PURPOSE: This study assessed the criterion validity and responsiveness of the Incidental and Planned Exercise Questionnaire (IPEQ) specifically developed for aging research. METHODS: The sample comprised 315 community-dwelling inactive older adults (mean age = 73.2 yr) who participated in a trial investigating the effect of a walking program on falls. At baseline, a subsample (n = 177) also wore an accelerometer (ActiGraph GT1M) for 7 d, and 126 of those had four valid days or more of accelerometer data. Validity coefficients (Spearman ρ) were calculated between accelerometer counts per minute, average steps per day, average moderate-to vigorous-intensity physical activity (MVPA) using two cut points (760 and 1041 counts per minute), and IPEQ-MVPA (the sum of physical activity hours per week derived from nine IPEQ items excluding the indoor chores question). Responsiveness was the mean IPEQ change in the intervention group divided by the SD of the mean change in control group. RESULTS: The correlation coefficients between IPEQ-MVPA and counts per minute per day and steps per day were 0.33 and 0.31, respectively. The coefficients with accelerometer MVPA at low and medium cut points were 0.29 and 0.33, respectively, and 0.26 and 0.35 for walking. The Bland-Altman plot showed increased errors with higher values of IPEQ-MVPA. IPEQ incidental physical activity questions and IPEQ as a whole were significantly correlated with accelerometer light intensity (100-760 counts per minute, ρ = 0.29 and 0.23). The 12-month responsiveness of total IPEQ was 0.30 and 0.44 for the "planned walking" item. CONCLUSIONS: IPEQ provides a practical and valid measure of MVPA in surveillance and intervention studies. Incidental activities are mostly of a light-intensity nature, and their low ambulatory component may explain the lower correlation between IPEQ as a whole and accelerometer measures.
- physical activity