This document discusses various methods for measuring physical activity, including questionnaires, diaries, direct observation, accelerometers, pedometers, heart rate monitoring, indirect calorimetry, and room calorimetry. It provides details on the principles, strengths, limitations, and validity of each method. The optimal choice of method involves balancing the research question, available resources, and feasibility of the study. Objective methods like accelerometers are now suitable for large epidemiological studies, while more precise tools are needed to quantify relationships between physical activity and health outcomes.
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XNN001 Methods to measure physical activity at the individual and population levels
1. METHODS TO MEASURE PHYSICAL
ACTIVITY
XNN001 Population nutrition and physical
activity assessment
2. Definitions of physical activity
Physical Activity is ”any bodily movement produced by
skeletal muscles that results in energy expenditure”
The energy cost of physical activity may not
necessarily be equivalent to body movement
Exercise is ”a specific type of PA that is planned,
structured and repetitive done to improve or maintain
physical fitness”
Physical fitness is ”a set of attributes either health- or
performance related” and is not synonymous with
physical activity
3. Why bother to measure physical
activity ?
To specify which dimension of physical
activity is of most importance for a particular
health outcome
To make cross-cultural comparisons
To monitor temporal trends within populations
To measure the effect of interventions
4. Four parameters to describe PA
Type
The main physiological systems that are activated
during the activity
Frequency
The number of times a person engages in an activity
over a pre-determined period of time
Duration
The temporal length of the activity
Intensity
The degree of overload an activity imposes on
physiological systems in comparison to resting states
5.
6.
7.
8. Validity terminology 1
Criterion validity:
A questionnaire is validated against an objective
method.
The relationship is frequently reported as a
correlation coefficient (Pearson,Spearman)
9. Validity terminology II
Absolute validity:
The absolute outcome (i.e. EE or time spent in
activity) is compared to data from an objective
instrument which provides the same outcome
measure.
The association is usually reported as the
degree of agreement (Bland and Altman
method).
10. Validity terminology III
Concurrent validity:
A questionnaire is compared to another self-
report instrument (i.e. diary or another
questionnaire).
Although a high correlation between two
subjective instruments suggest validity, the
instruments are not of a different type and may
be subject to correlated error.
12. Questions to be asked of any
questionnaire
What type of PA is it trying to assess ?
What is the frame of reference of the
questionnaire ?
Is the validation sample representative of the
study population?
Has the questionnaire been validated against an
appropriate comparison method ?
Is the instrument reliable?
13. PAQs used in the general
population
Aerobic Center Longitudinal Study PAQ
Baecke PAQ
Bouchard 3-day physical activity record
CARDIA physical activity history
Framingham Physical activity index
Godin Leisure-time exercise questionnaire
HIP activity questionnaire
Historical leisure activity questionnaire
Kuopio Ischemic Heart Disease Study Q’s
Lipid research clinics questionnaire
Minnesota Leisure-time PA
Modifiable Activity Questionnaire
Paffenbarger Physical Activity Questionnaire
Seven-Day Physical Activity Recall
Stanford Usual Activity Questionnaire
Tecumseh Occupational PAQ
14.
15.
16.
17. Reliability and Validity of the
International Physical Activity
Questionnaire (IPAQ)
8 forms
14 centres in 12 countries
Test-retest reliability (n=2632)
Criterion validity (n=1854)
Accelerometry as comparison instrument
https://sites.google.com/site/theipaq/questionnaires
18.
19. Summary; Questionnaires
Reliability; usually good to excellent
Criterion validity; poor to moderate (although
significant)
Absolute validity; questionable
Questionnaires provide prevalence estimates of
physical activity
Questionnaires provide the possibility to categorise
respondents into activity categories
Questionnaires provide a poor measure of the
absolute time spent at different intensity levels and the
associated energy expenditure
Questionnaires should be used with caution in
children
20. Looking for validation studies?
http://appliedresearch.cancer.gov/tools/paq/validation.ht
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22. Stanford 7-day recall
Interviewer administered questionnaire
~15 minutes to complete
Acceptable validity and reliability
High concurrent validity (r = 0.82 – 0.83)
High test-retest reliability (r = .31, p = .021), and
very hard activities (r = .61, p = .0001)
Acceptable validity
http://sallis.ucsd.edu/measures.html
23. Summary of subjective measures
of PA
Many questionnaires available
No gold standard measure
All self-report measures associated with error
Effective indicators of which people/ sub-
groups are more/ less active
24. Direct observation
Used widely among children
Children observed using specific observational system. Rating of
PAL into computer/ coding form.
Number of available sustems (many validated against
accelerometry, heart rate monitoring, or energy expenditure
assessed by indirect calorimetry)
Fargo Activity Timesampling Survey (FATS)
Activity Patterns and Energy Expenditure (APEE)
Behaviours of eating and physical activity for children’s health evaluation system
(BEACHES)
Childrens activity rating scale (CARS)
Studies of children’s activity and nutrition: Children’s activity Timesampling survey
(SCAN CATS)
Level and Tempo of children’s activity LETO
System for observing play and leisure activity in youth (SOPLAY)
System for observing play and recreation in communities (SOPARC)
Observational system for recording physical activity in children – preschool version
(OXRAC-P)
25.
26. Assessment of body movement
based
on accelerometry
Principle:
Direct measure of body movement (acceleration).
When a person moves, the body is accelerated in
relation to the muscular forces responsible for the
acceleration of the body, and in theory to EE.
The acceleration can be measured in one
(vertical), two (vertical + medio-lateral) or three
(vertical + medio-lateral+anterior-posterior)
directions.
27. Physical activity assessment by the
MTI
Actigraph accelerometer
• Provide a detailed description of activity
patterns
•Excellent data storage capacity
• Extensively validated
• EE from complex movements are not reflected
by acceleration of the body (i.e. bicycling,
upper body work, walking up/down, carrying
goods etc.)
• Accelerometer data needs careful
interpretation
28. Summary of laboratory based
validation studies
Strong association (r > 0.75) between EE and
activity counts in controlled settings
EE prediction equations and thus, cut-off
points for different intensity levels, differ
depending on the calibration activities
performed and the setting of these activities
Published cut-off points are highly variable
29. Summary; Accelerometers
Extensively validated
Applicable to children and adults
Provide data on patterns of physical activity
Valid for assessing the total amount of PA
Cut-off points are arbitrary
Laboratory based EE prediction equations are
not valid for free-living
Applicable in relatively large studies (n=4000)
30. Pedometers
Provide information about number of steps
Should not be used to estimate energy
expenditure/ distance
Cheap, readily available
Unable to assess intensity of activity/ activities
other than walking
Valid compared to accelerometers (r=0.86)
Ideally worn over 7 days but 3 sufficient
34. Summary; Heart Rate
monitoring
Extensively validated in adults, children
athletes, and obese
Applicable in relatively large studies (n = 1000)
Provide data on EE and pattern of PA
Require individual calibration
HR is affected by other factors than PA
35.
36. The next generation of free-living
physical activity assessment
Actiheart is a combined HR and movement
sensor (8g, waterproof) currently being
validated
It will combine the advantages of body
movement and HR for prediction of PAEE
during free-living conditions
37. Indirect calorimetry
Measurement of the amount of heat produced
by a subject by determination of the amount
of oxygen consumed and the amount of
carbon dioxide eliminated.
38. Doubly labeled water
Hydrogen & oxygen in water partially or completely replaced
with atypical isotopes deuterium & 18O
Ingested by subject – elimination rate of deuterium isotope
assessed by measuring concentration in body water over
time
CO2 production measured during the interval between first
and last body water samples
O2 in body water equilibrates with the body's bicarbonate and
dissolved carbon dioxide pool, lost from body in CO2
Additionally lost through body water loss
Deuterium is lost only in water deuterium change in body
water over time can be used to mathematically compensate for
the loss of tracer 18O to provide estimate for total carbon dioxide
production
Can be used to calculate BMR
39. Room calorimetry
Energy expenditure to be calculated
based on measurements of air
samples
Study subject remains in closed
room
Constant and measured supply of
fresh air
Gas analysers attached to the unit
measure oxygen consumed and
carbon dioxide produced
Balance of oxygen consumed and
carbon dioxide produced varies
according to activity and the
utilisation of different fuels by the
body (carbohydrate, protein and fat).
40. Other ways to measure PA at the
community/ population level
Environmental
Miles of trails per capita
# of PA facilities per capita in schools
Availability of facilities to the public
# of programs for PA in community
# of agencies that sponsor PA events
Zoning regulations
Behavioral Outcome Measures
Observation of usage
Membership in PA organizations (YMCA, Health clubs)
Sales of selected PA equipment, videos, etc.
41. Other ways to measure PA at the
community/ population level
Policy & Regulations
PE in school curriculum
Amount/% of local budget per capita devoted to
physical activity/recreation
Density of recreation facilities & new construction
Information
% of health-care providers that engage the public to
exercise more
# of worksite materials linked to PA
% of schools offering curricula in grades k-12
# of medical reports dealing with PA
“Point of purchase” education materials on PA
42. SUMMARY
The choice of a method is a trade off between
the research question, the available resources
and feasibility
Valid objective methods are now available
which can be used in relatively large scale
epidemiological studies (n~5000)
Precise methods are needed in order to
quantify dose-response relationships, gene-
environment interactions, and longitudinal
changes in activity patterns
Hinweis der Redaktion
Maximum oxygen uptake - HR monitoring, reported daytime energy expenditureThe relatively low validity may be a reflection of the difficulty in capturing the between-individual differences in energy expenditure in a simple questionnaire. One of the obvious limitations is that a single estimate of the energy cost of an activity taken from a published compendium is applied to all individuals.19 This does not allow for any between-individual variation in energy expenditure for a given activity and so cannot take account of differences in intensity (e.g. through people playing sport at different competitive levels), or through variations in mechanical and metabolic efficiency.
StrengthsSuitable for many populationsQuick easy to administer, limited participant burdenGood – excellent reliabilityProvide information on type and context of physical activityCaptures quantitative and qualitative informationCheap Can be used to assess a large sample of individuals quickly LimitationsQuestionable validity May not assess intensityPotential for response, memory and recall bias- Reliability and validity problems associated with recall of activity Often not suitable for childrenAmong children Previous Day Physical Activity Recall - Good Reliability . Early physical activity measures for children were completed by parents or teachers Typically were not valid or reliable 7-Day Recall--invalid and unreliable
StrengthsProspective (limits memory/ recall bias)Gives indication of duration, type, intensity and context of activityNo need for observationDetailed information can be obtained Can be modified to suit specific behaviourLimitationsMore days = higher participants burden (less likely to complete)Potential to change behaviours as result of monitoringExpensive to reduce the data to analyzable form
The Stanford 7-day Physical Activity Recall Scale (PAR) estimates both work-related and non work-related physical activity. For each day of the past week, participants report the approximate number of hours they slept and spent in moderate, hard, and very hard activity. The scope of the PAR is meant to include any physical activity ranging from, for example, household cleaning to exercising to playing sports or practicing a musical instrument. Also included are four write-in questions for participants to evaluate the effectiveness or validity of the instrument itself.Subjects are asked to recall the number of hours spent sleeping and engaged in moderate, hard and very hard physical activity for week end and week day activities separately. MET levels are assigned to each class of activities. An estimate of the total kilocalories of energy expenditure per day is calculated.StrengthsShort, easily administeredLimited participant burdenSystematic processHigh reliability, acceptable validitySpeed and ease of administration Calculation of total energy expenditure Occupational and leisure activities. LimitationsRequire trained personnel, potentially expensiveResponse biasInterviewer biasIssues with memory/ recallPrevious week may not provide typical participation
The Fargo Activity Timesampling Survey (FATS) – was the first attempt to develop a research instrument for describing children’s activity and related parent behaviour. The FATS used an interval time sampling procedure; observing behaviour for 10 seconds and then record behaviour for 10 seconds (Klesges et al, 1984).Activity Patterns and Energy Expenditure (APEE) – observes free play by 15 second momentary time sampling and rates activity level into one of 5 categories (Epstein et al, 1984).Children’s Physical Activity Form (CPAF) – was designed to measure physical activity during physical activity classes using partial time sampling at 1 minute intervals. There are four activity level categories (O’Hara, 1989).Behaviors of Eating and Physical Activity for Children’s Health: Evaluation System (BEACHES) – measures physical activity in a range of settings. It uses momentary time sampling at 1 minute intervals and 5 activity level categories (McKenzie et al, 1991).Children’s Activity Rating Scale (CARS) – is a five level scale (resting, low, medium, medium-to-high, vigorous), designed to categorise the intensity of physical activities and discriminate between levels of energy expenditure in young children. The system uses partial time sampling at 1 minute intervals (Puhl et al, 1990).Studies of Children’s Activity and Nutrition: Children’s Activity Timesampling Survey (SCAN CATS) – measures physical activity in a range of locations with an interval time sampling procedure to observe behaviour for 10 seconds and then record behaviour for 10 seconds. There are four activity categories: stationary, minimal activity, slow movement, rapid movement (Klesges et al, 1990).System for Observing Fitness Instruction Time (SOFIT) – measures activity during physical education classes using momentary time sampling; 10 second observe/record intervals. Five activity categories are used (McKenzie et al, 1991).Level and Tempo of Children’s Activity (LETO) – measures physical activity in natural settings including the home using 3 second time sampling. Activity is categorised as 14 postures with 3 intensity levels (Bailey et al, 1995).System for Observing Play and Leisure Activity in Youth (SOPLAY) – designed to capture behavioural and contextual information in groups of (rather than individual) children and adolescents. The target area is scanned to record the number of boys and girls, their activity level and additional information including, the time, temperature, equipment provision, level of organisation and supervision. This system was validated with self-reported physical activity (r=0.35-0.73); inter-observer reliability was found to be high, with intraclass reliability coefficients for activity levels ranging from 0.76-0.99 and percentage agreement for physical activity context ranged from 88-97% (McKenzie et al, 2000).System for Observing Play and Recreation in Communities (SOPARC) has recently been developed from SOPLAY. The aim is to capture physical activity and contextual information in people attending community-based settings such as parks and recreation areas. An area is scanned systematically from left to right. The activity levels and types are recorded for boys and girls, concurrently with contextual information (Brown et al, 2006).Observational System for Recording Physical Activity in Children – preschool version (OSRAC-P) – has recently been developed to collect contextual and behavioural information at an individual level in a range of pre-school settings. The OSRAC-P measures: physical activity level using the CARS system; type of activity; location of activity; social context; prompts for activity. The data are entered directly into a personalised digital assistant (PDA) or Pocket PC (McKenzie et al, 2006). Inter-observer agreement for OSRAC-P in three preschoolers was assessed and percentage agreements for each of the major variables ranged from 89% to 100% (Brown et al, 2006).Advantages: Provides detailed contextual informationEliminates bias due to recall, limits response bias It is accurate It involves little inference with the participant’s routine Diverse dimensions related to physical activity can be quantified It can be used as a criterion method for validating other measures of physical activity Limitations: It is time-consuming Observation is expensive Observations may not reflect habitual physical activity Subjective - does not allow intensity or energy expenditure to be assessed. Considerable time and effort required – potentially expensive
Activity monitors have the potential to provide substantial benefits over self-report--they avoid the biases and inaccuracies of recall.
Pedometers are simple movement device counters that can estimate habitual physical activity over a relatively long period. Less obtrusive devices Light weight clip onto a belt or are worn around the ankle Limitations with the reliability and validity of mechanical and electronic pedometers. Low validity Some devices show high deviations from the actual step rate Objective is to accumulate 10,000 steps per week
Can provide minute-by-minute data for up to 48 hours.
Good validity Limitations Heart rate monitors cannot distinguish accurately between light and moderate intensity activities Elevated heart rates can be produced by mental stress in the absence of physical activity Heart rate monitors can be inconvenient to use Various electronic devices interfere with the recording resulting in lost data
LimitationsExpensive equipment – requires subjects to wear apparatusSenesitive to measurement error
AdvantagesObjective and accurate measurement of EE however…Limitations of objective measuresExpensive equipmentIntensive on participantHigh cost