Reliability and validity of the international physical activity questionnaire in the Nord-Trøndelag health study (HUNT) population of men

<p>Abstract</p> <p>Background</p> <p>There is no standardized method for the assessment of physical activity (PA). Therefore it is important to investigate the validity and comparability of different measures. The International Physical Activity Questionnaire (IPAQ) has been developed as an instrument for cross-national assessment of PA and has been validated in 12 countries. These instruments have acceptable measurement properties for monitoring population levels of PA among 18–65 year-old adults in diverse settings. However, there are some concerns that IPAQ may over-report PA.</p> <p>The purpose of this study is to evaluate the reliability and validity of IPAQ, short version, last 7-days in the Nord-Trøndelag Health Study (HUNT) population of men.</p> <p>Methods</p> <p>The questionnaire was administered twice to a random sample of 108 men aged 20–39 and validity by comparing results with VO_2maxand ActiReg, an instrument that measures PA and energy expenditure (EE). ActiReg discriminates between the body positions: stand, sit, bend forward and lie and also registers if there is motion or not in each of them or both.</p> <p>Results</p> <p>Our results for reliability of the IPAQ short version were good for vigorous and fair for moderate activities. Intraclass correlations ranged from a low of 0.30 for moderate activity hours, to a high of 0.80 for sitting hours. Concerning validity, our results suggest that total IPAQ vigorous PA was a moderately good measure of vigorous activity, having moderately strong, significant correlations with VO_2max, r = 0.41 (p ≤ 0.01), but correlated not with metabolic equivalent (METs) values of 6 or more measured with ActiReg. Only total IPAQ walking was fair correlated with METs 1–3 and METs 3–6, respectively r = -0.27 and 0.26 (p ≤ 0.05). The index for IPAQ sitting hours per week was moderate correlated with METs values of 1–3 and negatively correlated with METs values of 3–6. Classification of PA in three levels (low, moderate and high) correlated also most strongly with VO_2max(0.31 p ≤ 0.01) and METs 3–6 and METs 1–3 from ActiReg (r = 0.32 and -0.31, p ≤ 0.01). Classification of BMI in three levels (normal, overweight and obese) correlated most strongly negative with VO_2max(-0.42 p ≤ 0.01) and MJ from ActiReg (r = 0.31 p ≤ 0.01).</p> <p>Conclusion</p> <p>Our results indicate that IPAQ short version for men has acceptable reliability and criterion validity for vigorous activity and sitting. Walking has moderate reliability. Only the IPAQ for walking had a fair correlation with METs 6+. The questions about moderate activity had fair reproducibility and correlated poorly with most comparison measures.</p

Validation of ActiReg (R) to measure physical activity and energy expenditure against doubly labelled water in obese persons

ActiReg® is an instrument that uses combined recordings of body position and motion to calculate energy expenditure (EE) and physical activity (PA). The aim of the study was to compare mean total energy expenditure (TEE) measured by ActiReg® and doubly labelled water (DLW) in obese subjects. TEE was measured by the DLW method during a period of 14 d in fifty obese men and women with metabolic risk factors. During the same period ActiReg® recordings were obtained for 7 d. RMR was measured by indirect calorimetry and also estimated by standardized equations. Because EE may be disproportionately increased in obese subjects during weight-bearing activities, we established a new set of physical activity ratios (PAR). These ratios were based on oxygen uptake measurements during treadmill walking. The mean TEE according to the DLW was 13·94 (sd 2·47) MJ/d. Mean TEE calculated from the ActiReg® data and measured RMR was 13·39 (sd 2·26) MJ/d, an underestimation of 0·55 MJ (95 % CI 0·13, 0·98; P = 0·012) or 3·9 %. RMR derived from standard equations based on weight, age and sex were overestimated while the RMR based on fat-free mass values in addition was underestimated. Despite slight underestimation ActiReg® may be used to measure TEE in obese subjects on two premises: RMR should be measured, and the increased EE during weight-bearing activities in obese subjects should be considered

Description and validation of the ActiReg

The Stable Marriage problem (SM) is an extensively-studied combinatorial problem with many practical applications. In this paper we present two encodings of an instance I of SM as an instance J of a Constraint Satisfaction Problem. We prove that, in a precise sense, establishing arc consistency in J is equivalent to the action of the established Extended Gale/Shapley algorithm for SM on I. As a consequence of this, the man-optimal and woman-optimal stable matchings can be derived immediately. Furthermore we show that, in both encodings, all solutions of I may be enumerated in a failure-free manner. Our results indicate the applicability of Constraint Programming to the domain of stable matching problems in general, many of which are NP-hard