Physical activity in children 1-5 Flashcards
Define Physical activity
Any bodily movement produced by skeletal muscle that results in a substantial increase in energy expenditure above resting levels
Define exercise
PA that is planned, structured, repetitive and results in impovement or maintainence of ne or more facets of physical fitness
Define training
Systematic, specialised practice for a sport/ discipline for most of the year or for specific short term programmes
Define physical fitness
A set of attributes that people ave or achieve that relate to their ability to perform PA
Define SB
Any waking bevaviour characterised by energy expenditure <=1.5MET while in a sitting or reclining posture
The WHO health definition
HEalth is a state of complete physcial mental and social well-being not merely the absence of disease or infirmity
Describe the behavioural epidemiology framework (diagram)
Establish links - Exposures and health outcomes e.g. PA/SB Measure PA/ SB - Needs an accurate measuring device Correlates/Determinants Intervention Translation into practice
List 6 differences between children and adults
Different body composition
Different body size/ proportions
Different thermoregulation
Changes in stance
Changes in caloric utilization
Different physical and social developmment
All mature to adult state at different rates
Describe post natal age descriptions
Neonate = birth to week 4
Infant -5 to 1
Early childhood - 1-6 (primary dentition)
Middle childhood 7-10 (permanent dentition)
Late childhood - pre-pubescent
Adolescent - onset of puberty to maturity (about 5 years)
Types of growth
Changes in size of individual as a whole or in parts due to:
Hypertrophy
- increase in cell size
Hyperplasia
- increase in cell number
Accretion
- fusion or combining of different componenets. (increase in intracellular substances)
What is maturation?
The process of being mature (physcially normal) or progressing towards the mature state
Occurs in all organs/systems
2 components: timing and temp
Wide variation in both
What is development?
Biological: Relating to process of differentiation (e.g. intrauterine)
Behavioural: Relating to development of competence in a variety of interrelated domains e.g. cognitive, emotional, social, moral ect (culture specific)
Acquisition and refinement of behaviours expected/ set by society
Growth principles - maturity explain
All children possess the potential for a pattern of growth characteristically human; every child passes through the same stages as every other child.
Tempo and timing may change
WIde variation in timing tempo and magnitude
How varied can variation in biological maturation be between the same sex/ age?
5 years difference in biological age
Average years earlier girls mature than boys? implication?
2
Maturation status link to success in sport? why? Some sports this is not true?
Early maturers develop more FFM, and are strong and more athletic than their peers so may enjoy/ practice sport more.
Sports where being smaller is better e.g. jocky, diving, dance (aesthetic sports)
Average duration of onset of puberty to maturity
5 years
Describe pattern of growth long term
sigmoidal shape.
Inititially fast, slows to age of 12, then increases again.
Boys PHV = 14, girls =12
Describe pattern of growth day by day
step-wise/ saltation growth
Growth occurs in 24 hr periods followed by stasis periods.
2-100 days apart.
Adds 0.5-2.5cm
At what age does height between boys and girls differ?
14 - PHV in boys
Give 4 reasons why males are taller than females?
Later growth spurt so 2 more years of growth (average 5cm a year from this)
Stop growing later- 18yrs vs 15
Longer growth spurt
More height gained per year during growth spurt (extra 2cm/yr)
Describe the body mass distance curve and difference between boys and girls
Sigmoidal
Doesn’t stop until later (filling out)
Similar to height - difference at 14
Influences on body mass growth pattern x4
Height is dependent on genetics (unless malnutrition).
Training (lean mass)
Diet
PA
Describe the BMI distance curve
Rises quickly initially
Descrease until age 3-7 (adiposity rebound) mean around 6. then increases to 18 years. Boys continues to increase longer “filling out”.
More similar in boys are girls
How are BMI cut offs for children calculated and what is a flaw with this method/ what is good
Mathematical formula applied to adult cut offs.
Based on chronological age not biological age.
Does not reflex adiposity/ body composition - heavily influenced by height and lean mass.
Height explains decreases when diet and activity levels have remained constant.
Good correlation with fatness estimates in children on large scale but large variability present.
What causes changes in BMI in children?
Height
Exercise (lean mass)
Diet
National Child measurement Programme describe and limtations
Reception and year 6 pupils are weighed in Uk and BMI calculated. Allows national surveillance (good) and individual feedback. No evidence feedback is useful - may not be accurate (due to BMI) and may hamper e.g. demotivate
Describe how body proportions change with growth
Larger proportion of head in first .5 year of life.
Growth in the proportion of limbs at 9 months followed continual increase in the proportion taken by legs
How does sitting height differ between males and females?
Pre pubertal - same same
Post pubertal - males have longer legs but trunk is the same so sitting height is the same
How does shoulder to hip ratio vary between sexes?
LArger in males - better swimmers
Describe stance at different ages.
18 months bow legs
3 yrs knocked knees
6 yrs straight legs
Describe the differential growth rate in lymphoid, neural and genital systems
lymph grows to peak at 12 then regresses
Neuro early
Gondo late
Descibe thermoregulation differences between children and adults
Larger SA:Body
Difficulties with longer legs?
With growth spurt comes longer legs - heigher centre of gravity so less stable and coordination - factor in pubertal athletes- may impair performance. As people get taller proportionally more weight on top.
From Malina 20014, Difference between Motor competence and motor development? What do these reflect?
Competence = acquisition and refinement of skillful performance
Development = attainment of movement milestone e.g. walking
Correlate
Genetics (NM development) and environmental exposures
From Malina 20014, describe how context of PA varies and implications
gender/age/ culture different things seen as good/bad
e.g. homework seen as good
From Malina 20014, Difference between FM and FFM growth pattern
FFM - more sigmoidal with clear adolescent growth spurt
FM - more gradual
From Malina 20014, different ways of assessing skeletal age and gonadal age and issues. Better measure?
Xray - skeletal age - radiation - of hand and wrist
Tanner stages - examnation or self assesment - both seen as invasive
-wide variation in skeletal age with each stage -especially some without overt stage e.g. prepubertal - no info on how ling they have been in that stage
Normally in girls is age at menarche
PHV also used as an indicator
-Requires 6-7 years longitudinal height measuring, only be used looking back (post facto indicator)
From Malina 20014, Describe trends in performance and puberty, difference between boys and girls
Improves with age, boys better than girls
Boys accelerate in improvement in adolescents.
Girls levels off at 13 to 14 years (average)
Certain tasks see spurts in boys
Peak gain in static strength, power and functional strength after PHV (similar to muscle mass)
Peak gains in speed, agility, lower back flexibility before PHV
Legs experience maximal growth first in boys that may influence running speed and lower trunk flexibility
Girls
Less data
Similar trends but lower magnitude
Related to PHV not menarche (however occurs after PHV)
From Malina 20014, describe trends in PA through childhood - relation to maturity
Gradually increases to peak between 12-14 and subsequently decline
Boys more active
Attenuated when maturity status is controlled
Decline in MVPA from 9 to 15 in both sexes
Higher on weekday
Genotype and common environmental influences from twin studies
Biological maturity an indicator
From Malina 20014, Is regular PA essential to support normal growth and maturation? potential times when PA is bad?
What type and amount is needed for bone, muscle and adipose health outcomes.
Extended to include CVS and metabolic disease in youth.
Youth that regularly exercise have less aduiposity
Changes in strength independent of changes in body comp with resistance training.
Strength studies should account for maturity
Overtraining way have negative effects
From Malina 20014, is BMI the most appropriate metric for overweight and obesity in youth?
Not a measure of body comp
Correlated with FFM and FM in normal wieght youth
Several cut off value available
Ethnic variation in comp, distribution and BMI
Can be used with skinfolds - specific to pubertal status (Tanner stages).
Assuming maturation overlooks variation - doesn’t account for biological maturity
BMI considered part of physical fitness but also influences fitness
From Malina 20014, What is the implication of the adiposity rebound for subsequent weight status and PA
BMI increases around middle childhood at 5 to 6 years (adiposity rebound)
Earlier rebound = increased rates of relative weight gain, fatness in middle childhood and high BMI in adolescence and young adlthood.
Skeletal age does not predict time of rebound but does later in life (late maturation in later life = late rebound)
Early menarche also associated with early rebound.
Increase in adiposity actually occurs after BMI rebound - first part due to FFM
Better to call BMI rebound
low PA and increased TV in rebound age range may influence timing of rebound?
From Malina 20014, What is the role of PA in prevention of unhealthy weight gain during childhood and adolescence?
More activity 4-11 may attenuate rebound and later adiposity
Intensity and duration?
Variation in growth (timing and tempo) mean that hard to say unhealthy weight gain.
From Malina 20014, Is there a critical level of movement proficiency that facilitates PA and sport participation in children and adolescents
Deficiency causes difficulty attempting complex activitiesdevelopment of motor schills correlated with movement proficiency, find other correlated?social barriers add to this?
Though middle childhood as when children start programs
From Malina 20014, What is the role of movement proficiency or lack of proficiency in the development of obesity?
Through causing inactivity
Variance in PA explained by motor proficiency is small
Obesity - lower motor coordination and performance related fitness tests
Coordination less in overweight and obese children
Which way round?
Does PA mediate?
From Malina 20014, What is unique about individuals who do not respond as expected to PA programs or interventions?
Interventions neglect variability of a sampleDespite overall increase some decrease.
What characteristics?
From Malina 20014, Is adult-based concet of health-related physical fitnes relevant for children and adolescents? Based on what? What affects this? CVS?
Based on:
Fitness improves healthPA in child influences PA in adult
Current data - moderate relationship between PA in youth and adulthood
Many cultural influences on thiscomplexity of growing up
What factors influence the tracking (maintainence) of activity
Also includes CVS risk factors?
Childhood PA, CR-fitness and adiposity independent predictors but limited explanation of variance
From Malina 20014, What is the impact of individual differences in biological maturation on fitness and performance during childhood and adolescence? Does maturity-associated variation persist into adulthood?
Data more for boys, also influences growth.
Early maturers = advantage in strength, power and speed tasks in boys - characteristic in male athletes.
Average or Late maturity in females - preferential selection?/ development reasons?
PHV used as marer
From Malina 20014, early menarche correlates to what health outcomes?
higher BMI, elevated fatness, and poorer metabolic profile
From Malina 20014, What is the influence of individual differences in biological maturation on PA? An important corollary of this question is methological: What is the validity of non invaseive estimates of biological maturity status and timing
Indirect affects of societal and cultural factors
Nonvasive as skeleta age requires radiation, invasive sex characteristics (can use self-assessments but some find these invasive too), PHV needs 6-7 years of longitudinal height records, recalled age at menarche has limitations (late sign).
Non invasive measures:
Percentage of predicted adult stature at time of study
Moderate concordance with skeletal age
predicted maturity offset
Maturity offset/ Predicted age at PHV
Give 2 reasons why measuring PA is important
Variability in human growth - need to capture
Need accurate PA/ SB for the flow diagram - to influence health outcomes
Very sensitive to measure effect of interventions - may be 5%
Why are guidelines and strategies for PA now more important?
Want schools to promote 30 minutes of PA a day - interventions relevant
Now Ofsted have this in their criterea
Describe the settings and complexity of children’s PA
Transport - active vs sedentary
School - SB in lesson
At home - most of the time engaged with screens
Especially complex as intermittent nature - most less than 2s in duration (difficult to capture via questionnaire)
What to measure with PA/SB?
Used to be FITT - freq, intensity, time, type
Look at energy expenditure (convert) - relationship with health outcome
Now increasingly look at who, what, how, why, when, where As we are gathering info to try and change Socially - who are they with? Where? Green space? Urban? Sports club? When? Golden window - 3-6pm What? Intensity and type e.g. Movement or sport etc. Why? Crucial - hard to understand
Describe common methods of monitoring PA and the validity/ feasibility trade off
Questionaire
Diary
Pedometers
Steps
Total number
Intensity e.g. Per minute
Accelerometers
Heart Rate Monitors - invasive? Good for intensity, limited by stress, caffeine, food
Direct Observation - Time intensive, (maybe subjective) shown to be accurate
Indirect Calorimetry (gases), Doubly labelled water
Calorimetry
Advances might make this more feasible/ valid
Challenges with questionnaires (x5)
Cognitive burden - takes effort - development and maturation issues (10 onwards) wording and number of questions may pose an issue. Longer ones can take 20-25 minutes
Who completes it? - parental proxy report (more accurate at younger ages)
Social desirability - “everybody lies” trying to overreport PA 25-30% overreporting
Inaccurate recall - Especially as most is in small bouts (more than adults)
Is the last 7 days typical? E.g. Ill or competition training (also accelerometers)
Also intermittent nature of PA
Challenges with accelerometers (x5)
Returning of the monitors
Absence, forgotten 5-10% lost in field
Compliance
Removal of sleep (naps) - partition from SB (mainly preschoolers having naps)
Did someone/ something else wear the monitor - practical issues.
Reactivity - Hawthorne event (observer effect) - appear more socially desirable - start doing loads of PA. Human/ subjective factor still affect.
How do accelerometers work?
Get acceleration wave
Magnitude (relatively proportional to energy expenditure) (not always e.g. Weights)
Frequency
Use magnitude and frequency to ensure that movement is human - can remove via filter.
Describe extent of Hawthorne effect with accelerometer
5% more PA on the first day, more marked in younger children.
Get to wear 8 days and cancel out first day
Describe different locations of wearing accelerometers
Physiological reasons for trunk - related to energy expenditure
Good correlations with wrist too.
More SB at hip than wrist (orientation and wrist movement in wrist)
Few wrist “cut points”/ comparability
Children are uniques - waving arms and writing
How many days are needed to reliably estimate outcome variables in children? accelerometer
2 and a bit - but children are more variable so 4-7days needed (1 weekend day)
Describe how accelerometer cut points are created and issues with these?
Energy expenditure of kids in the lab using accelerometers
Create thresholds
E.g. Above 3000 is vig
Get counts per minute
Apply programs to calculate intensities
Variation in individuals can affect due to range of movement.
Different cut points has resulted in comparibility issues between different countries uless you have same cut points, measures, stats ect.
Impacts results
Describe accelerometer epochs and issues
(summary time intervals)
Sensitive to MVPA vs sensitive to SB - time smoothing
Due to this integrated data you get number of counts in a window within a minute. Need to apply appropriate cut offs e.g. 5 sec cutoff for 5 second data. Risk of underestimating vigorous data.
Tend to be 5-15 seconds - used to be 60 but would miss out data.
Different questionnaires for SB and advantages/limitations
IPAQ - just asks mins and hrs you have been sitting or lying
Domain specific e.g. sitting and music, homework - lots of boxes
-people tend to overeport
-Wording out of date
-laborious
-Cognitive burden
However
-better than global due to breakdown - better measure of sitting but overreprting
Objective measures of SB describe and limitations (brand names please
bjectively measured Accelerometers (Actigraph) - absence of movement (below 100 cpm often), an assumption. <100 counts could be lying, sitting or standing (only first 2 are true SB) No one has looked at misclassification between adults and children. Inclinometers E.g. ActivPAL (also accelerometer) Time spend in SB (Sitting/Standing) Typically mid-thigh Expensive Also standing vs stepping Inclinometer assessed SB Posture sensor Also assesse
Future developments in accelerometer waveform
Find type of behaviour/ activity based on waveform
GPS use?
may be combined with accelerometer to get setting info
According to Loprinzi 2011,What does accurate measurement of PA/SB allow?
Relationship between SB/PA and health outcomes
Dose of PA to elicit outcomes
Determinants of PA/SB
PA/ SB interventions on prevalence of obesity/overweight
According to Loprinzi 2011, What factors influence measurent choice?
Age Sample size Respondent burden Method/ delivery mode Assessment time frame PA info required Data management Measurement error Cost (instrument and administrational)
According to Loprinzi 2011, Describe types of self report measurement
Can be in interveiws, diaries or self-administered
Benefits of self report measurements
Simple, inexpensive
Type and context of PA in large sample
According to Loprinzi 2011, Limitations of self report measuements (add)
Item interpretation Recall Sporadic activity patterns and short duration make it difficult Social desirability Often overestimate Not good under ten
According to Loprinzi 2011, Proxy-report describe, benefits and limitations
Item interpretation Recall Sporadic activity patterns and short duration make it difficult Social desirability Often overestimate
According to Loprinzi 2011, Heart rate benefits
Objective, indirect assessment of frequency, intensity and duration of PA.
Inexpensive and unobtrusive
According to Loprinzi 2011, Heart rate limitations (x6)
Weak relationship between HR and energy expenditure during high and low intensity levels.
Measurement error thereforee due to high percentage in sedentary and light of children
Relationship with HR also influenced by age, body size, environment, stress and cardioresp fitness.
Delay in HR response after movement (mask intermittent pattern of children)
More specific for methods that control for variation
Variation in resting HR definition and protocol used to measure resting HR
Influencing HR factors
Impraticle in large studies.
According to Loprinzi 2011, Describe different measures of heart rate that can control for individual differences and limitations
- Physical activity heart rate (PAHR) index - mean HR minus resting HR.
- Percentage of HRs that are 25% above resting HR (PAHR25)
- PAHR 50
According to Loprinzi 2011, Gold standard HR testing
Assess relationship between HR and O2 consumption
E.g. HR flex method - resting average found
REASONABLE ACCURACY AT GROUP LEVEL but at individual level large diff with doubly labelled water.
According to Loprinzi 2011, What are the benefits of accelerometers?
Battery of accelerometer (5s epoch for 2 weeks) and caturing intermittent data, overall strong positive correlation with indirect calorimetry, high correlation between left and right (reliable) both positives. Add**
According to Loprinzi 2011, Uni-axial vs tri-axial accelerometers
Childrens activity thought to be in multiple planes e.g. tri-axial (Tritrac) planes may be more accurate, few studies examine if more accurate than uni-axial for energy expenditure or PA intensity.
Most studies showed similar correlations.
According to Loprinzi 2011, Issues with number of monitoring days and ideal times to measure children and adolescents to 0.8 reliability
Too long = burder
Too short = not reflective of habitual
4-5 days = reliability of 0.8 in children and 8-9days for 0.8 in adolescents
Sig diff in weekday and weekend so should include 1 weekend day.
Cut-offs and equations for predcting energy expenditure or time in different intensities using indirect calorimetry.
Multiple count cut-points exist - no population-based data.
Not good for individual or group level energy expenditure but reasonable for MVPA in children
Hard to compare data
According to Loprinzi 2011, Issues with calibration of accelerometers add*
Variation in cut offs
Not Good for individual or group, Reasonable Mvpa in children
Hard to compare data
According to Loprinzi 2011, Pedometry benefits
cost-effectuve and well-tolerated alternative to accelerometry
Insensitive to certain modes of exercise such as bicycling (similar to accelerometry)
Valid in children of PA, strong assocaitation at self paced walking speeds but less at lower speeds.
Strong assoc with acceleometer and O2 uptake
Reliable in children
Similar across attachment sites
Normally ambulatory movement contributes to the majority of overall PA in populations so good
According to Loprinzi 2011, Pedometry limitations
Not good for lower spped
Some sports cant measure (bicycling)
According to Loprinzi 2011, Direct observation describe
Free-living PA is objectively classified for a predetermined period of time
In natural setting
Also provide type and intensity
Variety of diff settings
Give contex - other factors related to behavior
Can be coded from videotape and be entered directly into computer/ softwar
Valid and reliable- video increases
According to Loprinzi 2011, Direct observation limitations
Takes time
Variable measures
Dependent on highly trained pbservers and specific protocol being followed
According to Loprinzi 2011, Describe doubly labelled water technique
Total energy expenditure in a 2 week period by directly measuring CO2 production
Heavy water - containing 2 isotopes of deuterium-labeled water and oxygen-18-labeled water. Deuterium labeled water eliminated through water loss and Oxygen 18 water as CO2 and water loss.
Difference between elimination rates is directly proportional to CO2 production or energy expenditure
According to Loprinzi 2011, Benefits of doubly labelled water technique (4)
Accurate within 10% of calorimetry
Non invasive
Natural setting
With indirect calorimetry can measure individual components
According to Loprinzi 2011, Disadvantages of doubly labelled water technique (4)
Expensive
Availability of stable isotopes
Inability to determine intensity, duration, frequency of PA and components of energy expenditure
Not good on population level
According to Loprinzi 2011, Describe the measurement of SB and limitations
Often by TV viewing or other technologically based SB but only partial picture in a typical working day e.g. homeowrk, transport, sitting and talking.
Self reort survery, diary, proxy, direct of screen time
Little have been psychometrically tested
Varying reliability
Many subjective
Cant use PA as only a weak correlation between PA and TV viewing
Accelerometry use - count cut points, age specific
Cut point depends on epoch length, better for PA
Why should prevention occur with grandma?
Tracking between health behaviours between generations - prevention should even occur with grandmother
Why is it not a level playing field at birth?
Not all children have the same ability to perform PA at birth
What is life course epidemiology?
The study of long term effects on later health or disease risk of physical or social exposures during gestation, childhood, adolescence, young adulthood and later adult life.
What is DOHAD?
Developmental origin of health and disease.
Undernutrition at gestation
Important RF for health - CVS and metabolic (DM)
Explain the permanent impact of undernutrition at birth
Due to fetal programming
This way a permanent impact - disease risk for ever by changing strucutre and metabolism
What is the Barker hypothesis?
Birth weight is a strong predictor of mortality And CHD before 65 years Even large babies had a low RF for CHD Smaller - less nutrition or quality A gradient exists
How is birth rate related to deaths from CHD before 65 years?
up to 9.5lb there is a decrease
> 9.5lb increased risk but still less than 8.5
Describe crucial period in growth and development. What questions surround this? and what reccomendations exist?
First 1000 days may be crucial (2-3 yrs)
Altered growth - predisposed to disease, even mental health
Breast feeding mitigate some of risk and what foods weaned onto and when?
Now recommended at 4 - stay away from sugary foods
Continue to be breast fed for >1 yr of life
Many health conditions originate in early years, it’s a critical period and developmental plasticity can impact future health.
What is developmental plasticity? Describe variation
The ability of one genotype to produce more than one phenotype when exposed to different environments
E.g. Height - undernutrition - negative impact of height potential
Some things may be highly variable e.g. Ability to lay down body fat? Even air pollution may affect adiposity of child.
Different impact of gender interuterine
May affect immune system in later life also
May change ability to perform PA
Some facotors may be highly variable and have a strong genotype- environment interaction
How is metabolism altered by slow growth in pregnancy? Consequences?
Slow growth in pregnancy (underweight at body) then grow really quickly afterwards (compensatory) - metabolism altered (programmed to be in scarce food environment)
Affect immune system and metabolic disease risk - may give a survival advantage in nutrient scarce environment e.g. earlier fertility
Adiposity rebound and birth weight relationship? Double whammy?
LBW/SGA increase in early AR - both RFs for increased adiposity
Issues with studying DOHAD
Observational only Many confounders Need big sample sizes Ethical implications - can't randomise Take a long time
Describe evidence for DOHAD from natural experiments (not findings)
The hunger Winter
Western Netherlands 1944-45 (6-7months)
7 months people were only getting 500-1000 calories per day
Widespread starvation including pregnant women
Population impact
Reduced fertility in this period
Severe stress also
Affected weight gain and maternal BP
Well fed beforehand
Research potential
Effect on different gestations
As it was 7m period - able to look at different points of gestation to see if it had any impact
Comparisons groups not affected by famine
Born prior to famine
Netherlands have good health rocord
Good data in netherlands - also from conscription got later stats
Short term impacts from Netherland’s winter
Same BW if in 1st/2nd trmesters,
-300g in third trimester - sim to smoking
Longer term impacts from Netherland’s winter
Reduced lipid and glucose reg
Female offspring greater and earlier fertility
Female offspring breast cancer (1st trimester)
Higher BMI (1st trimeter)
Greater than if just low BW
Likely to have adipose, shizophrenia and diabetes
Benefits of natural experiments for research?
Exposure preceedes outcome
Examine the outcome with differing exposure strengths/ timing
Adjust analysis for other confounders/ mediators
Explain the thrifty phenotype - nutrition
LBW/ undernutrition in gestational period effects epigenome - conveys survival advantage in nutrient scarce environment but increased susceptibility to metabolic disesae
What is the epigenome?
Compounds that can be added to DNA to regulate their activity
How does early growth impact on PA and food choices?
Decreased motivation and more sedentary lifestyle
Individual variation in types of foods - prefer high nutrient foods e.g. Sugar
Food choices may influence PA
Psychosocial impacts
May affect amount of fat and fat distribution - apple vs pear
PA:
If not as able due to disease ect.
More adiposity, may get chosen last ect and have less enjoyment.
Secular trends (do not vary) in AR and motor control, LBW/SGA (small for gestational age) at higher risk of poor motor control.
Risk of increased SB
Decreased variety of activities that children take part in
Risk of a preterm birth (<37 weeks)
Resp infection and asthma
Decreased lung capacity
Decreased PA
Risks of a very low BW (1.5kg) <7lb
Decreased strength, decreased endurance, decreased flexibility
How may timing of birth influence PA?
Start of the year- more athletes vs end of year
Improvements to mortality risk from LBW by PA?
May mediate early life risks
What is switching ‘on’ and ‘off’ of genes?
What affects this in mice
Methylation/ demethylation.
Food intake
How do genetics affect PA?
Lead to adiposity/ epigenome - less likely to engage in sport as children/ not get picked etc.
50% genetic component
Evolved for activity and food scarcity
How does PA affect genes? Clinical significance, evidence from twin studies
Switches on genes both short term and long term - positively influences: metab, muscl growth, inflammation, blood formation.
1.8 x changes 7000 genes.
Interactions are numerous and varied, different environments benefit different people - personalised medicine/ prevention.
From twins - short exposure to PA changes metab (metabolomic changes) - remain after PA.
Why do effects of PA differ?
Many interrelating factors: Genetics Gestational period Newborn exposures -Different phenotypes Postnatal health -Environment -Delivery mode -Gestational age -Physiological adaptations
Most studies on PA, do they really look into levelling the playing field?
Don’t consider LBW/ SGA when looking at response to intervention
most young healthy males
Findings from born in brad on level playing field?
South Asian populations need lower BMI (differnt point at which you should be classed as overweight) - new cut points
More likely to be born small gest age SGA or LBW
Higher risk of cardio-metabolic conditions
Children of SA backhround more likely to be obesity
National child monitoring - height and weight at beginning and end of school
Children of SA more likely to obese leaving school.
SA needed to undertake more exercise to have same impact on blood markers
Benefits of PA in pregnancy
Mother -stress relief - Decreased glucose/ improved control -Aid in post preg weight loss - Prep for physical demands of motherhood - Decrease in pre eclampsis and C section Offspring: Benefits to offspring too Better insulin markers Reduction in obesity? Active mum = active child though Better bonding? Long term impacts?
Negative effects of PA in pregnancy?
Decreased athletic performance Greater injury risk Greater laxity of joints Increased tiredness Less resistant to heat stress
Impacts of pregnancy on elite athletes?
No more musculoskeletal problems than normal pops Lost weight quicker Increased strength Decreased aerobic capacity BUT limited evidence
PA recommendation in preggers
Avoid contact sports
Contraindicated if certain clinical conditions
60-90MHR
15 min sessions for 3xpw progressive to 30mins, 4xpw
From Van Deutekom 2015, what were the methods
n=194, cohort
Aerobic fitness using 20-m MSRT (multistage shuttle run test), neuromusc fitness using standing broad jump (SBJ) and hand grip strength.
MVPA and sb with accelerometry
FFM with bioelectrical impedance analysis
LBW = <10 percentile and accelerated infant growth (AIG) s.d. >0.67 weight gain between birth weight and 12 months
Took into acount confounders - SES, Duration of breastfeeding, mat and pat BMI, smoking during preggers
From Vant Deutekom 2015, Resuls
LBW and AIG = lower aerobic fitness (MSRT) adjusted for confounders
LBW alone not associated
LBW and AIG independently associated with hand grip but not after height and BMI adjustment
No association with SBJ (NM fitness)
FFM mediated 75% of association with hand grip strength
FFM, MVPA and SB did not mediate aerobic fitness
No mediating effects on effects of height or BMI gain on variables
Strongest relevance with aerobic fitness - both combined not only one (similar scores to normal children)
Birth weight and weight gain positive with hand grip strength
Using growth as BMI gain not weight gain, was neg associated with both SBJ test and hand grip strength and not mediated.
From Van Deutekom 2015, mechanism that BW and IG affect hand grip strength and aerobic fitness
FFM:
Birth weight and IG related to number of muscle fibres estabolished in early growth, compensating hypertrophy may be inadequate (as grip strength largely due to FFM)
Aerobic: Linked to muscle strength? However FFM did not account for deficits Differences in PA? Nope - mediation doesn’t show SB? Nope Timing of AR Related to setting of Energy balance and risk of later obesity Could mediate fitness
From Van Deutekom 2015, Implications
Support strategies to optimize BW and IG
Target later physical performance and potentially obesity and CVD risk which are associated with suboptimal health
From Van Deutekom 2015, Limitations
Dutch ethnicity, healthy, people who accepted fitness testing (bias) - generalisability
FFM at 5yrs - done at 8-9yrs
SBJ - includes weight
From Van Deutekom 2015, strengths
Objective measures
Reasonably large cohort
Prospective
Many exposures recorded - lots of confounders addressed
What are we looking for with measures of children’s PA
Representative of geography, ethnicities, age groups ect. Accuracy and reliability/ validity Objective measures where appropriate Same/equivalent measures between Sites Time points Populations
Describe Under 5s guidelines for PA
1) Children of pre school age that are capable of walking unaided should be physically active for at least 180 minutes (3hr) spread throughout the day.
2) All under 5s should minimised the amount of time spent being sedentary (being restrained or sitting) for extended periods (except time sleeping) No autonomy in children so amunt of time is dependent on adults Restrain time e.g. with ipad, pushed with buggy
Describe 5-18s guidelines for PA
1) All children and young people should engage in moderate to vigorous intensity PA for at least 60 minutes and up to several hours a day.
2) Vigorous intensity activities, including those that strengthen muscle and bone, should be incorporated at least three days a week
3) All children and young people should minimise the amount of time spent being sedentary for extended periods
In Canada point 3 is less than 2hrs
Why might the 2008 health survey be flawed?
Paper suggests it’s flawed
Questionnaire from interviewer to kids or adults
Overestimation of MVPA by self-report - gross up to 2008
122min of MVPA a day overestimation
Variation in prevalence of PA and SB in boys and girls nationwide
Different patterns worldwide
Problem in developed and developing countries
How did 2012 health survey differ? Findings?
2 in 10 meeting recommendations
Different measure this time
Prevalence of children meeting guidelines from millenium cohort study? Variation in ethnicity
2008-2009 with actigraph 7 years old About half meeting recommendations Boys more active than girls Variances by ethnicity (generally white more than south Asian -may be afterschool periods?)
Trend in activity level decline from Dumith 2011 annually
Decline around 4-6% in boys annually (from 9-12y) but rise in girls
Describe the ICAD and key findings
Taken raw data and re analyse it with set cut offs
Gender disparity more in older children
Variation between countries
Random places in each countries - may not be representative
Age and gender related decline in PA
Only small proportion met guidelines on all measured days (hugely influences by number of days measured)
However 46% of days >60min for boys and 22% for girls.
Issues with ‘met guidelines’ term and other ways of assessing guideline compliance
Look at if they meet the average over week t
Lookif they meet guidelines on everyday studies
If so how many days
% of days they do meet guidelines
More conservative or not?
Most don’t comment
Describe ISCOLE
Different from ICAD as not precollected data, decided what they wanted to do first then did it.
Not representative data for each country
Quite high averages, if not 60 then 50min/day MVPA
Why is it difficult to establish trends from secular data for children? What do trends suggest?
Questions changed in surveys on a whim - hard to establish patters
More from adults (occupational)
Decrease in active leisure, travel, domestic and occupational PA (slight rise in 80s)
Increase in SB
Describe trends in PE time allocation
Decreasing nationwide
Now no recommendation on how much allocation (used to be 2 hours)
Describe trends in outdoor play in UK
Decreased 37% in US, also data from canada - similar culture in UK
1997-2003
Describe trends in UK children’s PA?
Public health England - decrease of 7% in boys, 3% in girls between 2008 to 2012
‘Intuitive’ reasons for decline in PA and rise in SB?
Availability of entertainment
Active transport
Labour saving devices also apparent in children’s live
Increased technology
Eroded out incidental PA.
More Tv, smartphones, gaming
Decline in paper rounds
Family’s spend less time together now?
Children starting young with screen time now
Screen time to subdue children
People annoyed with kids that play outside
Technology always detrimental?
Educational benefits
Geocatching -Pokemon
Active gaming
Describe trends in parent concerns of safety? Clin sig?
Parental concerns over safety
Also new dangers e.g. motorways - physical environment
More restriction on where e.g. street play programmes
Prevalence of active communiting? ways to measure this
16% of primary living within 2 km travel by car aged 5-10
7% youth aged 11-16
Describe trends in car journeys, public transport, walking and cycling in the last 20 years
No more trips but longer journeys in last 20 years
Small drop 10% in walking activities
Cycling remains stable
Most stable
In gen, public transport use has declined
National travel survey
Prevalence of provision and involvement in sport in UK? Much change in school? Variation in boys and girls?
Provision and involvemetn in Uk fairly stable
Some small decline in participation in school (not stat sig) from 08/09 to 14/15 (5-10 only)
Primary school -boys doing more than girls outside of school.
Target, particularly around maturational ages
Boys with higher sports participation
Changes in SB with gender and age?
Time spent SB increasing with age in boys and gals
Girls always higher than boys but pretty much increases proportionally
Increases at weekends
Ofcom media use data findings with age?
Weekly hours with ages
TV similar
Internet increases,
Gaming varies but highest in older age group
How has access to different media changed over time?
Big increase In self reported media exposure in hrs/ week (includes radio ect) between 2000 and 2010
TV hasn’t changed since 60s??? Last couple of years seen biggest change in media use.
Tablet computer ownership increased markedly
Games console use declining
TV usage consistently high
Lapton/ desktop starting to decrease
Lots of access to tech in rooms
In bedrooms all declining too
Tablets taking over!
Media use reflective of SB?
Proxy measure - tend to be sitting but not a given
Smart phone ownership in children by age?
Increases with age
93% by 15
How can we ‘go back in time’- communities? Findings?
Commuting, chores, sports and free time all done traditionally in certain groups
Amish - represent 20 years ago, how lives are different and make comparisons.
Old order menanites - use transport more like 50s
Compare groups - see what it used to be like using accelerometer, BIA, CVS RFs
Similar sleep pattern
Amish then meninites then urban then rural for vig and mod - urban more as they can access more places
Suggests less active than they used to be
No difference in light/ sedentary really.
How can we ‘go back in time’- preindustriallised? Findings?
Kenya using pedometers
Rural and urban similar in developed
Less in ural in developing.
TV watching way higher in urban kenya.
The impact of surveillance on advocacy? Report card goals?
Raise public awareness Increase accountability Surveillance info provided (drive policy) Advocacy tool Identify research needs Challenge other countries and jurisdictions to implement similar processess to allow comparisons and facilitate improvements e.g. no parking 500m by school
Indicators used in the report card system? and grade boundaries
Overall levels (meeting guidelines0% organised sport
% active play
% active transport
% SB
Family and peer encouragement and provision e.g. buy trainers for sport
Messy data
Neighbourhood and the built environment
Schools
Minimum PE levels
Hours per week
Government strategies and investment
Findings from report card PA?
PA is part of way of life not a choice in the countries that are doing the best
38 countries
Slovinia, Zimbabeway (must walk to school), NZ (active play)
Lots of media coverage in some countries, no media coverage in UK
From Mackett (2012), describe the national travel survey (NTS) and flaws
A large household survey by the Department for transport since 1965
Results published annually
Changes in definition and questions mean it’s difficult to compare over entire period
From Mackett (2012), describe differences and similarities in why adults and children use cars? Implications?
Education vs commuting
Linked by escort trips - going with for benefit of another
Not just educational escort byt also, friends, school activities etc (12% of adult trips total)
16% of childrens trips are escort, 42% of which are by car
Suggests
Car travel = mobile child care
Meeting needs of children generates a lot of car trips
Car ownership and families with children relationship?
Show by in families with children with a high car% compared with general pop, multiple car ownership higher too
Car use growing in children as a % mostly at expense of walking
Reasons for more car use? (4 and expand)
Complexity of modern life
- More women in employment
- More trips not to school (larger % now by car)
Parental perceptions of traffic danger and risk of abduction - Live within 1.6km less walking (also due to women working and dropping off en route)
Government policy giving parents the choice of school/ Increasing distance to school
Decentralisation of urban areas - more availability of cars
-More perception of danger being outdoors
Issues of children losing walking independence?
Social networks and PA both important for development
Relationship between gender and urban rural location on independence
Boys allowed out 6 months younger than girls
Independence increases with increasing urban density
Not just density but also the nature of the built environment
Why cant kids walk alone to schools?
Mostly due to traffic
Also because parents dropping off en route
Only in UK was risks posed by other adults a significant factor
Increase in children with mobile phones means children can call parents if they feel unsafe
Also means that children can summon parents which may contribute to car use
Most intense PA for children done when? Consequences of guarding and tech?
Playing, clubs and travel are most intense PA for children
More guarding and more tech means less playing
Intensities of different modes of transport? comparison?
Walking most
Then cycling (may be underestimated by accelerometers
Then bus
Car the least
For 12-13yr olds walking to and from school burned more calories than PE or games lesson for 2h
Aside from burning more calories during walking to school, other effects?
Children who walk to school are also more energenetic in the activities when they arrive that those who travel by car.
Children who walk more than they use the car are more energetic in all activities on average.
Positive relationship between time spent walking/ cycling and proportion of the day spend in MVPA
Self - selection an issues as those that enjoy being active may choose to walk to school
Issues of shift in free play time to going to organised clubs?
Less intense PA at clubs than free play. More likely to travel there by car
Describe physical measures that have been introduced to increase activity?
Traffic calming - make safer
Safer routes
School infrastructure including providing secure cycle parking and lockers
School crossing patrol with an adult stopping the traffic to enable children to cross safely
Describe organising school trips measures that have been introduced to increase activity?
Walking bus - larger group of children with small number of adult volnteers
Describe funding measures that have been introduced to increase activity?
Emploiy travel plan co-ordinators and school travel advisers
Money to spend on measures identified in travel plans e.g. walking buses
Describe Campaigns that have been introduced to increase activity?
‘Are you doing your bit?’ about sustainable development by encouraging people to change their travel habits including children travelling to school
The ‘Healthy Schools Programme’ - whole school approacb to physical and emotional well-being focussed on 4 core themes
Safe travel schemes
Envourage bike and walking to school - charity committed
Describe Educational programms that have been introduced to increase activity?
‘Kerbcraft’ - taught road safety skills and making choices in walking and cycling
Describe Information access ways that have been introduced to increase activity?
School Travel Advisory Group (STAG) - sread best practice and identify ways to reduce car use to school, issued guidence for local authorities
Issues surrounding the effectiveness of measures for increasing children’s walking and cycling?
Lack of systematic evaluations of the initiatives.
Unknown what works
Danger of resources being wasted
Would changing how kids walk to school significantly impact travel by car?
Only 27% of total trips by children are by car
When is the best time to intervene in a child’s life?
No just one timing
Several periods across life when it’s important to intervene
For health/ delay ageing
Adolescence - activities carry on throughout life
Normally see a sharp decline
Focus on 0-5, for many first key period.
Children arnt that active at this age and if they are maybe they will be more active later?
Good tracking to later life of SB and PA, Iowa study
How many children normally meet SB guidelines?
Most studies only 20% of children meet guidelines (watching 0 hrs of tv a day)
Most from TV viewing, parental report - issues
Benefits of PA in Early childhood
Better CVs
Cognitive development e.g. Language
Psychoscocial health
Motorskill development
Harms of SB in early childhood
Adiposity
Worse cognitive development
Worse psychosocial - isolation, bullying
Correlates with top quarter BMI
Top quarter of BMI, lower PA, lower VPA, higher SB
Describe the link between PA and motor skill development
Key age to develop motor skills
Simple to complex - kicking
Needed to play complex sports later on
Prevent discouragement and dropout in adolescence
Skills can only be learned through practice=PA
Discuss rising obesity in early children monitoring and the risks of high BMI
Increasing overweight/ Obesity to 2004 but more stable since
Tends to track to adulthood
National program - measures at reception (4-5) to year 6
1/5 at reception are obese 22%
Adiposity rebound occurs here
Earlier the rise in BMI, the higher risk of later obesity
BMI >=85% higher risk of being overweight at a different timepoint if high BMI
85% women and 92% of men that were overweight children were overweight adults at some point.
Why identify correlates/ determinants
Interventions cost resources Need to know what factors influence PA/ SB to identify targets How they influence also What can/ can't be changes How to change
Describe the sources of influences on PA using a framework
Socio-ecologic framework Individual factors -Biological/ demographic - psychological, Cognitive, emotional, - Behavioural Social and Cultural Phycial environment
Describe biological factors
Boys vs girls - boys more active than girls even <5yrs,
Not sure why?? Parents encourage boys more than girls?
Genetic/ metabolic?
Cant change gender
But can target girls PA
Ethnicity
Parents weight
Overweight parents then less active
Change parents weight?
Maybe not weight but shared environemnt that affects this.
Describe behavioural factors (x3)
Child prompts How much they ask parents to go outside related to PA Get kids to ask parents via teachers TV viewing More time watching TV are less actve Target parents Set limits e.g. 1hr Higher energy/snack intake Correlates with TV viewing Reason? Proabbly not a reason for SB so not much point targetting
Describe social and cultural factors (5)
Most important is family - parents 1More active parents are more active kids are Could intervene at family level 2Parents TV viewing also associated with kids TV viewing 3Time spent playing with parents More active 4Parental support More active
Childcare Childcare staff education - higher education, the more active children are and the less they watch TV Highlights training for childcare staff
Describe physical environment factors (4)
Time spent outdoors
More PA
Play outside at breaks
Weather conditions
Seasonal variation
Think of activities they can do in autumn/ winter
Preschool environment e.g. Lots of space helps
Childcare attended
Distance from public parks/ playgrounds
Closer = more active
Influencing factors at all ages
Age, weight, ethnicity SES Access to TV/ comps e.g. In bedroom Parents behaviours (role modelling) Teacher's behaviour (e.g. Enthusiasm) Availability of opportunities/ equipment Urban vs Riral areas
From Bingham et al 2016, Biological correlates of TPA, MVPA and LPA
Boys all 3 (LPA?)
From Bingham et al 2016, Biological determinants of TPA, MVPA, LPA
Sex and TPA
None MVPA
From Bingham et al 2016, Social/cultural correlates of TPA, MVPA and LPA
PArental support
Parental PA
Correlates of TPA
MVPA none
From Bingham et al 2016, Social/ cultural Determinants of TPA, MVPA and LPA
Time spent playing with parents
Determinant of TPA
From Bingham et al 2016, Physical/ environmental correlates of TPA, MVPA and LPA
Preschool attendance
Time outdoors in play spaces
TPA
Private or faith school over government school
MVPA
From Bingham et al 2016, Physical/ environmental determinants of TPA, MVPA and LPA
none
From Bingham et al 2016, Difference between a correlate and determinant
Correlate - corss sectional association
Determinant - longitudinal study - temporal association
From Bingham et al 2016, consideration of methological quality?
Poor quality
Compares subjective and objective
From Bingham et al 2016, age and education criteria?
0-6 not in statutory education
From Bingham et al 2016, limitations
Small number of longitudinal
Exlusion of non-English publications, may explain lack from low and middle income countries
From Bingham et al 2016, future research focuses
Future research should focus on:
1. improved reporting of measurement methods so study
quality can be accurately assessed;
2. longitudinal/prospective studies to assess temporal
associations (determinants);
3. additional ecologic domains relevant for PA early in
life (e.g., policies, macroeconomics); and
4. the inter-relationship of constructs within and
between domains.
Gap in individual correlates/ determinants (not just demographic)
Low to middle needed
How to measure leg length?
Stature - sitting height Stadiometer Sitting height = height- height of chair Best practice -no shoes Head shoulder blades, buttocks and heels touching the wall/behind MEasurement error (x3)
Is it normal to move up a growth centile
Yes, effect in reference pop is blunted
Measurement error in height
Shoes vs not shoes Time of day - shrink and become heavier Posture Stadiometers are flexible Breathing in or out - difference to height
References vs standards
Reference makes no judgement about the desirability or the quality of the size of the dimension
Standards is based on a sample of individuals preselected because they have specific characterisitic of interest (how it ought to be)
For prescribing not just describing
WHO child growth standards
Biological and technical drawback of references Created growth standards from children who were Breast fed Not exposed to smoking Free of disease Immunized Good nutrition How the child should grow
How to calculate age increment?
Age at end of year minus age at beginning of year
How to calculate age centre
Height at start of year + height at end of year /2
How to calculate simple velocity
In one year - How many cm they grow
How to calculate whole year velocity
Simple velocity/age increment
How to calculate age of peak height velocity?
Find highest whole year velocity
Look at year above and below
Which is higher?
Likely to lie inbetween these two (use proportional allotment)
What is proportional allotment?
An adjustment accounting for variation in growth velocity in order to increase the accuracy of age at peak velocity
May be given equation
Values of A, VA, X and Y in proportional allotment
A = age centre at peak velocity VA = velocity value at peak X = velocity 1 year before Y = Velocity 1 year after
How to find magnitude of Peak Velocity and age of peak velocity
Age of = Proportional allotment (yrs)
Magnitude = from whole year velocity (cm)
Is there a pattern or sequence in which peak velocities occur?
Leg length, height, sitting height
Females pattern
Total earlier than male
Female leg length earlier
Sitting height is similar
Define intervention
the action or process of intervening
Define Health care intervention
Any type of treatment, preventative care or test that a person could take or undergo to improve health or to help with a particular problem.
Factors to consider when planning an intervention
Behaviour/ problem - what and why Setting - where Population of interest - who Mediators - mechanisms of change Barriers/ motivations - how Strategies for behaviour change - how
Success of interventions to increase PA in children
Small but significant effects
Possible but lack of similarity across studies
How could focus be shifted to sedentary behaviour?
Many studies focus on light to mod shift (due to guidelines) but sedentary to light shift may also be significant
Give some potential reasons for small changes in behaviour from an intervention
Population - not targetted the correct pop
Method
Time of day
Setting
Poor delivery and uptake
Time/ duration of follow up
Poor evaluation
Theoretical
Need control group - maintaining may be an effect
Not targeting right mediators or mechanisms of change
Intervention aren’t being designed to overcome barriers
Define a strategy
Plans of action designed to achieve a long-term or overall aim
What is the behaviour change method?
Theory-based method for changing one or several determinant of behaviour such as a person’s self efficacy or attitude towards the behaviour
Difference between a correlate and deteminant
Correlates - association, affect participation but cannot infer causality
Determinants - causality has been established
What is a mediator?
Mediator - an intervening variable that is necessary to complete a cause-effect link between an intervention and physical activity e.g. self efficacy, social support, physical environment change, weight status for diabetes. Intervention changes this which changes PA outcome.
what is a moderator
Moderator - an intervening variable that affects the direction, strength or both of the relationship between an intervention and mediator or mediator and PA; stratification by the moderator will show different strength relationships between the program and PA behaviour e.g. intervention works for girls not boys
