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Validity and Reliability of International Physical Activity Questionnaire–Short Form in Chinese Youth Chao Wang a
a b
a
, Peijie Chen & Jie Zhuang
a
Shanghai University of Sport
b
Capital University of Physical Education and Sports Published online: 04 Dec 2013.
To cite this article: Chao Wang , Peijie Chen & Jie Zhuang (2013) Validity and Reliability of International Physical Activity Questionnaire–Short Form in Chinese Youth, Research Quarterly for Exercise and Sport, 84:sup2, S80-S86, DOI: 10.1080/02701367.2013.850991 To link to this article: http://dx.doi.org/10.1080/02701367.2013.850991
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Research Quarterly for Exercise and Sport, 84, S80–S86, 2013 Copyright q AAHPERD ISSN 0270-1367 print/ISSN 2168-3824 online DOI: 10.1080/02701367.2013.850991
Validity and Reliability of International Physical Activity Questionnaire – Short Form in Chinese Youth Chao Wang
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Shanghai University of Sport Capital University of Physical Education and Sports
Peijie Chen and Jie Zhuang Shanghai University of Sport
Purpose: The psychometric profiles of the widely used International Physical Activity Questionnaire –Short Form (IPAQ – SF) in Chinese youth have not been reported. The purpose of this study was to examine the validity and reliability of the IPAQ –SF using a sample of Chinese youth. Method: One thousand and twenty-one youth (Mage ¼ 14.26 ^ 1.63 years, 52.8% boys) from 11 cities in China wore accelerometers for 7 consecutive days and completed the IPAQ– SF on the 8th day to recall their physical activity (PA) during accelerometer-wearing days. A subsample of 92 youth (Mage ¼ 15.90 ^ 1.35 years, 46.7% boys) completed the IPAQ– SF again a week later to recall their PA during accelerometer-wearing days. Differences in PA estimated by the IPAQ – SF and accelerometer were examined by paired-sample t test. Spearman correlation coefficients were used to examine the correlation between the IPAQ– SF and accelerometer. Test –retest reliability of the IPAQ – SF was determined by the intraclass correlation coefficient (ICC). Results: Compared with accelerometer, the IPAQ – SF overestimated sedentary time, moderate PA (MPA), vigorous PA (VPA), and moderate-tovigorous PA (MVPA). Correlations between PA (total PA, MPA, VPA, and MVPA) and sedentary time measured by 2 instruments ranged from “none” to “low” (r ¼ .08 –.31). Test – retest ICC of the IPAQ– SF ranged from “moderate” to “high” (ICC ¼ .43– .83), except for sitting in boys (ICC ¼ .06), sitting for the whole sample (ICC ¼ .32), and VPA in girls (ICC ¼ .35). Conclusion: The IPAQ – SF was not a valid instrument for measuring PA and sedentary behavior in Chinese youth. Keywords: accelerometer, adolescent, assessment, validation
Reliable and valid measurement of habitual physical activity (PA) is essential for all studies on PA, such as identifying the causal relations between PA and health outcomes, monitoring the prevalence and differences in PA between individuals, evaluating the effects of PA interventions, and establishing public health recommendations (Lagerros & Lagiou, 2007). Commonly used methods to
Correspondence should be addressed to Peijie Chen, Shanghai University of Sport, 399 Chang Hai Road, Shanghai, 200438, P. R. China. E-mail: [email protected]
measure PA include self-report questionnaires, indirect calorimetry, direct observation, heart rate telemetry, and movement sensors. Relative to objective measures of PA, subjective measures such as questionnaires are of particular value in that they are relatively inexpensive and convenient and can be self-administered, which makes them a more suitable method for assessment of PA in populations (Ainsworth et al., 2012). Numerous questionnaires have recently been developed for measuring PA in children and youth (e.g., Biddle, Gorely, Pearson, & Bull, 2011; Chinapaw, Mokkink, van Poppel, van Mechelen, & Terwee, 2010; Helmerhorst, Brage, Warren,
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VALIDATION OF IPAQ–SHORT FORM IN CHINESE YOUTH
Besson, & Ekelund, 2012). Given the discrepancy in PA measurements provided by different questionnaires, it is difficult to compare results across studies. To address the demand for a comparable PA instrument, a set of standardized international PA questionnaires (the International Physical Activity Questionnaire [IPAQ]) was developed (Craig et al., 2003). The IPAQ was designed to assess PA of adults (aged 18–65 years old) and has a short (7 items) and a long form (31 items). The IPAQ–Short Form (IPAQ–SF) measures the frequency and duration of moderate PA (MPA), vigorous PA (VPA), walking, and sedentary behavior (SB) using 7 questions and is considered more suitable for population surveillance and large-scale studies compared with the long form (Craig et al., 2003). The IPAQ–SF was validated for adults in 12 countries and was shown to have adequate test–retest reliability (Spearman r ¼ .76) and convergent validity against accelerometer (Spearman r ¼ .30; Craig et al., 2003). The IPAQ –SF has been modified to measure habitual PA of youth in Vietnam and Norway (Lachat et al., 2008; Rangul, Holmen, Kurtze, Cuypers, & Midthjell, 2008). Lachat and colleagues (2008) reported that the reliability (intraclass correlation coefficient [ICC] ¼ .15 –.40) and validity (r ¼ 2.01 to .29 against accelerometer) of the IPAQ –SF were low in two hundred and twenty-seven 16-year-old Vietnamese youth. Rangul and colleagues (2008) demonstrated a better reliability (ICC ¼ .10– .62) and a range of 2 .29 to .43 correlation coefficients against PA level assessed by the ActiReg motion sensor among 71 Norwegian youth. Nonetheless, the Chinese version of the IPAQ –SF has been developed and demonstrated to be reliable and valid in Chinese younger to middle-age adults (age range ¼ 15– 55 years, n ¼ 49; Macfarlane, Lee, Ho, Chan, & Chan, 2007) and older adults (Mage ¼ 65 years, n ¼ 224; Deng et al., 2008). Because psychometric profiles of self-report instruments can be impacted by culture or language differences (Macfarlane et al., 2007) and by agerelated cognitive ability (Cerin et al., 2010), the feasibility of the IPAQ – SF in Chinese youth is unknown. Therefore, the purpose of this study was to examine the reliability and validity of the IPAQ –SF using a sample of Chinese youth from the Chinese City Children and Youth Physical Activity Study (CCCYPAS).
METHODS Participants Data were collected, as a part of CCCYPAS, during schooldays from April 2011 to May 2012 in 11 cities across China, including Chengdu, Fuyang, Ganzhou, Guangzhou, Shanghai, Shenyang, Tianjin, Tongzhou, Wenzhou, Xian, and Yingtan. One to two middle/high schools in each city were recruited to participate in the study. A total of 2,092
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healthy youth (1,069 boys and 1,023 girls) from 11 middle schools and 7 high schools volunteered to participate in the study. All participants were required to complete the IPAQ – SF and wear the accelerometer to examine the concurrent validity of the IPAQ – SF. A subsample of 216 youth (113 boys and 103 girls) from a middle school and a senior high school in the city of Fuyang completed the IPAQ – SF twice to assess the test – retest reliability of the IPAQ – SF. The purpose and procedure of the study were comprehensively introduced to all participants. Signed written assent forms were obtained from all participants, and signed written consent forms were obtained from their parents or guardians. The methods and protocols were approved by the Ethics Advisory Committee of the Shanghai University of Sport.
Measures Demographic Variables The participants reported their birth date and gender. Age (years) was calculated as months between the birth date and measurement date divided by 12 with the integer number of years being kept. Anthropometric Variables Height and weight measurements were conducted in a private setting with participants dressed in light clothing. Height was measured to the nearest 0.1 cm using a freestanding portable stadiometer. Weight was measured to the nearest 0.1 kg with an electronic weighing scale (HN-358, Omron, Tokyo, Japan). Body mass index (BMI) was calculated as weight (kg) divided by height (m) squared (kg/m2). PA and SB Measurement by Accelerometer The participants wore ActiGraph GT3Xþ or GT3X accelerometers (ActiGraph, LLC, Pensacola, FL) for 7 consecutive days to measure their PA and SB. The sampling interval (epoch) in the present study was set at 60 s. Participants were instructed to wear the accelerometers on the right hip and secured by an elastic belt. The PA was reported as time spent in light PA (LPA), MPA, VPA, and moderate-to-vigorous PA (MVPA). The cutoff points (i.e., counts per minute [CPM]) for defining intensities of PA were 101 CPM to 2,799 CPM for LPA, 2,800 CPM to 3,999 CPM for MPA, and $ 4,000 CPM for VPA. These cutoff points were developed specifically for Chinese youth by our research group (for more details, see Z. Zhu, Chen, & Zhuang, this supplement). SB was defined as activity counts of less than 100 CPM (Trost, Loprinzi, Moore, & Pfeiffer, 2011). Details of the accelerometer data processing protocol were reported in Wang, Chen, & Zhuang (this supplement).
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PA and SB Measurement by the IPAQ – SF The IPAQ –SF used in the present study adopted the Chinese version of the IPAQ – SF translated by Macfarlane and colleagues (2007). The IPAQ – SF consists of seven items and provides information on the time spent in VPA, such as aerobics, MPA, such as leisure cycling, walking, and sedentary activities (Lee, Macfarlane, Lam, & Stewart, 2011). Participants were asked to recall the number of days they performed each activity (frequency) and the length of time (duration) they were involved daily in each activity during the last 7 days or were asked to recall a regular 7 days of activity for them. In addition, participants were asked to record the amount of time during which they were sedentary. Data from the questionnaire were summed within each item (i.e., vigorous intensity, moderate intensity, and walking) to estimate the total amount of time spent in PA per day. Using the official IPAQ – SF scoring protocol, total daily PA (metabolic equivalent [MET]·min/day) was estimated by summing the product of reported time by a PA category with its corresponding category MET value and was expressed as a daily average MET score. MET values for vigorousintensity activities, moderate-intensity activities, and walking are 8, 4, and 3.3, respectively; MPA and walking measured by the IPAQ –SF were categorized into MPA when it was validated against the MPA measured by accelerometers (Wolin, Heil, Askew, Matthews, & Bennett, 2008).
Procedure Before the commencement of the study, informed written assent/consent forms were obtained from all participants and their parents or guardians. Local helpers in each city were trained to conducted the anthropometric measurements and administer the IPAQ – SF in a standardized manner. The accelerometer distribution and collection in the 11 cities were conducted by the same researcher, who was also responsible for processing all accelerometer data. The whole data collection lasted for about 1 year, from April 2011 to May 2012. The same protocol was used for each city. On Day 1, after weight and height of the participants were measured by local helpers, all participants were instructed to wear the accelerometers for 7 consecutive days on the right hip and secured by an elastic belt. They were asked to wear the devices when they were awake and to take the devices off when swimming, bathing, and sleeping. Written instructions were also given to all participants and their parents/guardians to remind them to wear the accelerometers in order to increase compliance. The participants were also asked to follow their normal daily routines during the monitoring period. On Day 8, the participants returned the accelerometers and completed the IPAQ – SF for the first time to recall their PA during the previous 7 days. When filling out the questionnaire, the participants were in groups of 20 to 30 participants in a classroom following the instructions of
researchers. The participants were required not to communicate with each other to avoid possible undesirable interference in their responses. One week later, a subgroup of participants (n ¼ 216) completed the IPAQ – SF for a second time to recall their PA during the same 7 days when they wore accelerometers. After cleaning the data for missing and out-of-range values, questionnaire data that were valid for both applications were included in the final analysis. Statistical Analysis All analyses were conducted using the Statistical Package for the Social Sciences Version 18.0 (SPSS Inc., Chicago, IL). Descriptive statistical analyses were conducted to calculate the means and standard deviations for all anthropometric and PA variables. Gender differences of anthropometric variables were examined by independentsample t test. Differences between PA behaviors measured by the IPAQ – SF and the accelerometer were examined by paired-sample t test. The convergent validity of the IPAQ – SF was examined by correlating PA behaviors measured by the IPAQ –SF with those measured by accelerometers, and Spearman’s correlation coefficients were computed. The correlation values were interpreted as the following: A range of .00 to .19 was considered no correlation, .20 to .39 was considered a low correlation, .40 to .59 was considered moderate, .60 to .79 was considered moderately high, and .80 to 1.00 was considered a high correlation (W. Zhu, 2012). ICCs were used to examine the test –retest reliability of the IPAQ – SF. The interpretation of ICC values for reliability was as follows: A range of .00 to .20 was considered slight reliability, .21 to .40 was considered fair, .41 to .60 was moderate, .61 to .80 was substantial, and .81 to 1.00 was almost perfect reliability (Landis & Koch, 1977). The significance level was set at p , .05. RESULTS Participants’ Characteristics Of the total 2,092 participants involved in the validity study, 24 were excluded due to accelerometer malfunction or loss, 31 due to missing demographic or anthropometric data, and 8 due to illness. Among the rest of the 2,029 participants, 438 were excluded due to an insufficient number of valid accelerometer-wearing days, and 570 were further excluded due to failing to complete the IPAQ – SF. No differences in age, body weight, and height were found between the excluded participants and the included participants. The final analytic sample of the validity study consisted of 1,021 participants (539 boys and 482 girls) aged 12 to 18 years old with complete data. Within the 216 participants who were involved in the reliability study, 92 (43%) provided complete questionnaire data on two occasions and were included in the final data analysis.
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TABLE 1 Anthropometric Characteristics of the Participants by Gender (Mean ^ SD) Validity Study
Age (years) Height (cm) Weight (kg) BMI (kg/m2)
Reliability Study
Boys (N ¼ 539)
Girls (N ¼ 482)
Total (N ¼ 1,021)
Boys (N ¼ 43)
Girls (N ¼ 49)
Total (N ¼ 92)
14.29 ^ 1.60 165.38 ^ 9.44* 56.73 ^ 14.26* 20.54 ^ 3.90
14.21 ^ 1.65 158.20 ^ 6.25 51.51 ^ 9.67 20.51 ^ 3.21
14.26 ^ 1.63 161.99 ^ 8.85 54.27 ^ 12.57 20.52 ^ 3.59
15.85 ^ 1.34 173.51 ^ 4.46* 64.20 ^ 10.32* 21.26 ^ 2.92
15.94 ^ 1.37 162.33 ^ 4.59 55.18 ^ 6.87 20.93 ^ 2.39
15.90 ^ 1.35 167.56 ^ 7.19 59.39 ^ 9.73 21.09 ^ 2.64
Note. BMI ¼ body mass index. *Significant difference between boys and girls, p , .05.
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TABLE 2 Differences of PA Measured by the IPAQ–SF and the Accelerometer
Boys IPAQ–SF Accelerometer Girls IPAQ–SF Accelerometer Total IPAQ–SF Accelerometer
Sedentary (min/day)
MPA (min/day)
VPA (min/day)
MVPA (min/day)
Meeting MVPA Recommendation (%)
569.20 ^ 178.39* 549.73 ^ 111.50
46.26 ^ 40.86* 20.37 ^ 10.65
19.76 ^ 23.01* 14.53 ^ 11.78
66.02 ^ 52.00* 34.90 ^ 20.00
44.9 10.4
608.01 ^ 183.17* 562.94 ^ 100.20
39.24 ^ 37.65* 15.77 ^ 9.44
8.09 ^ 15.98 6.76 ^ 7.09
47.32 ^ 41.80* 22.54 ^ 14.30
30.9 1.9
587.52 ^ 181.61* 555.96 ^ 106.47
42.94 ^ 39.51* 18.20 ^ 10.35
14.25 ^ 20.82* 10.86 ^ 10.58
57.19 ^ 48.35* 29.06 ^ 18.59
38.3 6.4
Note. MPA and MVPA measured by the IPAQ-SF include walking. *Significant difference between the accelerometer and the IPAQ-SF, p , .05.
The anthropometric characteristics of the participants are shown in Table 1. For both samples in the validity and reliability study, no gender differences were found for age and BMI, but boys were taller and heavier than girls. Differences of PA Measured by Accelerometer and IPAQ –SF Table 2 presents the PA levels measured by accelerometer and the IPAQ – SF. For the overall sample and for boys, the IPAQ –SF seemed to overestimate time spent in sitting, MPA, VPA, and MVPA compared with what accelerometer reported. This was also true for girls except for VPA.
Correlations Between PA Measured by the IPAQ – SF and Accelerometer The results of correlations of PA behaviors measured by the IPAQ –SF and accelerometer are presented in Table 3. “No” to “low” correlations were found in all PA categories between two measures, with Spearman correlation coefficients ranging from 0.08 to .31.
Test – Retest Reliability of the IPAQ – SF The results of test – retest reliability of the IPAQ – SF are shown in Table 4. The ICC values for most measured PA
TABLE 3 Correlation Between PA Measured by the IPAQ–SF and the Accelerometer Spearman Correlation Coefficients IPAQ –SF Measure
Accelerometer Measure
Total activities (MET·min/day) MPA and walking (min/day) VPA (min/day) MVPA and walking (min/day) Sitting (min/day)
Overall PA (CPM) MPA (min/day) VPA (min/day) MVPA (min/day) Sedentary (min/day)
Note. CPM ¼ counts per minute.
Boys
Girls
Total
.25 .14 .13 .15 .24
.27 .24 .08 .19 .10
.31 .20 .22 .22 .18
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TABLE 4 Test–Retest Reliability of the IPAQ– SF
Boys VPA (min/day) MPA (min/day) Walking (min/day) Sitting (min/day) Total PA (MET min/day) Girls VPA (min/day) MPA (min/day) Walking (min/day) Sitting (min/day) Total PA (MET min/day) Total VPA (min/day) MPA (min/day) Walking (min/day) Sitting (min/day) Total PA (MET min/day)
Test 1
Test 2
ICC
95% CI
p
14.22 ^ 17.65 13.76 ^ 17.15 21.69 ^ 28.84 580.74 ^ 148.79 240.36 ^ 235.79
19.97 ^ 23.47 27.78 ^ 30.40 28.03 ^ 29.66 582.56 ^ 121.64 363.39 ^ 283.81
.83 .45 .62 .06 .74
.71, .91 .18, .66 .40, .77 –.24, .35 .57, .85
.000 .001 .000 .347 .000
3.92 ^ 6.82 7.79 ^ 15.39 27.30 ^ 33.85 628.78 ^ 234.74 152.61 ^ 146.24
6.93 ^ 9.16 13.04 ^ 18.34 30.65 ^ 36.54 592.65 ^ 144.20 208.70 ^ 200.87
.35 .60 .69 .43 .68
.08, .57 .39, .76 .50, .81 .17, .63 .50, .81
.006 .000 .000 .001 .000
8.73 ^ 13.96 10.58 ^ 16.42 24.68 ^ 31.56 606.33 ^ 199.66 193.62 ^ 197.18
13.02 ^ 18.47 19.93 ^ 25.66 29.42 ^ 33.35 587.93 ^ 133.50 281.00 ^ 253.93
.79 .53 .66 .32 .74
.70, .86 .36, .66 .53, .76 .12, .49 .63, .82
.000 .000 .000 .001 .000
Note. MPA and MVPA do not include walking.
categories showed “moderate” to “high” reliability with ICCs ranging from .43 to .83, except for sitting in boys (ICC ¼ .06), sitting for the overall sample (ICC ¼ .32), and VPA in girls (ICC ¼ .35).
DISCUSSION The purpose of this study was to examine the validity and reliability of the IPAQ – SF in Chinese youth. To our knowledge, this is the first study to validate the IPAQ – SF in this population. Unfortunately, the IPAQ –SF tended to overestimate MPA, VPA, MVPA, and sitting compared with accelerometer, and this was true for both the whole sample and subsamples by gender. The correlations between the two instruments were from “no” to “low” and therefore rejected the convergent validity of IPAQ – SF. In general, the test – retest reliability of IPAQ –SF was from “moderate” to “high,” with a few exceptions in boys and the whole sample’s sitting, and in girls’ VPA. Validity of the IPAQ – SF in Youth The first comprehensive validation study of the IPAQ –SF was conducted in 12 countries and revealed a wide range of correlations with accelerometer across countries (from .02 to .47; Craig et al., 2003). This indicated the need to validate the IPAQ – SF in different populations. The PA questionnaire validity was usually examined by correlating data derived from the questionnaire with those derived from an objective measure and/or by computing the absolute differences between PA assessed by the questionnaire and by the objective measure (Lee et al., 2011).
In this study, “no” to “low” correlations were found between the total PA assessed by the IPAQ – SF and by accelerometer for the whole sample and for the subsamples by gender (r ¼ .25 –.31). Similarly, a recent systematic review indicated that 20 of 23 validation studies of the IPAQ – SF demonstrated a range from .21 to .39 of correlation coefficients of total PA with objective measures (Lee et al., 2011). For specific intensities of PA, the correlations between the IPAQ – SF and accelerometer were generally low, and the lowest correlations were found in VPA with the correlation coefficients being .13 in boys and insignificant in girls. In contrast, previous studies of youth revealed higher correlations in VPA than other intensities of PA between the IPAQ – SF and accelerometer (Hagstromer et al., 2008; Lachat et al., 2008). This may be caused by limited VPA engaged in by Chinese youth. Under greater academic pressure, Chinese students seldom participated in any organized PA outside of school (Tudor-Locke, Ainsworth, Adair, Du, & Popkin, 2003); moreover, due to concerns for safety, structured exercise organized by schools usually does not involve high-intensity activities. The present study also showed a low correlation between sitting measured by the IPAQ –SF and by accelerometer in both genders. Overall, this is an understudied area and limited information is available. In a comparable validation study of IPAQ – SF in youth, a negative correlation was found between sitting measured by the IPAQ – SF and the PA level determined by the ActiReg motion sensor in boys (r ¼ 2.68; Rangul et al., 2008) On average, the IPAQ –SF overstated the time spent in MPA, VPA, MVPA, and sitting compared with accelerometry in both boys and girls in this study. This is consistent with the findings summarized in a recent review
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that revealed an average over-report by the IPAQ – SF of 106% for total PA compared with accelerometer (Lee et al., 2011). The overestimation of the IPAQ – SF compared with accelerometer found in this study was the most evident in MPA (nearly 136%) and was least evident in sitting (nearly 6%). Large differences in classifying youth into meeting the 60-min/day PA recommendation between these two instruments were also observed in the present study (38.3% vs. 6.4% for the whole sample). These findings indicated that the IPAQ –SF was not appropriate for measuring the specific intensity of PA nor was it suitable for monitoring compliance with the PA recommendation among Chinese youth. Reliability of the IPAQ –SF Despite the widely accepted high reliability of the IPAQ –SF among adults (Craig et al., 2003), only limited studies have examined the reliability of the IPAQ – SF in youth (Lachat et al., 2008; Rangul et al., 2008). Rangul and colleagues (2008) found that the reliability (indicated by ICC) of the IPAQ –SF among 71 youth in Norway ranged from .10 (sitting) to .62 (walking frequency). Another validation study demonstrated an ICC range of .15 (MPA) to .40 (VPA) of the IPAQ –SF among Vietnamese youth (Lachat et al., 2008). The current study showed a relatively higher test –retest reliability of the IPAQ – SF in Chinese youth (ICC ¼ .06 – .83). The short recall interval employed in this study may be the reason. The interval time in the studies by Rangul et al. and Lachat et al. (2008) were 8 to 12 days for a Norwegian sample and 2 weeks for a Vietnamese sample. In fact, shorter intervals between test and retest have been found to be associated with higher reliability coefficients (Helmerhorst et al., 2012). In this study, relatively low reliability was found in estimated sitting in boys (ICC ¼ .06) as well as in the whole sample (ICC ¼ .32). This may be because sitting accounted for a large amount of the daily activities of the studied sample (nearly 10 h), which made the accurate recall of such behavior a challenge for them. Lower reliability in sitting was also observed by a previous study in youth, which found the reliability indicated by ICC of sitting in the IPAQ –SF to be .27 (Rangul et al., 2008). Lower reliability was also observed in estimated VPA in girls compared with boys (ICC ¼ .35 vs. .83) in this study. As indicated previously, girls had a significantly lower level of VPA than did boys, with the average gender difference for VPA being 44.7% (Rowlands, 2007). Similarly, this study revealed a much lower VPA level estimated by the IPAQ – SF in girls compared with boys (e.g., 6.76 min/day vs. 14.53 min/day; see Table 2). Moreover, young people tended to be involved in more free-time PA than in organized sports (Centers for Disease Control & Prevention, 2003). The limited and possibly unorganized intense activities in girls may explain the low recall reliability of the IPAQ –SF in girls.
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Strengths and Limitations This study had several strengths. First, despite the limited number of validation studies conducted in youth, this is the first study to examine the reliability and validity of the IPAQ – SF in Chinese youth. Second, this study involved a large sample of youth that was geographically spread out in 11 cities all over China. Third, the accelerometer cutoff points for defining MPA and VPA used in this study were specifically developed for Chinese youth. This study also contained some limitations. First, compliance of wearing the accelerometers and completing the IPAQ – SF twice was low in this study (49% and 43%, respectively). Moreover, cycling is a popular commuting activity in Chinese youth, yet accelerometers are unable to detect this activity and this may underestimate the PA levels in the studied sample. Furthermore, the results of this study could only be applied in Chinese city youth as all participants came from city areas.
CONCLUSION Overall, the IPAQ – SF provided reliable estimation of total PA and specific intensities of PA in Chinese youth with exceptions for sitting in boys and the whole sample, as well as VPA in girls. However, the correlations of data obtained from the IPAQ –SF and accelerometer were from “no” to “low.” Moreover, the IPAQ – SF overestimated the time spent in all intensities of PA and SB compared with those measured by accelerometer, and the most evident difference existed in MPA and MVPA. These results did not support the IPAQ –SF as a valid tool in assessing PA and SB in Chinese youth.
WHAT DOES THIS ARTICLE ADD? As an internationally comparable PA instrument, the IPAQ – SF was demonstrated to be reliable and valid for measuring PA and SB in adults. However, its psychometric profiles for youth populations were only provided in limited studies, which indicated that the feasibility of the IPAQ – SF among Vietnamese and Norwegian youth was not satisfactory. The current study examined additional validation evidence of the IPAQ –SF by checking its validity and reliability in a large sample of Chinese youth. The results of this study, similar to those studies of Vietnamese and Norwegian youth, indicated that the IPAQ – SF was not a valid tool in assessing PA and SB in Chinese youth. These findings indicated that the current version of the IPAQ –SF seemed not to be feasible in youth. Efforts to improve the IPAQ – SF’s adaption to the youth population are urgently needed.
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Lagerros, Y. T., & Lagiou, P. (2007). Assessment of physical activity and energy expenditure in epidemiological research of chronic diseases. European Journal of Epidemiology, 22, 353–362. doi:10.1007/s10654007-9154-x Landis, J. R., & Koch, G. G. (1977). The measurement of observer agreement for categorical data. Biometrics, 33, 159– 174. Lee, P. H., Macfarlane, D. J., Lam, T. H., & Stewart, S. M. (2011). Validity of the International Physical Activity Questionnaire Short Form (IPAQ– SF): A systematic review. International Journal of Behavioral Nutrition and Physical Activity, 8, 115. doi:10.1186/1479-5868-8-115 Macfarlane, D. J., Lee, C. C., Ho, E. Y., Chan, K. L., & Chan, D. T. (2007). Reliability and validity of the Chinese version of IPAQ (short, last 7 days). Journal of Science and Medicine in Sport, 10, 45 –51. doi:10.1016/j.jsams.2006.05.003 Rangul, V., Holmen, T. L., Kurtze, N., Cuypers, K., & Midthjell, K. (2008). Reliability and validity of two frequently used self-administered physical activity questionnaires in adolescents. BMC Medical Research Methodology, 8, 47. doi:10.1186/1471-2288-8-47 Rowlands, A. V. (2007). Accelerometer assessment of physical activity in children: An update. Pediatric Exercise Science, 19, 252–266. Trost, S. G., Loprinzi, P. D., Moore, R., & Pfeiffer, K. A. (2011). Comparison of accelerometer cut points for predicting activity intensity in youth. Medicine & Science in Sports & Exercise, 43, 1360– 1368. doi:10.1249/MSS.0b013e318206476e Tudor-Locke, C., Ainsworth, B. E., Adair, L. S., Du, S., & Popkin, B. M. (2003). Physical activity and inactivity in Chinese school-aged youth: The China Health and Nutrition Survey. International Journal of Obesity and Related Metabolic Disorders, 27, 1093 – 1099. doi:10.1038/ sj.ijo.0802377 Wang, C., Chen, P., & Zhuang, J. (this supplement). A national survey of physical activity and sedentary behavior of Chinese city children and youth using accelerometers. Research Quarterly for Exercise and Sport, 84(Suppl. 2). Wolin, K. Y., Heil, D. P., Askew, S., Matthews, C. E., & Bennett, G. G. (2008). Validation of the International Physical Activity Questionnaire– Short among Blacks. Journal of Physical Activity and Health, 5, 746–760. Zhu, W. (2012). Sadly, the earth is still round ( p,0.05). Journal of Sport and Health Science, 1, 9 –11. Zhu, Z., Chen, P., & Zhuang, J. (this supplement). Intensity classification accuracy of accelerometer-measured physical activities in Chinese children and youth. Research Quarterly for Exercise and Sport, 84 (Suppl. 2).
Research Quarterly for Exercise and Sport Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/urqe20
Validity and Reliability of International Physical Activity Questionnaire–Short Form in Chinese Youth Chao Wang a
a b
a
, Peijie Chen & Jie Zhuang
a
Shanghai University of Sport
b
Capital University of Physical Education and Sports Published online: 04 Dec 2013.
To cite this article: Chao Wang , Peijie Chen & Jie Zhuang (2013) Validity and Reliability of International Physical Activity Questionnaire–Short Form in Chinese Youth, Research Quarterly for Exercise and Sport, 84:sup2, S80-S86, DOI: 10.1080/02701367.2013.850991 To link to this article: http://dx.doi.org/10.1080/02701367.2013.850991
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Research Quarterly for Exercise and Sport, 84, S80–S86, 2013 Copyright q AAHPERD ISSN 0270-1367 print/ISSN 2168-3824 online DOI: 10.1080/02701367.2013.850991
Validity and Reliability of International Physical Activity Questionnaire – Short Form in Chinese Youth Chao Wang
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Shanghai University of Sport Capital University of Physical Education and Sports
Peijie Chen and Jie Zhuang Shanghai University of Sport
Purpose: The psychometric profiles of the widely used International Physical Activity Questionnaire –Short Form (IPAQ – SF) in Chinese youth have not been reported. The purpose of this study was to examine the validity and reliability of the IPAQ –SF using a sample of Chinese youth. Method: One thousand and twenty-one youth (Mage ¼ 14.26 ^ 1.63 years, 52.8% boys) from 11 cities in China wore accelerometers for 7 consecutive days and completed the IPAQ– SF on the 8th day to recall their physical activity (PA) during accelerometer-wearing days. A subsample of 92 youth (Mage ¼ 15.90 ^ 1.35 years, 46.7% boys) completed the IPAQ– SF again a week later to recall their PA during accelerometer-wearing days. Differences in PA estimated by the IPAQ – SF and accelerometer were examined by paired-sample t test. Spearman correlation coefficients were used to examine the correlation between the IPAQ– SF and accelerometer. Test –retest reliability of the IPAQ – SF was determined by the intraclass correlation coefficient (ICC). Results: Compared with accelerometer, the IPAQ – SF overestimated sedentary time, moderate PA (MPA), vigorous PA (VPA), and moderate-tovigorous PA (MVPA). Correlations between PA (total PA, MPA, VPA, and MVPA) and sedentary time measured by 2 instruments ranged from “none” to “low” (r ¼ .08 –.31). Test – retest ICC of the IPAQ– SF ranged from “moderate” to “high” (ICC ¼ .43– .83), except for sitting in boys (ICC ¼ .06), sitting for the whole sample (ICC ¼ .32), and VPA in girls (ICC ¼ .35). Conclusion: The IPAQ – SF was not a valid instrument for measuring PA and sedentary behavior in Chinese youth. Keywords: accelerometer, adolescent, assessment, validation
Reliable and valid measurement of habitual physical activity (PA) is essential for all studies on PA, such as identifying the causal relations between PA and health outcomes, monitoring the prevalence and differences in PA between individuals, evaluating the effects of PA interventions, and establishing public health recommendations (Lagerros & Lagiou, 2007). Commonly used methods to
Correspondence should be addressed to Peijie Chen, Shanghai University of Sport, 399 Chang Hai Road, Shanghai, 200438, P. R. China. E-mail: [email protected]
measure PA include self-report questionnaires, indirect calorimetry, direct observation, heart rate telemetry, and movement sensors. Relative to objective measures of PA, subjective measures such as questionnaires are of particular value in that they are relatively inexpensive and convenient and can be self-administered, which makes them a more suitable method for assessment of PA in populations (Ainsworth et al., 2012). Numerous questionnaires have recently been developed for measuring PA in children and youth (e.g., Biddle, Gorely, Pearson, & Bull, 2011; Chinapaw, Mokkink, van Poppel, van Mechelen, & Terwee, 2010; Helmerhorst, Brage, Warren,
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VALIDATION OF IPAQ–SHORT FORM IN CHINESE YOUTH
Besson, & Ekelund, 2012). Given the discrepancy in PA measurements provided by different questionnaires, it is difficult to compare results across studies. To address the demand for a comparable PA instrument, a set of standardized international PA questionnaires (the International Physical Activity Questionnaire [IPAQ]) was developed (Craig et al., 2003). The IPAQ was designed to assess PA of adults (aged 18–65 years old) and has a short (7 items) and a long form (31 items). The IPAQ–Short Form (IPAQ–SF) measures the frequency and duration of moderate PA (MPA), vigorous PA (VPA), walking, and sedentary behavior (SB) using 7 questions and is considered more suitable for population surveillance and large-scale studies compared with the long form (Craig et al., 2003). The IPAQ–SF was validated for adults in 12 countries and was shown to have adequate test–retest reliability (Spearman r ¼ .76) and convergent validity against accelerometer (Spearman r ¼ .30; Craig et al., 2003). The IPAQ –SF has been modified to measure habitual PA of youth in Vietnam and Norway (Lachat et al., 2008; Rangul, Holmen, Kurtze, Cuypers, & Midthjell, 2008). Lachat and colleagues (2008) reported that the reliability (intraclass correlation coefficient [ICC] ¼ .15 –.40) and validity (r ¼ 2.01 to .29 against accelerometer) of the IPAQ –SF were low in two hundred and twenty-seven 16-year-old Vietnamese youth. Rangul and colleagues (2008) demonstrated a better reliability (ICC ¼ .10– .62) and a range of 2 .29 to .43 correlation coefficients against PA level assessed by the ActiReg motion sensor among 71 Norwegian youth. Nonetheless, the Chinese version of the IPAQ –SF has been developed and demonstrated to be reliable and valid in Chinese younger to middle-age adults (age range ¼ 15– 55 years, n ¼ 49; Macfarlane, Lee, Ho, Chan, & Chan, 2007) and older adults (Mage ¼ 65 years, n ¼ 224; Deng et al., 2008). Because psychometric profiles of self-report instruments can be impacted by culture or language differences (Macfarlane et al., 2007) and by agerelated cognitive ability (Cerin et al., 2010), the feasibility of the IPAQ – SF in Chinese youth is unknown. Therefore, the purpose of this study was to examine the reliability and validity of the IPAQ –SF using a sample of Chinese youth from the Chinese City Children and Youth Physical Activity Study (CCCYPAS).
METHODS Participants Data were collected, as a part of CCCYPAS, during schooldays from April 2011 to May 2012 in 11 cities across China, including Chengdu, Fuyang, Ganzhou, Guangzhou, Shanghai, Shenyang, Tianjin, Tongzhou, Wenzhou, Xian, and Yingtan. One to two middle/high schools in each city were recruited to participate in the study. A total of 2,092
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healthy youth (1,069 boys and 1,023 girls) from 11 middle schools and 7 high schools volunteered to participate in the study. All participants were required to complete the IPAQ – SF and wear the accelerometer to examine the concurrent validity of the IPAQ – SF. A subsample of 216 youth (113 boys and 103 girls) from a middle school and a senior high school in the city of Fuyang completed the IPAQ – SF twice to assess the test – retest reliability of the IPAQ – SF. The purpose and procedure of the study were comprehensively introduced to all participants. Signed written assent forms were obtained from all participants, and signed written consent forms were obtained from their parents or guardians. The methods and protocols were approved by the Ethics Advisory Committee of the Shanghai University of Sport.
Measures Demographic Variables The participants reported their birth date and gender. Age (years) was calculated as months between the birth date and measurement date divided by 12 with the integer number of years being kept. Anthropometric Variables Height and weight measurements were conducted in a private setting with participants dressed in light clothing. Height was measured to the nearest 0.1 cm using a freestanding portable stadiometer. Weight was measured to the nearest 0.1 kg with an electronic weighing scale (HN-358, Omron, Tokyo, Japan). Body mass index (BMI) was calculated as weight (kg) divided by height (m) squared (kg/m2). PA and SB Measurement by Accelerometer The participants wore ActiGraph GT3Xþ or GT3X accelerometers (ActiGraph, LLC, Pensacola, FL) for 7 consecutive days to measure their PA and SB. The sampling interval (epoch) in the present study was set at 60 s. Participants were instructed to wear the accelerometers on the right hip and secured by an elastic belt. The PA was reported as time spent in light PA (LPA), MPA, VPA, and moderate-to-vigorous PA (MVPA). The cutoff points (i.e., counts per minute [CPM]) for defining intensities of PA were 101 CPM to 2,799 CPM for LPA, 2,800 CPM to 3,999 CPM for MPA, and $ 4,000 CPM for VPA. These cutoff points were developed specifically for Chinese youth by our research group (for more details, see Z. Zhu, Chen, & Zhuang, this supplement). SB was defined as activity counts of less than 100 CPM (Trost, Loprinzi, Moore, & Pfeiffer, 2011). Details of the accelerometer data processing protocol were reported in Wang, Chen, & Zhuang (this supplement).
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PA and SB Measurement by the IPAQ – SF The IPAQ –SF used in the present study adopted the Chinese version of the IPAQ – SF translated by Macfarlane and colleagues (2007). The IPAQ – SF consists of seven items and provides information on the time spent in VPA, such as aerobics, MPA, such as leisure cycling, walking, and sedentary activities (Lee, Macfarlane, Lam, & Stewart, 2011). Participants were asked to recall the number of days they performed each activity (frequency) and the length of time (duration) they were involved daily in each activity during the last 7 days or were asked to recall a regular 7 days of activity for them. In addition, participants were asked to record the amount of time during which they were sedentary. Data from the questionnaire were summed within each item (i.e., vigorous intensity, moderate intensity, and walking) to estimate the total amount of time spent in PA per day. Using the official IPAQ – SF scoring protocol, total daily PA (metabolic equivalent [MET]·min/day) was estimated by summing the product of reported time by a PA category with its corresponding category MET value and was expressed as a daily average MET score. MET values for vigorousintensity activities, moderate-intensity activities, and walking are 8, 4, and 3.3, respectively; MPA and walking measured by the IPAQ –SF were categorized into MPA when it was validated against the MPA measured by accelerometers (Wolin, Heil, Askew, Matthews, & Bennett, 2008).
Procedure Before the commencement of the study, informed written assent/consent forms were obtained from all participants and their parents or guardians. Local helpers in each city were trained to conducted the anthropometric measurements and administer the IPAQ – SF in a standardized manner. The accelerometer distribution and collection in the 11 cities were conducted by the same researcher, who was also responsible for processing all accelerometer data. The whole data collection lasted for about 1 year, from April 2011 to May 2012. The same protocol was used for each city. On Day 1, after weight and height of the participants were measured by local helpers, all participants were instructed to wear the accelerometers for 7 consecutive days on the right hip and secured by an elastic belt. They were asked to wear the devices when they were awake and to take the devices off when swimming, bathing, and sleeping. Written instructions were also given to all participants and their parents/guardians to remind them to wear the accelerometers in order to increase compliance. The participants were also asked to follow their normal daily routines during the monitoring period. On Day 8, the participants returned the accelerometers and completed the IPAQ – SF for the first time to recall their PA during the previous 7 days. When filling out the questionnaire, the participants were in groups of 20 to 30 participants in a classroom following the instructions of
researchers. The participants were required not to communicate with each other to avoid possible undesirable interference in their responses. One week later, a subgroup of participants (n ¼ 216) completed the IPAQ – SF for a second time to recall their PA during the same 7 days when they wore accelerometers. After cleaning the data for missing and out-of-range values, questionnaire data that were valid for both applications were included in the final analysis. Statistical Analysis All analyses were conducted using the Statistical Package for the Social Sciences Version 18.0 (SPSS Inc., Chicago, IL). Descriptive statistical analyses were conducted to calculate the means and standard deviations for all anthropometric and PA variables. Gender differences of anthropometric variables were examined by independentsample t test. Differences between PA behaviors measured by the IPAQ – SF and the accelerometer were examined by paired-sample t test. The convergent validity of the IPAQ – SF was examined by correlating PA behaviors measured by the IPAQ –SF with those measured by accelerometers, and Spearman’s correlation coefficients were computed. The correlation values were interpreted as the following: A range of .00 to .19 was considered no correlation, .20 to .39 was considered a low correlation, .40 to .59 was considered moderate, .60 to .79 was considered moderately high, and .80 to 1.00 was considered a high correlation (W. Zhu, 2012). ICCs were used to examine the test –retest reliability of the IPAQ – SF. The interpretation of ICC values for reliability was as follows: A range of .00 to .20 was considered slight reliability, .21 to .40 was considered fair, .41 to .60 was moderate, .61 to .80 was substantial, and .81 to 1.00 was almost perfect reliability (Landis & Koch, 1977). The significance level was set at p , .05. RESULTS Participants’ Characteristics Of the total 2,092 participants involved in the validity study, 24 were excluded due to accelerometer malfunction or loss, 31 due to missing demographic or anthropometric data, and 8 due to illness. Among the rest of the 2,029 participants, 438 were excluded due to an insufficient number of valid accelerometer-wearing days, and 570 were further excluded due to failing to complete the IPAQ – SF. No differences in age, body weight, and height were found between the excluded participants and the included participants. The final analytic sample of the validity study consisted of 1,021 participants (539 boys and 482 girls) aged 12 to 18 years old with complete data. Within the 216 participants who were involved in the reliability study, 92 (43%) provided complete questionnaire data on two occasions and were included in the final data analysis.
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TABLE 1 Anthropometric Characteristics of the Participants by Gender (Mean ^ SD) Validity Study
Age (years) Height (cm) Weight (kg) BMI (kg/m2)
Reliability Study
Boys (N ¼ 539)
Girls (N ¼ 482)
Total (N ¼ 1,021)
Boys (N ¼ 43)
Girls (N ¼ 49)
Total (N ¼ 92)
14.29 ^ 1.60 165.38 ^ 9.44* 56.73 ^ 14.26* 20.54 ^ 3.90
14.21 ^ 1.65 158.20 ^ 6.25 51.51 ^ 9.67 20.51 ^ 3.21
14.26 ^ 1.63 161.99 ^ 8.85 54.27 ^ 12.57 20.52 ^ 3.59
15.85 ^ 1.34 173.51 ^ 4.46* 64.20 ^ 10.32* 21.26 ^ 2.92
15.94 ^ 1.37 162.33 ^ 4.59 55.18 ^ 6.87 20.93 ^ 2.39
15.90 ^ 1.35 167.56 ^ 7.19 59.39 ^ 9.73 21.09 ^ 2.64
Note. BMI ¼ body mass index. *Significant difference between boys and girls, p , .05.
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TABLE 2 Differences of PA Measured by the IPAQ–SF and the Accelerometer
Boys IPAQ–SF Accelerometer Girls IPAQ–SF Accelerometer Total IPAQ–SF Accelerometer
Sedentary (min/day)
MPA (min/day)
VPA (min/day)
MVPA (min/day)
Meeting MVPA Recommendation (%)
569.20 ^ 178.39* 549.73 ^ 111.50
46.26 ^ 40.86* 20.37 ^ 10.65
19.76 ^ 23.01* 14.53 ^ 11.78
66.02 ^ 52.00* 34.90 ^ 20.00
44.9 10.4
608.01 ^ 183.17* 562.94 ^ 100.20
39.24 ^ 37.65* 15.77 ^ 9.44
8.09 ^ 15.98 6.76 ^ 7.09
47.32 ^ 41.80* 22.54 ^ 14.30
30.9 1.9
587.52 ^ 181.61* 555.96 ^ 106.47
42.94 ^ 39.51* 18.20 ^ 10.35
14.25 ^ 20.82* 10.86 ^ 10.58
57.19 ^ 48.35* 29.06 ^ 18.59
38.3 6.4
Note. MPA and MVPA measured by the IPAQ-SF include walking. *Significant difference between the accelerometer and the IPAQ-SF, p , .05.
The anthropometric characteristics of the participants are shown in Table 1. For both samples in the validity and reliability study, no gender differences were found for age and BMI, but boys were taller and heavier than girls. Differences of PA Measured by Accelerometer and IPAQ –SF Table 2 presents the PA levels measured by accelerometer and the IPAQ – SF. For the overall sample and for boys, the IPAQ –SF seemed to overestimate time spent in sitting, MPA, VPA, and MVPA compared with what accelerometer reported. This was also true for girls except for VPA.
Correlations Between PA Measured by the IPAQ – SF and Accelerometer The results of correlations of PA behaviors measured by the IPAQ –SF and accelerometer are presented in Table 3. “No” to “low” correlations were found in all PA categories between two measures, with Spearman correlation coefficients ranging from 0.08 to .31.
Test – Retest Reliability of the IPAQ – SF The results of test – retest reliability of the IPAQ – SF are shown in Table 4. The ICC values for most measured PA
TABLE 3 Correlation Between PA Measured by the IPAQ–SF and the Accelerometer Spearman Correlation Coefficients IPAQ –SF Measure
Accelerometer Measure
Total activities (MET·min/day) MPA and walking (min/day) VPA (min/day) MVPA and walking (min/day) Sitting (min/day)
Overall PA (CPM) MPA (min/day) VPA (min/day) MVPA (min/day) Sedentary (min/day)
Note. CPM ¼ counts per minute.
Boys
Girls
Total
.25 .14 .13 .15 .24
.27 .24 .08 .19 .10
.31 .20 .22 .22 .18
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TABLE 4 Test–Retest Reliability of the IPAQ– SF
Boys VPA (min/day) MPA (min/day) Walking (min/day) Sitting (min/day) Total PA (MET min/day) Girls VPA (min/day) MPA (min/day) Walking (min/day) Sitting (min/day) Total PA (MET min/day) Total VPA (min/day) MPA (min/day) Walking (min/day) Sitting (min/day) Total PA (MET min/day)
Test 1
Test 2
ICC
95% CI
p
14.22 ^ 17.65 13.76 ^ 17.15 21.69 ^ 28.84 580.74 ^ 148.79 240.36 ^ 235.79
19.97 ^ 23.47 27.78 ^ 30.40 28.03 ^ 29.66 582.56 ^ 121.64 363.39 ^ 283.81
.83 .45 .62 .06 .74
.71, .91 .18, .66 .40, .77 –.24, .35 .57, .85
.000 .001 .000 .347 .000
3.92 ^ 6.82 7.79 ^ 15.39 27.30 ^ 33.85 628.78 ^ 234.74 152.61 ^ 146.24
6.93 ^ 9.16 13.04 ^ 18.34 30.65 ^ 36.54 592.65 ^ 144.20 208.70 ^ 200.87
.35 .60 .69 .43 .68
.08, .57 .39, .76 .50, .81 .17, .63 .50, .81
.006 .000 .000 .001 .000
8.73 ^ 13.96 10.58 ^ 16.42 24.68 ^ 31.56 606.33 ^ 199.66 193.62 ^ 197.18
13.02 ^ 18.47 19.93 ^ 25.66 29.42 ^ 33.35 587.93 ^ 133.50 281.00 ^ 253.93
.79 .53 .66 .32 .74
.70, .86 .36, .66 .53, .76 .12, .49 .63, .82
.000 .000 .000 .001 .000
Note. MPA and MVPA do not include walking.
categories showed “moderate” to “high” reliability with ICCs ranging from .43 to .83, except for sitting in boys (ICC ¼ .06), sitting for the overall sample (ICC ¼ .32), and VPA in girls (ICC ¼ .35).
DISCUSSION The purpose of this study was to examine the validity and reliability of the IPAQ – SF in Chinese youth. To our knowledge, this is the first study to validate the IPAQ – SF in this population. Unfortunately, the IPAQ –SF tended to overestimate MPA, VPA, MVPA, and sitting compared with accelerometer, and this was true for both the whole sample and subsamples by gender. The correlations between the two instruments were from “no” to “low” and therefore rejected the convergent validity of IPAQ – SF. In general, the test – retest reliability of IPAQ –SF was from “moderate” to “high,” with a few exceptions in boys and the whole sample’s sitting, and in girls’ VPA. Validity of the IPAQ – SF in Youth The first comprehensive validation study of the IPAQ –SF was conducted in 12 countries and revealed a wide range of correlations with accelerometer across countries (from .02 to .47; Craig et al., 2003). This indicated the need to validate the IPAQ – SF in different populations. The PA questionnaire validity was usually examined by correlating data derived from the questionnaire with those derived from an objective measure and/or by computing the absolute differences between PA assessed by the questionnaire and by the objective measure (Lee et al., 2011).
In this study, “no” to “low” correlations were found between the total PA assessed by the IPAQ – SF and by accelerometer for the whole sample and for the subsamples by gender (r ¼ .25 –.31). Similarly, a recent systematic review indicated that 20 of 23 validation studies of the IPAQ – SF demonstrated a range from .21 to .39 of correlation coefficients of total PA with objective measures (Lee et al., 2011). For specific intensities of PA, the correlations between the IPAQ – SF and accelerometer were generally low, and the lowest correlations were found in VPA with the correlation coefficients being .13 in boys and insignificant in girls. In contrast, previous studies of youth revealed higher correlations in VPA than other intensities of PA between the IPAQ – SF and accelerometer (Hagstromer et al., 2008; Lachat et al., 2008). This may be caused by limited VPA engaged in by Chinese youth. Under greater academic pressure, Chinese students seldom participated in any organized PA outside of school (Tudor-Locke, Ainsworth, Adair, Du, & Popkin, 2003); moreover, due to concerns for safety, structured exercise organized by schools usually does not involve high-intensity activities. The present study also showed a low correlation between sitting measured by the IPAQ –SF and by accelerometer in both genders. Overall, this is an understudied area and limited information is available. In a comparable validation study of IPAQ – SF in youth, a negative correlation was found between sitting measured by the IPAQ – SF and the PA level determined by the ActiReg motion sensor in boys (r ¼ 2.68; Rangul et al., 2008) On average, the IPAQ –SF overstated the time spent in MPA, VPA, MVPA, and sitting compared with accelerometry in both boys and girls in this study. This is consistent with the findings summarized in a recent review
VALIDATION OF IPAQ–SHORT FORM IN CHINESE YOUTH
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that revealed an average over-report by the IPAQ – SF of 106% for total PA compared with accelerometer (Lee et al., 2011). The overestimation of the IPAQ – SF compared with accelerometer found in this study was the most evident in MPA (nearly 136%) and was least evident in sitting (nearly 6%). Large differences in classifying youth into meeting the 60-min/day PA recommendation between these two instruments were also observed in the present study (38.3% vs. 6.4% for the whole sample). These findings indicated that the IPAQ –SF was not appropriate for measuring the specific intensity of PA nor was it suitable for monitoring compliance with the PA recommendation among Chinese youth. Reliability of the IPAQ –SF Despite the widely accepted high reliability of the IPAQ –SF among adults (Craig et al., 2003), only limited studies have examined the reliability of the IPAQ – SF in youth (Lachat et al., 2008; Rangul et al., 2008). Rangul and colleagues (2008) found that the reliability (indicated by ICC) of the IPAQ –SF among 71 youth in Norway ranged from .10 (sitting) to .62 (walking frequency). Another validation study demonstrated an ICC range of .15 (MPA) to .40 (VPA) of the IPAQ –SF among Vietnamese youth (Lachat et al., 2008). The current study showed a relatively higher test –retest reliability of the IPAQ – SF in Chinese youth (ICC ¼ .06 – .83). The short recall interval employed in this study may be the reason. The interval time in the studies by Rangul et al. and Lachat et al. (2008) were 8 to 12 days for a Norwegian sample and 2 weeks for a Vietnamese sample. In fact, shorter intervals between test and retest have been found to be associated with higher reliability coefficients (Helmerhorst et al., 2012). In this study, relatively low reliability was found in estimated sitting in boys (ICC ¼ .06) as well as in the whole sample (ICC ¼ .32). This may be because sitting accounted for a large amount of the daily activities of the studied sample (nearly 10 h), which made the accurate recall of such behavior a challenge for them. Lower reliability in sitting was also observed by a previous study in youth, which found the reliability indicated by ICC of sitting in the IPAQ –SF to be .27 (Rangul et al., 2008). Lower reliability was also observed in estimated VPA in girls compared with boys (ICC ¼ .35 vs. .83) in this study. As indicated previously, girls had a significantly lower level of VPA than did boys, with the average gender difference for VPA being 44.7% (Rowlands, 2007). Similarly, this study revealed a much lower VPA level estimated by the IPAQ – SF in girls compared with boys (e.g., 6.76 min/day vs. 14.53 min/day; see Table 2). Moreover, young people tended to be involved in more free-time PA than in organized sports (Centers for Disease Control & Prevention, 2003). The limited and possibly unorganized intense activities in girls may explain the low recall reliability of the IPAQ –SF in girls.
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Strengths and Limitations This study had several strengths. First, despite the limited number of validation studies conducted in youth, this is the first study to examine the reliability and validity of the IPAQ – SF in Chinese youth. Second, this study involved a large sample of youth that was geographically spread out in 11 cities all over China. Third, the accelerometer cutoff points for defining MPA and VPA used in this study were specifically developed for Chinese youth. This study also contained some limitations. First, compliance of wearing the accelerometers and completing the IPAQ – SF twice was low in this study (49% and 43%, respectively). Moreover, cycling is a popular commuting activity in Chinese youth, yet accelerometers are unable to detect this activity and this may underestimate the PA levels in the studied sample. Furthermore, the results of this study could only be applied in Chinese city youth as all participants came from city areas.
CONCLUSION Overall, the IPAQ – SF provided reliable estimation of total PA and specific intensities of PA in Chinese youth with exceptions for sitting in boys and the whole sample, as well as VPA in girls. However, the correlations of data obtained from the IPAQ –SF and accelerometer were from “no” to “low.” Moreover, the IPAQ – SF overestimated the time spent in all intensities of PA and SB compared with those measured by accelerometer, and the most evident difference existed in MPA and MVPA. These results did not support the IPAQ –SF as a valid tool in assessing PA and SB in Chinese youth.
WHAT DOES THIS ARTICLE ADD? As an internationally comparable PA instrument, the IPAQ – SF was demonstrated to be reliable and valid for measuring PA and SB in adults. However, its psychometric profiles for youth populations were only provided in limited studies, which indicated that the feasibility of the IPAQ – SF among Vietnamese and Norwegian youth was not satisfactory. The current study examined additional validation evidence of the IPAQ –SF by checking its validity and reliability in a large sample of Chinese youth. The results of this study, similar to those studies of Vietnamese and Norwegian youth, indicated that the IPAQ – SF was not a valid tool in assessing PA and SB in Chinese youth. These findings indicated that the current version of the IPAQ –SF seemed not to be feasible in youth. Efforts to improve the IPAQ – SF’s adaption to the youth population are urgently needed.
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