Kinesiology Quiz #1

Arthrokinematics motions

Arthrokinematics motions are movements between the joint surfaces.

• Roll - occurs when one surface rolls over another, like a tire rolling on the ground (ex: shoulder or hip - ball & socket joint)

• Spin - when one surface rotates on a fixed axis, like a doorknob turning (ex: radial spinning - pronation/supination)

• Glide (or translation) - when one surface slides over another, like a drawer sliding open (carpals of wrist (deviation, or waving motion, tarsals of foot)

Osteokinematic motions

• Osteokinematic motions are movements of limbs through space about a joint.

• Describes clear movements of bones which are visible from the outside.

• Movement occurs around a joint axis

• Gross movement

  • flexion/extension

  • abduction/adduction

  • medial rotation/lateral rotation

Concave-Convex Rule

• Convex moving on concave (glide) - movement occurs in opposite direction

• Concave moving on convex (rolls/slides) - movements occurs in the same direction

Kinetic Chain

• It is the series of connected rigid links

  • refers to interrelated parts of the body (i.e., joints and muscles) and how they work together to perform movement.

• limb segments

• influence the type of movements

• closed kinetic chain: distal segment is fixed, proximal segment free to move

• open kinetic chain: distal segment free to move, proximal segment fixed

Planes of Movement

• Sagittal plane passes through body

  • divides body into right and left

• Frontal plane passes through body

  • divides body into anterior and posterior

• Transverse plane passes through body

  • divides body into superior and inferior

Axes of Movement

• Sagittal axis passes through joint

  • anterior to posterior

• Frontal axis passes through joint

  • side to side

• Vertical axis passes through joint

  • superior to inferior

Pack Positions - Closed Pack Position

• Congruent

• Ligaments & capsule under max tension

• Joint surface tightly packed

• Cannot be pulled apart with traction

  • Most stable position

Pack Positions - Loose Packed Position

• Resting position

• Ligaments and capsule relaxed

• Max space within joint

• Can be pulled apart by traction

Newton’s First Law of Motion

First Law of Motion:

• an object at rest will remain at rest unless acted on by an external force

• tendency to resist changes in a state of motion is inertia

Newton’s Second Law of Motion

Second Law of Motion:

• The acceleration of an object depends on the mass of the object and the amount of force applied

• Bigger mass = more force required

Newton’s Third Law of Motion

Third Law of Motion:

• For every action force, there is a reaction force equal in strength and opposite in direction

• Law of action-reaction

  • for every action there is an equal and opposite reaction

Biomechanics

• The application of mechanics to the study of human movement.

• Mechanics is the study of forces exerted on an object.

  • Kinetics: force

  • Kinematics: Time, space, mass

Force

• Amount of push or pull applied to objects or body segments

  • push creates compression → ←

  • pull creates traction ← →

• Internal forces: muscle contraction, ligamentous restraint

• External forces: gravity, any externally applied resistance

Gravity

• Mutual attraction between the earth and an object

  • Ground reaction: upward force a supporting surface exerts when an object pushes downward on the support surface

  • ex: stepping on a tissue box vs. a brick

Friction

• Force between two surfaces that increased resistance to motion of one surface across another

  • increased by compression

  • decreased by traction

Force

Linear forces: two or more forces acting along the same line; ex - tug of war

Parallel forces: occur in the same plane and in the same or opposite direct; ex - brace

Force couple: two or more forces act in different directions; produces clockwise or counterclockwise rotation; ex - merry-go-round

Concurrent forces: two or more forces acting on an object; push or pull in different directions

• ex - anterior and posterior deltoid applying force, creating concurrent force in the middle deltoid

Optimal Length

• sarcomeres length that produces greatest amount of force

  • ex: bicep completely flexed = muscle is short (actin filaments smashed up on M line)

  • bicep/arm extended = fully lengthened muscle (actin far away from M line, not a lot of force generating)

• Optimal length = in between fully shortened & fully lengthened; in the middle

  • ex: bicep curl - middle is optimal length

Optimal Muscle Length Tension

• In order to allow for one part of the muscle to have enough ability to generate the force the other one has to slack off

  • If both muscles are in optimal tension = no function

• Ex: Hamstrings (cross hip & knee joint) - hip extension & knee flexion

  • In order to allow the hip to work through the two positions, one must shorten, one must lengthen

  • one portion has to tighten, other relaxes

Active Insufficiency

• Muscle is contracted/shortened

  • actin will slide into m-line and will not be able to move further due to shortened muscle

• no further room for muscle to shorten; lacking further actin motion because the muscle is as short as it gets

• slack one of the joints in order to get optimal length (extend knee)

• In order to see true hip extension, slack distal end of hamstring via knee extension

Passive Insufficiency

• Both ends of muscle is lengthened

• Add force = risk of tearing

  • rip actin off myosin heads

  • no sarcomere

  • muscle tear

Avoid active & passive insufficiencies

• Compound exercises

  • more muscles involved

  • acting in optimal length

  • avoid injury

    • squats, deadlifts, push ups

    • squats - involve glutes, quads, hamstrings, gastroc, trunk

Range of Motion

Active (AROM): what individual is able to do

Active assistive (AAROM): muscle doing part of work w/ provided assistance

Passive (PROM): no muscle activating, external force to move joint)

Self - passively ranging themselves

Functional - what joint needs to do for that task, for that person; ROM required for task

Limitations for ROM:

• muscle weakness

• changes in muscle movement

• orthopedic issues

• circulation issues

• pain swelling

• structural impairment (ex: scar)

• ligament or tendon injury

ROM Contraindications

• joint dislocation

• unhealed fracture

• soft tissue damage around a joint (tear)

• heterotopic ossification (HO) [bone grows in tissues where it typically wouldn't]

MMT Grades

• 5 (Normal): Complete ROM against gravity with full resistance

• 4 (Good): Complete ROM against gravity with some resistance

• 3 (Fair): Complete ROM against gravity

• 2 (Poor): Complete ROM with gravity eliminated

• 1 (Trace): Evidence of slight contractility; no joint motion

• 0 (Zero): No evidence of contractility

How gravity impacts MMT

• Gravity impacts MMT by showing how hard a muscle has to work during this test. When testing a muscle with gravity, it makes it easier for the muscle to move. In order to test the strength of the muscle, the movement should be done against gravity to show how strong the muscle actually is.

  • If the muscle cannot overcome the force of gravity (cannot go against gravity, muscle not strong enough), the muscle should be tested with gravity eliminated.

• Depending on the test location, gravity can either support or hinder muscular movements during MMT. While gravity resistance might make muscles appear weaker, gravity-assisted test positions can make muscles appear stronger. In order to lessen this impact and provide a more accurate measurement of the muscle’s actual strength, therapist may move the body in postures that diminish or completely eliminate the effect of gravity.

Gravity impact on MMT

Gravity affects muscle manual testing(MMT) by adding natural resistance. Testing against gravity shows stronger muscles while testing in gravity-eliminated positions helps assess weaker muscles.

Types of joints

• non-axial joint: slight gliding motion

  • intercarpal & intertarsal joints

• uniaxial joint: motion in one place about one axis (one degree of freedom)

  • pivot joint - allows rotation on a single axis

    • radioulnar joint - allows rotation of forearm

  • hinge joint - elbow, knee, ankle

  • flexion & extension

• biaxial joint: two planes of motion about two axes (two degrees of freedom)

  • MCP flexion/extension & abduction/adduction

• triaxial joint: three planes of motion about three axes (three degrees of freedom)

  • ball & socket joint - hip & shoulder joints

Types of end feel (osteokinematics)

• sensation perceived when passively moving a patient’s joint to the end of its ROM

  • use to determine reason for the limitation of further motion at the joint

• normal end feel: what is expected at end of normal ROM

• abnormal end feel: when end of ROM is not normal

  • pain, swelling, muscle guarding, changes in anatomy