Measuring levels of Physical Activity National Physical Activity Guidelines & Methods of Assessing Physical Activity

Measuring Physical Activity among Individuals and Populations Measuring the amount of physical activity is a complex procedure. Information collected needs to address the types of activities, frequency, intensity and duration. Physical activity covers many domains.domains Why measure our levels of activity? Document how active our population is Gives feedback on government health programs An active nation is a healthy nation Study the factors that influence our participation

Methods of Measuring Physical Activity

Dimensions of Physical Activity Frequency – Number of times a person engages in an activity Duration – Length of time engaged in an activity Intensity – How hard an activity is Type – Domains Context – Where you are, when, who with etc. Energy – Measured in METs Expense – Cost in dollars Reactivity – How much the measure biases towards the result.

METS, Time and Intensity

Subjective Measures Examples of subjective (remembering physical activity done) are self-reported recall measures, diaries and logs. Eg. Active Australia Survey and IPAQ. Written Report 1.7 p.23 StrengthsWeaknesses Assess multiple domains Can be quickly administered to large groups Low reliability and validity Social biases in answers given Poor recall skills in children

The Active Australia Survey

Objective Measures Direct Observation Direct Observation – Involves watching people and noting specific behaviours and activities they are participating in. Commonly used on children while playing. Advantages Quantitative and qualitative information Behaviour observed Wider variety of information gained Software available Used in school and community settings Disadvantages Difficult with large populations Obtrusive and time consuming Can cause bias

Physical Activity logs/diaries Advantages Disadvantages

Objective Measures - SOPLAY System of Observing Play and Leisure in Youth (SOPLAY) Used to asses groups of people (Commonly school settings). Uses a time-sampling technique in a given target area. See table 1.8 p.1.8 See SOPLAY formSOPLAY form SOPLAY Laboratory 1.8 p.27

Measurement Options – Direct Observation Advantages Disadvantages

Objective Measures – SOFIT and BEACHES SOFIT (System for Observing Fitness Instruction Time) Measures physical activity during PE classes Content and behaviour is observed (See graph) BEACHES (Behaviours of Eating Activity for Children’s Health Evaluation System) Measures children’ eating and physical activity patterns at home and at school.

Measurement Options – Direct Observation

Objective Measures HR Monitors HR monitors measure our hearts response to exercise intensity and energy expenditure. HR is very useful in the laboratory and in sports training. Is unobtrusive and gives quick data collection. However, HR is not influenced by intensity alone. There is also a lag between HR change and intensity.

Measurement Options – HR monitors Advantages Disadvantages

Objective Measures - Pedometers Advantages Low cost & non-invasive Easy to use motion sensor Determine distance travelled on foot Newer models also measure energy expended and time. 10,000 steps a day is recommended. Heart foundation planner Disadvantages Assess only hip movement Can’t store data Unable to record magnitude of the movement Not useful when comparing different age groups Energy expenditure based on adult results only. Laboratory 1.9 & 1.10 p.31

Measurement Options - Pedometers Advantages Disadvantages Laboratory 1.9 & 1.10 p.31

Measurement Options - Accelerometers Advantages Disadvantages See fig.1.20 p.32

Objective Measures Doubly Labelled Water DLW – Used to accurately measure total energy expenditure in field settings. A person is given a known sample of two isotopes (Deuterium and oxygen- 18) and a urine sample is given. A fortnight later, another urine sample is given and the level of isotopes is recorded. The greater the difference in isotopic concentrations, the greater the energy expenditure. The method is based on two stable isotopes (naturally occurring compounds) of water found in the body: 2 H 2 O (deuterium-labelled water). – Is lost from the normal body routes via sweat, urine, evaporative losses. H 2 18 O (oxygen-18 labelled water) – Is lost at a slightly faster rate because in addition to the normal routes of loss it also lost via carbon dioxide production. The difference between the two isotopes is the rate of carbon dioxide production. The subject is given a dose of the two isotopes orally. The new levels are then measured via a urine sample. The person then returns to normal living for 7-14 days. Then returns to the lab where a final urine test is performed and the difference between the two isotopes is established. Hence the rate of carbon dioxide production is determined. p.35

Doubly labelled Water Advantages Unobtrusive and non invasive. Accurately measures total energy expenditure related to physical activity over a one or two week period. Allows for the calculation of VO 2 Can be used with any age group. Disadvantages Extremely expensive, around $2000 per person per test. Doesn’t provide any information relating to activity type, frequency, intensity or duration. Doesn’t provide any contextual information (settings where someone is being active) about the physical activity behaviour of an individual.

Web Links – Chapter 1 Australian Sports Commission: Find 30 promotion (Government of WA Department of Health): Walking School Bus promotion (UK): Ministry of Health (New Zealand) toolkits: The 10,000 Steps Rockhampton project: Travelsmart Australia: World Health Organisation: Heart Foundation Australia: VicHealth (The Victorian Health Promotion Foundation): Be Active promotion (Government of South Australia): Go For Your Life: Physical Activity Resources for Health Professionals – Introduction (Centre for disease control and prevention – USA): Health Promotion (Public Health Agency of Canada): Strategic Inter-Governmental Forum on Physical Activity and Health (SIGPAH): Healthy youth (Centre for disease control and prevention (USA): America On The Move promotion: Papers from the International Journal of Behavioural Nutrition and Physical Activity: Department of health and aging (Australian government): Building a healthy, active Australia (Australian government): National Public Health Partnership: Be Active promotion (Government of South Australia): Sport and Recreation Australia: Australian government physical activity recommendations for children and young people: pubhlth-strateg-active-recommend.htmhttp:// pubhlth-strateg-active-recommend.htm Children’s leisure activities report (Centre for Physical Activity and Nutrition Research – Deakin University): Australian Sports Commission: VicHealth (The Victorian Health Promotion Foundation): Physical Activity Resources for Health Professionals – Introduction (Centre for disease control and prevention (USA): Strategic Inter-Governmental Forum on Physical Activity and Health (SIGPAH): Sport and Recreation Australia: