tuberosities, the length of the muscle increases, thus increasing the moment arm and the ability of a muscle to generate more force

Question 47

stress-strain curve

Answer 47

explains the behaviour of a tissue in response to a stress/load/force placed upon in at a given moment in time; includes the elastic and safe zone and then the plastic and damage zone, followed by the ultimate failure point

Question 48

difference in force output in normal lungs vs damaged lungs

Answer 48

in order to achieve the same alveolar length, the damaged lungs have to exert about double the amount of force compared to healthy lungs; for the same amount of force between each group, less O2 is delivered to tissues in damaged lungs

Question 49

net moments not equal to 0 result

Answer 49

angular motion

Question 50

forces relative to a concentric contraction

Answer 50

internal forces > external forces

Question 51

forces relative to an eccentric contraction

Answer 51

external forces > internal forces

Question 52

angular unit of position

Answer 52

degrees or radians

Question 53

angular unit for velocity

Answer 53

degrees/second or radians/second

Question 54

angular unit for acceleration

Answer 54

degrees/second^2 or radians/second^2

Question 55

during gait, when is the potential for vertical acceleration the greatest?

Answer 55

at the bottom of the step

Question 56

what can create a larger moment?

Answer 56

a larger force or a larger moment arm

Question 57

what will going beyond your maximum capacity to adapt result in?

Answer 57

pain during activity, pain after activity, and morning stiffness and you are in the plastic zone

Question 58

what will going below your minimum capacity to adapt result in?

Answer 58

no adaptation and detraining may occur

Question 59

what causes angular motion

Answer 59

forces applied at a distance from an axis of rotation

Question 60

what is the angular equivalent of force?

Answer 60

moments

Question 61

what don't muscles exert linear forces?

Answer 61

because their Os and Is are away from the axis of rotation, translating these linear forces into angular forces (moments)

Question 62

what is the moment if the moment arm is 0

Answer 62

0

Question 63

where in muscles are forces generated?

Answer 63

along the musculotendinous unit

Question 64

what transmits the force from a muscle to the bone?

Answer 64

tendon

Question 65

what are 3 key things to do when re assessing strength after an initial test?

Answer 65

same position (joint angle and general body position), restriction of other moving body parts, and apply the necessary force to maintain an isometric contraction