Quiz 2

What are the 4 types of studies? (increasing in ACCURACY, VALIDITY, and COMPLEXITY)

1. case study: 1 person
2. cross sectional: 1 group
3. longitudinal: 1 group over time
4. mixed cross sectional/longitudinal: CROSS-SEQUENTIAL: many groups over time

When would the case-study option be useful? What is an in-class slides example?

- need to obtain an in-depth appreciation of issue/event of interest in its natural, real-life context
- 1 person OR event

e.g. case study progressive resistance training during pregnancy (before, during, and after pregnancy while doing resistance training)

When would a cross-sectional design be useful? (5)

Measurement of individuals:
- at given age
- only ONCE in the sample

- Snapshot picture at the age/sex/specific group
- Provides info on GMD + physical activity STATUS
- Variability WITHIN the sample group

When would a longitudinal design be useful?

- provides info on STATUS + CHANGE over time
- RATE of change in growth/maturation

When would the mixed-longitudinal design be helpful? What are 2 of the MULTIPLE cohort approaches to studying GMD? (e.g. 3 cohorts)

BOTH:
- SAME start time/duration of study, DIFF start + end ages
- individuals measured repeated times

1. NO overlap b/ween cohorts (diff. individuals)
2. WITH overlap b/ween cohorts

What are the pros and cons (5) of having a true LONGITUDINAL study?

- takes 20-25 years
- expensive
- LONG term research team required (commitment)
- commitment of PARTCIPANTS
- tech changes over time

What are the pros and cons (5) of CROSS-SECTIONAL studies?

- Short term study
- Less $$$
- Shorter commitment of researchers and participants
- Technology more stable

HOWEVER: careful SAMPLE SIZE (should be accurate to the population you are examining) calculation to be true cross-section of population, information on STATUS

What are the pros and cons (6) of MIXED-LONGITUDINAL studies?

- Recruit participants at different starting ages (e.g., age 0, 4, 8, 12, 16)
- Measure each group for four years
- Overlap of groups at age 4, 8, 12
- Then you can compare: 0-4, 4-8, 8-12
- 4 year long research team is more practical

HOWEVER: We can only speculate that we would see similar results in a true longitudinal design, but we cannot make those exact inference (DIFF. people at DIFF. stages in the study, not true longitudinal)

What are we taking measurements of? (3) What 2 underlying processes are being observed?

1. dimensions
2. performance
3. level of activity

UNDERLYING PROCESSES
1. stages of maturity
2. patterns of activity

What devices can be used to take these measurements of GMD? (6)

1. ultrasounds
2. scales
3. calipers
4. ergometers
5. accelerometers
6. tape measures

When are ultrasounds usually used?

- prenatal growth assessment

What are 5 pieces of information derived from ultrasounds (ultrasonography) during PRENATAL GROWTH assessment (PGA)?

1. fetal NUMBER
2. fetal AGE
3. fetal POSITION
4. potential deformities
5.fetal SEX @ 12 weeks

How does an ultrasound work? (2) How does it benefit the child/healthcare provider? (2)

- HIGH frequency sound waves --> through abdomen via TRANSDUCER device (shows DISTANCE that wave travelled)
- sound waves RECORDED --> turned into PHOTO/VIDEO of baby

BENEFIT:
- evaluate baby's GD
- some cases... evaluate PROBLEMS to help confirm DIAGNOSIS

When does week 1 start (in order to calculate DUE DATE)? Why is it difficult to measure ONSET of pregnancy? (5)

WHY DIFFICULT?
- Sperm enters the female reproductive system, where they compete for a chance to fertilize the egg
- A healthy sperm can live inside a woman’s body for 2-5 DAYS!!!
- Sperm must reach a released egg
- Fertilization process is 24 HOURS
- Fertilized egg will travel through the fallopian tube, enters the uterus in another 3-4 DAYS

What is the period of the egg? Embryo? Fetus?

EGG:
- first 2 weeks after fertilization
- after second week, cells IMPLANT onto uterine wall

EMBRYO:
- weeks 2-8 of PRENATAL life

FETUS:
- weeks 9-40

What is the state of prenatal growth at week 5?

- cells BURROWED INTO UTERINE WALL
- measures around 2mm end-to-end
- FOUNDATIONS for all organs in place
- baby --> INSIDE AMNIOTIC SAC (bag of fluid=protection)

--> about size of a bristle on hair brush!

What happens at week 8?

- switch from embryo to fetus

What is the state of prenatal growth at 9 weeks of fetus?

- head straightened out + more fully developed
- EARS growing, visible toes = looks more human
- development of ESSENTIAL ORGANS: heart, brain, lungs, kidneys, and liver

--> size of a piece of macaroni!

What is the state of prenatal growth of the fetus at 11 weeks?

- heart formed + pumping
- brain developing still
- nerves + muscles begin to work together

--> size of a brussels sprout!

What is the state of prenatal growth of the fetus at 14 weeks?

- sex becomes apparent
- almost 3.5 inches long
- head = rounder

--> size of a nectarine!

What is the state of prenatal growth of the fetus at 18 weeks?

- hiccup
- yawn
- swallow

--> length of a baby shampoo bottle!

What is the state of prenatal growth of the fetus at 22 weeks?

- eyelids still fused shut, but EYES MOVE
- tear ducts forming + has eyebrows / little tufts of fine hair
- baby is more responsive to external stimuli

--> size of an avocado!

What is the state of prenatal growth of the fetus at 30 weeks?

- hands formed, fingernails growing
- baby is grabbing their feet
- hair growing
- kicking

--> size of a cabbage!

What is the state of prenatal growth of the fetus at 40 weeks?

- avg. full-term 40-week baby: measures 20.2 inches from CROWN to HEEL
- weighs 7.6lbs
- lungs are LAST organ to finish developing

--> size of a watermelon!

PRETERM BIRTHS: What is Amilla's story?

AT 22 WEEKS:
- born in 2007
- FIRST BABY known to have survived at less than 23 weeks (22)
- 25 cm
- 283g or 0.62lbs
- most PREMATURE baby to ever have survived

Who was the most premature baby to ever have survived? What was the baby's height/weight/weeks born at?

AMILLA
- 22 weeks at birth
- 25cm
- 0.62lbs or 283g

Who was the SMALLEST surviving premature baby to survive? What was the baby's height/weight/weeks born at?

SAYBIE
- 23 weeks at birth
- 8oz or 0.5lbs (HEALTHY WEIGHT SHOULD BE: 5-8lbs)

Are there risks if the baby is overdue? (posterm)

- it's normal if baby arrives earlier/later than due date as it's only an estimate
- may appear ABNORMALLY THIN

What are the different terms of pregnancy? (5)

PREterm: <37
EARLY term: 37-39 weeks
FULL TERM (optimal birth outcome): 39-41 weeks
LATE term: 41-42 weeks
POSTterm: > 42 weeks

Why might some post term babies appear ABNORMALLY THIN?

- not receiving sufficient nutrition at the end of pregnancy
- function of placenta DECREASES at the end of preg. = fewer nutrients + less oxygen to fetus

POSTNATAL GROWTH ASSESSMENT: What is somatic growth measurement? What is an index that was mentioned in this measurement?

- somatic cells: cells other than sperm/egg (germ cells)
- NORMAL somatic growth req. hormonal + metabolic + other growth factors
- describe physical growth parameters over time

3 MOST COMMON MEASUREMENTS:
1. weight
2. length
3. head circumference

PONDERAL INDEX: commonly used for low birth weight babies - like calc. BMI

What are anthropometric measurements? (4)

- set of standardized techniques to systemically measure body/segments
- defined LANDMARKS (bone)
- specific POSITIONING
- appropriate instruments

What information does measuring the head circumference give you? How would you measure it?

- IMPORTANT from BIRTH to age 3-4
- shows BRAIN GROWTH
- measure: tape measure above eyes

What information does measuring the infant length give you? How would you measure it?

- use base board stretch + lay down child = measure
- baby grows 1 inch/month (first 6 months)
- grows 0.5 inc/month (6-12 months)

What factors can affect an infant's height/length/weight?

- gender
- sleep pattern
- physical activity
- overall health
- genetics
- nutrition
- born premature/past due date
- SINGLE baby weight > MULTIPLE baby weight

MOST IMPORTANT: child has a HEALTHY GROWTH TREND rather than their growth being compared to other children

LIFESPAN GROWTH MEASUREMENTS

- anthropometric / tape measure
--> standing height (shoulder blades, butt, heels touch tape)
--> sitting height + decomposing stature
- research connects sitting height to disease/nutrition levels
--> waist circumference= assess obesity-related health risks - STANDING tape measure across belly button, measure on EXHALE

LIFESPAN GROWTH MEASUREMENTS (anthropometric): What are calipers?

- skinfold
- indicator for subcutaneous adipose tissue
- change associated w GMD
- 12 sites for relative fat distribution of extremities + trunk
- MOST COMMON FOR GROWTH: triceps + subscapular
OTHER: medial calf, suprailiac, abdominal

What are the assumptions, challenges, and value of skinfold assessments (calipers)?

ASSUMPTION:
- Double fold of skin and adipose tissue (no muscle)

CHALLENGES:
- Inter-rater reliability (meaning if two different people perform the same skinfold assessment on a client, will they get the same results?)
• PAINFUL if done incorrectly

VALUE:
• Inexpensive / easy / identify direction of change

What can you do with the Jackson and Pollock equation?

--> calculate body density
- % fat
- fat weight
- fat-free weight
- body weight goal

OVERALL: What assumptions can you come to with anthropometric data in general?

- Accurate and reliable data
- Standardized technique (dec. variability)
- Training of the researchers – compare measurement between trainees and expert anthropometrists (make sure everyone is doing it in the same way)

OVERALL: What measurement errors can you have with anthropometric data in general?

- Intra-rater variability: how consistent an individual is at measuring
- Inter-rater variability: how consistent different individuals are at measuring the same task
- Instrument variability: pertains to the tool used to obtain the measurement

OVERALL: What systematic errors can you have with anthropometric data in general?

- Consistent over / under measurement (technique, instrument calibration/brand)
- Leads to a directional error = bias in data set (not good)
- To CONTROL for this: repeat measurement on same participant, more than one researcher measure same participant, over
multiple time intervals (1 month later)

OVERALL: What technical errors of measurement can you have with anthropometric data in general? What participant variation may occur?

- instruments/user error or measurement
- kg/cm/lbs

PARTICIPANT VARIATION:
- physiology- muscle tension, sweat (skinfold) = impact results
- temperaments, cooperation, anxiety = impact participant's readiness/ability to give you data

What are the gender differences in dimensions in pre-adolescence, adolescence, and adulthood?

PRE- ADOLESCENCE:
- minimal diff.

ADOLESCENCE:
- earl- females have size adv.
- growth spurt at younger age
- males surpass girls in most dimension after growth spurt
- at 18 years old, both males/females reach 100% full height

ADULTHOOD:
- avg. males are larger

BODY SIZE: What are the most common measurements for body weight (mass) and body height (stature)?

BODY WEIGHT/mass:
- all tissues: bones, fat, organs
- standardized measurement (scale)

BODY HEIGHT/stature:
- linear measurement
- plantar surface to vertex of skull
- composes of: feet, legs, trunk, neck, skull

What is diurnal variation?

- changes + fluctuations over the course of the day

When are we the heaviest? Tallest? Why?

HEAVIEST:
- end of the day
- affected by nutrition, hydration, physical activity

TALLEST:
- morning
- verbal discs UNCOMPRESSED (unloaded) at night
- weight bearing will shrink disks 1cm
TO CONTROL FOR THIS VARIATION: collect participant data at the same time each day

CDC vs. WHO vs. AAP: What are their stances on growth charts?

CDC:
- provide growth charts that include older data and are a reference for how children grew during a period in the United States
- recommends using the WHO chart for all babies during first TWO years

WHO:
- growth charts contain more data from breastfed babies

AAP:
- agrees with the CDC recommendation

What can you do with the ratio between weight:stature in pre-adolescence, adolescence, and post-adolescence?

- studies on GROWTH, PHYSIQUE, OBESITY RISK, UNDERNUTRITION

PRE:
- indicator of nutritional stature
- too heavy/adequate/too light for height

ADOLESCENCE:
- growth spurt avg.
- height first and then weight follows- catching up

POST:
- useful tool for BMI

What can you do with the ratio between sitting height:stature?

- 2nd most COMMON ratio in growth studies
= sitting height/stature x 100
- proportion of height accounted for by trunk/leg length
- compare diff. b/ween individuals

e.g. if child A leg length is 54% of stature and child B is 46% stature = child A has LONG legs for stature comp. to child B

What can you do with a hip:shoulder ratio? What is the special terminology for this?

Bicristal breadth: Biacromial breadth
= bicristal/biacromial x 100

- helps track proportional changes in ratio
--> most apparent during adolescence for athletes
--> swimmers/gymnasts
- female athletes vs. non-athletes: wider shoulders in female athletes comp. to hips