Biomechanics Unit

Front 1

Biomechanics

Back 1

-Response of biological systems to mechanical forces
-Application of mechanical laws to living systems

Front 2

Statics

Back 2

Equilibrium of bodies at rest or moving with a constant velocity

Front 3

Dynamics

Back 3

Bodies in motion, forces that act to produce motion
-Kinematics and Kinetics

Front 4

Kinematics

Back 4

Geometry of motion w/o consideration of forces

Front 5

Kinetics

Back 5

Force analysis of bodies in motion
Relationship between forces acting on a system

Front 6

Forces

Back 6

Mechanical Disturbance or Load
-Produce, halt or change direction of motion
-Magnitude and Direction - Vectors
-F=ma

Front 7

Magnitude

Back 7

Amount of Force applied

Front 8

Orientation

Back 8

Angular position of the line

Front 9

Line of application

Back 9

angle with body that force is acting on

Front 10

Moment of Force

Back 10

Magnitude of force x perpendicular distance to the axis of rotation

Front 11

Torque

Back 11

Force x Perpendicular distance to center of rotation
Produces rotation

Front 12

Moment Arm

Back 12

Shortest distance between axis of rotation and force

Front 13

Torque =

Back 13

Force x Moment Arm
-Rotary equivalent of force
-Force produced by a muscle

Front 14

Mass

Back 14

Amount of matter composing an object

Front 15

Weight

Back 15

Force acting on an object due to gravity
-Depends on mass of object and strength of gravitational pull

Front 16

Center of Gravity

Back 16

-Rigid body behaves as if its entire mass were acting at its COG
-Point at which total mass of body is considered to be concentrated
-Depends on body's shape and mass distribution
-Point of Application of force due to gravity
-Located normally around S2

Front 17

Line of Gravity

Back 17

Line extending from COG vertically downward
Vector representation of the weight of a segment

Front 18

Base of Support

Back 18

Outline on ground encompassing all parts of the patient which touch the ground
-To be stable the COG must fall in the BOS

Front 19

To incrase stability

Back 19

Increase BOS and Lower COG

Front 20

Friction

Back 20

Tangential force acting between two bodies in contact which opposes motion

Front 21

First Class Levers

Back 21

Fulcrum always located between Effort and Resistance
-C1

Front 22

Second Class Levers

Back 22

Effort Arm is always greater than Resistance Arm
-1st MTP Standing

Front 23

Third Class Levers

Back 23

Resistance Arm is always greater than Effort Arm
-Biceps Curl

Front 24

Mechanical Advantage

Back 24

-Efficiency of a lever
-Effectiveness of Effort compared to Resistance
-EA/RA

Front 25

Law of Inertia

Back 25

A body at rest remains at rest, and a body in motion remains in uniform linear motion, unless acted upon by an outside force

Front 26

Inertia

Back 26

Resistance to initiation or change of motion

Front 27

Law of Acceleration

Back 27

-Body acted on by a force will accelerate in direction of force in proportion to its mass

Front 28

Law of Reaction

Back 28

-For every action there is a reaction, equal in magnitude but opposite in direction

Front 29

Coplanar

Back 29

2 or more forces acting in the same plane

Front 30

Concurrent

Back 30

2 or more forces acting on the same point

Front 31

Collinear

Back 31

2 or more forces acting along the same line

Front 32

Parallel Forces

Back 32

Tensile Forces
-Normal force perpendicular and directed away from surface
Compressive Forces
-Normal forces perpendicular and directed towards the surface
*Forces that are parallel, coplanar but have different point of application

Front 33

Coplanar Forces

Back 33

Resultant force is algebraic sum of vectors

Front 34

Parallel Forces/Force Couples

Back 34

2 parallel forces equal in magnitude and opposite in direction, but not in same straight line
-Cause rotation of parts around thier anatomical axis

Front 35

Concurrent Forces

Back 35

2 forces with same point of application but different direction of action lines
-Coplanar, concurrent, not collinear

Front 36

Rectangular Components

Back 36

Muscle force applied to bone (via tendon)
-When muscles contract to produce movement, some force is used for rotation and some is used for compression

Front 37

Translatory Component

Back 37

Portion of force applied parallel to lever
Pazss through joint axis, does not produce torque
Tangential component of force