Exam 1- Kinese

What is kinematics?

Motion of body without regard to the forces or torques that produce the motion

2 types of motion?

translation & rotation

What is translation?

straight line, linear motion, parts moving parallel to every other part of body

What is rotation?

rigid body moves in circular path about a pivot

pivot=?

axis of rotation

rotational motion occurs around what?

axis

active rotation?

muscular contraction

passive rotation?

other than muscle

Sagittal picture

sagittal movement?

flex/ext, dorsi/plant

Frontal pic

Frontal movement?

abd/add, ulnar/radial deviation

Transverse pic

Transverse motion

medial & lateral rotation, superior & inferior

What is osteokinematics?

bones rotate about a joint in a plane that is perpendicular to an axis of rotation

Degrees of freedom definition?

# movements allowed at a joint

-max is 3

Ball-and-socket joints (e.g., shoulder, hip) DF?

3

Hinge joints (e.g., elbow) DF?

1

Condyloid joints (e.g., wrist) DF?

2

1st DOF plane?

flex/ext, sagittal

2nd DOF plane?

abd/add, frontal

3rd DOF plane?

lateral/medial, transverse

open kinetic chain?

-the distal segment is free to move

-Movement usually occurs at one joint

Closed kinetic chain?

-The distal segment is fixed (in contact with ground or surface)

-Movement occurs at multiple joints simultaneously

OKC examples?

bicep curl, seated knee extention

CKC examples?

squat, push-up, pull-up

OKC or CKC kicking soccer ball?

distal is moving, OKC

What is arthrokinematics?

motion that occurs between the articulating surfaces

1-roll-multiple/multiple

Multiple points on the moving surface contacts multiple points on the stationary surface

-Occurs when both joint surfaces are moving

2- slide- slide/multiple

One point on the moving surface contacts multiple points on the stationary surface

-Prevents impingement and maintains joint congruency

3- spin single/single

One point on the moving surface rotates on one point of the stationary surface

-Pure rotation around a fixed axis

Concave on convex is?

roll & slide in the same direction

EX of concave on convex?

Knee extension, elbow flexion & extension

Convex on concave?

roll & slide opposite

EX Convex on concave?

Shoulder abduction, closed chain knee flexion, hip flexion

CPP is?

articular surface max congruency

-capsule & ligaments are taut

-least amount of accessory movement

-near end of ROM

LPP is?

all other poisitons

-greatest amount accessory movement

-greatest near mid range ROM

Joint is most stable at?

CPP

CPP examples?

Knee: Full extension

Hip: Full extension, abduction, IR

Shoulder (GH): Full abduction + external rotation

Ankle (talocrural): Full dorsiflexion

Elbow: Full extension

LPP examples?

Knee: ~25-30° flexion

Hip: ~30° flexion, 30° abduction, slight ER

Shoulder (GH): ~55° abduction, 30° horizontal adduction

Ankle: ~10° plantarflexion

Elbow: ~70° flexion, 10° supination

Joint mobilization is best at?

LPP

Kinetics describes?

the effects of forces on the body

Forces typically move or stabilize a body though if excessive can cause?

injury

plastic region in stress strain curve is?

-Permanent deformation

-Tissue does NOT return to original length

elastic zone in stress strain curve?

-Tissue deforms under load

-When the load is removed, tissue returns to original length

-NO permanent deformation

Tissues that exhibit chances with time are?

viscoelastic

What is creep?

gradual deformation (elongation) of a material over time when a constant load or stress is applied

What is this the definition of? "Holding a constant stretch on a hamstring—initial stretch occurs immediately, then the muscle-tendon unit continues to lengthen over time."

creep

What is rate of loading?

The mechanical response of a viscoelastic material depends on how quickly a load is applied

Example of rate of loading?

-A sudden ankle twist (high rate of loading) → ligament injury

-Slow stretching → increased flexibility with less injury risk

issues that have both elastic and viscous

properties --> influences what?

amount and rate of passive tension

What is elasticity?

the ability of muscle (and other tissues) to store energy when stretched and release that energy when returning to its original length

T or F: Elasticity Helps absorb forces, reducing stress on tissues and the stored energy can be reused during recoil to improve efficiency

T

Viscosity defintion?

the rate-dependent internal resistance to motion encountered between two surfaces of fluid-like tissue

Do Viscosity + elasticity act as damping mechanisms to absorb and dissipate energy & Limit excessive or rapid tissue deformation?

YES

In viscosity, when force is applied rapidly, does it slow or fasten tissue deformation?

slows

Internal resistance of muscle to elongation INCREASES or DECREASES

with the rate of stretch?

increases

Rate dependent resistance encountered between

2 surfaces of fluid-like tissue or solid like tissue?

fluid-like

Forces may be either internal or external, what is internal?

within the body

-Act to stabilize, move, or control body segments

-Produced primarily by muscle contractions

EX of internal forces?

-Muscle tension during movement

-Compressive forces at joints

-Passive tension in connective tissue

What are external forces?

-outside the body

-Must be overcome, controlled, or redirected by internal forces (muscle action)

-Influence posture, balance, and joint loading

EX of external forces?

-Gravity - constant downward force acting on body mass

-Imposed load - any external resistance such as:

Weights, Resistance bands, External objects being lifted or pushed

Forces may create ___________ or ____________?

translation or rotation

What is translation?

-The body or segment moves in a straight line

-All points on the object move the same distance in the same direction

EX of translation?

-Pushing a sled straight across the floor

-Linear sliding of a joint surface

What is rotation?

-The body or segment rotates around an axis

-Different points move through different distances, but all follow a circular path around the axis

-Usually caused by forces applied away from the center of mass (creating a torque or moment)

EX of rotation?

Bending the elbow during a curl

Kicking a soccer ball (rotation at the hip joint)

Internal torque (IF x D)=?

external torque (EF x D1)

3 types of contractions?

isometric, concentric, eccentric

isometric contractions & EX?

-Muscle length stays the same, Force is generated but there is no movement at the joint

EX:

-Plank position (core muscles active, body doesn't move)

-Holding a weight steady without moving your arm

Concentric contractions & EX?

-Muscle shortens while generating force

-Produces movement in the direction of muscle action

EX:

-Lifting a dumbbell towards you during a bicep curl

-Rising onto tiptoes

Eccentric contractions & EX?

-Muscle lengthens while generating force

-Controls or resists movement, often absorbing energy

-more force than concentric

EX:

-Lowering a dumbbell slowly in a bicep curl

-Descending stairs or landing from a jump

What is line of pull?

-the direction in which a muscle exerts force when it contracts

-Shows the primary direction of movement the muscle can produce

What are degrees of freedom (DOF)?

How many independent movements a joint can make

-Muscles can only produce movements allowed by the joint's DoF

Elbow DOF?

1 (Flex & Ext)

Shoulder DOF?

3 DoF (flexion/extension, abduction/adduction, rotation)

What is the relationship between line of pull & axis of rotation?

-Line of pull relative to the joint axis determines action:

-Perpendicular to axis → produces rotation (torque)

-Parallel to axis → produces compression or stabilization

-Small changes in position can alter the effectiveness of the muscle

Explain how muscle actions can change depending on what the position in joint angle is?

-When your arm is hanging down by your side, the biceps helps lift it forward, at this position, the line of pull relative to the shoulder allows torque for shoulder flexion

-but when your elbow is bent, the biceps mainly acts to flex the forearm, the shoulder contribution is less because of the arm's position; the line of pull now favors elbow rotation

-The angle of the joint changes the moment arm

What is agonist?

-the muscle that is primarily responsible for producing a specific movement

-Role: Contracts to create the desired motion

EX of agonist?

-Biceps brachii during elbow flexion

-Quadriceps during knee extension

Antagonist is?

-The muscle that opposes the action of the agonist

-Relaxes or controls the movement to prevent overshooting; can also act eccentrically to slow motion

EX of antagonist?

-triceps during elbow flexion (opposes biceps)

-Hamstrings during knee extension

What is synergist?

Synergist EX?

-Brachialis and brachioradialis assist biceps in elbow flexion

-Rotator cuff muscles stabilize shoulder while deltoid abducts the arm

What is force couple?

-two or more muscles produce forces in different directions, but together create a rotational movement

-Coordinate to rotate a joint smoothly

EX of force couple?

-Upward rotation of the scapula:

-Upper trapezius → pulls up

-Lower trapezius → pulls down/back

-Serratus anterior → pulls forward/laterally

-Together, these muscles rotate the scapula upward

What is a lever?

Rod suspended across pivot or axis

Levers convert force into?

torque

"leverage" Is?

relative moment arm length

Internal & External forces create torques via ?

levers throughout the body

1st class lever is?

-Fulcrum is between force and resistance

-Axis of rotation between opposing forces

EX of 1st class lever?

-Head balanced on the atlas (atlanto-occipital joint)

-Fulcrum: neck joint

-Force: neck extensors

-Resistance: weight of the head

2nd class lever is?

-Axis of rotation located at end

-IMA > EMA (>1) (always favors force)

EX of 2nd class lever?

-Standing on tiptoes

-Fulcrum: metatarsophalangeal joints

-Resistance: body weight

-Force: gastrocnemius-soleus via Achilles tendon

3rd class lever?

-Axis of rotation located at end

-IMA < EMA (

EX of 3rd class lever?

-Elbow flexion with biceps curl

-Fulcrum: elbow joint

-Force: biceps insertion on radius

-Resistance: weight in hand

joint is?

Junction or pivot point betwn bones

Joint functions allow?

-movement of body

- Transfer / Dissipate forces

Integrity of a joint will influence what?

its quality of movement

Synarthroses - Fibrous Joints is?

-Synarthroses are immovable joints connected by fibrous connective tissue

-Bones held together by dense irregular connective tissue

-Rigid junction with little to no movement

-Designed for stability and protection