The validity and reliability of selected physical activity questions were assessed in both Seventh-day Adventist (N = 131) and non-Adventist(N = 101) study groups. Vigorous activity questions similar to those used by others and new questions that measured moderate and light activities were included. Validation was external, comparing questionnaire data with treadmill exercise time, resting heart rate, and body mass index(kg·m-2), and internal, comparing data with other similar questions. Both Adventist and non-Adventist males showed significant age-adjusted correlations between treadmill time and a “Run-Walk-Jog Index” (R = 0.28, R = 0.48, respectively). These correlations increased substantially when restricting analysis to exercise speeds exceeding 3 mph (R= 0.39, R = 0.71, respectively). Frequency of sweating and a vigorous physical activity index also correlated significantly with treadmill time in males. Correlations were generally weaker in females. Moderate- and light-intensity questions were not correlated with physical fitness. Internal correlations (R= 0.50-0.78) between the above three vigorous activity questions were significant in all groups, and correlations (R = 0.14-0.60) for light and moderate activity questions were also documented. Test-retest reliability coefficients were high for vigorous activity questions (R = 0.48-0.85) and for one set of moderate activity questions (R = 0.43-0.75). No important differences in validity and reliability were found between Adventists and non-Adventists, but the validity of vigorous activity measures was generally weaker in females.
Center for Health Research, Loma Linda University, Nichol Hall,#2008, Loma Linda, CA 92350
Submitted for publication May 1995.
Accepted for publication January 1996.
We gratefully acknowledge the effort and skills of secretary Cathy Provencio in typing this manuscript and the expert advice of Dr. Ralph Paffenbarger in helping to design the study. This research was supported by the National Heart, Lung, and Blood Institute, grant HL34174, and the National Cancer Institute, grant 5-R01-CA14703.
Address for correspondence: Pramil N. Singh, Center for Health Research, Loma Linda University, Nichol Hall, #2008, Loma Linda, CA 92350.
Present address for Dr. Tonstad: Solstad Terrasse 34, N-1364 Hvalstad, Norway.