Biomechanics Week 1

kinesis

to move

logy

study of

Kinesiology

study of movement

Biomechanics

A discipline that uses principles of physics to quantitatively study how forces interact within a living body

The study of forces applied to the outside and inside of the body and the body's reactions to those forces

biomechanics

Biomechanics branches

kinematics and kinetics

Kinematics

Describes the motion of a body WITHOUT regard to the forces/torques that may produce the motion

Kinematics includes

osteokinematics and arthrokinematics

Kinetics

study of forces associated with the motion of a body

kinetics includes

forces, torques and physics principles

Translation

linear motion

Translation definition

All parts of a rigid body move parallel to and in the same direction as every other part of the body

rectilinear

moving in or forming a straight line; having many straight lines

curvelinear

curved lines

Translation is measured in

meters or feet

Translation can cause

linear displacement

Accessory movement

movement that could occur at a joint that's passive

linear displacement

change in location, or the directed distance from initial to final location in the same direction

Excessive translation of a bone relative to the joint indicates

injury

Abnormal laxity in translation may indicate

pathological stiffness in surrounding connective tissue

distraction

pulling apart-separated

compression

joint surfaces pulled towards each other

rotation

Rigid body moves in a circular path around a pivot point

All points in the body simultaneously rotate in the same

angular direction

All points in the body simultaneously rotate across the same

# of degrees

rotation is measured in

degrees or radians

angular displacement

All points on the body segment rotate in the same direction and same distance

Axis of rotation

the point around which a body rotates

Does an axis rotate

no

2 multiple choice options

Axes are usually located

near the joint

Axes run through

the convex partner of a joint.

Evolute Axis of Rotation

migrating axis of rotation, the axis changes throughout the ROM

Sagittal plane

divides body into left and right

Frontal plane

divides the body into anterior and posterior portions

horizontal or transverse plane

Any plane dividing the body into superior and inferior portions.

Sagittal axis

medial and lateral

frontal axis

anterior and posterior

horizontal axis

vertical/ longitudinal

The Axis of rotation is perpendicular to

The cardinal plane of motion

Degrees of freedom

Number of independent directions of movements allowed at a joint

Uniaxial

movement in one plane and 1 axis and 1 degree of freedom

biaxial

joints that move in two planes around 2 axis and have 2 degrees of freedom

biaxial joints

condyloid, ellipsoid, saddle

Uniaxial joints

hinge, pivot

Triaxial

joints that move in all 3 planes abouts 3 axes and 3 degrees of freedom

Triaxial joints

ball and socket joints

Is naming the plane of motion considered part of kinetics or part of kinematics

Kinematics because it doesn't deal with the forces

Translation vs. Rotation

Translation: linear motion in which all parts of a rigid body move parallel to and in the same direction as every other part of the body

Rotation: motion in which an assumed rigid body moves in a circular path around some pivot point (axis of rotation)

Active movement vs passive movement

Active is controlled by the pt, while passive is controlled by an external force

Lumbar flexion plane

sagittal

shoulder abduction plane

frontal

Hip IR plane

horizontal

Knee flexion plane

sagittal

Cervical rotation plane

transverse, horizontal

finger abduction plane

frontal

Shoulder ER Axis of Rotation

vertical

elbow flexion Axis of rotation

medial lateral

hip abduction AoR

Anterior-posterior

Ankle DF AoR

Medial lateral

2 multiple choice options

Cervical rotation AOR

vertical

MCP Flexion AOR

Ant-post

Coxafemoral joint degrees of freedom

3

Tibiofemoral joint degrees of freedom

1

1st MTP joint degrees of freedom

3 it's a ball and socket

Uniaxial joint example

knee

biaxial joint example

wrist

triaxial joint example

hip

Osteokinematics

motion of bones relative to the 3 cardinal planes of the body

osteokinematic Movement the occurs between

the shafts of 2 adjacent bones as they move with regard to each other

Osteokinematics concern with

the movements of bony partners or segments that make up a joint

Goniometry is an example of

osteokinematics

Arthokinematics

Motion that occurs between the articular surfaces of joints

Arthrokinematics focuses on

minute movements occurring within the joint and between the joint surfaces

Arthrokinematics can be

Can be rotary or translatory

example of arthokinematics

joint mobilization

end feels

Joint's resistance to further movement; sensation perceived by clinician when assessing passive range of motion at the end of a joint's ROM

Soft end feel

(soft tissue approximation) ex: elbow flexion, knee flexion

Firm end feel

muscular stretch

capsular stretch

ligamentous stretch

Hard end feel

(bone to bone) ex: elbow extension

empty end feel

movement is beyond anatomical limit

- pain occurs before end range (complete lig rupture)

end feels are abnormal when

they appear where they shouldn't

Kinematic chains

combination of several joints uniting successive segments

Open kinematic chain

distal segment is free to move

Open kinematic chain movement

Distal segment moves on a fixed proximal segment (bicep curl)

Closed kinematic chain

distal segment is fixed

Closed kinematic chain movement

Proximal segment moves on a fixed distal segment (Push up)

convex

curved outward

concave

curving inward

most joints are a mix of

convex/concave

Arthrokinematics can include

Rolling, sliding and spinning

Rolling

rotary or angular motion

slide (glide)

translatory motion, sliding of one joint surface over another

spin movement

One joint surface rotates on another (ie: forearm is rotate from the hand facing down to the hand facing up).

Convex-Concave Rule

determines the direction of decreased joint gliding and the appropriate direction for the mobilizing force

Convex on concave

roll and slide in opposite directions

concave on convex

roll and slide in same direction

Spin joint example

Radial head spins as it attaches to the capitulum.

Close-packed position

joint orientation for which the contact between the articulating bone surfaces is maximum

Very stable

Reduced need for muscle forces

Accessory movements are minimal

Near end range

open packed position

minimal stress on joint, minimal congruency of joint, great laxity in ligament position, no volitional separation of joint surface, increased accessory movement, preferred during long periods of immobilization

Kinetics

study of forces associated with the motion of a body