Kinesiology/Biomechanics

Kinesiology

study of human movement, and includes biomechanics, anatomy, and physiology

Kinematics

the study of motion without regards to the forces or torques that they may produce

(What motion happened, not what caused it)

In regards to kinematics, what are the two types of motion?

1) Rotation/Angular 2) Translation/Translitoric

Rotation/Angular Movements

points of a body move in a circular fashion around an axis; all points movie in the same direction, at the same speed, and across the same # of degrees

Osteokinematics

study of angular movements

Translation/Translatoric Movements

linear motion in which all points in an object move parallel, in the same direction and at the same speed as every other point of the same object

Arthrokinematics

looking at what is happening right at the joints surface/ study of translatoric movements.

When raising a glass to your mouth, consider if the elbow joint is translatoric or angular?

Angular/Rotational

When considering a point on the top of one's head while walking forward, is this movement translatoric or angular?

translatoric (straight line)

When considering the hip joint when kicking a soccer ball, is this movement an angular or translatoric movement?

Angular/rotational

Anatomical Position

reference point to describe movement or location of structures

fundamental position

same as anatomical position except arms are at the sides and palms face the sides of the body

Osteokinematics and the motion of bones can occur in 3 cardinal plane:

Sagittal, frontal, and transverse

Sagittal plane

Divides the body into right and left

Sagittal plane axis of rotation

Medial/Lateral FRONTAL PLANE AXIS

Examples of Sagittal plane motion

Flexion/Extension

frontal plane (coronal plane)

Divides the body into front and back portions (anterior and posterior)

Frontal plane axis of rotation

Anterior/Posterior SAGITTAL PLANE

Examples of frontal plane motion

Abduction/Adduction

transverse plane (horizontal plane)

divides the body into upper and lower sections

Examples of transverse motions

External/Inernal rotation

Degrees of freedom

Number of permitted planes of angular motion at a joint

How many degrees of freedom are possible?

3, the 3 planes

DOF in the Shoulder

3 motions
Flexion/extension
Abduction/Adduction
IR/ER

DOF in the Elbow (HU)

1; flexion and extension

DOF of wrist

2; flexion/extension, radial/ulnar deviation

Normal muscle action

distal segment (further from the center of the body) moves on a relatively fixed proximal segment

Example: tibia on femur flexion (knee flexion)

reverse muscle action

proximal segment moves on a relatively fixed distal segment

EX: femur on tibia flexion (squat)

Are we moving proximal on distal or distal on proximal when kicking (hip)?

Normal- distal partner is moving (the foot) not the hip

Are we moving proximal on distal or distal on proximal when stepping up on a curb?

Reverse, the tibia is stable, but the femur is moving. The feet are planted, but the femur is moving.

Are we moving proximal on distal or distal on proximal when throwing (shoulder)?

Normal- the hand is the distal part of the body and it is moving, the shoulder is proximal and is closer to the body.

Are we moving proximal on distal or distal on proximal when doing a push up (elbow)?

Reverse- the elbow is closer to the body and the hands are distal and are fixed.

Normal and Reverse actions of the hip flexors

N: Marching R: Squat/Bowing

Normal and reverse actions of the elbow flexors

N: Bicep curl R: Chin up

Normal and reverse actions of knee extensors

N: Kicking a ball/LAQ R: Climbing stars, stepping up on a curb

kinematic chain

System of joints and body segments arranged so that motion of one joint will produce motion at other joints in the system in a predictable manner. Most accurate when distal and proximal ends are fixed.

closed chain

when the distal segment of a kinematic chain is fixed, the distal segment (further part) is not moving

open chain

When the distal segment of a kinematic chain is not fixed (moving) the moving part of the body is furthest away from the center of the body

Closed-Chain Examples

mini squats, sit to stand, push up, pull up,

Open-Chain Examples

3 way hip, star taps, reverse lunge, lat pull downs, bench press

What can limit angular motion?

-Shape of joint surface, Joint capsule, ligaments, muscle bulk (soft tissue approximation), musculo-tendinous structures, bony structures, pain

End feel

feeling imparted into the examiners hand at the end of a passiv emotion

Hard- Normal end feels

bone impacting against bone (elbow extension)

Soft- Normal End feels

Soft tissue approximation (elbow flexion muscular coming into contact with another)

Firm- Normal End feels

feeling a firm but lightly yielding stop, from the stretch of capsules, ligaments, and other connective tissues.

Capsular (Firm) Normal End Feels

slack in the joint capsule is taken up (all motions of the shoulder)

Elastic (Firm) Normal end feels

musculotendinous slack is taken up and a rebound is felt (EX knee extension)

What type of Normal End feels are normal for alot of joints?

Firm Normal End Feels

Empty Abnormal End-Feels

feeling that there is nothing mechanically stopping motion except for subject's complaint of pain

Abnormal End Feel may include:

Wrong time or quality. EX every shoulder should be firm, but it might appear hard/soft

closed packed position

joint surfaces are maximally congruent, and ligaments and capsules are maximally taut/stretched

Characteristics of CPP

greatest stability, resistant to forces that cause distraction of joint surfaces, accessory motions are limited

loose (open) packed position

joint surfaces have the most freedom of movement, the ligaments and capsule are slackened, the resting position of the joint, increased translatoric movements (sliding/gliding) and less compressive forces within the joint.

Arthrokinematics- Right at the joint

Accessory motions: motions that occur between the articular surfaces

These are involuntary (volitional)

Can occur due to a muscle contraction or because of the natural laxity of the joint structures

Can be restored manually with mobilizations

Accessory motions include, roll, glide, spin

roll

occurs when new equidistant points on one joint surface come into contact with new equidistant point on another surface

analogy- a tire rotating across a stretch of pavement

glide

occurs when the same point on one surface comes into contact with new points on another surface

Spinning

a single point on one surface rotates on a single point on the other surface

Concave Rule

When a concave surface moves on a fixed convex surface, the concave surface rolls and glides in the same direction

Concave = Same

Convex Rule

When a convex surface moves on a fixed concave surface, the convex surface rolls and glides in the opposite directions

Convex= Opposite

Osteokinematic is...

where the roll is going (direction)

Arthrokinematics is...

Where the glide/slide is (that direction)

distraction

separation of the joint surfaces (EX traction) S

Approximation

joint surfaces get closer to each other (Closer/Compression) EX Bearing weight

Kinetics

What is creating this movement?

The study of motion under the action of forces

Forces can be internal or external

Internal (Muscle contraction)
External (Applied force)

What is able to tolerate significant forces and resist changes in shape

Heathy tissues

What are the types of forces on musculoskeletal tissues?

Tension (pulling)
Compression
Bending
Shear
Torsion
Combined loading

What does the stress strain curve tell us?

About the ability of the connective tissues to tolerate load

Deformation can occur in between zones...

C and D

Zone A

slightly stretched and minimal amount of tension

Zone B

Elastic zone, linear relationship between stress and strain (rebound, but no deformation of collagen fibers)

Zone C

plastic zone, minimal increase in tension as it continues to elongate. Microscopic failure and permanent deformation (IDEAL ZONE FOR TREATMENT)

Zone D

initial point of failure

Zone E

Complete failure

Viscoelastic

tissues in which the stress-strain curve is affected by time

Creep Viscoelastic Property

progressive strain when exposed to a constant load over time, creep increases with increasing temp. EX hamstring stretch, easier the longer you hold it and reason why patients are warmed up

Stress Relaxation (Viscoelastic property)

Describes the decrease in stress over time that occurs when a body is suddenly strained, and the strain is maintained at a constant magnitude afterward.

Stress-Strain Curve

sensitive to the rate of loading of the tissue, slope increases when rate of loading increases

concentric contraction

Normal action, and muscle produces a force as it shortens

concentric

muscle attachments move closer together; muscle is shortening

Movement is usually occurring against gravity, lifting or raising an object up
Acceleration activity

Isometric contraction

muscle produces a force while maintaining a constant length (No movement but contraction is occurring)

Eccentric Contraction

muscle produces a force while being elongated REVERSE ACTION

Eccentric (SLOW AND CONTROLLED)

muscle attachments move farther apart; muscle is lengthening

movement usually occurs with gravity, lowering down activity

Deceleration activity

Agonist

muscle mostly responsible for creating a motion

Antagonist

muscle that is usually doing the opposite action of the agonist

Co-contraction

simultaneous contraction by an agonist and antagonist

usually isometric contraction*

Synergists muscles

pair of muscle that work together to produce a motion

Force Couple

When 2 or more muscles work together to produce forces in different linear directions yet the torques act in the same rotary motion

EX Pelvic tilting Anterior vs posterior

Active Tension

From an active muscle contraction

Active tension increase by:

1) increasing the number of motor units recruited
2) Recruiting motor units with a larger number of muscle fibers
3) Increasing cross bridge formation
4) Recruiting muscle with larger cross sectional area

Passive Tension

Resistance developed by the connective tissues within a muscle when that muscle is being lengthened

none volitational (not intentional) Happens as somethin else is stretched/moved

Length tension relationship

there is an optimal length of a muscle where maximal tension can be developed

At a mid range, there are maximal cross bridges formed and maximal tension can be achieved

Tension decreases if...

muscle is fully shortened or lengthened

tenodesis

tendon action of a muscle, occurs in multi-joint muscles EX finger extensors and flexors

Muscles must cross 2 or more joints

Involves the elastic or non-contractile tissues

Occurs in the antagonist to the motion

active insufficiency

diminished ability of muscle to produce or maintain tension, occurs in the agonist to the motion, and occurs when the muscle has been excessively shortened or elongated to point of no crossbridge formation (CAN'T PRODUCE ANY MORE)

Can occur in 1 joint muscles, more significant in the multi-joint muscles

Involves contractile elements

All of the force that can be created is created-MAX

What factors affect muscle function?

Passive insufficiency of antagonist muscles (force has to be coming from somewhere outside the muscle)

Active Insufficiency of agonist muscles

Mechanical Advantage

Mechanical Advantage

Ratio of internal moment arm to the external moment arm

Good Mechanical Advantage

Ratio >1 equals to good mechanical advantage- Larger internal moment arm

Bad Mechanical Advantage

Ratio < 1 means poor mechanical advantage (Larger external moment arm)

Joint Classification

Based on the anatomy of the joint and its movement potential

3 types: Synarthrosis, Amphiarthrosis, and Diarthrosis