Reliability of a measure of prediagnosis physical activity for cancer survivors

Med Sci Sports Exerc. 2006 Apr;38(4):715-9. doi: 10.1249/01.mss.0000210196.94952.8b.


Purpose: This study was conducted to examine the test-retest reliability of a measure of prediagnosis physical activity participation administered to colorectal cancer survivors recruited from a population-based state cancer registry.

Methods: A total of 112 participants completed two telephone interviews, 1 month apart, reporting usual weekly physical activity in the year before their cancer diagnosis. Intraclass correlation coefficients (ICC) and standard error of measurement (SEM) were used to describe the test-retest reliability of the measure across the sample; the Bland-Altman approach was used to describe reliability at the individual level. The test-retest reliability for categorized total physical activity (active, insufficiently active, sedentary) was assessed using the kappa statistic.

Results: When the complete sample was considered, the ICC ranged from 0.40 (95% CI: 0.24, 0.55) for vigorous gardening to 0.77 (95% CI: 0.68, 0.84) for moderate physical activity. The SEM, however, were large, indicating high measurement error. The Bland-Altman plots indicated that the reproducibility of data decreases as the amount of physical activity reported each week increases. The kappa coefficient for the categorized data was 0.62 (95% CI: 0.48, 0.76).

Conclusion: Overall, the results indicated low levels of repeatability for this measure of historical physical activity. Categorizing participants as active, insufficiently active, or sedentary provides a higher level of test-retest reliability.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Colorectal Neoplasms / diagnosis
  • Colorectal Neoplasms / physiopathology*
  • Female
  • Humans
  • Interviews as Topic
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Motor Activity / physiology*
  • Quality of Life
  • Registries
  • Reproducibility of Results
  • Survivors*
  • Walking / physiology*