Physical inactivity is one of the four leading risk factors for global mortality. Accurate measurement of physical activity (PA) and in particular by physical activity questionnaires (PAQs) remains a challenge. The aim of this paper is to provide an updated systematic review of the reliability and validity characteristics of existing and more recently developed PAQs and to quantitatively compare the performance between existing and newly developed PAQs.A literature search of electronic databases was performed for studies assessing reliability and validity data of PAQs using an objective criterion measurement of PA between January 1997 and December 2011. Articles meeting the inclusion criteria were screened and data were extracted to provide a systematic overview of measurement properties. Due to differences in reported outcomes and criterion methods a quantitative meta-analysis was not possible.In total, 31 studies testing 34 newly developed PAQs, and 65 studies examining 96 existing PAQs were included. Very few PAQs showed good results on both reliability and validity. Median reliability correlation coefficients were 0.62–0.71 for existing, and 0.74–0.76 for new PAQs. Median validity coefficients ranged from 0.30–0.39 for existing, and from 0.25–0.41 for new PAQs.Although the majority of PAQs appear to have acceptable reliability, the validity is moderate at best. Newly developed PAQs do not appear to perform substantially better than existing PAQs in terms of reliability and validity. Future PAQ studies should include measures of absolute validity and the error structure of the instrument.

Physical activity has a fundamental role in the prevention and treatment of chronic disease. The precise measurement of physical activity is key to many surveillance and epidemiological studies investigating trends and associations with disease. Public health initiatives aimed at increasing physical activity rely on the measurement of physical activity to monitor their effectiveness. Physical activity is multidimensional, and a complex behaviour to measure; its various domains are often misunderstood. Inappropriate or crude measures of physical activity have serious implications, and are likely to lead to misleading results and underestimate effect size. In this review, key definitions and theoretical aspects, which underpin the measurement of physical activity, are briefly discussed. Methodologies particularly suited for use in epidemiological research are reviewed, with particular reference to their validity, primary outcome measure and considerations when using each in the field. It is acknowledged that the choice of method may be a compromise between accuracy level and feasibility, but the ultimate choice of tool must suit the stated aim of the research. A framework is presented to guide researchers on the selection of the most suitable tool for use in a specific study.

Background: Few questionnaires that assess usual physical activity have been reported to be valid for all different subdimensions of physical activity. Objective: The objective was to assess the validity and reliability of the Recent Physical Activity Questionnaire (RPAQ), which assesses usual physical activity (PA) in 4 domains (work, travel, recreation, and domestic life). Design: Total energy expenditure (TEE) was measured for 14 d by using the doubly labeled water technique combined with a measure of resting metabolic rate to yield PA energy expenditure (PAEE) in 25 men and 25 women. Simultaneously, intensity of activity was measured by using combined heart rate and movement sensing for 11 d. Repeatability of the RPAQ was assessed in an independent sample of 71 women and 60 men aged 31-57 y. Results: Estimated TEE and PAEE were significantly associated with criterion measures (TEE: r = 0.67; PAEE: r = 0.39) with mean (6SD) biases of 23452 6 2025 kJ/d and 213 6 24 kJ Á d 21 Á kg 21 . The correlation between self-reported and measured time spent was significant for vigorous PA (r = 0.70) and marginally insignificant for sedentary time (r = 0.27, P = 0.06). The mean biases were relatively small for sedentary time and vigorous PA: 0.7 6 2.8 h/d and 212 6 24 min/d, respectively. The intraclass correlation coefficient for repeatability of total PAEE (kJ/d) was 0.76 (P , 0.0001). Conclusion: The RPAQ is the first questionnaire with demonstrated validity for ranking individuals according to their time spent at vigorous-intensity activity and overall energy expenditure.Am J Clin Nutr 2010;91:106-14.

BMI, FM, and WC may predict sedentary time, but our results do not suggest that sedentary time predicts future obesity.

These findings suggest that public health recommendations should consider advising a reduction in TV time, a predominant leisure activity in modern society, in addition to advocating physical activity.