Most questionnaires used for physical activity (PA) surveillance have been developed for adults aged ≤65
years. Given the health benefits of PA for older adults and the aging of the population, it is important to include adults
aged 65+ years in PA surveillance. However, few studies have examined how well older adults understand PA
surveillance questionnaires. This study aimed to document older adults' understanding of questions from the
International PA Questionnaire (IPAQ), which is used worldwide for PA surveillance.