KINE 2P84 Final Exam Flashcards
What is status?
Physical size, maturation, performance levels
What is progress?
Rate of development: Height, weight, etc.
What are some common research challenges in children and youth?
Ethical, variability, methodological issues, generalizability
Describe a cross-sectional study design.
Comparison of 2+ groups at one point in time. Efficient and quick to complete. Cannot detect changes over time.
Describe a longitudinal study design.
A study over a period of time. Costly. Changes over time/growth can be detected.
What are examples of “plastic processes” and what do they lead to?
Nutrition, childhood disease, physical activity, environmental stress all interact with genes for biological variation.
What are the 3 major ideas of the course that can intertwine with each other?
Growth, Maturation and Development
What is development?
The progressions and regressions that occur throughout the lifespan. Can be separated into biological and behavioural.
What is growth?
The structural aspect of development. Hyperplasia = increase in number of cells. Hypertrophy = increase in cell size. Accretion = increase in intercellular substance
What is maturation?
The functional changes in human development. Highly related to growth. Focuses on progress or rate of attaining mature state.
What are the time periods of development?
Prenatal, infancy, childhood, adolescence and adulthood
Is hyperplasia or hypertrophy more common early on in growth?
Hyperplasia is more common early on in growth while hypertrophy increases later on.
What is a distance curve?
Change in height over age
What is a velocity curve?
Change in RATE of change in height over age
What is difference between maturation and maturity? Timing vs tempo?
Maturation = process. Maturity = status. Timing is the age of occurrence of event. Tempo is the rate of change over time. Maturation cannot be measured directly.
What is chronological, biological and maturational age?
Chronological age = in calendar years and months. Biological age = growth/observable and measurable. Maturational age = unobservable and inferred (sexual maturity)
True/False: Chronological age is not the same as biological age.
True
What are the 3 prenatal stages?
Egg, embryo and fetus
Explain the egg stage of prenatal development.
it is the first 2 weeks and cell division/differentiation happens.
Explain the embryo stage of prenatal development.
Weeks 2 through 8 and increase in cell number + differentiation occur.
Explain the fetus stage of prenatal development.
Weeks 9 through 40 and Increase in cell size and mass occurs.
What are prenatal changes in body proportions?
At 9 weeks, the head is roughly 50% of the body and at week 38, it is 25% of the body. Fetal growth is not linear.
List a few of the main fetal activities and when they begin.
Heart: 4 weeks; Trunk, arms and legs: 6-9 weeks; Reflexes: 36 weeks
True/False: Birth weight is an indicator of health. Low birth weight is associated with impaired immune function and increased risk of disease.
True
What are the 3 main factors that can affect a babies birth weight from the parent?
Nutrition, smoking and alcohol
What are the physical activity recommendations during pregnancy?
150 minutes of MVPA per week over 3 days
Are distance curves standards or norms?
No
If a girl is in the 10th percentile for height, how does she compare to other girls her age?
She is shorter than 90% of girls her age and taller than 10% of girls her age.
Is there more variability on the growth charts in height or weight?
Weight has more variability
Why do we use percentile charts?
Evaluation of growth on an individual child or sample of children
What is an early maturer and a late maturer?
Early maturers progress earlier on in development while late maturers will be below average for most of the time on growth charts.
Why are men taller than women?
Girls have growth spurt sooner but their rate of growth is less (accumulating less cm per year) and boys grow for longer period of time than girls.
What is “scaling” for body size?
adjusting physiological variables for body size
What is physique?
Body form/body build
What is somatotyping?
Classification of physique (short and stocky, tall and slender). Sheldon’s Classification is Endomorphy (muscular) to Mesomorphy (chubby) to Ectomorphy (skinny).
What is bone tissue made up of?
Collagen, minerals, cells (calcium and phosphate)
What is an osteoblast?
Bone formation
What is an osteoclast?
Bone resorption (eat away at bone)
What is an osteocyte?
regulation of flow of minerals and nutrients (signals whether osteoblasts or osteoclasts should kick in)
Resorption, Reversal, Formation, Resting: How long does this process take to complete?
3 months
Where are long bones and flats bones located?
Long bones are arms, legs, etc. Flat bones are the skull.
What is growth + remodelling rate of bones in infancy compared to adulthood?
50% annually in infancy and 5% annually in adulthood.
What is the status of osteoblasts and osteoclasts in youth, adult and old age? What ailment does this lead to in old age?
Youth: Formation is greater than resorption. Adult: Equal. Old age: Resorption is greater than formation and this leads to osteoporosis.
How can you prevent osteoporosis?
Exercise, Nutrition and Pharmaceuticals (slow down the rate)
How to increase peak bone mass at a young age?
good nutrition and exercise will help increase peak bone mass. “Put bone in the bank” during childhood and adolescence (critical period) is very important.
What is intramembraneous bone formation?
between embryonic membranes (skull)
What is endochondral bone formation?
replacement of cartilage (long bones)
What is longitudinal growth called?
epiphysis
What is width/thickness growth called?
appositional
What is the growth plate?
responsible for linear growth
What are the growth zones for bones?
Reserve, proliferating, hypertrophic and zone of ossification
List some important hormones in bone growth in length.
Growth hormone, corticosteroids, cytokines, Insulin growth factor 1 (IGF - 1)
What is peak height velocity (PHV)?
indicates where the growth spurt has taken place
What does the mechanostat theory state?
increase in bone length occurs before the increase in bone mineral content.
What are some optimal activities and timing to improve bone strength?
Swimming, resistance training, basketball in adolescence/puberty and childhood/pre-puberty
What are the 3 types of muscle tissue?
Skeletal (energy consumption), Smooth (organs) and Cardiac (heart) muscle tissue
What is the muscle chemical composition?
Intracellular ions, extracellular ions, water and protein. All increasing with growth
What is myogenesis?
Occurs in embryo. Increase number of fibres. Mesodermic cell, myoblast, myotube, muscle fibre
What is myostatin?
slows down muscle growth.
What is hyperplasia?
increase in cell number
What is hypertrophy?
increase in size
What is whole structure versus microstructure in terms of muscle growth?
Whole structure = structure, size. Microstructure = fibres, myofibrils, sarcomeres
List the types of connective tissue
endomysium, perimysium and epimysium. With growth, tendon becomes more stiff which leads to increased explosiveness.
What are the methods of classification for muscle fibre types?
Small/large, slow/fast, red/white, high/low-glycolytic
What are the 3 muscle fibre types?
Type l (red, small, low), Type llA (white/red, intermediate, high), Type llB (white, large, high)
What does maximal force depend on?
muscle size and neural activation
List some changes with growth regarding skeletal muscle.
number of fibres/unit increases with age. Units per muscle decreases with age. Activation increases with growth. Increase of maximal strength.
What is motor unit comprised of?
Motor neuron, neuromuscular junction and innervated muscle fibres.
How do Contractile Properties differ?
Differ for type l and type ll. the muscles contractile properties depend on muscle composition
How does Motor unit activation deficit change with growth?
activation deficit decreases with growth
How does Muscle fibre size change with growth? Aging?
increased diameter with growth. decreased diameter with aging.
How do Muscle fibre size and muscle mass change with age? Boys vs Girls?
Size and number both increase with age. More in boys than in girls.
What are the functions of fat tissue?
Energy storage, insulation, mechanical protection, regulation of biological function (endocrine, paracrine, autocrine)
What is an adipocyte?
fat depots, large number of fats cells held together by structural molecules. Nerves and blood vessels. Fuel storage and regulation of biological function
What are some of the molecules secreted by adipocytes?
adipsin, adipokines, leptin, IGF-1, C3 and more
What is leptin?
regulation of energy balance, appetite, glucose and lipid metabolism, puberty, reproductive function, bone formation
What is the significance of leptin in overweight people?
in overweight people, their body’s do not react to leptin like they should. Doesn’t always mean they are leptin deficient.
What do LPL, IGF - 1 and PAI - 1 each do?
LPL = regulation of lipid storage. IGF - 1 = regulation of growth. PAI - 1 = increase in blood clotting
What are the stages of adipogenesis?
Adipoblasts, pre-adipocytes, very small adipocytes, mature adipocytes. It starts prenatally and continues postnatally.
White Adipose Tissue vs Brown Adipose Tissue
White fat cells looks white, are larger and found subcutaneously. Brown fat cells have smaller looking cells within them, are smaller overall and darker. They also have a central nucleus.
What are the different levels of body portioning?
Atomic, molecular, cellular, tissue and whole body
What are the main methods of estimating body composition?
Densitometry, DXA, BIA, anthropometry
What is densitometry?
Density = mass/volume. The higher the density the lower the fat. Examples include underwater weighing or bod pod.
What is DXA?
Analyzes bone mineral content, fat mass, fat free mass. Need to use specific formula for children. Cons: large unit not portable and expensive. needs trained personnel.
What is BIA (Bioelectrical impedance analysis)?
Analyses total body water and fat free mass. Sends electrical signals through your body and checks how quickly the current travels. Influenced by nutrition and need to use specific formula for kids.
What is anthropometry?
Handheld measuring tool with 2 clips that measure your body density and fat mass. Different formulas for males and females. There can be variability however it’s cheap, portable and non-invasive.
What is BMI?
Body mass index. Mass/Height squared. Simple to use, good for estimation but not very accurate.
True/False: The prevalence of overweight and obesity in children has not changed in the last 30 years in Canada.
False. It has tripled.
What is BMR (Basal Metabolic Rate)?
what your body burns from using nutrients. Base calories your body uses
What are some reasons for increases in obesity?
Increased caloric consumption (fat consumption) and decreased physical activity
What does childhood obesity lead to?
Increased risk of high blood pressure, heart disease, high cholesterol, diabetes, respiratory problems, orthopaedic problems, psychological problems
How likely is an obese child to become an obese adult?
If a child is obese at age 6, they are 10x more likely of being an obese adult. Therefore, interventions must being early!
What could happen if we don’t try and fix the childhood obesity problem?
the youth of today may live less healthy and possibly even shorter lives than their parents
How does physical activity change with age?
Decreased physical activity with increased age. Boys are overall more active than girls. By late adolescence, almost all girls were inactive.
What is the ParticpACTION report card?
Sweat, Step, Sleep, Sit
What are some reasons for decreases in physical activity?
Increased urbanization, safety considerations, facilities, technology
Example: 12-13 year old boys basketball team. Why is there so much variability in height?
Biological age does not always correspond with chronological age.
What are the measures of maturity?
Skeletal, Sexual, Somatic, Dental
Explain Skeletal Maturity
Bone age. Spans the entire period of growth. Can be assessed using radiographs (looking at bones that can easily be viewed)
What are the methods of assessment of skeletal maturity?
Greulich-Pyle (GP): most common. Tanner-Whitehouse (TW): provide a score for each bone they can see. Ultrasound. MRI
What is the relevance of skeletal maturity?
§ Health - percentile growth charts. Assessment of skeletal maturity - can give you some information on whether a child is late or early maturity.
§ Sports - used to determine where an athlete should be placed in a team. Select more or less skeletal mature players.
Explain sexual maturity
ability to reproduce. sexual differentiation to puberty and ends with sexual maturity and fertility.
What initiates puberty?
Kisspeptin (protein that acts on pituitary gland and beings process of maturation)
How do you assess sexual maturity?
It is only relevant during pubertal years. In girls, look for pubic hair, breast dev’t, menarche (age of first period). In boys, look for pubic hair, penis and testicle dev’t. 5 stages which include pre-pubertal to end of puberty (Tanner stages). Assessed according to secondary sex characteristics.
Other important notes on sexual maturity?
Continuous process that varies in tempo. Self assessment and there is subjectivity. Each stage does not equate with each other.
What is the most common indicator of maturity in girls?
Age of menarche
What are some causes of late menarche in girls?
Genetics, pre-selection, environmental factors (exercise, nutrition and energy balance)
Explain somatic maturity
Physical growth. Age of peak height velocity and tempo. Age at onset. % of adult height. There is individual variability.
Does maturity affects sports participation? If so, how does it?
Body size changes (taller, bigger, heavier). Body build changes. Strength. Motor skills. The more developed they are, the more likely they are to participate in sports.
Explain dental maturity
Age of eruption (baby teeth and permanent teeth). Calcification (permanent teeth). Not well related to other methods.
How does muscle mass change with age?
Increase muscle mass with age but more of an increase in boys than girls.
Muscle Structure: Number of fibres
○ Determined close to birth. Girls = boys. Women = men. Therefore, the increase in muscle mass is not due to an increase in the number of fibres (they are already determined at birth, maybe a little bit later)
○ Fibre Cross-sectional area: During childhood there is a large increase. Similar in boys and girls. (x 15-20) During adolescence, increases in both boys and girls but increases much quicker in boys.
○ Fibre Length: Increase in contractile proteins.
What is absolute strength?
how much you can lift
What is relative strength?
how you can lift while taking body size into account
Does maturity affect muscle strength?
early maturers are stronger at all ages. More apparent during adolescence.
When is Somatic maturity determined? Are late maturers always less physical able?
maturity determined according to age at PHV. Late maturers caught up in adulthood.
What are the factors explaining strength differences between individuals?
Muscle size and composition, muscle function (coordination and activation pattern)
Explain motor unit activation
ITT (interpolated twitch technique). Children have an overall lower activation of motor units even after we take into account muscle size.
What is the Differential Motor Unit Activation Hypothesis?
Children do not use their higher-threshold (type ll) motor units to the extent typical of adults.
Who has greater explosive strength? Children vs Adult
Children < Adult
What are some factors explaining slower force kinetics in children?
lower % age of type ll fibres, lower muscle-tendinous stiffness, differential motor unit activation.
What is the take home message of children and motor unit activation?
motor units recruited at a later stage and less of them than in adults. Onset of accelerated recruitment of higher-threshold (type ll) motor units occurs later in boys compared to men. Also compared between males and females.
What are factors explains strength differences between children and adults?
Morphological factors, neuromuscular factors, utilization of type ll fibres
