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					    Measuring Physical Activity
• Physical activity is difficult to measure as it
  involves complex motions and provides different
  physiological stresses.
• Physical activity ranges from maximal exercise to
  fidgeting when at rest.
• You need to determine the frequency, intensity
  and duration of different activities to estimate a
  person’s daily or weekly physical activity.
• The most common measure of physical activity is
  energy expenditure in kilocalories (kcal).
       Measuring Physical Activity
• There is an inverse relationship between the accuracy of
  measuring physical activity and the ease and affordability
  of measuring physical activity.
• Activity measurements using self-reports and activity logs
  are simple and easy to administer, but provide limited
  accurate data.
• Scientific measures using techniques such as indirect
  calorimetry, and doubly labeled water, can accurately
  measure energy expenditure, but are expensive and not
    Measuring Physical Activity
• Physical activity is hard to measure as the type
  and amount of physical activity change from day
  to day, season to season, year to year.
• Adults have less variation in their activity patterns
  compared to children.
• Physical activity can be estimated using self-
  reports and activity logs.
• More objective measures of physical activity
  include; indirect calorimetry, doubly labeled
  water, heart rate monitors, activity monitors,
  pedometers, GPS and direct observation.

Measuring Physical Activity by Self-
• Self-reports are a frequently used tool to measure
  the prevalence of physical activity in different
• Self-report questionnaires require the respondent
  to recall their activities over a specific time frame
  (1 day, 1 week, 1 year).
• Self reports may be administered by:
   – telephone            - mail
   – personal interview   - computer
   – app

  Measuring Physical Activity by Self-
• Respondents may be asked to recall leisure time activities,
  occupational activities, structured exercise or all three.
• In more detailed self-reports the respondent may be asked to
  recall the frequency, duration and intensity of each activity.
• The Harvard Alumni Activity Survey is the best known self-
  report study.
• The study is looking at the relationship between physical
  activity and heart attack.
• The respondent sends in a report with all of the activity they
  completed in the last week. The activities are given an energy
  expenditure and classified based on intensity.

     Measuring Physical Activity by Self-
• Typical self-report studies ask respondents about their participation
  in a broad range of activities.
• They are also asked to record their intensity and time spent doing
  each activity.
• Intensity is usually reported as vigorous, moderate, low or
  sedentary and then converted to METS (the ratio of metabolic rate
  during an activity to a reference metabolic rate).
• These 4 categories of activity can be correlated to indices for
  cardiovascular risk.
• The researcher then totals the activity duration and intensity for a
  specific time frame.
• This information can give an estimation of energy expenditure.

          Reliability and Validity of
• Poorly administered self-reports may produce:
   – Inaccurate activity estimates
   – Incorrect conclusions about interventions
   – Inconclusive findings regarding activity and health
• A good self-report will be:
   –   Reliable
   –   Valid
   –   Sensitive to change
   –   Will not influence the respondents behaviour
   –   Reasonable administration cost

         Reliability and Validity of
• Even the best self-reports have a considerable
  amount of error (usually overestimate).
• Even with the associated error, self-reports are still
  able to show a strong correlation between physical
  activity and health.
• Self reports are very good for determining what
  proportion of a population is active or inactive.
• Self-reports are not accurate enough to quantify
  the optimal amount of physical activity to improve
               Child Self-Reports
• Self-reports are commonly used with children due
  to the low cost and convenience.
• There are several types of child physical activity
   –   Self-administered recall
   –   Interviewer-administered recall
   –   Diary
   –   Proxy report (parent or teacher reports on activity)

• The accuracy of the recall depends on a number
  of factors (age, detail, time, prompts).

              Child Self-Reports
• Should not be used in children younger than 9 yrs.
• In children between 9 and 15 use caution with self-
  reports to improve reliability.
• Adolescents older than 15 will provide results similar
  in reliability to adults.
• Recalls of brief periods are always more accurate than
  recalling activity for an extended time period.
• Direct observation is the most valid approach.

        Doubly Labeled Water
• Ingest a known amount of isotopes of 2H and 18O.
• Isotopes distribute throughout body.
• 1 to 3 weeks later energy for the time period can be
• Labeled 18O leaves the body as water or as CO2.
• Loss of CO2 is closely related to O2 consumption and
  can be used to estimate energy expenditure.

           Doubly Labeled Water
• Gold standard for assessing energy expenditure.
• Assesses all forms of energy expenditure.
• Very high validity (less than 3% error).
• Used in lab or field, and is very safe.
• The main disadvantage is cost, each dose of 18O
  costs several hundred dollars.
• Requires a mass spec.
• Does not provide info on frequency, intensity and
  type of activity.
         Indirect Calorimetry
• Measurement of O2 consumption during
  physical activity.
• Previously needed to be conducted in a
  metabolic chamber.
• Currently there are lightweight oxygen
  monitors that can allow O2 measurement in
  the field.
• Newer O2 monitoring devices are becoming
  cheaper and more convenient, but it is still a
  time consuming and expensive process.
            Activity Monitors
• Activity and HR monitors have significant benefits
  over self-reports, by providing quantitative data
  on both physical activity and energy expenditure.
• There are still limitations to these monitors.
• Accelerometers and pedometers are the most
  common activity monitors.
• There are mechanical and electronic models that
  vary in reliability.

• The most commonly used activity monitors are
  accelerometers. Used for both children and adults.
• Assess vertical movement of the trunk. Usually placed
  on the hip of the subject.
• Electrical current proportional to the energy of
• Data reflects volume and intensity.
• Does not work for all activities (cycling, skating,
  swimming etc.)

• Small device that measures the number of
  steps taken during a given period of time.
• Very popular and inexpensive (ipod).
• Motivate people to be more active.
• Limited to counting steps.
• Does not provide information on upper
  body movement, and intensity.
    Global Positioning Systems
• Use satellites to track the location, direction
  and speed of subjects.
• GPS systems are getting cheaper and more
  readily available (smart phone).
• Can be used in conjunction with a Heart Rate
  monitor or accelerometer to analyze intensity
  and activity patterns.
   – Sport watches
        Heart Rate Monitoring
• HR is highly correlated to O2 consumption.
• HR can be used to estimate intensity of activity
  and energy expenditure.
• To estimate energy expenditure from HR you
  need to know the individual’s HR / O2 uptake
• Telemetry HR monitors are very accurate and HR
  data can be stored for up to 100 hours in some

   Heart Rate Monitor Limitations
• Individual variability in maximum HR.
• Hard to distinguish between light and moderate
  activity. Other variables may ¯ and ­
• Limited storage capacity.
• Problems with chest straps.
• Difficult with children.
• Electronic interference.

Combined Activity and HR Monitors
• Potential to overcome the limitations of both.
• Could place activity monitors on different body
  parts and record HR to get a reasonably accurate
  measure for a wide range of activities.
• Future R & D should provide instruments that can
  quantify the frequency, intensity and duration of
  different physical activities.

      Wearable Technology
• Watches
  – Garmin, Polar, Nike, Adidas (miCoach)
     • HR, speed, distance, elevation, calories etc.
• Fitness Trackers - bands
  – FitBit , Nike Fuel band, Spree, Jawbone
     • Steps, calories, sleep, stairs, distance (Apps)

• Glasses
  – Google Glass, Lumus
  • Head Monitoring Skull Cap - Reebok , Checklight
     • Wear with or without helmet during sports
     • Monitors impacts during activity
          Wearable Technology
• Clothing - embedded with sensors
  – Smart socks, sensors in the heel and toe that send
    signals to an ankle bracelet, to measure the force of
    your foot strike and stride length while running.
  – Vibrado sleeve, accelerators fitted at the biceps,
    forearm, and hand track your arm’s movements and
    calculate the arc of your basketball shot.
  – OptimEye, a GPS tracking device you wear on the
    back of your jersey. It records your every movement.
       Quantification of Training

Physiological adaptation to training may be
quantified through a number of diagnostic
   · Constant power
   · VO2max
   · Lactate threshold
   · Criterion performance
   · Resting and submax HR
· To date there is no formal training theory that
  quantitatively and accurately prescribes the
  pattern, duration and intensity of exercise to
  elicit a specific physiological adaptation.

· Without accurate quantification of a training
  dose, the results from training studies to date
  remain qualitative and argumentative.

The Epidemiology of Health &
     Exercise Behaviours
• In order to effectively utilize our knowledge of the health
  effects of being physically active, you need to understand
  the health behaviours of the entire population.
• Descriptive epidemiology attempts to determine the
  distribution of health behaviours in the total population
  and in specific groups within the population.
• Descriptive epidemiology tries to identify the physical
  activity level of different groups.
• The demographic characteristics of these groups include;
  age, gender, ethnicity, socioeconomic status and location
  of residence.
• The value of these studies is dependent on the
  quality of the measures used.
• Since most of these studies use self-reported
  data, there is a range of error in all of the
  statistics reported by these studies.
Good descriptive epidemiology data can provide
  valuable insight:
• Estimates the extent to which physical activity is
  integrated into people’s lives.
• Estimates how physical activity is distributed
  throughout the population.
• Identify less active groups, and provide the
  information required for intervention strategies
  for these groups.
• What are the physical activity trends, and do
  these trends vary with different groups.
          Adult Activity Levels
• In the past 25 years there has been a
  considerable amount of self-reported data
  collected on leisure time physical activity of
• This large volume of self-reported data provides a
  good estimate of the proportions of active and
  inactive people in the population.
• This data also allows for estimates of activity
  levels in different population groups.
              World Data
               Lancet, July 2012

• Available data obtained with standardised
  self-report instruments now provide
  estimates of physical activity for 122
  countries, or two-thirds of the 194 WHO
  Member States (90% of world population).
                 World Data
• Worldwide, 33% of adults do not achieve 30 min of
  moderate-intensity physical activity on at least 5
  days a week.
• The frequency of inactivity varies greatly between
  WHO regions, ranging from 17·0% in southeast Asia
  to about 43% in the Americas and the eastern
• 31.4% of adults report vigorous-intensity physical
  activity on 3 or more days per week.
                World Data
• A systematic review showed that adults'
  leisure-time physical activity, including sports
  participation, has increased in the past 20-30
  years in high-income countries.
• A comprehensive analysis of US data showed
  that daily energy expenditure in work-related
  physical activity has decreased.
• Trend: less activity at work, more activity in
  leisure time.
                 World Data
• 80% of 13 to 15-year-olds are doing less than
  60 min of physical activity per day.
  – moderate to vigorous intensity
         International Studies
• International studies significantly increase the
  sample size for data collection.
• When you compare data from these studies the
  results are relatively consistent.
• 25% to 35% of adults in Canada, US, England and
  Australia can be characterized as sedentary (no
  physical activity in leisure time).
• Only 10% to 15% of adults in these countries
  engage in regular vigorous exercise.
          Adult Activity Levels
• This high proportion of sedentary adults is a
  serious public health concern.
• Moderate intensity physical activity has some
  significant health benefits, but is harder to
  quantify compared to vigorous or sedentary
• Moderate intensity activity is harder to report
  because it can be accumulated during the day and
  is harder to remember compared to vigorous
  Demographic Variations in Adult
         Activity Levels
• Men are more active than women.
• Physical activity decreases with age.
• Activity increases with increasing levels of
  education and income.
• Physical inactivity is more common in
  countries of high income than in those of
  low income.
• According to statistics, young, educated males are
  the most likely to be active.
• There are difficulties in analyzing vigorous activity
  data from epidemiological studies.
• Vigorous activity clearly declines with age, but some
  of this decline is due to the fact that moderate
  activity for young individuals may be vigorous
  activity for older individuals.
• If a relative intensity classification is used, then
  older individuals do the same, if not more, vigorous
  activity compared to the younger adults.
• A problem with using age-adjusted, relative-
  intensity, classifications is that lower levels of
  fitness will increase relative intensity.

• This relative intensity problem also arises when
  you compare males to females, due to the lower
  cardiovascular capacity in females.
  Physical Activity Participation by
• There is less epidemiological data on youth
  compared to adults.
• Research studies show that more than half of
  Canadian youth are not active enough for optimal
  growth and development.
• Canadian girls are less active than boys with only
  38% of girls and 48% of boys considered active
    Physical Activity Participation by
• There is less epidemiological data on youth compared
  to adults.

• Children become less physically active as they age.
Total Daily Energy Expenditure (kcal/kg) (Several Countries)
  Age        6      8      10     12     14     16     18
  Boys       82     74     75     58     50     44     44
  Girls76    70     58     53     45     42     42
  Physical Activity Participation by
• Boys are more active than girls at all ages.
• A review of HR data found that boys spend 23% more
  time being active than girls.
• Overall physical activity levels drop steeply from ages
  13 to 16 in both boys and girls.
             Intensity Differences
• Girls spend more time doing light-intensity activity.
• Light intensity activity increases from age 13 to 21.
• Boys and girls report a similar amount of moderate
  activity, which declines with age.
• Boys spend much more time doing vigorous activity at
  age 13 compared to girls.
• By age 21 both boys and girls do a similar amount of
  vigorous activity (low level).
• It is not clear if these trends are due to biology or
  social influences.
   Active Healthy Kids Canada
• Established in 1994, a national organization
  with a passionate voice for the
  development of active healthy children and
  youth in Canada.

• Focused on making physical activity a major
  priority in the everyday lives of Canadian
      Active Healthy Kids Canada
• The 2012 report found that 46% of Canadian
  children and youth are getting less than 3 hours of
  active play (unstructured physical activity) each
• Kids are spending 63% of their free time after
  school and on weekends being sedentary.

• 92% of Canadian kids said, if given the choice, they
  would choose to play with friends over watching TV
   Active Healthy Kids Canada
• The proportion of Canadian kids who play
  outside after school dropped 14% over the
  last decade.

• At lunch and after school, kids are getting
  only 24 minutes of moderate- to vigorous-
  intensity physical activity out of a possible 4
        Physical Activity Levels
• Only 7% of children and youth are meeting
  Canada’s guidelines of 60 minutes of physical
  activity a day

• It is encouraging to note that 44% of Canadian
  kids are getting 60 minutes of physical activity
  on 3 days
Organized Sport & Physical Activity

• 75% of kids aged 5-19 participate in organized
  physical activities or sport.
• Kids from higher-income families have a 25%
  higher participation rate than those from
  lower-income families.
Organized Sport & Physical Activity

• Children and youth aged 5 to 17 average 7
  hours and 23 minutes of physical activity
  per week. This is down from 8 hours and 37
  minutes per week in 2005.
Screen-Based Sedentary Behaviour
• Children and youth get an average of 7
  hours and 48 minutes of screen time per
• Only 19% of kids aged 10-16 report meeting
  the Canadian Sedentary Behaviour
  Guidelines, which recommend no more than
  2 hours of recreational screen time per day
       Active Healthy Kids Canada
• The 2013 report found that 84% of 3- to 4-year-olds
  meet the Physical Activity Guidelines (180 min/day).

• 5% of 5- to 17-year-olds meet the CPA Guidelines for
  Children and Youth of at least 60 minutes of daily
  moderate- to vigorous-intensity physical activity.

• 40% of 5- to 17-year-olds in Canada accumulate at least
  60 minutes of MVPA at least 3 days per week.

• Kids are spending 63% of their free time after school and
  on weekends being sedentary.
   Reasons for Decline in Physical
         Activity in Youth

• Increase in sedentary activities: smart
  phones, internet, video games, TV, and

• The majority of Canadian children and youth
  need to make permanent changes to their
  routine physical activity patterns.
• Changes can include increased active
  transportation, engagement in a new sport or
  activity club, and regular outdoor active play.
• Children and youth should be encouraged to
  add bits of physical activity throughout their
  day: before school, during school, after
  school, in the evenings and on the weekend.
• If your child has no free time, consider
  reducing the number of scheduled activities.
• Encourage children to spend time outdoors,
  every day, instead of in front of a TV or video
• Parents should implement household rules on
  screen time and provide alternative
  opportunities for active play, sport and
  physical activity participation.

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