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00005768-200908000-0000700005768_2009_41_1580_pitetti_intellectual_8miscellaneous< 102_0_13_2 >Medicine & Science in Sports & Exercise© 2009 American College of Sports MedicineVolume 41(8)August 2009pp 1580-1586Physical Activity Levels of Children with Intellectual Disabilities during School[BASIC SCIENCES]PITETTI, KENNETH H.1; BEETS, MICHAEL W.2; COMBS, CINDY31Department of Physical Therapy, Wichita State University, Wichita, KS; 2Exercise Science, University of South Carolina, Columbia, SC; and 3Newton Unified School District, Newton, KSAddress for correspondence: Kenneth H. Pitetti, Ph.D., FACSM, Department of Physical Therapy, College of Health Professions, Wichita State University, 1845 Fairmount St, Wichita, KS 67260-0043; E-mail: ken.pitetti@wichita.edu .Submitted for publication September 2008.Accepted for publication January 2009.ABSTRACTIntroduction: Current guidelines recommend school-age children accumulate at least 60 min of moderate-to-vigorous physical activity (MVPA) on most days of the week. Little is known about the activity level of school-age children with intellectual disabilities (ID).Purpose: To evaluate physical activity patterns of children with ID during three school settings: adapted physical education (APE, 55 min), classroom (CR, 55 min), and recess (RE, 25 min).Methods: HR was measured by telemetry for 15 youth (6 boys, 9 girls, 8.8 ± 2.2 yr) with ID during APE, CR, and RE on three nonconsecutive school days. Resting HR (RHR) was measured on three nonconsecutive days between 8:00 and 8:45 a.m. The mean of the five lowest RHR was used to create MVPA cutoffs. Total MVPA was determined by the mean time spent (min) above 1.25% RHR (PAHR-25 Index) in each of the three school settings. Three (one for each environment) random effects two-level models (measures nested within child) were used to describe the proportion of time students spend in MVPA across the three environments and to examine the within-child variation across measures within locations.Results: The total daily MVPA across the three environments was 83.5 min (72.9-94 min). Intraclass correlations ranged from 0.06 to 0.53, suggesting considerable within-child variation across the three observations across settings.Conclusions: Although variation existed across observations for each child, on average, children met and exceeded recommendations for 60 min of MVPA during the day. Theses findings suggest that through allocation of time for APE and RE, coupled with programming designed to maximize activity opportunities, students with ID can achieve recommended levels of MVPA.For school-age youth, daily physical activity (PA) is essential for the promotion of health, growth, and development as well as reducing risk factors for adult onset of cardiovascular and metabolic diseases (33). Current PA guidelines recommend school-age children accumulate at least 60 min of moderate-to-vigorous PA (MVPA) on most days of the week (21,33,38,39). Although there has been extensive research on PA behaviors, patterns, and determinants of youth without disabilities (30), there is scarce information on the PA characteristics of youth with intellectual disabilities (ID) (5,7,16).The term ID covers the same population of individuals whose conditions were diagnosed previously with mental retardation in definition, classification, and systems of support (1). Examples of syndromes and conditions associated with ID include, but are not limited to, attention-deficit/hyperactivity disorder (ADHD), autistic syndrome disorder, Down syndrome, fragile X syndrome, and Klinefelter syndrome. Historically, there were limited studies that actually measured the PA patterns of youth with ID. Consequently, PA patterns of youth with ID were linked to or were based on their physical fitness status. It has been consistently reported that youth with ID have lower levels of cardiovascular fitness and muscular strength as well as high levels of adiposity (i.e., body mass index (BMI)) in comparison to their peers without ID (25,26). Therefore, it was assumed that youth with ID had lower PA patterns than youth without ID. However, to assume a direct relationship between physical fitness and physical activity would be problematic in that the relationship between physical fitness (usually cardiovascular fitness) and PA in youth is variable (i.e., correlations range from 0.16 to 0.8) (12,20,24) and that 80%-90% of the variance in physical fitness is not accounted for by PA (12). Indeed, it has been reported that no differences in PA levels exist between children with ID with low fitness when compared with children with low and high level of fitness without ID in similar school settings (i.e., physical education class and recess) (4). Physical activity and physical fitness (e.g., cardiovascular fitness) should therefore be viewed as independent health indicators. Given that PA in and of itself is an important health behavior for all youth (33), attempts should be made to evaluate PA behavior patterns of youth with ID (9,27).Although numerous methods exist to measure the intensity levels of PA of children and adolescents, HR monitoring is commonly used with children and adolescents because of its objectivity, reliability, and validity (2,3,14,17,19,22,35). Prior empirical investigations have used HR monitoring to measure PA of children and adolescents with ID (4,10,18,41). However, the focus of these studies was not to determine whether students with ID met recommended PA guidelines, rather, it was to compare PA levels in different school settings (i.e., physical education class, physical therapy, classroom activity, inclusive recess, and noninclusive recess) (4,10,18,41). Further, these studies had several methodological limitations (e.g., unrealistic HR, not expressing activity HR relative to resting HR (RHR)), and as a consequence, little is known about the amount of PA youth with ID are receiving in the school setting and whether they are achieving the recommended guidelines for PA.The purpose of this study was to evaluate MVPA behavior patterns using HR monitoring of children with ID in three school settings: adapted physical education (APE), regular classroom (CR), and recess (RE). The school setting was chosen in that all children, disabled and nondisabled, attend school, and the school is the primary institution for promoting PA (32,36,37).METHODSParticipants and School SettingsFifteen elementary school children (9 girls, 6 boys; 8.8 ± 2.2 yr) from a Midwestern city (population, 19,000) with mild ID participated in the project (see Table 1 for descriptive characteristics). All participants had been classified as having (ID) by qualified school district personnel according to the model for diagnosis by the American Association on Mental Retardation (1). The sample design was purposive in that participants had to meet the criterion for ID, were in a self-contained placement classroom, and could not have any limiting condition that would hinder their ability to engage in routine physical activity: cardiovascular disease, significant respiratory disorder, metabolic disease, or were taking HR- and blood pressure-altering medications. Informed parental consent and voluntary assent, along with district and school administration approval, were obtained before participation in the study. The study was approved by the Institutional Review Board at Wichita State University.TABLE 1. Descriptive statistics.Standing height (cm) and weight (lb) were obtained without shoes using a portable stadiometer (Model 214 Portable Height Rod; Seca, Hamburg, Germany) and a physician's scale (Balance Beam Scale; Detecto, Daugherty Webb City, MO). The units (e.g., lb to kg, inches to m) were converted, and BMI was calculated. Descriptive statistics are found in Table 1.Participants were from two special-needs classrooms located within the same elementary school (K-5) of approximately 400 students. The two special-needs classrooms contained six to eight students, a certified teacher of students with special needs who was assisted by two to three paraeducators. The amount of support (i.e., paraeducators) for each child depended on the needs of a child as stipulated by their individualized educational plan. Participants included in this study are representative (i.e., conditions listed in Table 1) of what one would find in any self-contained placement classroom.Setting characteristics.The noninclusive (i.e., only students with special needs) APE classes were lead by a certified APE instructor and took place in a gymnasium (60ft × 90 ft). The APE class (55 min) consisted of students from both special-needs classrooms (14-16 students) with five to six paraeducators assisting. The APE curriculum involved games and activities and were focused on constant movement and minimal instruction (i.e., when students are either standing or sitting). During classroom instructional activities (55 min), the students were sitting in chairs, but sometimes were involved in standing and moving activities (e.g., dancing, hopping) to a lesson plan that involved music.Inclusive recess occurred in conjunction with a minimum of two classes and a maximum of four classes of nondisabled schoolchildren. The 25-min recess period involved free play that took place on the school playground that consisted of a soccer field (125 m × 75 m) adjacent to an activity area (70m× 50 m) with recreational equipment (swings, monkey bars, slides, etc.). The soccer field was grass, whereas the area with recreational equipment was sand. During recess, the classroom teachers and paraeducators observed to ensure safety but did not direct or suggest activity or encouraged interactions between the children with ID and the nondisabled children. Ambient temperature during recess ranged from 40 to 82°F (4.4 to 27.8°C).ProceduresHR monitoring.For all settings, HR was measured by telemetry (S410™ Heart Rate Monitor; POlAR®, Helsinki, Finland). The receiver was programmed to record HR every minute and either was placed on the wrist or was attached to the back of a belt worn at the waist. The participant was observed and checked throughout the recording period to ensure that the receiver was not tampered with by the participant. Recorded HR data were downloaded to a computer via SonicLink™ (Polar, Helsinki, Finland) on the same day and analyzed with Polar Precision Performance software (version 4). The equipment was attached to the participant approximately 10 min before PE class, and it recorded consecutively during PE class, instructional class time, and recess. HR equipment was removed after recess.Resting HR.The protocol used for determining RHR followed the standardized methodology previously established for nondisabled children (2,3,23,34). However, adjustments were made to accommodate the special needs of these children according to the recommendations of the classroom instructors. Accordingly, measurements were taken upon arrival to their home-classroom (7:45-8:00 a.m.) within 30-60 min of waking and without prior exercise. The HR monitor was attached to the child, and whereas the other classmates attended PE class, the participant remained in the classroom and reclined on a beanbag. To control for behavioral complications, the child was read to for 30 min to by the author (K.H.P.) from a storybook selected by the classroom instructor. This procedure was performed on three different days separated by at least 72 h. RHR was calculated as the mean of the five lowest HR on the day the lowest RHR was recorded (28,29,31,39). RHR measurements were assessed before activity HR were measured for each participant (see below).HR indices of physical activity.All measures were administered during three regularly scheduled morning classes (8:00 to 10:25 a.m.), which included three different settings and took place in the following chronological order: 55 min of APE, 55 min of instructional class time (CR), and 25 min of inclusive recess (RE). The time spent in both PE and RE included the transition time to and from the setting, which averaged 1-2 min. This procedure was repeated on three nonconsecutive school days separated by at least 72 h. If data were interrupted during any of the settings, the measurements of HR were repeated on another day.On the basis of the RHR for each child, activity intensity for each setting was calculated by the time spent >1.25% RHR (PAHR-25) for moderate physical activity (MPA) and >1.50% RHR (PAHR-50) for vigorous physical activity (VPA). Studies have demonstrated that these indices are reliable and objectively discriminate between different levels of activity in children (3,11,15,23,29).Statistical AnalysisInitially, the reliability of the five lowest RHR (see above) was determined using a two-level (measures nested within child) random effects model. To determine reliability, an intraclass correlation coefficient (ICC) was estimated using a two-way mixed-model ANOVA for absolute agreement. The average minutes spent in MPA, VPA, and MVPA within each setting and the sum of the three settings were estimated using two-level random effects models. Further, because of the difference in the amount of time allocated to RE (25 min) in relation to both APE and CR (55 min each), the amount of time (min) spent in each of the activity intensity categories (see above) was transformed into percentages. This was done to make comparisons on the amount of activity the children were receiving proportional to the time allocated to be active. The variance of the estimates from the models was partitioned into between-subjects (from child to child) and within-subjects (from day to day) effects, along with the ICC to provide an indication of the stability in physical activity intensities across the three measurement days. All analyses were performed using xtreg in Stata (StataCorp, College Station, TX).ResultsThe estimates of the two-level models are presented in Table 2. The ICC for the RHR was 0.99 (95% confidence interval (CI), 0.98-0.99), indicating a high degree of consistency among RHR measures within each child. Within each of the three settings, the average times spent in MVPA were 43, 20.9, and 19.6 min for APE, CR, and RE, respectively. These translated into approximately 78.2%, 38.1%, and 78.3% of the time spent at a health-enhancing intensity level in each of the three settings. Overall, across the three settings, children in this study were engaging in an average of 83.5 min of MVPA per day (95% CI, 72.9-94 min of MVPA per day). Estimates of reliability ranged from an ICC of 0.20 (RE MVPA) to 0.79 (APE VPA). These ICC values indicate that a considerable amount of variability exists among observations for each child, suggesting that during the three nonconsecutive days of monitoring, the children engaged in varying amounts of activity.TABLE 2. Fixed and random effects for estimated RHR and time spent in moderate and vigorous physical activity during physical education, classroom academics, and recess (N = 15).DISCUSSIONThe results of the present study suggest that children with ID engage in approximately 83 min of daily MVPA, well above the recommended level. Thus, within this school's environment, children with ID are afforded time to be sufficiently active. Such findings indicate that schools can play a crucial role in promoting the physical activity levels of children with ID. Unfortunately, the results of this study lack generalization to other locations. That is, schools of differing class structures (e.g., inclusive or mainstreaming), teacher training, teacher-to-student ratio, and physical infrastructure, may experience greater or less difficulties in promoting the physical activity of students with ID. Nevertheless, these findings do indicate that considerable gains can be made within the time children with ID spend in health-enhancing physical activity in the school setting.HR monitoring is commonly used as an index of physical activity in children because it has been repeatedly shown to be objective, valid, and reliable (2,3,14,17,19,22,35). Prior studies have used HR monitoring to measure PA of youth with ID in the school setting but only focused on limited periods (5-30 min) and had several methodological limitations that render their findings difficult to compare with the present study. Faison-Hodge and Porretta (4) monitored PA through observation (System for Observing Fitness Instruction Time (SOFIT)) and HR of eight students with ID (aged 9.5 ± 1.2 yr) during inclusive physical education classes (30 min) and recess (<15 min). Although HR monitor data were used to correlate to SOFIT (r = 0.81), only the SOFIT data were used to determine MVPA (i.e., HR data were not reported). Lorenzi et al. (18) monitored PA of 17 children (aged 8.8 ± 1.9 yr) with ID during recess with combined HR measurement and accelerometry. However, reported HR were unrealistic, with mean activity HR ranging from 33 to 63 bpm. Horvat and Franklin (10), using combined HR monitors and accelerometry, reported PA levels during classroom activity and two different recess settings (i.e., inclusive and noninclusive) for 23 students (aged 9.4 ± 2.0 yr) with ID. However, data were collected at different times throughout the school day, and actual observational periods for all three settings were limited to 16 min. Moreover, RHR were not measured, and consequently, the actual intensity level for each participant could not be determined. This study therefore represents the first study to measure the PA level of children with ID using HR monitoring in three different school settings, for an extended period, and reported activity level expressed relative to RHR.Researchers have established that among children, activity intensity should be expressed relative to RHR because this would adjust the estimates to levels of fitness and age (2,3,15,23). However, there are inconsistencies as to how RHR is determined. Direct measurement of RHR (i.e., collected in the early morning) in children has involved variable periods of rest (10-30 min) and measurement time scales (every 1-5 min) (3,15,23,34). Another method, referred to as derived RHR, is determined from minute-by-minute HR collecting throughout the day. At the end of the day, HR are sorted in ascending order, and derived RHR is determined in the following manners: by the mean of the lowest HR + all those within three beats (6,11), mean of the lowest five HR (29,31,40), mean of the lowest 10 HR (11), or mean of the lowest 50 HR (8). Logan et al. (15) determined RHR using both the direct measurement (3) and the derived RHR methodologies (6,8,28,29,31) in children (aged 3-4 yr) without disabilities and reported mean RHR ranging from 85 to 101 bpm. The mean RHR reported in the present study (86 bpm; Table 1) is within the range of those reported by Logan et al. (15). Therefore, the RHR used in this study to determine the intensity of activity is similar to those reported for children without disabilities.There are four potential limiting factors in the methodology used in this study that should be addressed. The first concerns the collection period, which incorporated only 45% of the school day. Yet, despite this, the children eclipsed their recommended daily activity levels while only several hours into their school routine, suggesting that the children are engaging in higher levels of MVPA than previously reported (7). Moreover, prior studies indicate that the children's activity during the morning hours at school is not different from that during the afternoon (3). Thus, it is likely that the activity levels during the afternoon were similar. Therefore, when considering the present study, given that the mean accumulation of MVPA across these three environments was already 83.5 min, it could be assumed that the remaining school day would have added to the total MVPA accumulated during the collection period.The second potential limiting factor concerns the behavioral aspects of the syndromes and conditions associated with ID. Of the potential pool of participants, data from three participants were not included because of either difficulty of collecting RHR or refusal to be instrumented. One potential participant with ADHD would not comply with the necessary time needed to sit quietly while collecting RHR. The location of the HR monitor around the chest was so bothersome for two potential participants with autism spectrum disorder (ASD) that they refused to be instrumented. It should be noted, however, that of the 15 participants who completed the study, 2 had their conditions diagnosed with ADHD and 1 with ASD.The third potential methodological limiting factor involves the cutoff points used to determine MVPA. The PAHR-25 and PAHR-50 cutoff points for moderate and vigorous activity, respectively, were used to express data relative to RHR to adjust for differences in fitness and age among children (3,6,23). However, PAHR-25 may also include "light-moderate" PA (3,15), and therefore, some of the time the participants spent in PAHR-25 may include "light-moderate" activity. Of the total mean minutes spent in MVPA across the three morning settings, 47.5 min were spent in MPA and 36.0 min were spent in VPA (Table 2). Given that there are no established cutoff points to separate light physical activity from moderate physical activity within the PAHR-25, a conservative approach might estimate that 50% of the 47.5 min (i.e., 23.7 min) of PAHR-25 was actually moderate PA. This would result in a total mean of 59.7 min spent in MVPA in the first three settings of the school day. Given that the participants had a second recess period in the afternoon, it seems reasonable to conclude that even when taking a conservative approach to PAHR-25 intensity level, the participants in this study were accumulating the recommended 60 min of MVPA during their school day.The fourth potential limiting factor of this study involves the Rosenthal effect. That is, there could have been a desire for the participants to please the study investigators, which, in turn, could have affected their PA levels. Of the three authors involved in the data collection, one was the participants' regular APE teacher, so the presence of this author should not have precipitated a Rosenthal effect. The second author had spent a semester before data collection, acclimatizing the children to wearing the HR monitor, so his presence had become part of their weekly experience. It is thought, therefore, that given the participant's familiarity with two of the authors, the possibility of the Rosenthal effect increasing PA levels was minimal.When considering the number of trials and, therefore, amount of time necessary to collect three uninterrupted recordings for RHR and the three school settings, the issue of abbreviating (i.e., fewer trials) the methodology should be addressed. However, the finding that the estimates of the variance partitioning ranged from an ICC of 0.06 (RE MVPA) to 0.53 (APE VPA) indicates that a considerable amount of variability exists among observations for each child. That is, during the three nonconsecutive days of monitoring, the children engaged in varying amounts of activity. These findings strongly suggest the need for data collection on at least three separate days to gain a realistic representation of their activity levels.Whether the findings of this study are indicative of the activity level of children with ID within the school systems of the United States is problematic for the following reasons. First, the APE teacher for this study (C.C.) has been nationally recognized for her innovative and creative physical education curriculum for children with ID. Second, only 31.3% of schools in the United States (K-12) have separate adapted PE classes specific for children with mental and physical disabilities (13). Third, the likelihood of children with ID who are able to take adapted PE and have, in addition, an educator/paraeducator-to-student ratio of near 2:1 would be nominal. Fourth, the percentage of schools in the United States that require PE classes for all students in grades K-6 range from 49.7% to 68.1% (13). In addition, for those schools that have PE classes, the average numbers of days per week of scheduled PE are 2.4 and 2.6 times per week for first through fifth grades and for sixth grades, respectively (13). This equates to a weekly average of allotted PE ranging from 85.4 to 98.0 min (35). The participants in this study were provided adapted PE on all school days for 55 min per session, resulting in 255 min of adapted PE for a full week of school. Fifth, among all school districts in the United States, 38.5% require or recommend ≥30 min of recess per day, 23.0% require of recommend 20-29 min of recess per day, 15.9% require or recommend 10-19 min of recess per day, and 12.6% do not require or recommend recess (13). The participants in the present study were provided with two 25-min recess periods per school day (i.e., 50 min). Therefore, the results of this study may not be representative of activity level of children with ID in the school systems within the United States.The Individuals with Disabilities Education Act (IDEA) was passed in 1975, amended in 1997, and again in 2004, and it stated that children with disabilities are to be educated to the maximum extent with children who do not have disabilities. The school district that the participants in this study attended provided PE classes to all children without disabilities every school day for 55 min, and the participants were taught by a very dedicated, seasoned, and well-qualified teacher. Likewise, the children with disabilities were provided adapted PE classes every school day for 55 min and, as addressed above, were also taught by a very dedicated, seasoned, and well-qualified teacher. In addition, both the children with and without disabilities were provided two 25-min recess periods during the school day. Accordingly, the school district was abiding by the guidelines set forth by IDEA in that they were providing the same opportunities for physical activity within the school day for both their students with and without disabilities. The results of the present study clearly establish that given the opportunity, children with ID can and will participate in the allotted PE classes and recesses. More importantly, however, by participating in these school-day activities, they were able accumulate the necessary MVPA essential for the promotion of their health, growth, and development as well as for reduction of the risk factors to adult onset of cardiovascular disease.Funding: no funding received.Results of the study do not constitute endorsement by ACSM.REFERENCES1. American Association on Mental Retardation. Mental Retardation: Definition, Classification, and Systems Support. 10th ed. Washington (DC): American Association on Mental Retardation; 2002. p. 238. [Context Link]2. 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