Kinesiology Exam 1

Osteokinematics

Movement of bones around a joint axis

Arthrokinematics

The motions of joints in the body

Cephalic

Closer to head

Caudal

Closer to feet

Ventral

Front

Dorsal

Back

Sagittal plane

Divide body into right & left sections

Frontal/Coronal plane

Divide body into front & back sections

Horizontal/Transverse

Divide body into upper and lower sections

Axis of rotation is always perpendicular to the plane of motion

Sagittal plane-- Frontal axis

Frontal plane-- Sagittal axis

Transverse plane-- vertical axis

Linear motion

All parts of body move in same direction at same speed

Rotation (Angular) motion

Rotate on pivot point

Body parts move different distances at different angles depending on pivot

General motion

Combination of linear and angular motion

Human movement is mostly general

Anatomical position

Most of the joints are in neutral position

Least amount of tension for many structures

Motions of sagittal plane

Flexion & extension

DF/PF

Motions of frontal plane

Abduction & Adduction

Lateral flexion

ex) Ulnar/Radial deviation

eversion.inversion

Motions of horizontal plane

Internal & external rotation

ex) axial rotation

Pronation (foot)

Eversion + ABDuction + Dorsiflexion

Supination (foot)

Inversion + ADDuction + plantar flexion

Dorsal surface of foot

Superior (Top)

Plantar surface of foot

Inferior (Bottom)

Linear motion has no axis of rotation

Scapular depression/elevation - No axis of rotation

Motion: Walking

Plane of motion:

Axis of rotation:

Best view:

Motion: Walking

Plane of motion: Sagittal plane

Axis of rotation: Frontal axis

Best view: Side View

Motion: Lateral trunk flexion

Plane of motion:

Axis of rotation:

Best view:

Motion: Lateral side bend

Plane of motion: Frontal plane

Axis of rotation: Sagittal axis

Best view: Anterior/posterior

Motion: Lateral trunk rotation

Plane of motion:

Axis of rotation:

Best view:

Motion: Lateral side bend

Plane of motion: Transverse

Axis of rotation: Vertical axis

Best view: Top

Open chain

Proximal segment fixed

Distal segment free

Closed chain

Proximal segment free

Distal segment fixed

Closed chain movements

Push ups

pull ups

squats

deadlifts

lunges

dips

Open chain movements

Bicep curls

Hamstring curls

Leg extensions

Open chain:

Hip flexion

Right hip IR

Knee flexion

Ankle DF

Shoulder extension

Closed chain:

Trunk flexion

Trunk rotate to R hip

Squat

Tibia lean forward

"Muscle up"

Epimysium

Muscle body is surrounded by

Fascicle

Several bundles within muscle

Perimysium

Covers fasicles

Muscle fibers

Bundles together to form fasicle

Endomysium

Surrounds induvidual muscle fiber

Myofibrils

Bundled together to form muscle fibers

Myofilaments

Bundled together to make up myofibril

Components of myofilaments

actin

myosin

titin (passive)

Sarcomere

Contractile unit of muscle

Z line to z line defines sarcomere

Myosin head pulls actin fibers together

Fast glycolytic fibers

Fast twitch

Type II

Large motor units

High innervation ratio

Easily fatigued

Slow oxidative fibers

Small motor unit

Low innervation ratio

Fatigue resistant

Type I

Muscle morphology

Fusiform

Muscle fibers parrellel to each other and the tendon

Pennate

Muscle fibers attach to tendon at angle

Pennation angle

Angle of orientation between muscle fibers and tendon

affects the force production capabilities as well as the range of motion of a muscle

Pennation angle - 0 degree = 100% force transmission

Pennation angle - 30 degrees = 87% force transmission

Cross-sectional area

Amount of muscle available to generate active force

Titin

A series elastic component protein responsible for allowing the sarcomere to stretch and recoil

Attach myosin to tendon

Titin & Tendon

Series elastic components

Muscle contractions starts with

Myosin pulling actin

Cross bridge

Z-line shortens

Sarcomere shortens

Pulling on titin

Elongation of muscle tendon during contraction

Parellel elastic components

Wraps around muscle fibers

Not stretched in contraction

Does not have active tension during contraction

Series elastic component

Will be stretched during contraction

Titin

Tendons

Contractile (active) components

Actin

Myosin

Non-contractile (passive) components

Series elastic :

Tendon & Titin

Parallel elastic:

Extracellular connective tissue

(epimysium, perimysium, endomysium)

Structural proteins

Internal forces

Active forces

Active movement

External forces

Passive forces

-Stretch of connective tissue

Passive movement

Passive forces

-Pull of gravity

-Push from person

80-120% length of muscle

Optimal range for contraction

100% generates most force

Passive-length tension

as a muscle is progressively stretched, the tissue is slack during the muscle's initial shortened length until it reaches a critical length at which it begins to generate passive tension.

beyond this critical length, the tension builds as an exponential function

Total-length tension curve

Below resting length, active force is the only contributor to tension

After resting length, passive force contributes to tension

Elastic region and plastic region

Stress-strain relationship

Elastic region - physiological range

Tension increases linearly

Yield point separates elastic and plastic regions

Plastic region - Approaches failure point

Greater slope = greater stiffness

Strain %

deformation / original length

To increase range of motion, body part must stretched in...

Pastic region

Agonist

Directly related to the initiation and execution of a particular movement

Antagonist

Have the opposite action of a particular agonist

Synergists

All the muscles involved in the execution of a particular movement

No change in muscle length

No work

Shortening of muscle length

Concentric contraction

Positive work

Agonist is activated

Move in direction of internal force

Lengthening of muscle length

Eccentric contraction

Negative work

Antagonist activated

Move in direction of external force

Concentric elbox extension

Agonist - Elbow extensors

Antagonist - Elbow flexors

Activated muscles - Elbow flexors

Force output by contraction

1) Eccentric

2) Isometric

3) Concentric

Faster eccentric > slower eccentric

Faster concentric < slower concentric

Active insufficiency

A muscle crosses two or more joints is unable to produce effective tension at all joints at the same time

Failure to produce force when slack

active insufficiency examples

Flexor Digitorum Superficialis

•Crossing wrist and joints in the hand anteriorly

•Shortened in wrist flexion

•Shortened in finger flexion

Unable to form a tight fist with wrist fully flexed

active insufficiency examples

Crossing knee and ankle posteriorly

Shortened in knee flexion

Shortened in plantar flexion

Unable to produce sufficient plantar flexion with knee flexed

Also unable to produce sufficient knee flexion with dorsiflexion

passive insufficiency

A muscle crosses two (or more joints) is unable to stretch enough to allow full range of motion at both (or all) joints at the same time

Range of motion is limited by muscle length of a two-joint muscle

passive insufficiency examples

Finger flexors cross wrist and joints in the hand anteriorly

Stretched during wrist extension

Stretched during finger extension

Wrist extension is limited by finger extension

Finger extension is limited by wrist extension

Series elastic fibers

Tight in both concentric and eccentric contractions

Parallel elastic fibers

Only tight in eccentric contractions

Vector

Magnitude

Spatial orientation

Direction

Point of application

Relative reference frame

Specific joint is being considered

XY axis can be tilted

Global reference frame

XY axis not tilted

Free body diagram steps

•Step I: Identify and isolate the free body under consideration

•Step II: Establish a coordinate reference frame

•Step III: Draw the internal (muscular) and external forces that act on the system

•Step IV: Draw the joint reaction force

•Step V: Write the governing equations of motion

Internal forces in free body diagram

Muscle forces within diagram or muscle itself

External forces in free body diagram

Forces acting on the body

Including weight because it is a component of gravity

Dislocating component

Move away from the joint

Stabilizing component

Move into the joint

Joint-stabilizing force

Counteracts the muscle force

Load

Tension- Pul apart

Compression- Push together

Bending- Tension on convex side, compression on concave side

Shear- Displaced in opposite directions on top of each other

Torsion- Twist

Force

A push or a pull

Characterized by magnitude, direction, and point of application

F = ma

Unit is the Newton (N)

Torque

The rotary effect of a force

Torque = Force (N) × Moment arm (m)

T = Fd

Unit: Nm

Moment arm: perpendicular distance from the force's line of action to the axis of rotation

When drawing moment arm

Trying to connect axis and rotation to force line

When force passes over moment arm

No torque is produced

Isometric

No change of muscle length

No work

Internal Torque = External Torque

Concentric

Shortening of muscle length

Positive work

Internal Torque > External Torque

Direction of motion is the same with the direction of internal torque

Agonist is activated

Eccentric

Lengthening of muscle length

Negative work

Internal Torque < External Torque

Direction of motion is opposite to the direction of internal torque

Antagonist is activated

Torque generates angular acceleration (α)

Linear - F=ma

Angular - T=lα

Mass moment of inertia (I)

The inertial property for rotating bodies represents resistance to angular acceleration based on both mass and the distance the mass is distributed from the axis of rotation

I = mk^2

I= moment of inertia

m= mass

k= radius of gyration

Radius of gyration (k)

The distance from the axis of rotation to a point where the total mass of the body is supposed to be concentrated

Law of inertia

A body will maintain a state of rest or constant velocity unless acted on by an external force that changes the state

Static equilibrium - Not moving

dynamic equilibrium -Same direction & velocity

Net force/net torque is zero

Law of acceleration

F = ma