Timothy A. Brusseau

Epoch length and accelerometer outputs in children: Comparison to direct observation

PURPOSE To determine the effects of epoch length and activity count cutpoints on ActiGraph (AG; ActiGraph Health Services, Pensacola, FL) accelerometer estimates of time in moderate-to-vigorous physical activity (MVPA) in fifth-grade children monitored during physical education (PE) compared with a direct observation (DO) criterion standard. METHODS A sample of 32 fifth-grade males and females (mean age = 10.3 +/- 0.5 yr) wore an AG attached at the waist for a 30-min PE class. Participants were concurrently videotaped, and the Computerized System for Observing Fitness Instruction Time (C-SOFIT) was used to create a DO measure of MVPA time (DO_MVPA). AG data were collected in 5-s epochs then integrated into 10-, 15-, 20-, 30-, and 60-s epochs. AG activity counts were converted into time (in s) in MVPA using validated (and epoch-adjusted) childrens activity count cutpoints established by Treuth et al. (AG_T), Mattocks et al. (AG_M), and Freedson et al. (AG_F). RESULTS All AG_T and AG_M epoch detected significantly lower time in MVPA than DO_MVPA. The percentage of DO_MVPA detected by AG_T and AG_M epochs ranged from 46% to 61% and from 26% to 47%, respectively. All AG_F epochs yielded similar (i.e., nonsignificant) mean estimates of MVPA versus DO_MVPA, with modest increases in root mean squared error (RMSE) with increasing epoch length. The percentage of DO_MVPA detected by AG_F epochs ranged from 93% to 100%. CONCLUSIONS All AG_F epoch lengths provide comparable mean estimates to DO-detected MVPA time in fifth-grade children during PE. To minimize error among individual estimates, shorter epoch lengths should be used, with 5-s epochs yielding the lowest RMSE in the current study. Considerations of both epoch length and activity count cutpoint are important to improved detection of intermittent bouts of MVPA among fifth-grade children.

Children's Step Counts on Weekend, Physical Education, and Non-Physical Education Days

Childrens Step Counts on Weekend, Physical Education, and Non-Physical Education Days There have been well-documented increases in overweight and obese children, sedentary lifestyles, and increased prevalence of a hypokinetic disease over the past 20 years. Thus understanding the physical activity patterns of children is essential for developing effective interventions. Little evidence exists that illustrates the contribution of weekend, physical education, and non-physical education days to overall physical activity patterns of children. The purpose of the study was to examine differences in pedometer-determined physical activity patterns of fourth and fifth grade children during weekend, physical education and non-physical education days. Three hundred and sixty-three children (8-11 years old) from six Southwestern USA elementary schools participated by wearing pedometers (Yamax Digiwalker SW-200) for seven consecutive days. Children recorded their steps at arrival to school and when they woke up and went to bed on weekend days. During weekdays, the fourth and fifth grade children averaged 13,196 ± 3,334 and 11,295 ± 3,168 steps/day for boys and girls, respectively. This is compared to a weekend average of 7,660 ± 4,647steps/day (boys) and 7,317 ± 4,062 steps/day (girls). Children were significantly more active on physical education days, averaging 12,979 steps/day (14,197 ± 4,697 steps/day for boys and 12,058 ± 3,772 steps/day for girls),compared to non-physical education school days, when they accumulated 11,809 steps/day (12,788 ± 3,600 steps/day for boys and 11,047 ± 3,382 steps/day for girls). Based on the findings in this study, children and youth are more active during school days than on weekend days. Furthermore, children are more active on physical education days than non-physical education days. These findings suggest that increased physical activity programming and interventions during weekend days may be needed to increase physical activity. The expansion of school-based physical education across more school days may also serve to increase childrens physical activity during the school week.

Evaluation of Low-Cost, Objective Instruments for Assessing Physical Activity in 10–11-Year-Old Children

This study compared step counts detected by four, low-cost, objective, physical-activity-assessment instruments and evaluated their ability to detect moderate-to-vigorous physical activity (MVPA) compared to the ActiGraph accelerometer (AG). Thirty-six 10–11-year-old children wore the NL-1000, Yamax Digiwalker SW 200, Omron HJ-151, and Walk4Life MVP concurrently with the AG during school hours on a single day. AG MVPA was derived from activity count data using previously validated cut points. Two of the evaluated instruments provided similar group mean MVPA and step counts compared to AG (dependent on cut point). Low-cost instruments may be useful for measurement of both MVPA and steps in childrens physical activity interventions and program evaluation.

The Effect of a Comprehensive School Physical Activity Program on Physical Activity and Health-Related Fitness in Children From Low-Income Families

BACKGROUND The purpose of this study was to examine the effect of a Comprehensive School Physical Activity Program (CSPAP) on physical activity and health-related fitness (HRF) in children from low-income families. METHODS Participants included 1390 children recruited from kindergarten through sixth grade (mean age = 8.4 ± 1.8 years). Physical activity measures were collected at baseline and at 6 weeks and 12 weeks after program implementation, and HRF measures were collected at baseline and at 12 weeks after program implementation. RESULTS There were significant but weak-to-moderate increases in step counts (mean difference = 603.1 steps, P < .001, d = 0.39) and moderate-to-vigorous physical activity (mean difference = 4.9 minutes, P < .001, d = 0.39) at 12 weeks compared with baseline. There were also significant but moderate increases in Progressive Aerobic Cardiovascular Endurance Run laps (mean difference = 6.5 laps, P < .001, d = 0.47) at 12 weeks compared with baseline. Generalized mixed models respectively yielded 3.02 and 2.34 greater odds that a child would achieve step count and moderate-to-vigorous physical activity standards and 2.26 greater odds that a child would achieve aerobic fitness standards at 12 weeks compared with baseline (P < .001). CONCLUSIONS The 12-week CSPAP improved physical activity and HRF in children from low-income families; however, the magnitude of the effects was weak to moderate.

Effect of a Comprehensive School Physical Activity Program on School Day Step Counts in Children.

BACKGROUND Comprehensive School Physical Activity Programming (CSPAP) has the potential to increase physical activity (PA) in children over time. The purpose of this study was to examine the effect of CSPAP on school day step counts in children. METHODS Participants were 327 fourth and fifth grade children recruited from 4 elementary schools. The study was conducted within an Interrupted Time-Series Design framework. School day step counts were collected for 5 days across preintervention and postintervention time-points (10 days total) using NL-1000 piezoelectric pedometers. Robust piecewise regression examined pre- and postintervention intercepts and slopes, and the change in these parameters using postestimation statistics. RESULTS The slope coefficient was statistically significant across preintervention (β = -105.23, P < .001) but not postintervention time-points (β = -63.23, P = .347), suggesting decreases in steps counts across preintervention and stability of step counts across postintervention school days. Postestimation statistics yielded increases in school day step counts from the end of preintervention (day 5) to the start of postintervention (day 6; t(319) = -4.72, P < .001, Cohens d = 4.72). CONCLUSIONS The CSPAP intervention increased average school day step counts and attenuated decreases in step counts throughout the school week in children.

Seasonal variation of American Indian children’s school-day physical activity

Seasonal variation of American Indian children’s school-day physical activity Study aim: To examine the pedometer steps taken during the school-day by American Indian children during all four seasons. Material and methods: Participants included third-sixth grade children (n = 157) aged 9.6±1.07 (boys) and 9.7±1.2 (girls) attending school from one Southwestern US American Indian community. Children had a mean BMI of 23.9±7.7 with 70% being classified as overweight or obese. Children wore a pedometer (Yamax Digiwalker SW-200) for 20 days (5 days per season). Results: Children accumulated 4762±1544 (boys) and 4408±1194 (girls) steps/day across the four seasons with the highest totals occurring during the Fall (4899, males; 4796, females) and the lowest totals during the Winter (4463, males; 4043, females). Repeated measures ANOVA showed no significant differences in daily school-day steps across seasons. Children classified as normal weight averaged 5146±1688 steps/day, overweight children averaged 5020±1333 steps/day, and obese children accumulated 4275±1123 steps/day. Conclusions: PA stayed relatively consistent across seasons in this sample of children. However, children were the least active during Winter months. With 70% of the current sample being classified as overweight and with American Indian children at greater risk for numerous hypokinetic diseases there is a clear need for additional school-day PA opportunities.

Cross-Validation of Aerobic Capacity Prediction Models in Adolescents

Cardiorespiratory endurance is a component of health-related fitness. FITNESSGRAM recommends the Progressive Aerobic Cardiovascular Endurance Run (PACER) or One mile Run/Walk (1MRW) to assess cardiorespiratory endurance by estimating VO2 Peak. No research has cross-validated prediction models from both PACER and 1MRW, including the New PACER Model and PACER-Mile Equivalent (PACER-MEQ) using current standards. The purpose of this study was to cross-validate prediction models from PACER and 1MRW against measured VO2 Peak in adolescents. Cardiorespiratory endurance data were collected on 90 adolescents aged 13-16 years (Mean = 14.7 ± 1.3 years; 32 girls, 52 boys) who completed the PACER and 1MRW in addition to a laboratory maximal treadmill test to measure VO2 Peak. Multiple correlations among various models with measured VO2 Peak were considered moderately strong (R = .74-0.78), and prediction error (RMSE) ranged from 5.95 ml·kg⁻¹,min⁻¹ to 8.27 ml·kg⁻¹.min⁻¹. Criterion-referenced agreement into FITNESSGRAMs Healthy Fitness Zones was considered fair-to-good among models (Kappa = 0.31-0.62; Agreement = 75.5-89.9%; F = 0.08-0.65). In conclusion, prediction models demonstrated moderately strong linear relationships with measured VO2 Peak, fair prediction error, and fair-to-good criterion referenced agreement with measured VO2 Peak into FITNESSGRAMs Healthy Fitness Zones.

Development of an aerobic capacity prediction model from one-mile run/walk performance in adolescents aged 13–16 years

Abstract A popular algorithm to predict VO2Peak from the one-mile run/walk test (1MRW) includes body mass index (BMI), which manifests practical issues in school settings. The purpose of this study was to develop an aerobic capacity model from 1MRW in adolescents independent of BMI. Cardiorespiratory endurance data were collected on 90 adolescents aged 13–16 years. The 1MRW was administered on an outside track and a laboratory VO2Peak test was conducted using a maximal treadmill protocol. Multiple linear regression was employed to develop the prediction model. Results yielded the following algorithm: VO2Peak = 7.34 × (1MRW speed in m s−1) + 0.23 × (age × sex) + 17.75. The New Model displayed a multiple correlation and prediction error of R = 0.81, standard error of the estimate = 4.78 ml kg−1·min−1, with measured VO2Peak and good criterion-referenced (CR) agreement into FITNESSGRAM’s Healthy Fitness Zone (Kappa = 0.62; percentage agreement = 84.4%; Φ = 0.62). The New Model was validated using k-fold cross-validation and showed homoscedastic residuals across the range of predicted scores. The omission of BMI did not compromise accuracy of the model. In conclusion, the New Model displayed good predictive accuracy and good CR agreement with measured VO2Peak in adolescents aged 13–16 years.

Comprehensive School Physical Activity Programming and Classroom Behavior.

OBJECTIVES The purpose of this study was to examine the effect of a comprehensive school physical activity program (CSPAP) on classroom behavior in low-income children. METHODS The participants included 1460 children recruited from 3 low-income schools receiving governmental financial assistance. A total of 77 classrooms were observed across grades K through 6. Classrooms were observed one week prior to the implementation of CSPAP and at 6 weeks and 12 weeks after commencement of the program. Members of the research team observed classroom behavior using systematic observation, specifically a 5-second momentary time sampling procedure. A generalized linear mixed effects model was used to determine the change in odds of a classroom achieving at least 80% on-task behavior following the implementation of CSPAP. RESULTS There were 7.49 (95% CI: 2.83, 19.79) greater odds of a classroom achieving 80% on-task behavior at 6 weeks compared to baseline and a 27.93 (95% CI: 7.93, 98.29) greater odds of a classroom achieving 80% on-task behavior at 12 weeks compared to baseline (p < .001). CONCLUSIONS After the CSPAP was implemented, on-task classroom behavior significantly improved across all grade levels.

Acute Effects of 30 Minutes Resistance and Aerobic Exercise on Cognition in a High School Sample

Purpose: The purpose of this study was to determine differences in cognition between acute bouts of resistance exercise, aerobic exercise, and a nonexercise control in an untrained youth sample. Method: Ninety-four participants performed 30 min of aerobic exercise, resistance exercise, or nonexercise separated by 7 days each in a randomized crossover design. After each exercise intervention, participants were assessed using 2 cognitive tests. The Dot, Word, and Color elements of the Stroop Test (Victoria version) and Parts A and B of the Trail-Making Test were used to measure cognition. Results: Acute resistance and aerobic exercise resulted in similar improvements over nonexercise in all forms of the Stroop Test. Acute aerobic exercise led to improved performance over nonexercise and resistance exercise in Part B of the Trail-Making Test. Neither exercise intervention showed significant changes in time to complete Part A of the Trail-Making Test. Boys outperformed girls on the Stroop Dot and Color Test following acute aerobic exercise, in the Stroop Dot, Word, and Color Test following acute resistance exercise, and in the Stroop Color Test and Trail-Making Test Part B following nonexercise. Conclusions: Both acute resistance and aerobic exercise increased measures of cognition over a nonexercise control in untrained high school youth. These findings suggest the merits of acute resistance exercise as an alternative or complement to aerobic activity for educators aiming to increase youth physical activity and cognitive function concurrently.