355 Midterm 2 new content

what does a distance growth curve show you?

height (cm) at each age (years), analogy (road trip driving distance, cumulative distance vs time)

what are the characteristics for distance growth curves in terms of stature?

common shape for both sexes for both height and weight, males typically taller at full maturity, males slightly taller than females at all stages except 11-13 years when females attain peak growth, half of adult stature by age 2

what are the characteristics for distance growth curves in terms of body mass?

same shape for weight for both sexes, similar lag in growth in body weight seen in pre-natal development stage, ~20% of full adult weight size at 2 years, see plateau before increase

are the shapes of stature and weight curves the same for distance growth curves?

different, particularly in childhood years

what are the growth curve segments?

infancy (sharp increase in infancy), childhood, adolescence (sharp increase in adolescence), considerably less gains in body weight than in height

what is To and PHV in a velocity ccurve?

take off (low point prior to growth spurt), peak height velocity (when peak adolescent growth rate happens, max growth rate during adolescence and puberty)

what does a velocity growth curve for stature show you?

mostly deceleration until mid-childhood growth spurt, boys have prolonged (+2 years) appendicular growth at rate of 5.5cm/year (boys ~10cm/year, girls ~9cm/year), larger amplitude of spurt in boys (common in almost all boys and girls)

what are the characteristics of mid childhood growth spurt?

individual growth curve - occurs between 6-8 years, magnitude of velocity ~1cm/year increase, occurs earlier in girls by ~1 year, more common in boys ~80% vs 33%, much lower velocity compared to velocities during pubertal growth spurt

what information on sex differences in growth can we gather from velocity curve graphs?

consider timing and magnitude of changes (take off- initiation of growth spurt)

what are the characteristics of timing and sequence of growth pertaining to take off and PHV?

age at take off and PHV ~2 years earlier in girls, PHV is relatively early pubertal event in girls (~1 year before menarche), girls have slightly less intense growth spurt vs boys on average, but individual variation is considerable

what is the average age at take off for girls?

9

what is the average age at take off for boys?

11

what is the average age at PHV for girls?

11.5

what is the average age at PHV for boys?

13.5

what is the average PHV for girls?

8cm/year

what is the average PHV for boys?

9.5cm/year

how do we calculate age increment?

age2 - age1, difference between successive age

how do we measure height increment?

height2 - height1

how do we measure whole year velocity?

height increment/age increment, doesnt tell us what age its happening at but we assume its between to ages so we take the average height and plot that

how do we calculate age centre?

(age2 + age1)/2

what do velocity growth curves show you in terms of body mass?

early acceleration, then deceleration followed by acceleration at 2-3 years, pubertal growth spurt is period of sex dichotomy in body composition (boys >lean mass, girls >fat mass), age at peak weight velocity (PWV) usually later than PHV ~6 months

what are the primary factors that account for changes in stature and body mass?

endocrine, timing, age, maturity, genetics, sex

how do age and sex differences contribute to post-natal growth?

largely due to genetics, taller and heavier with increasing age, at adulthood (13cm difference in stature, 12kg difference in weight)

how does genetics influence adult stature?

twin model used to infer genetic affects, twin studies allow us to look at influence of genetics over environment, dizygotic-fraternal, monozygotic-identical, DZ 50% common (share 50% DNA in common), MZ 100% common (share 100% DNA in common)

how does maturity influence stature?

moderate to strong genetic influences on timing and amplitude of maturity, maturation itself doesnt affect final growth outcome just timing and tempo of growth

what are the diurnal effects of timing influencing growth?

tallest upon waking, shorter as day progresses

what are the seasonal effects of timing influencing growth?

typical growth pattern for canadian children, seasonal rate may vary by population and region, uncertain cause of seasonal variations (hormones, could be sunlight hours, vitamin D, growth hormone)

what are the secular trends in how timing factors influence growth?

influenced by social conditions (socioeconomic status, employment status), children measured in 1891 were born during depression of the 1870s, shift towards increased growth status in recent history

how do shape and body proportions change with post natal growth?

changes continually from conception throughout lifespan (round infancy, rectangular adolescence, triangular adult)

what is the general pattern of growth

infancy (rapid), early childhood (2-3, rapid), mild childhood (5-8, steady), adolescent spurt (rapid), into adulthood (slow)

what is the cephalocaudal principle?

top to bottom across growth (all years), early fetal stage (head grows fastest), infancy (trunk accelerates), childhood (legs accelerate)

what is the distal to proximal rule in growth?

maturity gradient, during adolescence (feet and hands - most growth distally, leg length, trunk length)

what factors impact patterns of growth and how?

genetic factors (determine general pattern of growth), environmental factors (determine whether genetic potential is reached - disease, nutrition), hormonal factors (specific to growth period)

what is stature and its characteristics?

sitting height + leg length, trunk is typically longer (all across growth) than legs (s-shaped curve for trunk), relatively greater sex difference in leg length vs sitting height (more noticeable size difference when standing vs sitting), both SH and LL increase with age, but the ratio changes during growth, SH in girls > boys for longer in growth period vs LL

what are characteristics of the sitting height/stature ratio?

dominance of trunk in infancy, progressively greater contribution from legs with age, decrease in SH/stature ratio pre-puberty, increased trunk length during puberty increases SH/stature ratio, trunk typically longer than legs, after puberty female have relatively greater trunk length (males greater leg length)

what are the characteristics of timing of segmental growth spurts?

later growth spurt in boys for all segments, growth progresses in a distal to proximal fashion during puberty

what are the effects of differential timing of growth spurts on different somatic tissues?

long bones grow in length first (distal to proximal), muscle mass increases after (LBM in plot), bone mass increases after (BMC in plot), muscle strength increases after muscle mass and size, relative weakness of limb during growth spurt, awkward and uncoordinated movements, prone to injury (clinical training and coaching implications, kids grow long before they grow strong)

what is the timing of growth related to peak height velocity?

first peak leg length velocity, stature (PHV), peak trunk length velocity, peak body weight/lean mass velocity, peak bone mass/strength velcoity

What are the age/maturity effects on physiological and practical consequences of changing body proportions?

fairness of competition (unfair for younger kids to compete with older kids or adults, early maturers may have temporary advantage in some sports), susceptibility to certain injuries during the growth spurt depending on location of growth

What are the sex effects on physiological and practical consequences of changing body proportions?

advantage to boys when competing with girls of equal height post puberty, when relative limb length changes are important, advantage to girls during puberty in some sports (earlier growth), advantage/disadvantage depends on type of sport, age, and maturity, a great coach/doctor/teacher takes advantage of this knowledge

how do we plot a velocity curve for growth data?

plot centered age

how do we plot a distance curve for growth data?

plot actual age and height

how does absolute peak growth differ between girls and boys?

lower in girls

what are growth contributions to sex differences in adult stature?

adult sex difference in height (13cm), prolonged pre-puberty in boys (boys have extra 2 years of pre-adolescent growth ~5cm/year, ~10cm, bulk of sex difference because of this), greater pubertal growth spurt in boys (~3cm)

what info do velocity curves give you?

when slope changes and what it means, info on sex differences in growth (timing and magnitude of changes, take off - initiation of growth spurt and peak), consider end values

what does a velocity growth curve tell you more about compared to a distance?

more info about when you’re growing fast/slow

what is the age at PHV and amplitude of PHV for DZ male?

0.42 (speaks to greater difference in genetics in MZ), 0.43

what is the age at PHV and amplitude of PHV for MZ male?

0.85 (speaks to greater difference in genetics in MZ), 0.75 (stronger correlation)

what is the age at PHV and amplitude of PHV for DZ female?

0.39, 0.48

what is the age at PHV and amplitude of PHV for MZ female?

0.78 (show MZ attain age at PHV very similarly), 0.48

during which developmental stage do we see early acceleration in body mass?

infancy

how does peak weight velocity differ from boys to girls?

girls hit PWV earlier than boys

how does a parents maturation impact their kids?

if your parents had earlier puberty and peak height its likely you will too

how do boys with early puberty channel?

temporarily jump channels in puberty then come back

what is meant by a “stretched” individual when testing timing factors and their influence on growth?

ask them to breathe in and this gives them a stretch

how does summer height vary from winter height velocities?

tend to be higher in the summer than during winter

what is meant by secular trends in growth?

look at difference in growth patterns between generations

how does correlation determine the inheritance of traits in twins?

the higher the correlation in MZ twins the more strongly the trait is predicted by genetics

what are secular trends in growth largely due to?

largely due to nutritional status and lack of access to proper nutrition and resources in earlier times, see this now too if someone immigrated from somewhere that lacks nutrition

when discussing horomonal, genetic and environmental factors how are environmental factors most easily depicted? In what realm?

most easily seen in secular trends of height and times of disease or famine

what are the observed sex difference in leg length vs sitting height?

boys tend to have longer legs than girls because of 2 year extra growth, sitting height tends to be longer than leg length for all in general

how does the ratio of SH and LL change with age?

increases with age, ratio comes closer together in adolescence before it splits again when comparing boys and girls

when looking at the relations of sitting height and leg length what does this help us see?

looks at how these growths give us a sense of maturation

what does the height difference between michael phelps and hicham el guerrouj tell us?

same leg length, height difference is completely due to Phelps torso

why do we see decreases in SH/stature ratio pre-puberty?

because legs start to grow longer

how do increases in trunk length during puberty and its impact on increasing SH//stature ratio differ between boys and girls?

a little earlier in girls because mature ealrier

after puberty why do females have a relatively greater trunk length and males greater leg length?

almost entirely because males get extra 2 years of growth spurt where legs increase in length

is the sitting height/stature ratio ever below 50%?

always above 50% on average so sitting height explains more than leg length

what is meant by the timing of segmental growth spurts?

when they’re having peak growth for each segment

what is usually the last segment to grow?

trunk, tibia is most distal so see growth spurt earlier

what is the order of growth spurt in somatic tissues?

long bones growth, after length changes muscle mass increases, then bone mass increases, then muscle strength increases

why do we see more fractures/injuries in early stages with bone growth?

when bone is first laid down its not as dense as later, takes a while to fill bone mineral

why do we see relative weakness of limbs during growth spurt?

whichever bone grows fastest is weakest because it hasnt had time to consolidate

why doesnt PHV occur at the same time as peak bone mass accrual if growth in stature = growth in bone length?

because it takes time for bone to mineralize

how do we see advantages of boys in sports?

girls usually have absolutely and relatively shorter leg length so boys have more advantage in things like running

what are some common phrases to show the sequence of events in growth and process?

kids grow long before they grow strong, first you stretch them then you fill them

what is the focus in weight centric views?

losing weight and/or maintaining a healthy weight

what are the core beliefs of a weight centric approach?

physical health is foundational for overall wellbeing, weight results from individual choices primarily related to food and movement, that can be optimized

what is the focus in weight neutral approaches?

adding sustainable healthy behaviour

what are the core beliefs of a weight neutral approach?

all dimensions of health are important, weight results from numerous factors, some of which are beyond individual control, reducing weight stigma helps everybody

what are the roots of the word obesity?

latin roots (eat too much), term can be victim blaming, preferred term is “people in larger bodies”

what are the key focuses on obesity treatment with a weight centric approach?

weight loss and weight regain (futile cycle), people eventually regain weight

what are the key focuses on obesity treatment with a weight neutral approach?

increase PA and fitness, body weight, add healthy behaviour without centering around weight, focus on healthy weight and manipulating eating and movement patterns to get healthy weight

how do some people describe the term obesity?

some describe as above the BMI scale and for some its people whose weight impacted their body or health in some way

what are the principles of intuitive eatingg?

eating according to appetite and satiety cues, self permission for all foods

what is intuitive eating associated with?

improved dietary intake and eating behaviours, improved psychological well being and decreased DE/ED, improved physiological wellbeing (cholesterol. BP)

what are the principles of eating competence?

being positive, comfortable and flexible with eating, being reliable about getting enough and satisfying food

what is eating competence associated with?

superior diets (variety, consistency, fiber, produce), improved health indicators (cholesterol, BP, diabetes), higher quality of life indicators (sleep, PA, body satisfaction, less DE/ED, better parenting with food)

what are the principles of health at every size?

body acceptance over weight loss, internal cues over external guidelines, active embodiment over structured exercise plans

what is health at every size associated with?

superior diet, improved health indicators (cholesterol and BP), increased PA, decreased ED/DE, improved psychological wellbeing (decreased anxiety, depression, increased esteem, body image, interoceptive awareness)

what did studies on society and weight show us?

better retention state and less likely to drop out, reduced risk of DE and weight centric focuses

what are some key ideas presented by diet culture?

weight seen as a proxy for health (society obsessed), morality/health equates to body size, binary food choices (good/bad), oppression/applauding people for reshaping

where can beliefs within diet culture be seen?

conversation, comments, thoughts

What does diet culture do? It is a system of beliefs that _____

equates body size with health and virtue, promotes body reshaping to gain status, demonizes some food groups and elevates others, oppresses those who dont match its ideals

what are some examples of weight bias?

sizeism, fatphobia, anti-fat prejudice (example: brooklyn 99- celebration of diversity, yet many fat jokes)

what is meant by weight bias?

negative stereotypes, prejudices and assumptions about people in larger bodies

how does weight bias occur?

on a continuum: bias (implicit bias, spoken assumptions), discrimination (judgment/unsolicited advices exclusion), oppression (verbal abuse/bullying, physical abuses/violence)

what is meant by implicit bias?

subtle, unspoken ways we interact with someone (Ex: how we make eye contact), treating larger people differently

what is meant by unspoken assumptions in weight bias?

assumption that everyone wants to exercise, people with larger bodies dont exercise, or people need to burn off halloween candy

what is meant by judgment/unsolicited advice in weight bias?

family, commenting on food choices, always being told they would just lose weight if they exercised or they have a long way to go