KNS 460 Exam 1

Motor Development

Continuous, age-related process of change in movement as well as the interacting constraints (or factors) in the individual, environment, and task that drive these changes

Characteristics of Motor Development

Change in movement behavior (Continuous, Age related, Sequential), Depends on underlying processes

4 domains of human development

Affective, Motor, Cognitive, Physical

Motor Development Related areas of study

• Motor Learning

  • Relatively permanent gains in motor skill capability associated with practice or experience

• Motor Control

  • The neural, physical, and behavioral aspects of movement

Terms related to motor development

Physical growth, physical maturation, aging

Newells model of constraints

Constraints discourage or limit certain movements and encourage or permit others movements, shape movements (individual, environmental, task)

Individual Constraints

Unique physical or mental characteristics

• Structural: related to the bodys structure

  • Height

  • muscle mass

• Functional: Relates to behavioral function

  • Attention

  • Motivation

Environmental Constraints

Properties of the environment

External

• Physical

  • Gravity

  • Surfaces

• Sociocultural

  • Gender roles

  • Culture norms

Task Constraints

• Specific task requirements or goals

  • External

  • NOT related to individual

  • Goal of task

  • Rules guiding task performance

  • Equipment

Constraints and Atypical Development

Disabilities: differences in structural or functional individual constraints may result in delayed, different motor development (In the extreme may arrest development and no further change is observed)

Developmental Trajectories

• We can plot the change in behavior over time or age

• Time or age on the horizontal axis

• Behavior on the vertical axis, with “more advanced” at the top

• An early constraint or influence can change the developmental trajectory for the remainder of development

Research Designs in Motor Development

longitudinal, cross-section, sequential, meta analysis, review paper

Paradox in development

universality vs. variability - Individuals in a species show great similarity in development but Individual differences exist

Theories of motor development

maturational, information processing, ecological (dynamic systems and perception action)

Maturational Perspective

• Motor development driven by maturation of systems specifically, the central nervous system

• Heredity and genes will determine development

• Minimal influence of environment

• Qualitative and Discontinuous

• Has an end

Long lasting beliefs of maturational perspective

• Basic motor skills emerge automatically.

• There is no need for special training.

• Mild deprivation does not arrest development.

• The nervous system is most important

Information Processing Perspective

• Motor development is driven by external processes (nurture).

• The brain acts like a computer.

  • The passive human responds to stimuli in the environment

  • Important concepts: input, encoding, processing, feedback.

Ecological Perspective

• Development is driven by the interrelationship of individual, environment, and task (importance of multiple systems).

• The neural system is one of many responsible for action.

• Two Branches: dynamic systems and perception action

Dynamic Systems

Movement develops through self-organization - not from a pre-programmed CNS blueprint. Body systems + environment + task demands interact to produce new movement skills

Principles of Dynamic Sysems Theory

• Nonlinear & discontinuous: development is continuous but occurs at uneven rates with qualitative changes.

• No fixed direction/blueprint: there is no single “best” or predetermined movement pattern.

• Multiple systems contribute: different body systems develop/change at different rates.

• Rate limiters: the slowest/developing or declining system can limit the rate of movement change across the lifespan.

• Goal = finding an optimal movement solution for a specific task/environment.

Perception Action

Perception and action are reciprocal - we act based on what we perceive, but our actions also create new perceptions, strengthening the connection between the two.

Affordance

The function or action an object/environment offers an individual, based on the person's body dimensions and abilities (Example: A chair affords sitting, but whether it affords sitting comfortably depends on the person's body size)

How are developmental changes predictable?

• based on optimizing biomechanical principles of motion and stability over time.

• can be seen across a variety of motor skills.

• often produce more force, velocity, or accuracy.

What are the 2 principles within biomechanics (physics of movement)

Motion and Stability

Newtons First Law

• An object at rest stays at rest and an object in motion stays in motion until acted upon by a force.

• Inertia is resistance to motion related to mass.

• Momentum is the product of mass and velocity.

• When a force is exerted on an object the object will accelerate in the direction of the force.

Newtons 2nd Law

• Object’s force is related to mass and acceleration

  • F = m x a

• Object’s acceleration is related to force applied and inversely related to mass

  • a = F / m

People can throw only as hard as they can throw - Given this peak force level, how could you increase acceleration?

• Increase force delivered to object

• Increase distance over which force is applied

Netwons 3rd Law

To every action, there is an equal and opposite reaction

How to utilize newtons 3rd law

• Increase rotational velocity (swing faster)

• Increase relative length (fully extend it at release)

Stability

• Ability to resist movement

• To increase:

  • Increase base of support

  • Lower center of gravity

  
  

Balance

• Ability to maintain equilibrium

• To increase:

  • Increase stability

  • Improve Strength, coordination, and proprioception

Stability-Mobility Trade off

• New movers adopt strategies that maximize stability and balance but hinder quick movement

• With development and improvement in ability to maintain upright posture during movement, movers shift to mobility strategies so they can move faster.

Spontaneous Movements in early motor development

Movements not caused by known external stimuli

• Original theory: extraneous, no purpose

• Current theory: building blocks, similar to some voluntary movements

• Examples:

  • Spontaneous arm movements (resemble reaching)

  • Spontaneous kicking (resembles adult walking)

Reflexive Movements in early motor development

• Stereotypical responses elicited by specific external stimuli

• Involve a single muscle or a specific group of muscles (not whole body)

• Cannot be extinguished at any one time

• Purposes:

  • Built-in responses facilitate survival

  • Allow “dialogue” with environment

  • Result in sensory consequences (adaptation)

  • Provide building blocks for future movement

Primitive Reflexes

Critical for protection, nutrition, and survival, appear during gestation or at birth and are suppressed by ~ 4 months of age

Which reflexes are primitive

ATNR, STNR, Palmar Grasp, Rooting, Babinski

ATNR (Birth - 4 months)

• Stimulus: Infant starts in supine position and head is turned to one side

• Response: Limbs on the face side will extend, while limbs on opposite side will flex

STNR ( 6-7 months)

• Stimulus: While baby is in a supported sitting position and tipping the baby backwards or forwards

• Response: If tipped backwards, the baby’s neck will extend, the arms will extend and legs will flex. If tipped forwards, the neck will flex, the arms will flex and the legs will extend.

Palmar Grasp (Prenatal - 4 months)

• Stimulus: Touching palm of hand

• Response: Fingers curl to close around object

Rooting (search)

• Stimulation: softly stroking the area around the mouth

• Response: head will turn in direction of stimulus

Babinski (birth - 4 months)

• Stimulus: stroke the bottom, lateral portion of the foot and across the bottom of the toes

• Response: Toes will fan out

Postural Reflexes

Begin around 4 months, basic forms of more complex, voluntary movement later in life

Which reflexes are postural

parachute, labrynthe righting

Parachute

• Stimulus: infant is tipped in any direction

  • Exists past first year of life

• Forward

  • Response: Arms extend forward

• Downward

  • Response: legs extend and spread and feet rotate slightly outward

• Sideways

  • Arms and fingers will extend toward the side of the fall

• Backwards

  • Arms extend

Labyrinthine Righting

Infant is supported upright.

• Stimulus: Tilt infant.

• Response: Head moves to stay upright.

Locomotor Reflexes

Stepping

• Stimulation: Bottom of feet on hard surface

• Response: legs will lift and then descend (often occurs alternating legs)

Motor Milestones

• Infants acquire rudimentary skills in a relatively consistent sequence

• Patterns predictable by changes in individual constraints

  • Maturation of the CNS

  • Development of muscular strength and endurance

  • Development of posture and balance

  • Improvement of sensory processing

What are the selected milestones?

• 2 - lifts head in prone position

• 3 - lifts shoulders (turns head)

• 5 - rolls over, sits unsupported

• 7 - gets on hands and knees

• 8 - creeps on hands and knees

• 9 - pulls to stand; cruises furniture

• 10 - stands alone

• 12 - walks alone

Rate limiters

Individual constraints that inhibit or slow attainment of a motor skill (the limit preventing the skill from fully emerging), rapidly change during early childhood

Limiters for posture and balance contain a combination of

sensory information and motor responses

Locomotion

Moving from place to place on one, two, or four limbs

Kinds of Locomotion

Pre-walking, walking, running, jumping, hopping, leaping, Galloping, Sliding, and Skipping

Pre-Walking

• Crawling

  • Moving on hands and abdomen

• Creeping

  • Moving on hands and knees

• Locomoting with hands held

Walking

• First form of upright, bipedal locomotion.

• 50% phasing between the legs

• Affordances learned for crawling must be learned for walking

Gait cycle of walking

• Period of double support (both feet on the ground)

• Swing phase

• Period of single support

Early Walking Patterns

• Stability and balance are maximized over mobility.

• Arms are in high guard.

• Feet are out-toed and spread wide apart.

• Independent steps are taken.

• Rate controllers are strength (to support body on one leg) and balance

Proficient Walking Patterns

• Stability is traded for mobility.

• Stride length increases.

• Base of support is reduced.

• Pelvis is rotated.

• Opposition (arms to legs) occurs.

• Double knee-lock is adopted.

• Foot angle

Changes in older adulthood for walking

• Stability is maximized.

• Out-toeing increases.

• Stride length decreases.

• Pelvic rotation decreases.

• Speed decreases.

• Objects are used as balance aids

• Rate Controllers

  • Any of the changes associated with the aging process can act as rate controllers.

  • Decrease in muscle mass

  • Osteoporosis

  • Decrease stability, balance

  • Fear of falling

Running

• Occurs 6 to 7 months after walking starts.

• Major constraint change →

  • Task (speed)

• 50% phasing between the legs

• Flight phase → single support → recovery phase

• no double support phase like walking

Stages of Running Development

• Stage 1: Stability-focused → high arms, short strides, little rotation/knee flexion.

• Stage 2: Increasing mobility → lower arms, longer strides, more knee flexion, legs move more forward/backward.

• Stage 3: More coordinated movement → arms begin assisting rather than just balancing, heel-to-toe contact, longer strides, greater knee flexion.

• Stage 4: Mature running pattern → opposite arm/leg action, heel-to-toe contact, greater knee flexion and efficient recovery.

Proficient Run

• Less stability, more mobility

• Increased stride length

• Planar movement

• Narrow base of support

• Trunk rotation

• Opposition

Developmental Changes in running

• Patterns help increase stability and balance.

• Decreases appear in the following:

  • Stride length and number of strides

  • Range of motion

  • Speed

• Rate controllers are balance and strength.

• Exercise can allow seniors to run for years

Jump

Person propels self off ground with one or two feet; lands on two feet

Early Jumping

• Jumping only vertically

• One-foot takeoff or landing

• No or limited preparatory movements

Phases of Jumping

• Preparatory phase

• Takeoff phase

• Flight phase

• Landing phase

Proficient Jumper

• Preparatory crouch maximizes takeoff force.

• Both feet leave ground at the same time.

• Arm swing used 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

Rate Limiters of jumping

Development of enough force to bring own body into the air from a still position

Hop

Person propels self off ground with one foot; lands on same foot, starts later than jumping

Early Hop

• Support leg is lifted rather than used to project body.

• Arms are inactive.

• Swing leg is held rigidly in front of body.

• Girls > Boys

Proficient Hop

• 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

Rate limiters of Hopping

• Depend on the postural system’s ability to balance the body on one limb for a succession of hops

• Ability to generate enough force to lift the body with one limb, recover, and quickly generate enough force to hop again

Leap

Person propels self off ground with one foot, extends flight period, and lands on opposite foot

Galloping, Sliding, and Skipping

Involve a combination of skills previously obtained: stepping, hopping, leaping

Galloping and Sliding are _____ while skipping is ____

assymetric, symetric

What order do Galloping, Sliding, and Skipping emerge

Galloping then Sliding then Skipping

Early Galloping, Sliding, and Skipping

• Arrhythmic and stiff movements

• Little or no arm movement

• Little or no trunk rotation

• Exaggeration of vertical lift

• Short stride or step length

Proficient Galloping, Sliding, and Skipping

• Arms are no longer needed for balance.

• In skipping, the arms swing rhythmically in opposition to the legs and provide momentum.

• Child can use the arms for another purpose during galloping and sliding, such as clapping.

Rate limiters of Galloping, Sliding, and Skipping

• Galloping:

  • Coordination (uncoupling legs)

  • Differential force production (legs performing different tasks)

• Sliding: 

  • coordination (turning to one side)

• Skipping: 

  • Force & balance isn’t an issue

  • coordination (ability to perform two tasks with one leg)

Ballistic Skills

Performer applies force to an object to project it.

Throwing Assessment

• Product measures (outcome): accuracy, distance, ball velocity

• Process measures (movement pattern): developmental sequences

Forms of Throwing

underhand, sidearm, overarm

Phases of overarm throw

• Preparatory

• Execution

• Follow Through

Influencing factors of throwing

• Instruction

• Knowledge

• Cues

• Ball Size – Body scaling

• Gender Differences

• Sociocultural differences

Early Throwing

• Mostly arm action

• Elbow Pointed up

• Executed by elbow extension alone

Proficient Throwing

• Thrower uses preparatory windup (weight shifts and trunk rotates back; arm swings).

• Thrower uses opposite leg, long step, and differentiated trunk rotation.

• Upper arm and forearm lag.

• Movements are sequential to transfer momentum.

Developmental changes of throwing

• Trunk: None → block rotation → differentiated rotation

• Backswing: None → shoulder flexion → upward → downward/circular

• Upper arm: Oblique → aligned → lags behind

• Forearm: No lag → lag → delayed lag

• Foot: No step → same-side step → short opposite-side step → long opposite-side step

(Trunk rotates more → backswing becomes larger → arm/forearm lag increases → stepping progresses to a long contralateral step)

Throwing changes in adulthood

• Older adults demonstrate moderately advanced steps.

• Differences are observed between the sexes.

• Ball velocities are moderate.

• Musculoskeletal constraints might influence movement patterns used.

• Change is slow, involves decline (and more variability) in performance, and is typically related to control rather than coordination.

____ are used out of ____ combinations of Trunk, Humerus, and Forearm

14/27

Kicking

• Kicker strikes ball with foot.

• Kicker must have perceptual abilities and eye–foot coordination to make contact

Early Kicking

• No step is taken with nonkicking leg.

• Kicking leg pushes forward.

• No trunk rotation

• Retract leg immediately after contact

• Arms stationary at side

Proficient Kicking

• Preparatory windup is used (trunk rotated back, kicking leg cocked, knee bent).

• Trunk rotates forward.

• Movement is sequential: thigh rotates forward, then lower leg extends.

• Arms move in opposition to legs.

Punting

ball is dropped from the hands, more difficult than kicking for children.

Early Punting

• Ball is tossed up rather than dropped.

• Punter often contacts ball with toes rather than instep

Proficient Punting

• Arms are extended to drop ball before final stride.

• Arms then drop to sides and move into opposition to legs.

• Punter leaps onto supporting leg and swings punting leg vigorously up to make contact.

• Punting leg is kept straight; toes are pointed

Sidearm Striking

• Various body parts can be used.

  • Hands or feet

• Implements can be used.

  • Rackets

  • Golf clubs

  • Bats

• Mechanical principles are similar for all striking tasks.

• Perceptual judgement is critical

Early Sidearm Striking

• Look like unskilled overhand throwing

• Chopping motion (elbow extension)

• Little leg and trunk movement

• Child faces oncoming ball

Proficient Sidearm Striking

• Sideways preparatory stance and long step

• Differentiated trunk rotation

• Horizontal swing through large range of motion (arm extended before contact)

• Sequential movements

Developmental changes in sidearm striking

• Trend toward use of trunk rotation (none, then blocked, then differentiated).

• Plane of swing progresses from vertical to horizontal.

• Grip changes from power grip to “shake-hands” grip.

• Elbows are held away from body and extended before contact.

Overarm Striking

Without an implement (e.g., volleyball serve) or With an implement (e.g., tennis serve)

Early Overarm Striking

• Trunk rotation is limited.

• Striker swings with collapsed elbow.

• There is little or no lag with swing forward.

• Movement looks like early throwing