EDKP261 - Motor Development

relatively permanent gains in motor skill capability associated with practice or experience

the neural, physical and behavioral aspects of movement

quantitive increase in size or body mass

qualitative advance in biological makeup; cell, organ or system advancement in biochemical composition

process occurring with passage of time leading to loss of adaptability or full function and eventually to death.

- An individual or group is observed over time.
- It can require lengthy observation.

- Individuals or groups of different ages are observed.
- Change is inferred not actually observed

Mini-longitudinal studies with overlapping ages

Individuals in a species show great similarity in development

Individual differences exist

a group whose members share a common characteristic such as age or experience

- structural: related to body structure. ex: height, weight
- functional: related to behavioral function. ex: motivation, focus

related to the properties of the world around us(outside the body)
- physical: gravity, surfaces
- sociocultural: gender roles, cultural norms

related specifically to tasks or skills
Includes:
- goal of the task
- rule structure of the activity/movement
- equipment

- Individual (structural, functional)
- Environmental (physical, sociocultural)
- Task

- Maturational Perspective
- Cognitive/Information processing Perspective
- Ecological Perspective

- reflexive
- spontaneous

def: movements not caused by known external stimuli
- original theory: extraneous, no purpose
- current theory: building blocks, similar to voluntary movements

def: stereotypical responses elicited by specific external stimuli.

- persistence may indicate neurological problems

-> facilitate survival
-> allow "dialogue" with environment (functional purpose)
-> result in sensory consequences (adaptation)
-> provide building blocks for future movement

*structural explanation: left-overs from our evolutionary history

MOTOR INTERFERENCE

1. Zelazo challenged this by 'training' the walking reflec
2. Thelen questioned this experimentally
- placed small weights on infants
- placed older infants in water

MOTOR CONTINUITY

- as the brain matured it inhibited the reflex
- big gain in adipose tissue = leg too heavy & musculature not strong enough to support

- primitive
- postural
- locomotor

in the repertoire at birth or prenatal. Terminates generally at about 1-5 months

generally first evident at 3 months and generally terminate at 12 months

birth to 4-5 months

infant starts in supine position
- stimulus: turn head to one side
- response: same-side arm and leg extend

infant starts in supported position
- stimulus: extend head or neck or flex head and neck
- response: arms extend and legs flex or arms flex and legs extend

- stimulus: touch palm with finger
- response: hand closes tightly around object

- stimulus: stroke ball of foot
- response: toes contract tightly around object

infant starts in supine position
- stimulus: shake head (lightly)
- arms, legs and fingers extend then arms and legs flex

stimulus: stroke sole of foot from heel to toe
response: toes extend

stimulus: touch face above or below lips
response: sucking motion begins

stimulus: touch face above or below the lips
response: head turns to side stimulated

help to maintain posture in changing environment
initially are similar to reflexes but are later incorporated into the general repertoire

infant is supported upright
stimulus: tilt infant
response: head moves to stay upright

turn head on one side or legs or pelvis to one side = body follows in rotation

stimulus: lower infant to ground rapidly
response: legs and arms extend forward

- crawling reflex
- stepping reflex
- swimming reflex

Fundamental motor skills
- building blocks (lead to complex motor skills)
- cumulative, sequential

Specific movements that lead to general actions

- Individual constraints that inhibit or slow the attainment of a motor skill
- rapidly changing during early childhood period

moving on hands and abdomen

moving on hands and knees

walking is the first form of upright, bipedal locomotion

50% phasing of the legs
period of double support (bother fee on the ground) followed by period of single support

Early walking patterns tend to maximize stability and balance.
Arms are in high guard.
Flat feet are out-toed and spread wide apart.
Independent steps are taken.
Minimal trunk rotation or ankle extension.
C of G undulates quite signficantly
Rate controllers are strength (to support body on one leg) and balance.

- Visual perception of self-motion and optic flow are not the rate limiters.
- Rate limiters for posture and balance appear to involve coupling of sensory information and motor response

- Infants continuously recalibrate sensory motor response as environments and their bodies change

Stride length increases.
Base of support is reduced.
Pelvis is rotated.
Opposition (arms to legs) occurs.

occurs 6 to 7 months after walking starts

50% phasing legs
flight phase followed by single support

Stability over mobility: return of “old behaviors”

Arms in high guard, limited range of motion, short stride length, little rotation

Leg Action
1. Minimal flight
2. Cross over swing
3. Direct projection
Arm Action
1. High or middle guard
2. Bilateral swing
3. Opposition, oblique
4. Opposition, sagittal

Increased stride length
Planar movement
Narrow base of support
Trunk rotation
Opposition

Leg action component
Step 1: One foot takeoff
Step 2: Knee extension first
Step 3: Simultaneous extension
Step 4: Heels up first
Arm action component
Step 1: No action, may ‘wing’ after takeoff
Step 2: Arms swing forward, may abduct
Step 3: Arms extend, then partially flex
Step 4: Arms extend, then fully flex

Children often begin simple jumping before age 2.
Individuals can perform either vertical or horizontal (standing long) jump.
Early characteristics of jumping include
Only jumping vertically
one-foot takeoff or landing
no or limited preparatory movements

Preparatory crouch maximizes takeoff force.
Both feet leave ground at same time.
Arm swing utilized during jump.
For vertical jump, force is directed downward; body is extended.
For horizontal jump, force is directed down and backward; knees are flexed during flight.

Hopping starts later than jumping.

Early characteristics include the following.
Support leg is lifted rather than used to project body.
Arms are inactive.
Swing leg is held rigidly in front of body.

Swing leg leads hip and moves through full range of motion.
Support leg extends fully at hip.
Oppositional arm movement generates force.
Support leg is flexed on landing.