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