Until the early 2000s, the only cost-effective alternative to direct observation for assessment of habitual physical activity were subjective methods, predominantly in the form of self-report interviews, questionnaires and diaries (Dishman et al., 2001). Physical activity diaries document activities during a period of time, rather than retrospectively as with questionnaires, and provide information that is difficult to obtain other than by direct observation (Dishman et al., 2001). When completed judiciously, diaries provide detailed information on the type, frequency, and duration of activities. However, diaries are also highly burdensome on participants, particularly when required to account for regular time blocks (e.g. 15 min periods) (Dishman et al., 2001). As well, the mere act of recording physical activity might subconsciously motivate individuals to increase physical activity participation during the assessment period (Dishman et al., 2001). An alternative to physical activity diaries are retrospective physical activity questionnaires (PAQs). Such questionnaires can be self- administered or via interview, and are a convenient and unobtrusive instrument to assess physical activity levels of individuals or large populations (van Poppel et al., 2010; Steene- Johannessen et al., 2016). Their speed of administration, relative low cost and minimal
49 participant burden, make PAQs a feasible assessment option, especially in the epidemiological setting (Dishman et al., 2001). A wide range of PAQs are publically available, covering different assessment periods (e.g. 24-h recall, past month, lifetime) and activity domains (e.g. work, home, leisure) (Johnson-Kozlow et al., 2006; MRC Epidemiology Unit, 2006; Maddison et al., 2007; IPAQ, 2010; van Poppel et al., 2010). Many are tailored to specific populations (e.g. obese, elderly) or outcomes (e.g. bone health, work place physical activity) (Dolan et al., 2006; MRC Epidemiology Unit, 2006; Forsen et al., 2010; IPAQ, 2010; van Poppel et al., 2010).
Numerous validity and reliability studies have been conducted, validating specific PAQs against objective measures such as doubly labelled water or accelerometry (Prince et al., 2008; Boon et al., 2010; van Poppel et al., 2010; Helmerhorst et al., 2012; Cerin et al., 2016). Results from such studies reveal that very few PAQs score well on both reliability and validity (van Poppel et al., 2010; Helmerhorst et al., 2012). Most PAQs do seem to have acceptable reliability, although validity is often only moderate, at best (van Poppel et al., 2010; Helmerhorst et al., 2012). Due to the highly variable nature of physical activity among free-living individuals, valid assessment via self-report remains extremely difficult (Helmerhorst et al., 2012). Choosing the most appropriate PAQ for an intended research setting should consider the questionnaire validity and reliability in the particular setting (including population) along with the physical activity outcomes of interest (van Poppel et al., 2010). When using PAQs to compare physical activity against guidelines, questions on the frequency and duration of physical activity in all domains (i.e. transportation, work, home, leisure) should be included to uphold content validity (van Poppel et al., 2010).
The International Physical Activity Questionnaire (IPAQ) (in its numerous long and short forms), is the most commonly used and validated in the literature (Hagstromer et al., 2006; van Poppel et al., 2010; Silsbury et al., 2015) and has been cited in hundreds of publications (Rosenberg et al., 2008; Forsen et al., 2010; IPAQ, 2010; Harrison et al., 2011; Adams et al., 2013; Cerin et al., 2016; Steene-Johannessen et al., 2016). The IPAQ has been translated into 22 languages, and exists in 38 different forms (i.e. long v short, telephone v self-administered, different languages), some with cultural-specific adaptations (IPAQ, 2010). The IPAQ-long version is a 31-item assessment of physical activity, covering the previous seven days (or a usual week) in all domains (leisure, transport, occupation, home and sedentary) (Craig et al., 2003). The long version is intended for research use, particularly in domain-specific investigations of physical activity (Cerin et al., 2016). In comparison, the short form IPAQ contains just nine items and also covers the previous seven days (IPAQ, 2010). The IPAQ-short assesses time in different activity intensities and in sedentary behaviour, and is recommended
50 for prevalence and surveillance studies (Craig et al., 2003). Validation studies across many countries have reported the IPAQ as having sufficient validity (r = 0.33-0.39) and reliability (interclass correlation coefficient (ICC) = 0.87-0.90) (Craig et al., 2003; Hagstromer et al., 2006; Boon et al., 2010; Helmerhorst et al., 2012). Given the multitude of different versions of the IPAQ, wide variations in results have been reported (van Poppel et al., 2010; Helmerhorst et al., 2012; Cerin et al., 2016), but overall IPAQs tend to overestimate moderate, vigorous and total physical activity time, and underestimate sedentary time (Hagstromer et al., 2006; Boon et al., 2010; Helmerhorst et al., 2012; Cerin et al., 2016). However, the IPAQ-S7S was reported to have excellent reliability, correlated moderately with accelerometry, and was recommended as the most appropriate of all PAQs for clinical and research settings (Silsbury et al., 2015).
The New Zealand Physical Activity Questionnaire (NZPAQ) was developed for use in the annual New Zealand Health Survey (Moy et al., 2008; Boon et al., 2010) as a modified version of the IPAQ (both long and short versions) to increase its relevance to New Zealand populations and culture (Maddison et al., 2007; Moy et al., 2008). The NZPAQ-long differs from the IPAQ-long in that it gathers information using a retrospective 7-day diary covering the various lifestyle domains (Moy et al., 2008; Boon et al., 2010). Validation of the NZPAQ-short against doubly labelled water showed significant systemic underestimation (-59%) of total energy expenditure (r = 0.38) starting at 1,000 kJ (Maddison et al., 2007). In contrast, the NZPAQ-long overestimated total physical activity by 165% (r = 0.32) against accelerometry (Boon et al., 2010) and by 134% (r = 0.25) against heart rate monitors (Moy et al., 2008), but has been useful in monitoring trends in overall physical activity participation of the population.
The Recent Physical Activity Questionnaire (RPAQ) is an 11-item questionnaire developed as part of the European Prospective Investigation into Cancer and Nutrition Study (MRC Epidemiology Unit, 2006). The questionnaire covers the previous month in four lifestyle domains (work, transportation, leisure, home) and contains a list of 35 groups of leisure time activities against which the frequency and duration of participant engagement are recorded (MRC Epidemiology Unit, 2006). The RPAQ has been reported as a valid instrument for ranking individuals’ total and physical activity energy expenditure and time spent in sedentary and in vigorous physical activity (Besson et al., 2010). Significant correlations have also been reported with estimates of total (r = 0.67, p < 0.0001) and physical activity (r = 0.39, p < 0.0001) energy expenditure against doubly labelled water and of time spent in vigorous physical activity (r = 0.70, p < 0.0001) against a combination of heart rate and accelerometry (Besson et al., 2010). The RPAQ has shown good reliability for physical activity energy expenditure (ICC = 0.76) and
51 across activity intensities except transport (ICC 0.74-0.86; transport 0.32, p = 0.0001) (Besson et al., 2010).
A limitation of any questionnaire is the susceptibility for reporting bias, either intentional (e.g. social desirability bias) or accidental (e.g. cognitive limitations, memory), and PAQs are no exception (Adams et al., 2005; Prince et al., 2008). The degree to which such bias might influence outcomes has been related to specific populations. For instance, over-reporting of physical activity has been associated with overweight-obese populations (Prince et al., 2008), less active individuals (Moy et al., 2008) and non-European New Zealanders (Moy et al., 2008). Potential also exists for over-reporting when warm up/down periods are mistakenly included in total activity duration (Dyrstad et al., 2014), or misreporting when memorable activities (e.g. strenuous workouts) are accurately reported whereas less memorable activities (e.g. light, incidental activities) might be omitted (Dyrstad et al., 2014). Many PAQs, including those mentioned above, also have a tendency to underestimate physical activity energy expenditure with increasing volumes of activity (Besson et al., 2010; van Poppel et al., 2010) and with timeframes >7 days (Neilson et al., 2008). The focus of PAQs varies widely, as does the application. For instance, the RPAQ elicits frequency and duration of individual leisure-time activities (e.g. cycling, swimming, martial arts) across 35 activity groups whereas the IPAQ does not (Craig et al., 2003; MRC Epidemiology Unit, 2006). On the other hand, the IPAQ covers housework and child care activities, which is absent from the RPAQ (Craig et al., 2003; MRC Epidemiology Unit, 2006).
Notwithstanding the inherent inaccuracies and imprecision of participant recall and reporting bias (Adams et al., 2005; Prince et al., 2008; Dyrstad et al., 2014), few accurate and reliable alternatives to PAQs were available prior to the early 2000s for collecting physical activity data from free-living individuals (Montoye et al., 1983; Dishman et al., 2001; Troiano et al., 2014). Despite the now widespread use of accelerometers for physical activity assessment, PAQs provide complimentary data, often adding context to objective data, and detail of specific activities performed (Helmerhorst et al., 2012; Howitt et al., 2016). PAQs also remain a valuable tool in monitoring the effectiveness of large-scale physical activity interventions and for tracking physical activity trends at a population level (Helmerhorst et al., 2012).