Validity and Reliability of Three Self-Report Instruments for Assessing Attainment of Physical Activity Guidelines in University Students

The purpose of this study was to compare the validity and reliability of three short physical activity self-report instruments to determine their potential for use with university student populations. The participants (N = 155; 44.5% male; 22.9 ± 5.13 years) wore an accelerometer for 9 consecutive days and completed a single-item measure, the a brief two item measure and the International Physical Activity Questionnaire—Short Form questionnaires on day 1 and 9. Correlations between self-reported and accelerometer derived moderate-to-vigorous physical activity levels were moderate for the International Physical Activity Questionnaire—Short Form, while poor for the single-item measure and the a brief two item measure. The agreement level was high with the International Physical Activity Questionnaire—Short Form (77.4%) and moderate for both the single-item measure (45.2 %) and a brief two item measure (44.5 %). The intraclass correlations between the two administrations were moderate to strong across all measures (0.52–0.70) in 133 participants. The International Physical Activity Questionnaire—Short Form is the most suitable of these three self-report instruments for use with this population due to higher correlations and levels of agreement with accelerometry.     

International Physical Activity Questionnaire: Reliability and validity in a Spanish population

Abstract

Although questionnaires are useful for evaluating patterns of physical activity in populations, they need to be validated. The objective of this study was to determine the validity and reliability of the long version of the International Physical Activity Questionnaire (IPAQ) in a Spanish population. The participants wore a uniaxial MTI Actigraph (Computer Science and Application, Inc.) accelerometer for 7 days and self-completed the IPAQ questionnaire twice, to assess its reliability. Criterion validity was assessed by comparing data from the IPAQ and data from the MTI. The final sample included 54 adults for the validity analysis and 66 adults for the reliability analysis. The correlations (r) between the IPAQ and the accelerometer were 0.29 (P<0.05) for total physical activity (MET · min^?1 · day^?1) versus total counts per minute, 0.30 (P<0.05) for time spent in vigorous activity, and 0.34 (P<0.05) for time spent sitting. The IPAQ showed a good reliability coefficient for total physical activity (r=0.82, P<0.05), vigorous activity (r=0.79, P<0.05), moderate activity (r=0.83, P<0.05), and time spent walking (r=0.73, P<0.05). Total time spent on work-related physical activities (r=0.92, P<0.05), on household-related activities (r=0.86, P<0.05), and leisure-time physical activities (excluding walking) (r=0.82, P<0.05) showed good reliability coefficients. Bland Altman analysis showed that discrepancies between the two methods increased with the amount of moderate and vigorous physical activity undertaken. In conclusion, the long version of the IPAQ has acceptable validity for the measurement of total and vigorous physical activity, and good reliability coefficients for application in the Spanish population studied here. The questionnaire showed poor validity for reporting moderate-intensity activity in this Spanish population.     

Comparison of physical activity estimates using International Physical Activity Questionnaire (IPAQ) and accelerometry in fibromyalgia patients: The Al-Andalus study

Abstract

The International Physical Activity Questionnaire (IPAQ) has been widely used to assess physical activity in healthy populations. The present study compared physical activity assessed by the long, self-administrated version of the International Physical Activity Questionnaire with physical activity assessed by accelerometry in patients with fibromyalgia. A total of 99 (five men) participants with fibromyalgia completed the International Physical Activity Questionnaire and wore an accelerometer for nine consecutive days. We analysed the correlations of physical activity expressed as min · day^?1 of light, moderate, vigorous, and moderate to vigorous (MVPA) intensity, as well as time spent sitting, by the International Physical Activity Questionnaire and accelerometry by Spearman correlations. Bland and Altman plots were performed to verify the agreements between both instruments. The results showed weak yet significant correlations (Rs = 0.15–0.39, all P < 0.05) in all physical activity intensities between the two instruments, except for sedentary time. The highest correlations were observed for physical activity at home or in garden (Rs = 0.297, P < 0.01). The results suggest that the long self-administrated International Physical Activity Questionnaire is a questionable instrument to assess physical activity in patients with fibromyalgia. Therefore, physical activity measurement in fibromyalgia patients should not be limited solely to self-reported measures.     

Comparability of accelerometer- and IPAQ-derived physical activity and sedentary time in South Asian women: A cross-sectional study

Abstract

There is limited research documenting objectively measured physical activity (PA) and sedentary time (ST) in South Asian (SA) women, with no published evidence of the validity of self-report methods for assessment of PA/ST in SA. The purpose of this study was to compare accelerometer- and International Physical Activity Questionnaire (IPAQ)-derived PA/ST among SA women in the United Kingdom (UK) via a mixed-methods approach. One hundred and forty SA women wore an accelerometer for seven consecutive days; a sub-sample (n = 50) completed the IPAQ-Short Form (IPAQ-SF) and a brief structured interview. Accelerometer-derived metabolic equivalent (MET) minutes per week (min/wk) moderate-to-vigorous physical activity (MVPA) (mean ± SD) for the full sample was 793.94 (±519.44) and mean accelerometer-derived ST wk was 530.20 (±81.76). IPAQ-SF-derived MVPA (MET min/wk) was 636.80 (±2113.56) and mean ST wk was 315.31 (±266.98). Pearson correlations were not significant between accelerometer- and IPAQ-SF-assessed MVPA (r = ?.119, p = .579) and ST (r = ?.140, p = .229). Major themes synthesised from interviews included inability to recall sitting time and limited general knowledge of real-life examples of MVPA. These results suggest that the IPAQ-SF may not accurately measure PA/ST in the UK SA women. These findings are supported by qualitative evidence indicating several issues with interpretation and recall of PA/ST as assessed via this questionnaire.     

Reliability and criterion validity of the Self-Administered Physical Activity Checklist in Greek children

Abstract

The purpose of this study was to assess the test–retest reliability and criterion validity the Self-Administered Physical Activity Checklist (SAPAC) translated into the Greek language. To evaluate reliability, 72 students (35 girls and 37 boys) of the fifth and sixth grade completed SAPAC on two separate occasions, two weeks apart. Internal consistency was determined with Cronbach alpha coefficient and test–retest reliability with the intraclass correlation coefficient (ICC). To evaluate criterion validity, the RT3 Research Tracker accelerometer was used as standard measure, in 90 randomly selected Greek children (51 girls and 39 boys), aged between 10 and 13. Each subject participated for two consecutive days. On day one, an accelerometer was fitted when school started. On day two, the accelerometers were returned and each subject completed the questionnaire. The internal consistency and the test–retest reliability of SAPAC on total metabolic equivalent (MET) score, MET score of low physical activities (LPA) and MET score of moderate to vigorous physical activities (MVPA) were very satisfactory (all Cronbach's alpha > 0.87, and all ICC > 0.85, P <0.001). The Kendall's tau-b test revealed that the degree of agreement between SAPAC and RT3 accelerometer on total MET score and MET score of MVPA were 0.31 and 0.37, respectively (P <0.01). It was concluded that the Greek translated version of SAPAC is a reliable questionnaire that provides valid estimates of total, as well as moderate to vigorous activities MET scores.     

Validation of a short physical activity recall questionnaire completed by Spanish adolescents

Abstract

Self-report recall questionnaires are commonly used to measure physical activity in children and adolescents. However, they have been shown to have low to moderate validity, mainly due to inaccuracies in recall activity. The purpose of the present study was to determine the reliability and validity of an adapted version of the Assessment of Physical Activity Levels Questionnaire (APALQ) among a sample of Spanish adolescents. Test–retest reliability of the APALQ was assessed using a sample of 150 adolescents (72 males, 78 females), aged 13.6±1.1 years, who answered the APALQ twice within 7 days. Criterion validity was assessed using a sample of 77 adolescents (50 males, 27 females), aged 13.6±1.1 years, by comparing the APALQ against the Computer Science and Application (CSA) monitor. All participants were volunteers recruited from local schools in the Aragon region of Spain. Test–retest reliability for all items was high with intra-class coefficients of 0.77 for boys and 0.74 for girls. The APALQ demonstrated modest criterion validity with Pearson correlation coefficients (r) ranging from 0.53 between Physical Activity Index (PAI) and CSA minutes of moderate and vigorous physical activity, and 0.47 between PAI and CSA steps per day. When the data were analysed by gender, girls had higher correlations than boys (P < 0.01). The Spanish APALQ seems to be a valid and reliable short self-report physical activity questionnaire.     

Measuring physical activity in field studies: Comparison of a questionnaire, 24-hour recall and an accelerometer

Abstract

In a field setting, we compared a physical activity questionnaire (SQUASH), a 24-hour recall measure (Physical Activity Scale; PAS), and an accelerometer to: (1) quantify the amount of time spent in light, moderate, and vigorous physical activity; (2) calculate activity scores; and (3) categorize participants by physical activity tertiles. For 7 consecutive days, 103 participants (61% males, 39% females; mean age 36.8 years, mean body mass index 26.6 kg·m^?2) wore an accelerometer and completed the PAS. Immediately before these 7 days, the participants completed the SQUASH and underwent anthropometric measurements (weight and height). Time spent in light (<3 METs), moderate (3–6 METs), and vigorous (≥6 METs) activity was calculated. Significant correlations were observed between the PAS and accelerometer in the population as a whole (r=0.66, P<0.001), the males (r=0.76, P<0.001), participants of normal weight (r=0.62, P<0.05), and those who were overweight (r=0.53, P<0.01). Correlations between the SQUASH and accelerometer were only significant for males (r=0.62, P<0.05) and overweight individuals (r=0.40, P<0.05). Moderate agreement was observed between tertiles for the accelerometer and PAS activity scores in the overall population (weighted kappa =0.47; 95% confidence interval =0.27–0.67) but not between the accelerometer and SQUASH. In conclusion, a 7-day administration of the PAS is a useful measure for classification of physical activity in the population studied. The SQUASH has practical advantages in terms of convenience of administration, but its usefulness in estimating physical activity is limited.     

Calibration of context-specific survey items to assess youth physical activity behaviour

This study tests calibration models to re-scale context-specific physical activity (PA) items to accelerometer-derived PA. A total of 195 4th–12th grades children wore an Actigraph monitor and completed the Physical Activity Questionnaire (PAQ) one week later. The relative time spent in moderate-to-vigorous PA (MVPA_%) obtained from the Actigraph at recess, PE, lunch, after-school, evening and weekend was matched with a respective item score obtained from the PAQ’s. Item scores from 145 participants were calibrated against objective MVPA_% using multiple linear regression with age, and sex as additional predictors. Predicted minutes of MVPA for school, out-of-school and total week were tested in the remaining sample (n = 50) using equivalence testing. The results showed that PAQ β-weights ranged from 0.06 (lunch) to 4.94 (PE) MVPA_% (P < 0.05) and models root mean square error ranged from 4.2% (evening) to 20.2% (recess). When applied to an independent sample, differences between PAQ and accelerometer MVPA at school and out-of-school ranged from ?15.6 to +3.8 min and the PAQ was within 10–15% of accelerometer measured activity. This study demonstrated that context-specific items can be calibrated to predict minutes of MVPA in groups of youth during in- and out-of-school periods.     

The use of accelerometry in adolescents and its implementation with non-wear time activity diaries in free-living conditions

Abstract

The aim of this study was to evaluate the use of a non-wearing time activity diary (hereafter non-wear activity diary) when using accelerometry in adolescents to provide insight into their physical activity levels. In total, 213 Belgian adolescents (89 boys, 124 girls) were eligible for this study. Adolescents wore an accelerometer for seven consecutive days and kept a non-wear activity diary. On the last day, they completed the International Physical Activity Questionnaire for Adolescents. The differences between the accelerometer data with and without use of the non-wear activity diary were significant for all physical activity intensities according to the Wilcoxon signed rank test. Bland-Altman plots showed that with more time spent in any physical activity intensity, the difference between including and not including the non-wear activity diary increased. The correlation coefficient between the International Physical Activity Questionnaire for Adolescents and the accelerometer data increased when the non-wear activity diary was included. Differences in the percentage of adolescents reaching the physical activity recommendations between the accelerometer data only and the accelerometer with the non-wear activity diary were significant. We conclude that if the non-wear activity diary data are not included, some adolescents could be misclassified as not being physically active according to the physical activity recommendations. It is therefore recommended to use a non-wear activity diary for gaining insight into the physical activity levels of individuals.     

Self-reported physical activity within and outside the neighborhood: Criterion-related validity of the Neighborhood Physical Activity Questionnaire in German older adults

The Neighborhood Physical Activity Questionnaire allows to assess physical activity within and outside the neighborhood. Study objectives were to examine the criterion-related validity and health/functioning associations of Neighborhood Physical Activity Questionnaire-derived physical activity in German older adults. A total of 107 adults aged ≥60 years completed the Neighborhood Physical Activity Questionnaire and Short Form 12 Health Survey. A subsample of 58 participants wore piezoelectric pedometers for 7 consecutive days. Rank correlation coefficients (ρ) along with 95% confidence intervals (CIs) were computed for the criterion-related validity and health/functioning associations of single Neighborhood Physical Activity Questionnaire modules and total physical activity. Criterion-related validity was moderate (ρ ≤ .60) for total physical activity, total walking, and neighborhood walking, but low (ρ ≤ .40) for walking outside the neighborhood. Health/functioning associations were moderate for recreation walking and low for total physical activity, total walking, and walking within as well as outside the neighborhood. The study provides low-to-moderate validity evidence of Neighborhood Physical Activity Questionnaire-derived physical activity in older adults.     

Validity of the Marshall Sitting Questionnaire in people with multiple sclerosis

This study examines the validity of the Marshall Sitting Questionnaire (MSQ) in people with multiple sclerosis (MS) and presents a prediction model to improve the accuracy of the MSQ estimates. Participants (n = 63 [15M and 48F], age: 56.6 ± 7.3 years) wore an accelerometer on the hip for a 7-day period and completed the MSQ. Sedentary behaviour (SB) estimates were computed as min/day for both the MSQ and accelerometer. Associations between the two methods were examined using the Pearson correlation and agreement was assessed using a Bland-Altman plot. A linear prediction model was developed to improve the accuracy of the MSQ estimates using a selection of predictor variables routinely collected in MS research. There was a moderate correlation between MSQ and accelerometer SB estimates (r = 0.34, p < 0.01). The Bland-Altman plot indicated that the MSQ overestimated SB (mean bias: 80.54 min/day, 95% limits of agreement: ?410.5 to 571.5 min/day). The prediction model improved the MSQ estimates by 39% and virtually eliminated measurement bias (mean bias:-0.21 min/day; 95% limits of agreement:-109.8 to 109.4 min/day). The results indicate preliminary evidence for the validity of the MSQ in people with MS, and support the application of an alternative prediction model to improve the accuracy of the MSQ estimates.

Abbreviations: SB = sedentary behaviour; MS = multiple sclerosis; MSQ = Marshall Sitting Questionnaire; PA = physical activity; EDSS = Expanded Disability Status Scale; LPA = light physical activity; MVPA = moderate-to-vigorous physical activity; GLTEQ = Godin Leisure Time Exercise Questionnaire; PDDS = Patient-Determined Disease Steps; RMSE = root mean square error.     

Non-Exercise Estimation of VO2max Using the International Physical Activity Questionnaire

Non-exercise equations developed from self-reported physical activity can estimate maximal oxygen uptake (VO₂max) as well as sub-maximal exercise testing. The International Physical Activity Questionnaire is the most widely used and validated self-report measure of physical activity. This study aimed to develop and test a VO₂max estimation equation derived from the International Physical Activity Questionnaire–Short Form. College-aged males and females (n = 80) completed the International Physical Activity Questionnaire–Short Form and performed a maximal exercise test. The estimation equation was created with multivariate regression in a gender-balanced subsample of participants, equally representing five levels of fitness (n = 50) and validated in the remaining participants (n = 30). The resulting equation explained 43% of the variance in measured VO₂max (standard error of estimate = 5.45 ml·kg^–1·min^–1). Estimated VO₂max for 87% of individuals fell within acceptable limits of error observed with sub-maximal exercise testing (20% error). The International Physical Activity Questionnaire–Short Form can be used to successfully estimate VO₂max as well as sub-maximal exercise tests. Development of other population-specific estimation equations is warranted.     

The use of accelerometry in adolescents and its implementation with non-wear time activity diaries in free-living conditions

The aim of this study was to evaluate the use of a non-wearing time activity diary (hereafter non-wear activity diary) when using accelerometry in adolescents to provide insight into their physical activity levels. In total, 213 Belgian adolescents (89 boys, 124 girls) were eligible for this study. Adolescents wore an accelerometer for seven consecutive days and kept a non-wear activity diary. On the last day, they completed the International Physical Activity Questionnaire for Adolescents. The differences between the accelerometer data with and without use of the non-wear activity diary were significant for all physical activity intensities according to the Wilcoxon signed rank test. Bland-Altman plots showed that with more time spent in any physical activity intensity, the difference between including and not including the non-wear activity diary increased. The correlation coefficient between the International Physical Activity Questionnaire for Adolescents and the accelerometer data increased when the non-wear activity diary was included. Differences in the percentage of adolescents reaching the physical activity recommendations between the accelerometer data only and the accelerometer with the non-wear activity diary were significant. We conclude that if the non-wear activity diary data are not included, some adolescents could be misclassified as not being physically active according to the physical activity recommendations. It is therefore recommended to use a non-wear activity diary for gaining insight into the physical activity levels of individuals.     

Using the self-determination theory to understand Chinese adolescent leisure-time physical activity

Purposes: This study applies the self-determination theory (SDT) to test the hypothesized relationships among perceived autonomy support from parents, physical education (PE) teachers, and peers, the fulfilment of psychological needs (i.e., autonomy, competence, and relatedness), autonomous motivation, and leisure-time physical activity of Chinese adolescents. Method: There are 255 grade six to eight student participants from four middle schools around Shanghai, China included in this study. An accelerometer was used to measure the moderate-to-vigorous physical activity (MVPA). The participants completed the questionnaires regarding SDT variables. The structural equation modelling was applied to examine the hypothesized relationships among the study variables. Results: The model of hypothesized relationships demonstrated a good fit with the data [X²?=?20.84, df?=?9, P?=?.01; CFI?=?0.98; IFI?=?0.98; SRMR?=?0.04; RMSEA?=?0.05]. The findings revealed that autonomy support from parents, PE teachers, and peers foster social conditions in which the three basic psychological needs can be met. In turn, autonomy, competence, and relatedness are positively associated with autonomous motivation for MVPA. The autonomous motivation positively relates to the MVPA time of adolescents. The three psychological needs partially mediate the influence of autonomy support from parents (β?=?0.18, P?<?.01; Bootstrap 95% CI?=?0.06–0.33) and teachers (β?=?0.17, P?<?.01; Bootstrap 95% CI?=?0.03–0.26) in the autonomous motivation. Conclusion: In conclusion, these findings support the applicability of SDT in understanding and promoting physical activity of Chinese adolescents.     

Sedentary time and vigorous physical activity are independently associated with cardiorespiratory fitness in middle school youth

Abstract

The purpose of this cross-sectional study was to examine the relationship between objectively measured physical activity, sedentary time, and cardiorespiratory fitness in a diverse sample of youth. Participants were recruited from three middle schools and completed assessments of height, weight, cardiorespiratory fitness, and wore an accelerometer for a minimum of four days. Hierarchical general linear models controlling for age, body mass index (BMI) percentile, and sex were used to evaluate the association of time (minutes per day) spent sedentary, and in moderate physical activity and vigorous physical activity with cardiorespiratory fitness (i.e., heart rate response [beats per minute], dependent variable). Results indicated age (β = –0.16, P < 0.05), BMI percentile (β = 0.33, P <0.05), being male (β = 0.17, P < 0.05), sedentary time (β = 0.11, P <0.05), moderate (β = –0.03, P > 0.05) and vigorous (β = –0.22, P < 0.05) physical activity explained 29% of the variance in cardiorespiratory fitness. Evaluation of fitness among high sedentary/high vigorous, high sedentary/low vigorous, low sedentary/low vigorous, and low sedentary/high vigorous groups (defined by the median split) showed that high levels of vigorous activity removed the detrimental effect of high levels of sedentary time on cardiorespiratory fitness. These analyses suggest that the negative impact of sedentary time can be mitigated by engaging in vigorous activity.     

Development,content validity and test-retest reliability of the Lifelong Physical Activity Skills Battery in adolescents

Numerous skill batteries assess fundamental motor skill (e.g., kick, hop) competence. Few skill batteries examine lifelong physical activity skill competence (e.g., resistance training). This study aimed to develop and assess the content validity, test-retest and inter-rater reliability of the “Lifelong Physical Activity Skills Battery”. Development of the skill battery occurred in three stages: i) systematic reviews of lifelong physical activity participation rates and existing motor skill assessment tools, ii) practitioner consultation and iii) research expert consultation. The final battery included eight skills: grapevine, golf swing, jog, push-up, squat, tennis forehand, upward dog and warrior I. Adolescents (28 boys, 29 girls; M = 15.8 years, SD = 0.4 years) completed the Lifelong Physical Activity Skills Battery on two occasions two weeks apart. The skill battery was highly reliable (ICC = 0.84, 95% CI = 0.72–0.90) with individual skill reliability scores ranging from moderate (warrior I; ICC = 0.56) to high (tennis forehand; ICC = 0.82). Typical error (4.0; 95% CI 3.4–5.0) and proportional bias (r = ?0.21, p = .323) were low. This study has provided preliminary evidence for the content validity and reliability of the Lifelong Physical Activity Skills Battery in an adolescent population.     

Testing the Youth Physical Activity Promotion Model: Fatness and Fitness as Enabling Factors

As the prevalence of childhood obesity increases, it is important to examine possible differences in psychosocial correlates of physical activity between normal weight and overweight children. The study examined fatness (weight status) and (aerobic) fitness as Enabling factors related to youth physical activity within the Youth Physical Activity Promotion Model (YPAP). Youth ages 9–11 years (N = 1,103) completed the Children’s Physical Activity Correlates survey and the Children’s Physical Activity Questionnaire. Structural equation modeling was used to analyze the relationships among variables. Overweight children reported lower scores on global self-esteem, perceived competence, attraction to physical activity, and parental influence (Cohen’s d ranging from .23 to .45 for girls; Cohen’s d ranging from .31 to .43 for boys). Weight status showed a small positive direct effect on physical activity (standardized path coefficient = .11), but did not show effects on psychosocial correlates (p > .05). Furthermore, aerobic fitness proved to be a stronger Enabling factor (standardized path coefficient = .26) than weight status within the YPAP model. Future research using the YPAP model may extend its utility as an evaluation framework for youth physical activity intervention studies.     

Student outcomes of the physical education and physical literacy (PEPL) approach: a pragmatic cluster randomised controlled trial of a multicomponent intervention to improve physical literacy in primary schools

ABSTRACT

Background: Health organisations such as the United Nations continue to place an expectation on school physical education (PE) programmes and wider school strategies to ensure students develop physical literacy and receive the well-established benefits of meeting physical activity guidelines. Barriers to meet this expectation such as lack of trained PE teachers, lack of time and greater emphasis on academic achievement are ongoing challenges to schools. The purpose of this study was to evaluate the impact of the multi-component Physical Education Physical Literacy (PEPL) intervention, designed to improve students’ fundamental movement skill, perceived physical abilities and level of physical activity.

Method: A qualified PE teacher implemented the PEPL intervention across seven schools, and another seven schools formed a control group as part of a randomised cluster-based trial. Grade 5 students (N?=?318, age 10.4 years?±?SD 0.4) completed assessments of physical activity, fundamental movement skill, attitudes towards PE, and self-perceptions of physical abilities before and after a 33-week intervention. Intervention effects were examined using general linear mixed models. Post-intervention focus groups with students were used to develop insights into experiences and outcomes.

Results: With no significant gender interactions, the PEPL approach led to enhanced object control skills (β?=?1.62; SE?=?0.61; p?=?0.008), with little evidence of any other fundamental movement skill improvements in excess of those in the control group. There was also modest evidence for an effect on accelerometer measured moderate-to-vigorous physical activity (MVPA) during school time (β?=?4.50; SE?=?2.39; p?=?0.058), but this was not accompanied by any significant intervention effect over the entire week. Questionnaires indicated students in the PEPL programme became less satisfied with their own sporting ability (β?=??0.20; SE?=?0.08; p?=?0.013) but qualitative data analyses suggested that they enjoyed the PEPL approach experience, becoming more motivated and confident in their physical abilities.

Conclusions: Evidence of enhanced object control skill, increased confidence and motivation to be physically active, and moderate evidence of more MVPA during school time, indicate that the introduction of the PEPL approach contributed to the development of student physical literacy. A decrease in perceived sporting competence warrants greater attention on student’s self-perceptions in future iterations of the intervention.

Trial registration: Australian New Zealand Clinical Trials Registry identifier: ACTRN12615000066583.     

Ankle Accelerometry for Assessing Physical Activity Among Adolescent Girls: Threshold Determination,Validity, Reliability,and Feasibility

Purpose: Ankle accelerometry allows for 24-hr data collection and improves data volume/integrity versus hip accelerometry. Using Actical ankle accelerometry, the purpose of this study was to (a) develop sensitive/specific thresholds, (b) examine validity/reliability, (c) compare new thresholds with those of the manufacturer, and (d) examine feasibility in a community sample (low-income, urban adolescent girls). Method: Two studies were conducted with 6th- through 7th-grade girls (aged 10–14 years old): First was a laboratory study (n = 24), in which 2 Actical accelerometers were placed on the ankle and worn while measuring energy expenditure (Cosmed K4b2, metabolic equivalents [METs]) during 10 prescribed activities. Analyses included device equivalence reliability (intraclass correlation coefficient [ICC], activity counts of 2 Acticals), criterion-related validity (correlation, activity counts and METs), and calculations of sensitivity, specificity, kappa, and receiver-operating characteristic curves for thresholds. The second was a free-living study (n = 459), in which an Actical was worn for more than 7 days on the ankle (full 24-hr days retained). Analyses included feasibility (frequencies, missing data) and paired t tests (new thresholds vs. those of the manufacturer). Results: In the laboratory study, the Actical demonstrated reliability (ICC = .92) and validity (r = .81). Thresholds demonstrated sensitivity (91%), specificity (84%), kappa = .73 (p = .043), area under curve range = .81–.97. In the free-living study, 99.6% of participants wore the accelerometer; 84.1% had complete/valid data (mean = 5.7 days). Primary reasons for missing/invalid data included: improper programming/documentation (5.2%), failure to return device (5.0%), and wear-time ≤ 2 days (2.8%). The moderate-to-vigorous physical activity threshold (> 3,200 counts/minute) yielded 37.2 min/day, 2 to 4.5 times lower than that of the manufacturer's software (effect size = 0.74–4.05). Conclusions: Validity, reliability, and feasibility evidences support Actical ankle accelerometry to assess physical activity in community studies of adolescent girls. When comparing manufacturers' software versus new thresholds, a major difference was observed.