Publications by authors named "Lauren von Klinggraeff"

3 Publications

  • Page 1 of 1

Impact of a year-round school calendar on children's BMI and fitness: Final outcomes from a natural experiment.

Pediatr Obes 2021 Mar 25:e12789. Epub 2021 Mar 25.

Department of Exercise Science, University of South Carolina, Columbia, South Carolina, USA.

Background: Structure may mitigate children's accelerated summer BMI gain and cardiorespiratory-fitness (CRF) loss.

Objectives: Examine BMI and CRF change during school and summer for year-round and traditional calendar school children.

Methods: Three schools (N = 2279, 1 year-round) participated in this natural experiment. Children's BMI z-score (zBMI) and CRF (PACER laps) were measured from 2017 to 2019 each May/August. Mixed effects regression estimated monthly zBMI and CRF change during school/summer. Secondary analyses examined differences by weight status and race. Spline regression models estimated zBMI and CRF growth from kindergarten-sixth grade.

Results: Compared to traditional school, children attending a year-round school gained more zBMI (difference = 0.015; 95CI = 0.002, 0.028) during school, and less zBMI (difference = -0.029; 95CI = -0.041, -0.018), and more CRF (difference = 0.834; 95CI = 0.575, 1.093) monthly during summer. Differences by weight status and race were observed during summer and school. Growth models demonstrated that the magnitude of overall zBMI and CRF change from kindergarten-sixth grade was similar for year-round or traditional school children.

Conclusions: Contrary to traditional school children zBMI increased during the traditional 9-month school calendar and zBMI decreased during the traditional summer vacation for year-round school children. Structured summer programming may mitigate accelerated summer BMI gain and CRF loss especially for overweight or obese, and/or Black children.
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March 2021

Comparison of multichannel and single-channel wrist-based devices with polysomnography to measure sleep in children and adolescents.

J Clin Sleep Med 2021 Apr;17(4):645-652

Department of Exercise Science, University of South Carolina, Columbia, South Carolina.

Study Objectives: To compare sleep parameters produced by the Fitbit Charge 3 (Fitbit) and Actigraph GT9X accelerometer (Actigraph) to polysomnography in children and adolescents.

Methods: Participants (n = 56, ages 9.2 ± 3.3 years) wore a Fitbit and an Actigraph on their nondominant wrist concurrently with polysomnography during an overnight observation at a children's sleep laboratory. Total sleep time, sleep efficiency, wake after sleep onset, sleep onset, and sleep offset were extracted from the Fitabase and Actilife software packages, respectively, with the Sadeh algorithm. Bland-Altman plots were used to assess the agreement between wearable devices and polysomnography.

Results: Seventy-nine percent of participants were diagnosed with OSA. Compared with polysomnography, the Fitbit and the Actigraph underestimated total sleep time by 6.1 minutes (absolute mean bias [AMB] = 27.7 minutes) and 31.5 minutes (AMB = 38.2 minutes), respectively. The Fitbit overestimated sleep efficiency by 3.0% (AMB = 6.3%), and the Actigraph underestimated sleep efficiency by 12.9% (AMB = 13.2%). The Fitbit overestimated wake after sleep onset by 18.8 minutes (AMB = 23.9 minutes), and the Actigraph overestimated wake after sleep onset by 56.1 minutes (AMB = 54.7 minutes). In addition, the Fitbit and the Actigraph underestimated sleep onset by 1.2 minutes (AMB = 13.9 minutes) and 10.2 minutes (AMB = 18.1 minutes), respectively. Finally, the Fitbit and the Actigraph overestimated sleep offset by 6.0 minutes (AMB = 12.0 minutes) and 10.5 minutes (AMB = 12.6 minutes). Linear regression indicated significant trends, with the Fitbit underestimating wake after sleep onset and sleep efficiency at higher values.

Conclusions: The Fitbit provided comparable and in some instances better sleep estimates with polysomnography compared to the Actigraph. Findings support the use of multichannel devices to measure sleep in children and adolescents. Additional studies are needed in healthy children over several nights and in free-living settings.
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April 2021

Effects of Sharing Data With Teachers on Student Physical Activity and Sedentary Behavior in the Classroom.

J Phys Act Health 2020 Apr 25:1-7. Epub 2020 Apr 25.

Background: Data-driven decision making is an accepted best practice in education, but teachers seldom reflect on data to drive their physical activity (PA) integration efforts. The purpose of this study was to explore the impact of a data-sharing intervention with classroom teachers on teacher-directed movement integration and students' PA and sedentary behavior.

Methods: Teacher-directed movement behaviors from 8 classroom teachers in 1 primary school were systematically observed during four 1-hour class periods before (pre) and after (post) an intervention in which teachers individually discussed student movement data with a trained interviewer. Teachers' K-2 students (N = 132) wore accelerometers for 10 school days both preintervention and postintervention.

Results: Multilevel mixed effects regression indicated a nonsignificant increase in teacher-directed movement from preintervention to postintervention (+7.42%, P = .48). Students' classroom time spent in moderate to vigorous PA increased (males: +2.41 min, P < .001; females: +0.84 min, P = .04) and sedentary time decreased (males: -9.90 min, P < .001; females: -7.98 min, P < .001) postintervention. Interview data inductively analyzed revealed teachers' perspectives, including their surprise at low student PA during the school day.

Conclusions: Findings suggest that sharing data with classroom teachers can improve student PA and decrease sedentary behavior at school.
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April 2020