Midterm Flashcards
Change in movement behavior (3 types)
Continuous - all the time, from birth to death
Age related - expect to see changes based on someones age (not an absolute)
Sequential - one step leads to another
Motor Development
Process of change in movement along with the constraints/factors that drive these changes
Lots of factors in play - not self-contained
Motor Learning
Relatively permanent gains in motor skill capability associated with practice or experience
Motor Control
The neural, physical and behavioural aspects of movement - the system controlling movement
Physical Growth
Quantitative increase in size or mass
Physical Maturation
Cell, organ or system advancement in biochemical composition
Aging
Process occurs with passage of time, leading to loss of adaptability, full function and eventually death
In 1986 Karl Newell offered an important theory that suggested what?
Movements in the environment arise from the interaction of the organism itself, the environment in which the movement occurs and the task to be undertaken
Refers to the factors/constraints that alter motor development
What are the components of Newell’s Model of Constraints?
Individual constraints (functional vs structural) Environmental constraints Task constraints
need to take into account and examine interaction between constraints when talking about movement changes
Constraints
Discourage or limit certain movements
Encourage or permit other movements
“Shape” movement
Example of individual constraint
3 YO throwing a ball vs 20 YO
Example of task constraint
Asking people of similar physical features to throw a ball from different heights
Example of environmental constraint
Walking on ice and slipping
Individual constraints are ___. The two types are? (examples)
unique physical and mental characteristics (internal)
Structural - related to the body
e.g. height, muscle mass
Functional - related to behaviour
e.g. attention, motivation
Environmental constraints are __, not task specific. The two types are? (examples)
Global, not task specific (external)
Physical
e.g. gravity, surfaces
Sociocultural
e.g. gender roles, cultural norms
Task constraints are ___. Example?
Not related to the individual
E.g. goal of task, rules, equipment
Disabilities
Differences in structural or functional individual constraints
may result in delayed, different motor development
The Research Process
1) Research idea - forms hypothesis
2) Research design - how to test
3) Collecting data - must pass ethics board
4) Analyzing data - what did you find
5) Publication process - how is this useful for people
Why is an info graphic good?
Data conveyed very easily
Name two research designs
Longitudinal - an individual or group observed over time
Pro: concrete answer - change over time
Con: takes a long time
Cross sectional - snapshot; individual/groups of different ages observed
Con: change is inferred, not observed
A Model of Sequential Research Design
Mini longitudinal approach with cross sectional study
Paradox in Development
Universality - individuals in a species show similarity in development
Variability - individual differences exist
important to emphasize both
Theories of Motor Development
1) Maturational perspective
2) Information processing perspective
3) Ecological perspective
Explain the maturational perspective of motor development
Motor development is driven by maturation of systems (nature), specifically the CNS.
An internal or innate process driven by biology - “internal clock”
Minimal influence of environment
Who started the maturational perspective? What did he suggest?
Arnold Gesell
Suggested invariable genetically determined sequence of development - individuals can have unique timing
Research: co-twin study - give on twin more attention (food, etc) - over time the other twin will catch up
AKA the changes in motor development will be temporary
Why is Myrtle McGraw relevant?
He also believed in the maturational perspective.
Associated motor behavior changes with development of nervous system.
Posited that advancement in central nervous system triggers appearance of a new skill.
Nature, not nurture - doesn’t mesh with Newell
What are the long lasting believes from Maturation Theory?
Basic motor skills emerge automatically - no need for training
Mild deprivation does not arrest motor development
The nervous system is most important
Explain the Information Processing Perspective of Motor Development
Motor development is driven by external processes (nuture)
Basic tenet: brain acts like a computer - the passive human responds to stimuli in the environment
Concept: encoding - storage - retrieval
Young adults were studied first as comparison for children and adults
Why was the information processing perspective a good thing?
Helped shift focus off purely biological theory and get people thinking which is more important: biology or environmnet
Explain the Ecological Perspective of Motor Development
Development driven by interrelationship of individual, environment, and task (importance of multiple systems) - Newell’s model
Two branches: dynamical systems and perception-action
Both reject CNS as executive controller of nearly limitless opportunities for movement
Allows for new types of experiments
Explain the dynamical systems branch of the ecological perspective
Primarily deals with motor control and coordination
Body systems spontaneously self-organize (not solely by CNS) - this compares with the maturation perspective because it says we are soft-wired not hard-wired
The body systems, environment and task demands interact
If you change on part of chain and change is slow it affects whole system (i.e. rate limiter)
What is a rate limiter?
An individual constraint that slows the emergence of a new skill
Explain the perception-action branch of the ecological perspective
Based on work of JJ gibson - ecological validity
Affordance
Characteristics define objects meanings - round = doorknob
Object functions are based on individuals’ intrinsic dimension (i.e. are body scaled) rather than the objects objective dimension
We perceive our body to be able to do something based on what the environmental characteristics provide
Affordance
The function an environmental object provides to an individual
Developmental changes are predictable and they are important for ___. They can be seen across a variety of motor skills and function to produce more __, __, or __
Optimizing biomechanical principles of motion and stability over time
Produce more force, velocity or accuracy
What are two biomechanical principles within the larger field of biomechanics. What are they known as?
Motion and stability
Known as the “physics” of movement
Newton’s First Law
An object at rest stays at rest and an object in motion stays in motion until acted upon by a force
We must exert force to move objects/people
Inertia
Resistance to motion related to mass
(Newton’s first law)
More inertia means harder to move - more force must be applied
Momentum
Product of mass and velocity
Newton’s Second Law
Object’s force is related to mass and acceleration (F=ma)
Keep in mind a=F/m
People have limits with peak force level but can optimize acceleration by putting our mass behind it or increasing radius of lever
Newton’s Third Law
To every action, there is an equal and opposite reaction
i.e. When you push on something, it pushes back on you!
Conservation of Momentum
Momentum before collision = momentum after
newton’s third law
Elastic Collision
No loss of kinetic energy (heat, sound waves, compression, etc.)
Inelastic Collision
Loss of kinetic energy
e.g. tackle in football
When projecting an object an individual’s limb traces __
Part of a circle (an arc)
What is the relationship that exists for projectiles and the person projecting them?
Relationship between velocity of rotating limb and velocity of object
Linear velocity (of object) depends on rotational velocity and radius of rotation
We want to maximize both velocity and radius
What is the developmental implication for limb length increasing with growth?
We can’t expect kids who are developing to max out their throwing speed at 13 years old
How can we increase the velocity of a tennis serve?
Make sure at point of contact, the arm is in full extension
Serving with bent arm gives more control but less power
Why do athletes begin their throw/serve in a bent form?
To reduce the inertia that is slowing them down
Arm extended would slow down rotational velocity = slower linear velocity on projectile
Follows open kinetic chain principles
Sprinters are a good example of what law?
Newtons third law - push off ground with as much force as possible
That is why limb is in full extension at end of gait
How do we make an object move?
Increase the impulse
Increase FORCE applied for a given time
How do we stop an object?
Decrease the impulse
Increase TIME over which given force is applied
Stability
Ability to resist movement
Balance
Ability to maintain equilibrium
Stability-mobility trade off
A skilled performer uses a base of support just wide enough to provide sufficient stability for the activity.
They are related
E.g. in rugby you don’t want to be moved but you want to be able to move quickly when you have to
How do you increase stability?
Increase base of support (feet wider)
Lower center of gravity (bend knees)
5 Step Method for Fixing Errors
1) Observe (watch multiple times, slow mo, different angles)
2) Breakdown (into component parts, general performance)
3) Apply Mechanic Knowledge (stability-mobility trade-off, open kinetic chain, rotational limb velocity)
4) Error Detection (most major error first)
5) Solution (what are we going to change)
repeat over and over
What are the four parts to a checklist?
Pause point - point in time where you double check
Speedy - less than 60 seconds to complete
Supplement to existing knowledge - not allow you to turn off your brain
Field tested and updated constantly - based on real experiences
Growth and Aging are influenced by both __ and ___ factors. Patterns include:
Influenced by genetic and extrinsic factors
Patterns:
Universality - patterns that hold for all humans
Specificity - individual variation
Prenatal Development Process
Ovum and sperm fuse to produce zygote
Next few days is cellular cleavage - each day the cell is cleaved in half
Within the first 5 days it becomes a morula (16 cells)
Then blastocysts
Implantation
The blastocysts (~100cells) moves through fallopian tube and implants in the uterine wall
Embryonic Development (when is it and what is the main process that takes place?)
Occurs from conception to 8 weeks
Differentiation (specialization) - cells form specific tissues and organs - due to genetics
What forms at 4 weeks development?
Limb rudiments
What is noticeable at 8 weeks?
Human form (eyes, ears, nose, mouth, etc.)
Embryo
Developing pregnancy from the time of fertilization until the end of 8th week gestation
At 8 weeks it is now known as a fetus
Fetal Development (when is it and what processes occur?)
From 8 weeks gestation to birth
Continued growth through:
- Hyperplasia (cell number)
- Hypertrophy (cell size)
What is recognizable at 12 weeks?
The sex of the fetus
Development is __ and __
Cephalocaudal - head to toe
Proximodistal - near to far, center to outside
Plasticity (relevance?)
Capability of taking on a new function
Although most cells have differentiated, cells are able to re-model and re-specialize to carry out new functions
Fetal Nourishment
Occurs through placenta
Placenta connects fetus to uterine wall and allows to nutrient uptake, waste disposal, thermoregulation and gas exchange through the umbilical cord
Moderating Variables (example affecting fetal nourishment)
Variables that help us tease out what is affecting this relationship
Women who live at lower SES have lower birth weight infants
In every ethnicity being a college grad decreases incidence of low birth weight
Sources of abnormal development can be __ or __
Genetic
Extrinsic
Congenital Defect
Can derive from genetic or extrinsic sources
Present at birth
Not inherited
Genetic causes of abnormal development can be __ or ___ or ___. Their effects on growth is variable.
Dominant disorder - inherit defective gene from one parents
Recessive disorder - inherit defective gene from each parent
Result of gene mutation (environmental chemicals)
Down Syndrome (What causes it and what do we see?)
Trisomy 21
Genetic mutation causes extra copy of 21st gene
Cognitive and physical abilities of an 8-9 year old their whole life
What is a potent factor contributing to Down Syndrome?
Age of mother at conception
20 YO = 0.1%
45 YO = 3-5%
Extrinsic factors that can affect fetus through __
Nourishment of physical environment
Teratogens (How do they reach the fetus, what do they do, examples)
Delivered through nourishment system - pass through placenta
Act as malformation-producing agents
E.g.
Alcohol, drugs, hormones, cigarettes, Rubella, lead, mercury
E.g. radiation
Fetal Alcohol Syndrome
Entirely preventable
Characteristics: small eye openings, smooth philtrum, thin upper lip
Development of the maternal blood supply to the placenta is complete by ___
12-13 weeks
It can screen large substances but not teratogens
Which tissues are most vulnerable to teratogens coming through the placenta?
The tissues undergoing rapid development
Overall growth follows what pattern? What growth especially follows this pattern?
Sigmoid pattern
(s-shaped)
Weight and height
Peak Height Velocity for girls vs boys
Girls - 11.5 to 12 years
Boys - 13.5 to 14 years
Growth height tapers off around __ for girls and __ for boys
Girls - tapers at 14, ends around 16
Boys - tapers at 17, ends around 18
What contributes to the absolute height difference between males and females?
Longer growth period in males
After peak height velocity, males’ growth extends for ___ more years than females
2
Weight is susceptible to?
Extrinsic factors - diet and exercise
People grow up then __
Fill out
Peak weight velocity follows height velocity by __ in girls and __ in boys
Girls - 3.5 to 10.5 MONTHS
Boys - 2.5 to 5 months
Health study done in the US was based on 4 factors, what were they? How many people were “healthy”?
Proper BMI
Healthy diet
Non smoker
Achieved physical activity guidelines
Only 2.7%
Postnatal growth: distance curves show ___ and velocity curves show ___
Distance curves show EXTENT of growth
Velocity curves show RATE of growth
Where on a velocity curve shows when an individuals growth rate changes from fast to slow?
The peak
What is the equivalent to boys increasing in shoulder breadth in females?
Hip width increasing
Brain reaches 80% adult weight by what age? And contributes to how much height?
Age 4
1/4 of height
Why is our head so big when we are born?
Because the brain dictates a lot of the development so body allocates more resources to brain to develop it
Children may vary in maturation rate specifically regarding __ and __
Behavioural maturation
Sexual maturation
It is difficult to infer maturity from __, __ or __
Age alone
Size alone
Or age and size together
Secondary Sex Characteristics
Characteristics that appear as a function of maturation
What is the average age of menarche?
12.4 years
What are two possible causes for why menarche is happening earlier?
For each 1 kg/m2 increase in childhood BMI there is a 6.5% greater chance of experiencing early menarche - body weight
Disrupting chemicals/exogenous substances which can mimic endocrine hormones in body
Which secondary sex characteristics occur in both males and females?
Grow taller/growth spurts Voice changes Skin gets oily Acne Hair gets oily Hair grows in underarms Hair grows on genitals Sweat glands develop Body starts producing sex hormones
What is the problem with catch up growth?
Kids who exhibit catch up growth between ages 0 and 2 exhibit a significantly greater central (visceral) fat distribution
Why is visceral fat bad?
Signifies that organs will be surrounded by fat
Risks of NOT breastfeeding for infants?
Ear infections
Gastrointestinal infections
Asthma with or without family history
Type 2 Diabetes Mellitus
What does WHO say about breastfeeding?
Does not affect cholesterol Blood pressure barely affected Diabetes inconclusive Overweight/obesity results from not Intelligence significantly reduced without
Why does height decrease in older adulthood?
Compression of cartilage pads
Osteoporosis
Compression fractures of vertebrae leading to kyphosis
Age Related Hyperkyphosis (causes, affects, how to fix)
Causes: vertebral fractures, degenerative disc disease, muscle weakness
Affects: decrease quality of life and increased risk of mortality
Fix: strengthen back muscles - erector spinae and quadratus lumborum
How to treat age related hyperkyphosis?
Physical therapy - first line approach
Reduces risk of falls, fractures
Strengthening, stretching, postural alignment, bracing/taping
No medications have been proven to improve hyperkyphosis
Women with prior fracture should practice extension exercises not flexion to decrease risk of refracture
Calcium and vitamin D help prevent osteoporosis (12% reduction in fracture risk)
Body System factors:
The average pattern of change within each system
The range of individual variations for a system
When and where does ossification begin?
Begins at primary ossification centers in the midportions (diaphysis) of long bones before birth (fetal age of 2 months)
During early embryonic life the skull exists as __
Cartilage
At 2 months old there are __ total ossification centers.
800 (400 prenatal + 400 postnatal)
Postnatal growth in bone length occurs at __. What are these areas called?
Secondary centers at the end of long bones Epiphyseal plates (growth plates)
How do short bones (tarsal) grow?
Ossify from center outward
What are traction epiphysis?
Where muscle tendons attach to bones
List the Long Bones in the body
Femur Tibia Fibula Ulna Radius Clavicle Metatarsal Metacarpals Phalanges Humerus
Osgood Schlatter (cause and treatment)
Caused by repetitive stress or tension on a part of the growth area on the upper tibia (traction epiphysis) and characterized by inflammation
Treatment: avoid physical activity to prevent further irritation
Does cessation of growth at epiphyseal plates happen at different times for different bones? At what age to the plates close?
Yes different bones stop growing at different times
All typically close by 18 or 19 (depending on gender)
helps doctors know how long healing will take
Average humerus epiphyseal plate closes at __ for females and __ for males
- 5 for females
18. 1 for males
In youth, new bone is formed faster than old bone is absorbed. What about in adults?
In adults bone growth slows and fails to keep pace with reabsorption
Why does bone become more brittle as we age?
Unequal amounts organic and inorganic material
Osteoporosis (what is it?)
Bones become brittle as a result of loss of tissue, due to hormonal changes, calcium/vitamin D deficiency, diet, or exercise
Bone characterized as porous
Osteoporosis (what happens when you have it?)
Leads to rib cage collapse (hard to breathe), stooped posture and reduced height
Risk of micro-fractures in vertebrae - kyphosis
What is the go to recommendation for prevention and treatment of osteoporosis?
Cosman Guidelines*
For postmenopausal women and men over 50
1. Diet includes adequate calcium inake (1000-1200mg/day)
2. Vitamin D intake (800-1000 IU/day)
3. Regular weight bearing and muscle exercises to improve agility, strength, posture, and balance, maintain or improve bone strength
4. Assess risk factors for falls and offer appropriate modifications (home safety)
5. Ask to stop smoking and avoid excessive alcohol intake
DEXA (what is it?)
Specialized x ray machine that helps assess bone mineral density (assess body composition)
Prenatal muscular growth involves __ and _. Whereas postnatal muscular growth involves mainly ___
Hyperplasia and hypertrophy
Postnatal is mostly hypertrophy
Muscles grow by __
Addition of sarcomeres
Muscle mass differences between the sexes become marked in adolescence. Specifically when?
Men stops at 17 YO
Women stops at 13 YO
Loss of MM is minimal until age __. Only __% is lost between 20s until then. Loss in __ and __.
Age 50
Only 10% lost between 20 and 50
Loss in number and size
Loss of MM is less than loss of strength. What does this suggest? Relevance?
Suggest a decline in muscle quality
Maintaining or even gaining MM will not prevent age-related strength declines
Types of Muscle Fiber
Type 1 (slow twitch), type 2a, 2x and 2b (all fast twitch)
At birth 10-15% are undifferentiated and by age 1 they are distributed.
With age the heart can lose optimal function (decrease elasticity of vessels). Most of this is due to __ rather than aging.
Lifestyle
Fat increases rapidly until age ___; then gradually until __ years
Rapidly until 6 months
Gradually until 8 years old
Girls experience increase in fat after 8 years old but what happens to boys?
Boys experience decrease in fat in extremities and trunk
Body fat distribution changes with growth. Subcutaneous fat % increases from _ to _ in males and _ to _ in females
7 to 12 in males
7 to 17 in females
Is gaining fat in adulthood inevitable?
No
Norwegian lumberjack study - if you stay active there are certain populations who aren’t susceptible to this
Endocrine System (what does it do? why is it important?)
Regulates growth and maturation through chemical substances called hormones. excess or deficiency can alter growth.
Hormones secreted by the hypothalamus regulate the __, which in turn, regulates the _, _, and _
Pituitary gland
Regulates the adrenal gland, thyroid gland and release of sex hormones
Major hormones involved in growth:
Growth hormone (GH - secreted by ant. pituitary) - stimulates protein anabolism Thyroid hormones (T3 and T4) - regulate metabolism
Androgens (secreted from, purpose)
Secreted by testes (boys) and adrenal glands (boys and girls)
Result:
- epiphyseal growth plate closure
- growth of muscle mass
Estrogen (secreted from, purpose)
Secreted by ovaries (girls) and adrenal glands (boys and girls)
Result:
- epiphyseal growth plate closure
- accumulation of fat
Nervous System development is direct by __. But __ factors play an influence on formation of ___.
Driven by genes
Extrinsic factors
Synaptic connections
Prenatal Neural Development (what happens? what might disturb it?)
Rapid formation of immature neurons that only develop axons once in final position (6th prenatal month). Neurons then start to fire randomly before forming circuits (more efficient with experience)
Teratogens might disturb it
Postnatal brain growth includes:
Increase in size of neurons
Prolific branching to form synapses
Increases in glial cells for support and nourishment of neurons
Increases in myelin to insulate axons
What increases number of synaptic connections?
Stimulation of learning
Multiple Sclerosis (what is it? symptoms)
Loss of oligodendrocytes (responsible for maintain and creating myelin sheath) which help neurons carry electrical signals
Symptoms: numbness, tingling, walking difficulty
Nervous System in Older Adults (theory)
Loss of neurons, dendrites, etc.
One theory suggest as we age there are breaks in neural networks which cause detours and therefore slowing
What promotes cognitive function?
Exercise
Newborn Movement Classes (two types)
Spontaneous - movements not caused by known external stimuli
Reflexive - stereotypical, involuntary responses elicited by specific external stimuli
The Original Theory behind Spontaneous Movement
Movements were extraneous with no purpose
Though research should focus on reflexive movement instead
The Current Theory behind Spontaneous Movement
Spontaneous movement is the building blocks - similar to some voluntary movements
E.g. supine kicks in infancy resemble adult step
E.g. arm movements resemble reaching
Co-contraction occurs for roughly the first year. What is it?
Two muscle groups firing at the same time
Doesn’t happen in adults (our muscles use complimentary firing)
Reflexes (what are they, what do they involve, relevance?)
Specific to external stimuli, localized, and same stimulus will elicit a corresponding reflex over and over (reproducible)
Involve single muscle or group of muscles
Relevance:
- allow dialogue with environment
- result in sensory consequences (adaptation)
- building blocks for future (e.g. blinking reflex)
Infantile Reflexes
Only seen during early development
Three types: primitive, postural, and locomotor
Don’t have them because we develop control over movement
Spontaneous Movements
Do not result from external stimuli and are more generalized in nature
Same spontaneous movement twice is probably random
Primitive Infantile Reflex
Involuntary responses often mediated by lower brain centers
Postural Infantile Reflex
AKA gravity reflex - Help infant maintain posture in changing environment
Locomotor Infantile Reflex
Appears similar to a voluntary movement but disappears before an infant attempts these voluntary skills
Asymmetrical Tonic Neck Reflex (primitive, postural, locomotive)
Primitive reflex Infant starts in supine Stimulus: turn head to one side Response: same-side arm and leg extend Normal: 0-4 months Problematic: > 6 months
Babinski Reflex (primitive, postural, locomotive)
Primitive Stimulus: stroke sole of foot Response: toes extend Normal: 0-4 months - corticospinal pathways from brain to spinal cord not fully myelinated Problematic: > 6 months
Moro Reflex (primitive, postural, locomotive)
Primitive
Infant starts in supine
Stimulus: shake head (e.g. by tapping pillow)
Response: arms, legs and fingers extend; then arms and leg flex
Normal: 0-3 months
Problematic: > 6 months
Ladyrinthine Righting (primitive, postural, locomotive)
Stimulus: tilt infant in support upright position
Response: head moves upright (initiated by vestibular system - reference frames)
Time: 2-12 months (not primitive because it takes a couple months to show up)
Stepping Reflex (primitive, postural, locomotive)
Locomotor
Infant starts held upright and is placed on flat surface
Response: initiate walking pattern
Normal: 0-5 months
mimicking - if you let go they fall down
Difference between infancy and later infancy
Now have voluntary control of movement
Understand environment
Meaningful interaction with others
Progressive pattern of skill acquisition dependent on:
Maturation of CNS
Development of muscular strength and endurance
Development of posture and balance
Improvement of sensory provessing
Examples of Motor Milestones
Fundamental motor skills - building blocks that are cumulative and sequential
Specific movements that lead to general actions
WHO Multicenter Growth Reference Study (what happened? what was required?)
Motor milestones same all over world as long as in same type of home - AKA same SES
Required:
- absence of health __
- adherence to feeding recommendations
- absence of maternal smoking
- absence of significant morbidity
List of Motor Milestones
Sitting with slight support - 2.3 months Partial/complete thumb opposition - 4.9/6.9 months Sit alone momentarily - 5.3 months Standing with furniture - 8.6 months Walks with help - 9.6 months Standing alone - 11.0 months Walking alone - 11.7 months Jumps off floor (both feet) - 23.4 months
know order and whole months
Rate Limiters
Infant must develop a certain system to attain a certain milestone and parental handling can alter rate of development
First Child Syndrome
Period of prolonged holding (less time in prone position) - delayed onset of crawling
May cause other delays but will catch up
Cerebral Palsy (what is it? what causes it?)
Disorder that permanently affects muscle tone, movement and motor skills
Caused by damage to motor control centers of developing brain
Prediction: >37.5% delay in major motor milestones
Locomotion
The act or capability of moving from place to place
Are we born with early locomotion?
No, certain motor milestones must first be achieved
Crawling
AKA army crawl
Moving on hands and abdomen
Creeping
Moving on hands and knees
Locomotion Progression for Infants
1) Crawling
2) Low creep - stomach slightly elevated
3) Rock back and forth in high creep
4) Creeping with arms and legs working alternatively
What to keep in mind at all times when considering human motion
The environment must AFFORD certain things: a continuous path, flat surface, sufficient friction for balance
Walking is the first form of upright, bipedal locomotion. What is it defined as?
50/50 phasing between right and left legs
Period of double support followed by period of single support
Walking: Stance phase takes up __% of gait and consists of _, _, _ and _
60% of gait
Consists of: heelstrike, footflat, midstance and pushoff
Walking: Swing phase takes up _% of gait and consists of:
40% of gait
Consists of: acceleration, midswing and deceleration
Goal and Characteristics of Early Walking
Maximize stability and balance Characteristics: - arms in high guard (falling) - feet toed out and wide apart - independent, discrete steps (not smooth, one followed by another)
Eventually:
- trades stability for mobility
- stride length increases (absolute=longer legs and relative)
- base of support reduced
- opposition (arms and legs)
- pelvic rotation
- middle guard then low guard
- double knee lock in heelstrike and acceleration
By age _, essential components of advanced walk are present
4
Young adults have very little walking development and changes represent __
Individual variation
e. g. weight loss or gain
e. g. injury
Walking in Older Adulthood
- maximizing stability
- out-toeing increases
- stride length decreases
- reduced pelvic rotation (decreases walking economy)
- velocity decreases
- objects used as balance aids
Any changes associated with the aging process can alter __
Locomotion
e.g. osteoarthritis
Most common form of osteoarthritis. What is it?
Rheumatoid arthritis
Autoimmune disease, living in chronic pain, usually symmetric
Warning signs: stiff, fatigue, loss of function secondary to pain, gets better with movement, swelling in joints
Running (when does it occur? defined by?)
Occurs 6 to 7 months after walking starts
Defined by:
50/50 phasing between right and left legs
Flight or float phase followed by single support
% Breakdown of Running
Stance - 40%
Float - 15%
Swing - 30%
Float - 15%
Early Running Characteristics
Stability over mobility (return of older behaviours)
- arms in high guard
- limited ROM
- shorter stride
- little pelvic rotation
Proficient Running Characteristics
Less stability, more mobility
- increase stride length
- heel to butt
- narrow base of support
- trunk rotation
- right angle elbow
Later Running Characteristics (Older Adults)
Increase stability and balance Decreases in: - stride length - ROM - number of strides - speed
Robert Marchand Case Study
105 YO cyclist
Age 101: 1hr cycling = 24.25 km
Age 103: 1 hr cycling = 26.92 km (+11%)
VO2max increased from 31 to 35 (+13%)
Peak power increased from 90 to 125W (+39%)
Running to Mitigate Deterioration
Impaired walking performance is a key predictor of morbidity in older adults
Older runners had 7-10% better walking economy than older walkers (long-distance
corridor walk)
AND similar walking economy to sedentary young adults
Walking economy - energy to get from A to B
Conclusion: running is still better than walking - runners are more efficient at any speed
Jump
Person propels self off group with one or two feet; lands on two feet
Hop
Person propels self off ground with one foot; lands on same foot
Leap
Person propels self off ground with one foot; extends flight period, and lands opposite foot
Children begin simple jumping before age _. Explain Early Jumping Characteristics
Before age 2
Characteristics:
- jumping only vertically
- no or limited preparatory movements
Proficient Jumping Characteristics
Preparatory crouch to maximize takeoff force
Both feet leave ground at same time
Arm swing used
For vertical jump - force is directed downward, body extended
For horizontal jump - force is directed down and backward, knees flexed during flight
Rate Limiters in Jumping
Development in enough forces to bring body into air - muscles used/strength
Injury
Jumping is a two part movement. What are the movements?
Hip extension Knee extension Smaller contributors: Hip flexion - iliopsoas Plantar flexion - tib ant
Muscles involved in Hip Extension
Gluteus maximus Semitendinosus Semimembranosus Long head biceps femoris Adductor magus
Muscles involved in Knee Extension
Simultaneous with hip extension for vertical jump
Quadriceps femoris
Ingredients of High Jump
1) Fast run up
2) Plant foot on ground ahead of body - reduce forward momentum
3) Lift arms and other leg up
4) Low to ground at beginning of jump
can’t change path of projectile once ou have left the ground
Gallop and Slide are asymmetric. Explain
Gallop: forward step on one foot, leap on another
Slide: sideways step on one foot, leap on other
Skipping is __
Symmetric
Skip: alternating step-hops on one foot, then on the other
Proficient galloping, sliding, skipping
No longer need arms for balance
In skipping, arms swing opposite to legs and provide momentum
During galloping and sliding, child can use arms for another purpose (clapping)
Ballistic Skill (what is it? examples)
Performer applies force to an object to project it
e.g. throwing, kicking, striking
Forms of Throwing
Underhand (one or two hand)
Sidearm
Overarm (one or two hand)
What are the two ways to assess throwing?
Product measures (outcome): accuracy, distance, ball velocity
Process measure (movement pattern): developmental sequences
Early Overarm Throwing Characteristics
Mostly arm action Elbow pointed up Throw executed by elbow extension alone No step Note: excessive trunk flexion
Proficient Overarm Throwing Characteristics
Preparatory windup (weight shift and trunk rotates back)
Uses opposite leg, long step and differentiated trunk rotation
Upperarm and forearm lag
Movements sequential to transfer momentum
Differentiated Trunk Rotation
The trunk is rotating and the upper body lags (one level moving ahead of the next level - upper level behind)
Example of Developmental Changes in Overarm Throwing: Trunk Rotation
- None, no forward or backward movement
- Block rotation
- Differentiated rotation
When people are throwing for accuracy they may__
Revert to more developmental steps for accuracy-based throws than for forceful throws
To kick a ball you must have ___ and __ to make contact
Perceptual abilities
Eye-foot coordination
Early Kicking Characteristics
No step taken with non-kicking leg
Kicking leg pushes forward
Immediate retraction of leg - no follow throw
No trunk rotation
Proficient Kicking Characteristics
Preparatory windup - 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
Key Positions for Kicking (a-e)
a) Maximum hip retraction
b) Forward movement of the thigh and continued knee flexion
c) Ball contact
d) Post impact follow through
e) Knee flexion as follow through proceeds
Punting
The ball is dropped from the hands
More difficult than kicking for children
Early Punting Characteristics
Ball is tossed up rather than dropped
Contacts ball with toes rather than instep
Short step
Proficient Punting Characteristics
Arms extended to drop ball before final stride
Arms then drop to sides and move in opposition to legs
Leaps onto support leg, swing punting leg to make contact
Punting leg is kept straight; toes are pointed
Proficient Sidearm Striking Characteristics
Sideways preparatory stance and long step
Differentiated trunk rotation
Horizontal swing throw large ROM (arm extended)
Sequential movements
e.g. tennis forehand
Overarm Striking has two forms:
Without an implement (e.g. volleyball serve)
With an implement (e.g. tennis serve)
Developmental Changes in Overarm Striking: Racket Action
Similar for overarm throwing
- No racket lag
- Racket lag - some wrist extension/flexion
- Delayed racket lag - very far behind movement of arm
Prehension
Grasping of an object typically with hands
What did Halverson do?
Proposed phases on grasping development
Filmed infants grasping 1 inch cube
Saw transition from power (raw and gross movement) to precision (fine motor skills)
First 5-Month Grasping Development (Halverson)
Birth: no contact 1 month: limited contact 2 months: grasp with entire hand 3 months: adjust hand position 4 months: grasp with thumb on top 5 months: grasp with fingers only
What did Hohlstein do?
Studied grasping but used different object sizes and shapes
Found this influenced type of grasp (by 9 months - lag in visual perception)
Weren’t able to find the same progression shown previously - this told them that learning plays an important role in prehension
Neuromotor maturation is not the only structural constraint
Body Scaling
Adapting to characteristics of task/environment to fit overall size of the body part
Helps us carry out similar action because body scaled ratio is constant
Why do infants struggle with grasp accuracy?
Visual systems are lacking
Need to know hand size relative to object size
Pick-Me-Up for Infants Exploratory Skills Study
Used sticky mittens to see if it benefited kids in early development of skills needed to grasp an object
It was successful
Prereaching
Within the first few months infants exhibit random arm movements
How do infants learn to reach?
By experience they learn to control their arms
Infants become consistent in moving hand to the mouth at _ to _ months
3 to 4 months
Same time that prereaching transitions to reaching - no longer ballpark reaching
By _ months, they open the mouth in anticipation of the hand’s arrival
5 months
Bimanual Reaching and Manipulation - Timeline
2 months: infants show bilateral arm extension and raising
4-5 months: infants reach for objects with both arms
12 months: pulling apart and insertion actions (lego)
early year 2: infants use objects as tools
end of year 2: complementary activities (holding lid while taking something out)
Reaching improves when __
Infants can maintain postural control (6-7 months)
A research study looked at RT, MT, tapping and coordination. They found that manual performances declines after age __. What else declines? __ is maintained in well practice tasks like pouring a glass of water
Age 50
Strength declines
Decline in grip strength
Coordination of hand writing
Accuracy is maintained but coordination/strength are not
Rapid Aiming Movements (what is it? examples)
Involved an initiation and acceleration to peak velocity; then deceleration and termination phase
e.g. putting key in ignition, flicking a light switch - bring hand to switch but slow down as your approach
What happens in rapid aiming movements in older adults?
Older adults have longer deceleration phases
Ataxia
A neurological sign consisting of lack of voluntary coordination and control of muscle movements
Neurodegenerative disease that affects the cerebellum
Last 10% of movement is severely affected when you have ataxia
Fundamental Manipulative Skill (what is it? example)
Person gains control of an object
e.g. catching
Catching (where do we catch and what makes catching more difficult?)
Objects caught in hands is more ideal so they can be manipulated
Intercepting an object makes catching more difficult
Early Catching Characteristics
Children initially position arms and hands rigidly
Trap ball against chest
Turn head away or close eyes
Proficient Catching Characteristics
Hands “give” with the ball to absorb force
Move side to side or forward and back to intercept ball
Fingers pointed up for high balls and down for low balls
Developmental Changes in Catching: Arm Action
- Little response
- Hugging/trapping
- Scooping
- Arms “give”
Developmental Changes in Catching: Hand Action
- Palms up
- Palms face each other
- Palms to object flight and size
Developmental Changes in Catching: Body Action
- No adjustment
- Awkward adjustment
- Proper (smooth and coordinated) adjustment
How do you assess catching?
To compare, task and environmental constraints must be consistent
Number of catches in set of attempt can be scored
Developmental sequence can provide information about movement process
Coincidence-Anticipation Tasks
Anticipating completion of movement to coincide with arrival of moving object
Interception success is related to __, __, __, and __
Ball size
Speed
Trajectory
Other task and environmental constraints
How do children learn to arrive at the right place? What is this called?
Children learn through experience to move to keep similar angle of gaze
Constant bearing angle strategy - try to keep angle same - easier to catch
Older adults are __ on coincidence-anticipation tasks. But they can improve with practice.
Less accurate and more variable
Typical golfers practice __ repetitions in a __ period of time
Frequent repetitions
Short period of time
Studies show that blocked practice performance has better results than random practice. Why?
Because it is easier but NOT better
When a player wants to see permanent enhancement in learning __ results in better retention and __ than blocked practice
Random practice results in better retention and transfer than blocked practice
Random practice also add __ which elevates effort during practice
Desirable difficulty
Structure practice conditions like __
Game conditions
Contextual Interference
Interference generated due to context in which the skills are rpacticed
Randomizing - Produces decrements in performance during practice but enhances learning of tasks (decrease success in practice = success long term)
Elaborate Processing Hypothesis
Random practice promotes more elaborate processing; allows for more comparative and contrastive analyses of the actions required during competition setting
More opportunities to compare and contrast shots - good brain practice for game
Reconstructive Hypothesis
Promotes a more reconstructive method of processing performance. Forced to forget and remember how to do the actions over and over again
Some people suggest randomized mini blocks
