Measuring PA & Sedentary Behaviour Flashcards
Define ‘reactivity’
Methods that change your behaviour because you know you are being tracked
Define physical activity
Any waking movement that is 1.5 METs or above. Any bodily movement resulting in contraction of skeletal muscle that results in energy expenditure above resting levels
Define exercise
planned, purposeful, and repetitive (PPR)
How can you quantify PA & exercise
F- Frequency
I- Intensity (BPM, RPE, METs, WATTS…)
T- Time
T- Type
What does physical activity include (5)
sedentary behaviour
locomotion
work
leisure activities
exercise
How can we describe PA? (5)
- Total PA- calories burned during bodily movement
- sleep & wake time
- physical activity separated by sedentary, light, mod-vig intensity during wake time
- type- locomotive or occupational activities (walking, biking, jogging)
- posture- sitting, lying, standing
what is total (daily) energy expenditure (TEE)
the amount of energy you use in your day (24 hr)
What does total (daily) energy expenditure include?
activity energy expenditure (AEE) + Thermic effect of feeding (TEF) +Resting energy expenditure (REE).
Define Non-exercise activity thermogenesis (NEAT)
energy expended for everything we do that is not sleeping, eating or sports like exercise (walking to work, typing, work physical duties/chores) & fideting
what is included in Activity energy expenditure (AEE) (2)
Exercise energy expenditure (ExEE) and Non-exercise activity thermogenisis (NEAT)
How is Activity energy expenditure measured (AEE)
(7)
-indirect calorimetry
-heart rate monitor
-acceleromtery
-global positioning system
-pedometry
-questionairres
-observation (playgrounds)
what are 2 important characteristics used to classify PA measurement instruments
- degree of participant burden (too much recording…)
- whether they are subjective (self reported/surveys) or objective (tracked with fitness app or accessory)
how could reactivity change the validity
presence of a pedometer may cause you to increase your PA while wearing it. Although reliable this would affect the validity of using these scores as an indicator of usual PA
Desirable traits of measurement tools used to assess PA and EE (7)
- valid
- reliable
- provides a representative time period of measurement (are they wearing it long enough to measure what it needs to)
- non reactive
- socially acceptable and non-obtrusive
- low cost
- low subject burden
subjective methods to measure PA and sedentary behaviour
Requires participant/individual to use judgement in determining the score. Self administered, proxy or interview. Typically looks at a typical previous week, month or year. (annual survey).
-direct observation
-interviews
objective (indirect) methods to measure PA & sedentary behaviour
Outcome data: frequency, intensity, duration & Total.
Does not require interpretation of behaviours by participant. Removes the human source of error.
-Calorimetry
-Motion sensors (pedometers/accelerometers)
-HR monitors
-fit bit
-smartphone
-GPS
Objective direct methods to measure PA & sedentary behaviour
outcome data includes FITT, context, total and sedentary.
Trained individuals directly observe participants in restricted contexts (ex. school playground, PE class, workspace)
Pros/cons of direct observation
pro: provides details of all PA aspects, trained observers to evaluate PA, social cues or contexts of PA, can be used as criterion method against which to validate other methods
con: not practical for many settings, costly, rater may be bad at rating, rater may become fatigued (affects rating accuracy)
pro/cons for recall questionairres
pro: reactivity is less of an issue, inexpensive, can collect data on large scale in relatively short time (when done by survey)
con: accuracy of recall is critical, more labour intensive if done by an interviewer
PA diary pro/cons
pro: PA being interpreted during behaviour itself, all PA dimensions/patterns/total can be measured, can complete diaries anywhere
con: can be a burden to participant, difficult for those with disability, accurate recall may be difficult, can exaggerate or lie on diary.
self reported methods of PA pro/cons
pro: measure large numbers in short time, recall does not alter behaviour, measurement tool can be adapted to suit the population
con: recall challenges for some (children), semantics can be issue (what is mod-vig. intensity), completeness of answers, activity choices in questionairre may not be relevant to some populations
pedometers pro/cons
pro: inexpensive, easy use, track changes in daily PA
con: measures on one plane of motion, not all are same in terms of quality, inaccurate with slower walking speeds (elderly/deconditioned), does not account for height/leg length or stride length
10,000 steps per day recommended?
walking 10,000 steps per day does not gaurentee obtaining the health and fitness benefits of prolonged bouts of moderate activity, nor that a specified number of calories will be burned
Accelerometers pro/con
pro: counts motion on 3 planes, assess intensity/duration/time, can detect small motions
con: expensive, requires special software, not waterproof, sensitive to heat/humidity, older models are less accurate.
HR monitor pro/con
pro: convienient for intensity tracking, real life settins, easy to use, well established relationship between HR & O2
con: possible discomfor, expensive, HR cannot be used to assess sedentary time, HR/O2 relationship is not linear at all levels of PA
indirect calorimetry (3-4)
outcome data: frequency, intensity, duration, total
-measurement of gas exchange
-pedometers/accelerometers
-HR monitors
Direct calorimtery (1)
high participant burden & objective
Valid and reliable measure of heat production, used as an index of all components of TEE
Doubly labelled water
low participant burden & objective, gold standard.
TEE measured in free living conditions over 7-14 days. Measures C02 production to calculate TEE (cannot be used to separate TEE into it’s components)
what is the gold standard for sedentary behaviour tracking
posture sensors
uses accelerometer & inclinometer to measure sitting/lying, standing and walking
