Kimberly A. Clevenger

Energy Cost of Children's Structured and Unstructured Games.

BACKGROUND Limited data are available on energy cost of common childrens games using measured oxygen consumption. METHODS Children (10.6 ± 2.9 years; N = 37; 26 male, 9 female) performed a selection of structured (bowling, juggling, obstacle course, relays, active kickball) and unstructured (basketball, catch, tennis, clothespin tag, soccer) activities for 5 to 30 minutes. Resting metabolic rate (RMR) was calculated using Schofields age- and sex-specific equation. Children wore a portable metabolic unit, which measured expired gases to obtain oxygen consumption (VO2), youth METs (relative VO2/childs calculated RMR), and activity energy expenditure (kcal/kg/min). Descriptive statistics were used to summarize data. RESULTS Relative VO2 ranged from 16.8 ± 4.6 ml/kg/min (bowling) to 32.2 ± 6.8 ml/kg/min (obstacle course). Obstacle course, relays, active kickball, soccer, and clothespin tag elicited vigorous intensity (>6 METs), the remainder elicited moderate intensity (3-6 METs). CONCLUSIONS This article contributes energy expenditure data for the update and expansion of the youth compendium.

Using Video Direct Observation to Assess Children’s Physical Activity During Recess

PURPOSE Traditional direct observation cannot provide continuous, individual-level physical activity (PA) data throughout recess. This study piloted video direct observation to characterize childrens recess PA overall and by sex and weight status. METHODS Children (N = 23; 11 boys; 6 overweight; third to fifth grade) were recorded during 2 recess periods, coding for PA duration, intensity, location, and type. Duration of PA type and intensity across sex and weight status overall and between/within locations were assessed using 1- and 2-way analysis of variances. RESULTS The field elicited more sedentary behavior (39% of time) and light PA (17%) and less moderate to vigorous PA (41%) compared with the fixed equipment (13%, 7%, and 71%, respectively) or the court (21%, 7%, and 68%, respectively). Boys engaged in significantly more vigorous-intensity activity on the court (35%) than girls (14%), whereas girls engaged in more moderate to vigorous PA on the fixed equipment (77% vs 61%) and field (46% vs 35%) than boys (all Ps > .05). PA type also differed by sex and weight status. CONCLUSION Video direct observation was capable of detecting and characterizing childrens entire recess PA while providing valuable context to the behavior. The authors confirmed previous findings that PA intensity was not uniform by schoolyard location and further differences exist by sex and weight status.

Accelerometer responsiveness to change between structured and unstructured physical activity in children and adolescents

ABSTRACT This study examined if accelerometer-based assessments of physical activity were responsive to changes in physical activity level commensurate with performing structured versus unstructured activity in youth. Youth (6–16 years; N = 206) participated in a simulated after-school program that included structured and unstructured games on four occasions over a 3-year period. Recruitment occurred in 2007/2008 and data collection ended in 2011. Participants wore an Actigraph GT1M accelerometer on the hip. The Evenson cut-points were used to determine the time spent in each physical activity intensity, and standardized response means (SRM) were calculated and converted to standard effect sizes to be interpreted according to Cohen’s guidelines. SRMs ranged from trivial (0.16) to high (2.07), with the majority (75%) being classified as moderate or high. Our findings suggest that accelerometry was sensitive to differences in physical activity associated with structured compared to unstructured play, supporting the utility of accelerometry in evaluating activity-promoting interventions.

A School- and Home-Based Intervention to Improve Adolescents’ Physical Activity and Healthy Eating: A Pilot Study

This study evaluated feasibility, acceptability, and preliminary efficacy of a 12-week Guys/Girls Opt for Activities for Life (GOAL) intervention on 10- to 13-year-old adolescents’ body mass index (BMI), percent body fat, physical activity (PA), diet quality, and psychosocial perceptions related to PA and healthy eating. Parent–adolescent dyads from two schools were enrolled. Schools were assigned to either GOAL (38 dyads) or control (43 dyads) condition. The intervention included an after-school club for adolescents 2 days/week, parent–adolescent dyad meeting, and parent Facebook group. Intervention adolescents had greater autonomous motivation for PA and self-efficacy for healthy eating than control adolescents (both p < .05). Although between-group differences were not significant, close-to-moderate effect sizes resulted for accelerometer-measured moderate-to-vigorous PA and diet quality measured via 24-hr dietary recall (d = .46 and .44, respectively). A trivial effect size occurred for percent body fat (d = −.10). No differences emerged for BMI. Efficacy testing with a larger sample may be warranted.

Comparison of Accelerometer-Based Cut-Points for Children’s Physical Activity: Counts vs. Steps

Background: Accelerometers measure complex movements of children’s free play moderate-vigorous physical activity (MVPA), including step and non-step movements. Current accelerometer technology has introduced algorithms to measure steps, along with counts. Precise interpretation of accelerometer-based cadence (steps/min) cut-points is necessary for accurately measuring and tracking children’s MVPA. The purpose of this study was to assess the relationships and agreement between accelerometer-based cut-points (cadence and counts/min) to estimate children’s MVPA compared to measured values. Methods: Forty children (8–12 years; 25 boys) played 6–10 games while wearing a portable metabolic analyzer and GT3X+ to measure and estimate MVPA, respectively. Correlation, kappa, sensitivity, and specificity assessed the relationships and agreement between measured and estimated MVPA. Results: Games elicited, on average, 6.3 ± 1.6 METs, 64.5 ± 24.7 steps/min, and 3318 ± 1262 vertical (V) and 5350 ± 1547 vector-magnitude (VM) counts/min. The relationship between measured and estimated MVPA intensity was higher for cadence (r = 0.50) than V and VM counts/min (r = 0.38 for both). Agreement using V and VM counts/min for measuring PA intensity varied by cut-points (range: 6.8% (κ = −0.02) to 97.6% (κ = 0.49)), while agreement was low using cadence cut-points (range: 4.0% (κ = 0.0009) to 11.3% (κ = 0.001)). Conclusion: While measured and estimated values were well correlated, using cadence tended to misclassify children’s free-play MVPA.