N2 PA

• Physical Activity Assessment Methods


  • Self-Report Instruments
  • Accelerometry
  • HRM
  • Pedometers
  • Direct Observation
  • Doubly Labeled Water
  • Calorimetry – D and ID
  • Job classification
  • Dietary measures- energy balance
• Selection of assessment methods


  • Valid
  • Reliable
  • Accurate
  • Practical
  • Nonreactive
• Methods of Assessment


  • Calorimetry
  • Job classification
  • Survey procedures
  • Physiological markers of physical activity
  • Observation
  • HRM
  • Motion sensors
  • Dietary measures
• Direct calorimetry


  Measures heat, highly accurate (< 1% error), requires special chambers, expensive, limited to specific tasks, impractical for large populations / certain activities
• Indirect calorimetry


  Measures oxygen -heat production, error 2-3%, requires face mask or a mouthpiece, container, not useful for certain activities, costly, sub-samples
• Job classification


  Ranking jobs, assuming similar levels of EE, large population, minimal costs, nonreactive, may not be sufficiently valid and reliable
• Limitations of job classification


  • Variability
  • Misclassification
  • Secular changes
  • Seasonal changes
  • Selection bias
  • Omission of leisure /nonoccupational
• Components of Survey procedures


  • Time frame
  • Nature and detail (frequency, duration, intensity, type)
  • Mode of data collection (personal interview, telephone interview, self-administration, mail surveys/ online, combinations)
  • A summary index, Standard vales
• Types of Survey procedures

  • physical activity diary
  • physical activity recalls
  • quantitative history procedures
  • General surveys
• Diary surveys


  Epidemiologic and energy balance, perform and measurement of EE, Recording -diary, Calculation, Result
• Limitations of Diary surveys


  • Cost
  • Time
  • Acceptability
  • Alter their normal pattern
• Modified Diary surveys


  Published values, Differences between individuals, Adequate estimation, Epidemiology
• Recall surveys


  Highly demands on the participant, Epidemiology studies, Interview / self administered, Calculation -using published intensity values, Reliability and validity -appeared to be good, Weekly physical activity pattern
• Quantitative history surveys


  Time frames greater than 1 week, Detailed information on specific activities, Some up to 1 year + a list of specific physical activities
• General surveys


  Less detail than other techniques, Subjective impression
• Issues with Survey


  • Accuracy
  • Cross-cultural
  • The capacity of a person to remember
  • Methods of improving memory
  • 1-7 days - other
  • Long term -capacity of the individual to remember over long periods
  • Details -ability and willingness to complete
• Ability and validity


  Appeared to be good
• Quantitative history surveys


  • Time frames greater than 1 week
  • Detailed information on specific activities
  • Some up to 1 year + a list of specific physical activities
• General surveys


  • Less detail than other techniques
  • Subjective impression
• Survey


  • Epidemiologic
  • Issues: Accuracy, Cross-cultural, The capacity of a person to remember, Methods of improving memory
• Survey issues


  1. 1-7 days - other

  2. Long term -capacity of the individual to remember over long periods

  3. Details -ability and willingness to comply decrease

  4. Issue on specific activities or classes of activities

  5. Comparability - more specific activity participation
• Physiological markers of physical activity


  • PA influence cardiorespiratory endurance
  • Correlation modest to weak
  • Genetically suitable as indirect validation criterion
• Doubly labeled water technique


  • Isotopically labeled hydrogen and oxygen atoms
  • Proportions of unmetabolized water and water excretion
  • Overall TEE
  • Expensive
  • Error -2 to 10%
• Physiological markers of physical activity

  • Any age
  • Not restrict activity
  • Minimal burden
  • 2-3 days or several weeks
  • About USD225 per person
  • Validation studies
  • TEE -No patterns of physical activity
• Behavioural observation


  • An observer watches an individual and rates
  • The ratings – to estimate PAL
  • CCTV, random photographs or observer
  • Impractical – certain population
  • Consent
• Behavioural observation


  • Influence behaviour
  • Useful- validation
• Heart rate monitoring


  • Heart rate recording
  • Physiological parameter related to physical activity
  • Continuous record
  • Intensity and duration
• Heart rate monitoring


  • Assumption -linear relationship between heart rate and oxygen consumption
  • Regression curves
  • Personal regression curve – more accurate but time-consuming and expensive
• Heart rate monitoring


  • Heart rate and oxygen consumption relationship affected by the amount of muscle mass involved, type of muscular contraction, environmental temperature, state of physical training, fatigue, emotional stress
  • Confounding
• Motion sensors


  • Measuring "movement"
  • More active people typically move more
  • Movement vs estimates of energy expenditure
  • Many factors that influence energy expenditure: TEF, BMR, body weight, ambient temperature, age
• Motion sensors (Pedometers)


  • Walking behavior
  • Inter- and intra-instrument variability
• Motion Sensor (Pedometer)


  • Less accurate - distance and energy expenditure
  • Cannot discriminate between walking, running and stair climbing
  • Cannot detect arm movement, lifting pushing or carrying objects
  • Cannot provide pattern of activity
  • Slow walk
  • Vibration
• Motion sensors (Accelerometer)


  • Frequency and intensity
  • Commercially available
  • Quantity, intensity and duration of movement
• Sensors

  • Highly useful in assessing physical activity
  • Require little time from the investigator
  • Limited effort by the subject
  • Do not interfere with or influence physical activity
  • Acceptable
  • Currently costs decrease
  • Applicable to population studies
• Dietary measures


  • Food intake + energy expenditure -energy balance
  • Long-term assessment
  • Weighed dietary intake & PA diary -great demands on the subject
• Dietary measures


  • Variability - intra- and inter-individual variability