Reliability and validity of Canada's Physical Activity Monitor for assessing trends.

Area of Science:

• Public Health
• Epidemiology
• Health Monitoring

Background:

• Assessing physical activity trends in Canada relies on the Minnesota Leisure Time Physical Activity Questionnaire (MLTPAQ).
• Adapting the MLTPAQ for telephone interviews (Physical Activity Monitor) aims to maintain data quality for population surveillance.

Purpose of the Study:

• To evaluate the test-retest reliability of the Physical Activity Monitor.
• To determine the criterion validity of the Physical Activity Monitor against objective measures.
• To compare telephone-administered MLTPAQ data with self-administered survey data.

Main Methods:

• Telephone interviews with 512 adults for reliability (administered twice, 3 weeks apart).
• Criterion validity assessed via telephone interview and in-home step test (n=148) for maximum oxygen uptake.
• Comparison with the Campbell's Survey of Well-Being (CSWB) instrument in a separate sample.

Main Results:

• The Physical Activity Monitor demonstrated acceptable test-retest reliability (r=0.90).
• Criterion validity for total energy expenditure was found to be 0.36.
• Strong association (r=0.77) observed between the Monitor and CSWB instruments for energy expenditure estimates.

Conclusions:

• The Physical Activity Monitor is a reliable and valid tool for assessing physical activity in population studies.
• Telephone-based data collection for the MLTPAQ yields comparable results to self-administration, facilitating large-scale health monitoring.