Children's Activity Rating Scale Research Articles

Calibration and Validation of a Wrist- and Hip-Worn Actigraph Accelerometer in 4-Year-Old Children.

IntroductionTo determine time spent at different physical activity intensities, accelerometers need calibration. The aim of this study was to develop and cross-validate intensity thresholds for the Actigraph GT3X+ accelerometer for wrist and hip placement in four-year-old children.MethodsIn total 30 children (49 months, SD 3.7) were recruited from five preschools in Stockholm. Equipped with an accelerometer on the wrist and another on the hip, children performed three indoor activities and one free-play session while being video recorded. Subsequently, physical activity intensity levels were coded every 5th second according to the Children’s Activity Rating Scale. Receiver Operating Characteristic (ROC) curves was used to develop wrist and hip intensity thresholds, the upper threshold for sedentary, and lower threshold for moderate-to-vigorous physical activity (MVPA), for the vertical axis (VA) and for the vector magnitude (VM). A leave-one-out method was used to cross-validate the thresholds.ResultsIntensity thresholds for wrist placement were ≤ 178 (VA) and ≤ 328 (VM) for sedentary and ≥ 871 (VA) and ≥ 1393 (VM) counts/5 seconds for MVPA. The corresponding thresholds for hip placement were ≤ 43 (VA) and ≤ 105 (VM) for sedentary and ≥ 290 (VA) and ≥ 512 (VM) for MVPA. The quadratic weighted Kappa was 0.92 (95% CI 0.91–0.93) (VA) and 0.95 (95% CI 0.94–0.96) (VM) for the wrist-worn accelerometer and 0.76 (98% CI 0.74–0.77) and 0.86 (95% CI 0.85–0.87) for the hip-worn.ConclusionUsing wrist placement and the VM when measuring physical activity with accelerometry in 4-year-old children is recommended.

Active Videogaming Compared to Unstructured, Outdoor Play in Young Children: Percent Time in Moderate- to Vigorous-Intensity Physical Activity and Estimated Energy Expenditure.

The majority of children do not achieve recommended amounts of moderate- to vigorous-intensity physical activity (MVPA). Active videogames (AVGs) may be a source of MVPA for young children. Thus, the purpose of this study was to compare, in children 5-8 years of age, percentage of time engaged in MVPA, assessed via accelerometry and direct observation (DO), and estimated energy expenditure (EE), assessed via accelerometry, while playing AVG and unstructured, outdoor play (OP). Sixteen normal-weight young children (6.4±0.8 years old, 62.5 percent male, 81.3 percent white, standardized body mass index=-0.18±0.66) completed two 15-minute sessions of AVG and OP. For AVG, participants played "River Rush" (Xbox(®) 360 Kinect(®); Microsoft Corp., Redmond, WA), and OP was conducted in an outdoor playground. Three Actical (Philips Respironics Co. Inc., Bend, OR) accelerometers (hip and left and right wrists) measured percentage MVPA and estimated EE. DO was conducted using the Children's Activity Rating Scale, from which percentage MVPA was coded. Repeated-measures analysis of variance controlling for condition differences in humidity and condition order found greater percentage MVPA in AVG condition with the accelerometer located on the hip (AVG=74.6±31.1 percent versus OP=67.5±31.1 percent; P<0.05, d=0.23) and with DO (AVG=23.8±12.4 percent versus OP=13.2±13.0 percent; P<0.05, d=0.83). These findings suggest that AVGs may be a source of MVPA for young children.

Calibration and cross‐validation of a wrist‐worn Actigraph in young preschoolers

To calibrate the Actigraph GT3X+ accelerometer for wrist-worn placement in young preschoolers by developing intensity thresholds for sedentary, low- and high-intensity physical activity. Furthermore, to cross-validate the developed thresholds in young preschoolers. Actigraph GT3X+ was used to measure physical activity during structured activities and free play in 38 children (15-36 months). Activity was video recorded and scored into sedentary, low- and high-intensity physical activity based on Children's Activity Rating Scale (CARS) and combined with accelerometer data using a 5 s epoch. Receiver operating characteristic analysis was used to develop intensity thresholds in 26 randomly selected children. The remaining 12 children were used for cross-validation. Intensity thresholds for sedentary were ≤89 vertical counts (Y) and ≤221 vector magnitude (VM) counts per 5 s and ≥440 Y counts and ≥730 VM counts per 5 s for high-intensity physical activity. Sensitivity and specificity were 60-100% for the developed intensity thresholds. Strong correlations (Spearman rank correlation 0.69-0.91) were found in the cross-validation sample between the developed thresholds for the accelerometer and CARS scoring time in all intensity categories. The developed intensity thresholds appear valid to categorize sedentary behaviour and physical activity intensity categories in children 2 years of age.

Calibration and validation of the ActiGraph GT3X+ in 2–3 year olds

To calibrate and validate the ActiGraph GT3X+ to measure sedentary behaviour and physical activity in 2-3 year olds, using 5-s epochs; and to compare the predictive validity of the resulting cut-points with that of NHANES', Trost's, and Pate's 15-s cut-points. Cross-sectional study. Eighteen children (2.86 ± 0.60 years) wore an ActiGraph GT3X+ during video-recorded semi-structured calibration activity sessions. Activity was coded following Children's Activity Rating Scale. Receiver Operating Characteristic analysis was used to derive Axis1 and vector magnitude cut-points for sedentary behaviour and moderate-to-vigorous physical activity at 5-s epochs. Agreement with Children's Activity Rating Scale was assessed with Cohen's kappa, Lin's concordance, and Bland-Altman plots. Predictive validity of all cut-points was assessed in an independent sample of 20 children (2.99 ± 0.48 years) video-recorded during free-play, using the same procedures as the calibration phase. During calibration, vector magnitude cut-points (sedentary behaviour ≤ 96.12 counts; moderate-to-vigorous physical activity ≥ 361.94 counts) showed slightly better classification agreement with Children's Activity Rating Scale than Axis1 cut-points (sedentary behaviour ≤ 5 counts; moderate-to-vigorous physical activity ≥ 165 counts), but the latter showed the lowest bias in estimated sedentary behaviour and moderate-to-vigorous physical activity time. In the validation sample, 5-s Axis1 cut-points showed the best predictive validity and lowest mean differences of all cut-points between predicted and observed sedentary behaviour (-2.31%), light physical activity (-24.40%), and total physical activity time (-0.95%). Moderate-to-vigorous physical activity time was significantly overestimated by all cut-points (128.33-184.17%). Because moderate-to-vigorous physical activity was highly overestimated, using only the 5-s Axis1 sedentary behaviour cut-point to distinguish sedentary behaviour from total physical activity is advised. The high accuracy indicates that these cut-points are useful for epidemiological studies involving the sedentary behaviour and physical activity of 2-3 year olds.

Identification and Validity of Accelerometer Cut‐Points for Toddlers

The purpose of this study was to derive ActiGraph cut-points for sedentary (SED), light-intensity physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) in toddlers and evaluate their validity in an independent sample. The predictive validity of established preschool cut-points were also evaluated and compared. Twenty-two toddlers (mean age = 2.1 years ± 0.4 years) wore an ActiGraph accelerometer during a videotaped 20-min play period. Videos were subsequently coded for physical activity (PA) intensity using the modified Children's Activity Rating Scale (CARS). Receiver operating characteristic (ROC) curve analyses were conducted to determine cut-points. Predictive validity was assessed in an independent sample of 18 toddlers (mean age = 2.3 ± 0.4 years). From the ROC curve analyses, the 15-s count ranges corresponding to SED, LPA, and MVPA were 0-48, 49-418, and >418 counts/15 s, respectively. Classification accuracy was fair for the SED threshold (ROC-AUC = 0.74, 95% confidence interval = 0.71-0.76) and excellent for MVPA threshold (ROC-AUC = 0.90, 95% confidence interval = 0.88-0.92). In the cross-validation sample, the toddler cut-point and established preschool cut-points significantly overestimated time spent in SED and underestimated time in spent in LPA. For MVPA, mean differences between observed and predicted values for the toddler and Pate cut-points were not significantly different from zero. In summary, the ActiGraph accelerometer can provide useful group-level estimates of MVPA in toddlers. The results support the use of the Pate cut-point of 420 counts/15 s for MVPA.

Validation and Reliability of the New Lifestyles NL-1000 Accelerometer in New Zealand Preschoolers

Objective measures, such as accelerometers, are increasingly being used to measure physical activity (PA) levels in children, and the use of validated and reliable instruments is desirable when measuring the effectiveness of programs. The purpose of this study was to determine the validity and reliability of the New Lifestyles NL-1000 accelerometer among preschoolers using a modified version of the Children's Activity Rating Scale (CARS). Fourteen preschoolers wore the NL-1000 at their waist while the device measured activity levels [in seconds of moderate-to-vigorous physical activity (MVPA)]. They were also videoed for approximately 12 minutes while participating in normal activities at an early childhood center. At approximately 2-minute intervals, activity level readings derived from the NL-1000 were recorded. The video footage was analyzed using a modified CARS technique and the CARS scores compared with data obtained from the accelerometer. Within subject reliability was measured using intraclass correlation coefficients (0.58 for CARS and 0.59 for NL-1000). Furthermore, 95% of the variation in CARS could be explained by variation in the accelerometer counts, with 2.4% of the variation being participant-specific. The NL-1000 is a sufficiently reliable and valid tool for assessing MVPA in preschoolers.

Calibration and comparison of accelerometer cut points in preschool children

The present study aimed to develop accelerometer cut points to classify physical activities (PA) by intensity in preschoolers and to investigate discrepancies in PA levels when applying various accelerometer cut points. To calibrate the accelerometer, 18 preschoolers (5.8 ± 0.4 years) performed eleven structured activities and one free play session while wearing a GT1M ActiGraph accelerometer using 15 s epochs. The structured activities were chosen based on the direct observation system Children's Activity Rating Scale (CARS) while the criterion measure of PA intensity during free play was provided using a second-by-second observation protocol (modified CARS). Receiver Operating Characteristic (ROC) curve analyses were used to determine the accelerometer cut points. To examine the classification differences, accelerometer data of four consecutive days from 114 preschoolers (5.5 ± 0.3 years) were classified by intensity according to previously published and the newly developed accelerometer cut points. Differences in predicted PA levels were evaluated using repeated measures ANOVA and Chi Square test. Cut points were identified at 373 counts/15 s for light (sensitivity: 86%; specificity: 91%; Area under ROC curve: 0.95), 585 counts/15 s for moderate (87%; 82%; 0.91) and 881 counts/15 s for vigorous PA (88%; 91%; 0.94). Further, applying various accelerometer cut points to the same data resulted in statistically and biologically significant differences in PA. Accelerometer cut points were developed with good discriminatory power for differentiating between PA levels in preschoolers and the choice of accelerometer cut points can result in large discrepancies.

Combining Accelerometry and HR for Assessing Preschoolers' Physical Activity

With rising obesity and rapidly decreasing levels of physical activity (PA) in young children, accurate PA measurement is needed for early screening and intervention evaluation. Although the combination of accelerometry (ACC) with HR recordings is accurate in assessing PA intensity in older children, its utility in correctly classifying PA in preschoolers is unknown. Thirty-three children (64% were boys) were recruited from four German preschools. Data included direct observation and Actiheart (CamNtech, Cambridge, UK) monitoring during 2.5 T 0.7 h (derivation data) and 1.5 T 0.3 h (validation data). Observers assessed PA using the Children's Activity Rating Scale (CARS). Moderate-to-vigorous PA (MVPA) was defined by a CARS score of 4 or 5, and sedentary behavior (SB) was defined by a CARS score of 1 or 2. Actiheart recordings were linked to CARS level, with means and 95% confidence intervals calculated for ACC and HR at each observed CARS level and for MVPA/SB. Using receiver operating characteristic analysis, gender-specific ACC and HR cutoffs for correctly classifying MVPA and SB were first determined in a derivation data set and then tested in a separate validation data set of observations. By combining HR and ACC cutoffs, 91% and 87% of the 15-s intervals observed as MVPA were correctly classified in girls and boys, respectively. Although generally lower, correct classification rates for SB were highest when only ACC cutoffs were applied (69% for girls and 67% for boys) rather than when combined cutoffs were used. Devices that combine HR and ACC data yield an accurate classification of MVPA in preschoolers but perform less well for classifying SB. These differences underscore the need to match evaluation methods with the objectives of future PA interventions.

Accelerometry to Assess Preschooler's Free-Play: Issues with Count Thresholds and Epoch Durations

This study examines the utility of current accelerometer threshold definitions and epoch durations for physical activity intensity classification in preschool-aged children. Using video footage of children engaged in active play, directly observed 1-sec epoch physical activity intensity scores were derived from a modified version of the Children's Activity Rating Scale, averaged into 15-sec epochs (corresponding to the accelerometer scale), and compared to accelerometer-measured classifications. Overall, 6,540 individual 1-sec epochs were captured and classified from six children, yielding 429 time-matched 15-sec epoch physical activity intensity classifications from both methods. Children participated in 25 distinct physical activity behaviors and spent 75% of free-play in one intensity level for ≤5 sec. The maximum amount of time spent participating in an activity prior to changing activity intensity was 98 sec. Agreement between methods was generally poor (overall: κ = .22; child range: κ = .00 to .66), and the difference between methods was significantly asymmetrical (McNemar's test overall: p = .01). Accelerometer thresholds and epoch durations used to classify preschoolers' physical activity intensity yielded biased estimates in the current study. Further investigation is necessary to establish optimal physical activity measurement methods with this population.

Pedometer accuracy in physical activity assessment of preschool children

Yamax SW-200 pedometer validity during unstructured free play was assessed in 13 preschool children aged 4.1+/-0.6 years using the Children's Activity Rating Scale (CARS). Pedometer validity and hip placement reliability were also assessed during straight line walking. Data were analysed using regression analyses, 95% upper and lower prediction intervals and 95% limits of agreement. The prediction intervals for pedometry were wide when using the CARS as a criterion. Limits of agreement and prediction intervals for directly observed step counts were also wide for pedometers, calling into question their acceptability for use with preschoolers. Limitations of employing the CARS direct observation approach as a criterion measure of physical activity are also discussed.

The Use of Pedometry to Evaluate the Physical Activity Levels among Preschool Children in Hong Kong

The present study investigated physical activity trends among young children aged three, four, and five years old in Hong Kong preschools using pedometry. Subjects were eighty-six boys and sixty-two girls ( n = 148). The Digi-walker sw-200 electronic pedometers were utilized to collect activity data during daily regular physical activities in three preschools. School A was located at the rural area whereas School B and C were in urban areas. An observation inventory, Children Activity Rating's Scale (CARS), was used to categorize the intensity level of the physical activities and to validate the pedometer counts. In line with overseas studies, significant age and gender differences in physical activity levels were also observed among the Hong Kong preschool children. A two (gender) 2 three (age groups) analysis of variance indicated that both main effects were statistically significant ( p < 0.05). Older children in the school (School A) with a larger outdoor play space in a rural district were much more active than their counterparts in urban schools (Schools B and C) with limited indoor play space. The pedometer counts correlated significantly ( p < 0.05) with the CARS scores, which suggested that pedometry can be a reliable tool to measure the intensity of physical activity level of preschool children.

COMPARISON OF ACTIWATCH SENSORS AND CARS ON ASSESSMENT OF PHYSICAL ACTIVITY IN CHILDREN.

1577 The Children's Activity Rating Scale (CARS) is a rating scale that is used in direct observation of physical activity in children. Direct observation is costly, tedious, and accuracy may decrease as the observation period lengthens. Motion sensors have gained acceptance for assessment of physical activity. Actiwatch (Mini-Mitter) is a motion sensor with an omni-directional accelerometer. The purpose of this study is to compare 6-hr of activity levels using simultaneous monitoring of pre-school aged children with CARS and Actiwatch motion sensors. A total of 41 children had 3-6 hours of direct observation during waking hours while wearing a sensor on the waist. Simultaneous 10-min mean CARS scores and 10-min sensor activity counts were matched for each subject. The mean (+/− SD) CARS for the 41 children over the 3 to 6 hour period was low (1.76+/−0.28), with a range of 1.20 to 2.23. The range for the mean 10-min CARS scores was 1.0 to 4.49. The 10-min sensor counts ranged from 0 to 2,752 with a mean of 312 (median 230). Overall, 10-min sensor readings correlated with 10-min CARS (r=0.60, P<0.001). The within child correlations between the 10-min CARS score and the 10-min sensor readings from −0.09 to 0.96 with a median of 0.71. We found that the correlation between 10-min sensor readings and the CARS was dependent on the child's activity level for the day (r=0.38, P=0.01): a higher correlation was observed in those children who were more active, probably due to the larger ranges in the CARS scores. Using mixed model repeated measures, sensor readings were significantly associated with CARS (P<0.001). The results indicate that the 10-min CARS score correlates with 10-min sensor counts, favoring the use of the sensors in assessing physical activity in preschool-aged children. Supported by NIH RO1 AR 45310

The Relationship Among Television Watching, Physical Activity, and Body Composition of Young Children

Television watching has been reported to be associated with obesity, resting energy expenditure, and lower daily physical activity among both children and adolescents. However, most of these studies were based on self report or data collected in laboratory settings. This study examined the relationship among observed time of television watching, observed physical activity level and body composition among 3- or 4-year-old children. African-American (41.4%), Mexican-American (23%), and Anglo-American (35.6%) children (N = 191, males = 90) from the Texas site of the Studies of Child Activity and Nutrition program were observed from 6 to 12 hours per day up to 4 days over 1 year. Activity level each minute of the day was measured with the Children's Activity Rating Scale (interobserver reliability = .84 +/- .001). The interobserver reliability of time of television watching was .96 +/- .08. The median of the longest number of consecutive minutes of television watching was 15 (range = 1 to 79). The median percent of minutes of television watching of total observed minutes was 14.8% (0% to 58%) and the median percent of minutes of inside minutes was 17.9% (0% to 80.9%). There were no gender or ethnic differences in time watching television or physical activity during television watching. Physical activity during television watching was lowest during the longest bout of television watching (mean = 1.48 +/- .28) compared to outside minutes (mean = 2.38 +/- .21), inside non-television minutes (mean = 1.96 +/- .13) and inside television minutes (mean = 1.65 +/- .18). The level of physical activity during television-watching times was highest (P < .0031) during October and November and lowest during March, April, June, and July. Longest bout of television watching and percent of minutes watching television to total observed minutes were inversely associated with mean physical activity, percent of minutes of physical activity levels 3, 4, or 5, and percent of physical activity levels 4 or 5. Percent of television watching to inside minutes was negatively correlated with physical activity levels 4 or 5. Television-watching behavior was not associated with body composition. Television watching was weakly negatively correlated with physical activity levels, and physical activity was lower during television-watching than non-television-watching time in this sample of children. Television viewing behavior was not associated with body composition.

Evaluation of the Children??s Activity Rating Scale (CARS) in young children

We describe the daily activity patterns and the between-day and -year reliabilities of the Children's Activity Rating Scale (CARS) measured in 180 Anglo-, African-, and Mexican-American children aged 3 or 4 yr. Reliabilities were assessed at up to 11 measurement periods over 3 yr. CARS scores were measured by two trained observers (alternating 2-h shifts) up to 12 working hours. There were no significant ethnic or day of week differences in the activity levels. Males had higher mean activity levels than females and higher activity was performed in the summer and fall than the spring or winter. The all-measurements reliability for a mean of 5.34 d of observation over the 3 yr of measurement was 0.57. The reliability across all days and years of measurement was 0.73. The highest level of reliability (0.75) was found for the percent of minutes spent at CARS levels 3, 4, or 5 followed by an intraclass correlation of 0.74 for percent of minutes spent at CARS levels 4 or 5. These data support the utility of using the CARS as a measure of physical activity in younger children from different ethnic groups.

Association among serum lipid and lipoprotein concentrations and physical activity, physical fitness, and body composition in young children

To examine the relationships among indicators of physical activity, physical fitness, and body composition with serum lipid and lipoprotein levels in young children. Cross-sectional and 1-year prospective cohort. Studies of Child Activity and Nutrition (SCAN) program, Galveston, Tex. One hundred twenty-three 4- or 5-year-old black, Hispanic (of Mexican origin), and white children. Body composition, resting heart rate, and cardiovascular fitness variables and serum lipid and lipoprotein levels were measured at age 3 or 4 years (study year 1) and at age 4 or 5 years (study year 2), and day-long heart rate was measured and the Children's Activity Rating Scale was administered between study years 1 and 2. Year-1 waist/hip ratios were inversely correlated with total serum cholesterol (TSC) and low-density lipoprotein (LDL) levels. Mean activity level was inversely correlated with waist/hip ratios. On the basis of multiple regression analysis, the sum of seven skin-fold measurements, height, and gender explained 15.4% of the variation in triglyceride levels. The sum of seven skin-fold measurements was inversely correlated with the high-density lipoprotein (HDL) level. Resting heart rate, waist/hip ratio, and the slope of the exercise heart rate during fitness testing explained 19.5% of the variation in the concentration of an HDL subclass, HDL2. These children's levels of physical activity were associated with higher fitness levels. Year-1 waist/hip ratios and year-2 sum of seven skin-fold measurements were positively correlated with the LDL/HDL and TSC/HDL ratios. Higher levels of cardiovascular fitness and lower levels of fatness were associated with more favorable serum lipid and lipoprotein levels in these young children. Physical activity appeared to have an indirect association with serum lipid and lipoprotein values through its relationship with higher fitness levels and lower levels of fatness.

Children's Activity Rating Scale (CARS): Description and Calibration

A five-level Children's Activity Rating Scale (CARS) was designed to categorize the intensity of physical activities and discriminate between levels of energy expenditure in young children. The CARS was used by trained observers over a 12-month period to assess physical activities of 3-4 year-old children during field observations. Agreement among observers using the CARS was 84.1% for 389 paired observation periods. The energy expenditure for each level was assessed by measuring VO2s and heart rates of 5-6 year-old children (12 boys, 13 girls) while they performed eight activities representing the CARS levels. Mean VO2s for the eight activities in Levels 1-5 ranged from 7.1 to 37.5 ml.kg BW-1.min-1 (1 to 5.42 METS; 14.5% to 80.6% of VO2max). Mean heart rates ranged from 89 to 183 b.min-1 for activities in Levels 1-5. VO2s and heart rates at each level were significantly different from all other levels. These data demonstrate that the CARS encompasses a wide range of energy expenditures, discriminates between levels of energy expenditure, and can be used by trained observers to reliably evaluate physical activity and estimate energy expenditure of young children.