Biomechanics Pt. 2 (9/3c) Flashcards Preview

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Flashcards in Biomechanics Pt. 2 (9/3c) Deck (36)
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1

Proximal on Distal / Distal on Proximal

Different ways of moving, but provides same essential movement

If a Pt is struggling with a motion (EX: prox on dist), you could consider the complimentary motion (EX: dist on prox)

2

Kinetics

describes the effect of forces on the body

3

Force

a push or pull that can produce, arrest, or modify movement

Force = mass*acceleration

4

When acceleration is zero, force equals ___

zero

5

Standard International Unit for Force

Newtons (N) = 1 kg x 1 m·s2

6

Force is mathematically displayed/defined as a ___

vector

7

Vector

has magnitude AND direction, often represented by arrows

Magnitude = length

Direction = indicated by arrow head

8

Internal forces (IF)

forces derived from inside the body

9

External forces (EF)

produced by forces acting outside the body

10

Humans produce IFs mostly via ___ ___ to control EFs during movements

muscle activation

11

Interaction between IFs and EFs result in

Loading of body tissues

12

Active forces (IF)

forces produced by activated muscles

13

Passive forces (IF)

forces generated by passive tension in stretched tissues

14

Examples of external forces

Gravity, wind, friction

15

Point of application

where forces are being applied

Especially in relation to joint’s axis of rotation

16

Angle of insertion

orientation of the muscles insertion relative to the long axis of the bone

Dictates the direction of application of force to the bone

17

Moment arm/Mechanical advantage

distance between the force acting on the body and its axis of rotation

Muscle force is applied to the bone segment at a distance (D) from the axis of rotation of the joint

D1 moment arm > D moment arm

18

D1 moment arm is (less than/equal to/greater than) D moment arm?

Greater than >

19

Joint moment

muscle force x moment arm

D= muscle force moment arm

D1= external force of gravity acting on forearms center of mass

20

Moment

torque

21

Linear kinematic measures

Force

Newtons (N) OR Pounds (lbs)

22

Angular kinematic measures

Moment/torque

Newtons x meters (Nm) OR Foot pounds (ft-lbs)

23

Static Linear Equilibrium

internal force = external force

EX: Internal force= biceps muscle force
External force= weight of forearm
Joint reaction force= reaction force of humerus pushing down

24

Static Rotary Equilibrium

internal moment = external moment

no rotation occurs around the joint

25

Internal moment (IM)

muscle force x internal moment arm

26

External moment (EM)

external force x external moment arm

27

Muscle action

potential for a muscle to produce osteokinematic rotation around an axis of rotation in a plane of motion

based on anatomical positions and there can be multiple movements based on orientation

28

When a muscle contracts, the ___ segment moves

Freest

29

3 Types of Muscle Activation

Isometric
Concentric
Eccentric

30

Isometric muscle activation

muscle produces force while maintaining constant length

Internal moment = external moment