Article Text
Abstract
Background: Validation of instruments used to measure physical activity patterns are essential when attempting to assess the effectiveness of physical activity interventions.
Objectives: To assess the validity of two self-report physical activity questionnaires on a representative sample of New Zealand adults.
Methods: Seventy adults aged 18-65 years from around Christchurch, New Zealand were required to wear an ActiGraph GT1M accelerometer during all waking hours for seven consecutive days. Immediately following the 7-day accelerometer period participants were required to complete the long forms of both the New Zealand Physical Activity Questionnaire (NZPAQ-LF) and the International Physical Activity Questionnaire (IPAQ-LF).
Results: Both the NZPAQ-LF and the IPAQ-LF questionnaires showed small to moderate correlations to Actigraph data for time spent in moderate-intensity physical activity (r = 0.19 – 0.30), and total physical activity (sum of moderate and vigorous-intensity physical activity r = 0.30 – 0.32). Compared to the Actigraph data both self-report questionnaires tended to overestimate activity levels by ~ 165%. Total physical activity levels gathered from both questionnaires were strongly correlated to each other (r = 0.79) and showed good levels of agreement in the Bland-Altman plots.
Conclusions: We found the long forms of the NZPAQ and IPAQ had acceptable validity when detecting participant’s ability to meet activity guidelines based on exercise duration, but a significant amount of over-estimation was evident. This presents a need for both instruments to be further developed and tested in order to increase validity.