Measurement of Physical ActivitySubjective Measures

We also measure PA levels to:

• Evaluate current guidelines and trends S• Set recommended levels of physical activity• Investigate the relationship between physical activity and health conditions• Allow research to be conducted on large numbers of people, allowing us to generalise about a wider population.

ReactivityReactivity is a phenomenon that occurs when individuals alter their performance or behavior due to the awareness that they are being observed

Example: Direct observation in a PE class (SOFIT)

ValidityIn terms of assessment, validity refers to the extent to which a test can allow accurate conclusions

Example: Does walking 10,000 steps a day equate to meeting the national physical activity guidelines for adults?

http://www.10000steps.org.au/

So???A tests validity (accuracy and correct representation of the data) is highly dependent on the reactivity of test measure.

Social-desirability bias

• Social desirability bias is the tendency of respondents to answer questions in a manner that will be viewed favorably by others.

• It can take the form of over-reporting "good behavior" or under-reporting "bad," or undesirable behavior.

Subjective Measures

Depend on our perceptions (what we think/feel/value)

The are predominantly used for measurement of populations

Measure of AssessmentSubjective

Self report (diaries/logs)

Recall (surveys (SAPAC), questionnaires (GPAQ, IPAQ), proxy-reports)

Objective

Heart-rate telemetry

Pedometers

Accelerometers

Direct Observation (SOFIT, SOPLAY, BEACHES)

Self Report

Generally come in the form of a physical activity diary or log

They record individual activities an person performs in a day

They provide context, patterns of behavior, intensity and duration

Self ReportAdvantages

Suitable for small groups or individuals

Usually easy to complete

Able to provide detailed information on context of an activity (eg. Location, other participants, subjects feelings)

Disadvantages

Heavy subject burden (entries completed throughout the day)

Unreliable due to potential misinterpretation or inaccurate recording.

Recall Surveys

Include the IPAQ and SAPAC

Less likely to influence behaviour and require less effort compared to diaries/logs

5 – 15 minutes to complete (generally)

Provide basic data to assess the PA patterns in large populations

RecallAdvantages

Inexpensive

Large sample size (measures large populations)

Usually easy to complete

Able to collect a range of data (qualitative and quantitative)

Disadvantages

Unreliable due to potential misinterpretation of questions

Potential subjectivity or bias (eg. Subjects may provide ‘socially desirable’ responses’

Proxy Report

Either a diary/log or survey that is completed on behalf of a respondent

Generally it will be a parent of a child or a representative of an elderly person

“submitted by proxy”

Generally used when the respondent is not cognitively capably of understanding or remembering