All Publications

  • Syphting Through the Evidence: A Very Distinctive Cause of Neonatal Jaundice. Digestive diseases and sciences Ruiz, R. M., Bass, D. M. 2019

    View details for PubMedID 31041638

  • Novel patterns of physical activity in a large sample of preschool-aged children BMC PUBLIC HEALTH Ruiz, R. M., Sommer, E. C., Tracy, D., Banda, J. A., Economos, C. D., Jaka, M. M., Evenson, K. R., Buchowski, M. S., Barkin, S. L. 2018; 18: 242


    Moderate-to-vigorous physical activity (MVPA), shown to be associated with health benefits, is not well-characterized in preschool-aged children. MVPA is commonly described as a threshold amount to achieve. We examined a novel way to characterize MVPA patterns in preschool-aged children by gender and age.Preschool-aged children from Nashville, TN and Minneapolis, MN wore triaxial accelerometers. Four distinct MVPA patterns were identified: isolated spurt (IS), isolated sustained activity (ISA), clustered spurt (CS), and clustered sustained activity (CSA). Multivariable linear regression models were used to test associations of gender and age with each pattern.One thousand one hundred thirty-one children (3.9 years old, 51% girls, 30% overweight, 11% obese, and 76% Hispanic) wore accelerometers for 12.9 (SD = 1.4) hours/day for 6.7 (SD = 0.7) days. Children spent 53% of wear time in sedentary behavior and 13% in MVPA. On average, boys and girls achieved > 90 min/day of MVPA (98.2 min, SD = 32.3). Most MVPA (80%) was obtained in spurt-like (IS and CS) MVPA; however, girls spent a higher proportion of MVPA in IS and CS, and lower proportion of time in CSA (all p < 0.001). Controlling for gender, an increase of 1-year in age corresponded to a 1.5% increase in CSA (p < 0.05).How MVPA was obtained varied depending on the gender and age of the child. On average, boys spent more time in sustained MVPA than girls and MVPA was more sustained in older children. Utilizing these patterns could inform PA practice and policy guidelines.NCT01316653 , date of registration: March 3, 2011; NCT01606891, date of registration: May 23, 2012.

    View details for PubMedID 29439704

  • A Novel Approach to Characterize Physical Activity Patterns in Preschool-Aged Children OBESITY Ruiz, R. M., Tracy, D., Sommer, E. C., Barkin, S. L. 2013; 21 (11): 2197–2203


    Routine moderate-to-vigorous physical activity (MVPA) is associated with better health outcomes; the purpose of this work was to evaluate healthy preschooler physical activity patterns with objective measurement.An objective prospective study of 50 normally developing children 3-5 years old who were ≥50th and <95th BMI percentile and enrolled in a family-based healthy lifestyle study in 2011-2012. Participants wore a tri-axial accelerometer for 7 continuous days. Outcome measures consisted of wear time examining four common MVPA patterns: isolated spurt (IS), isolated sustained activity (ISA), clustered spurt (CS), and clustered sustained activity (CSA).Participants were 4.3 years, 56% female, 52% African-American, and 26% overweight. Forty-five children met wear time criteria. On average, children spent 14.5% of wake-wear time in MVPA, requiring 11.3 h to complete 90% of their daily MVPA. Children spent the majority of MVPA in CS (62.1%, followed by CSA (20.1%). Remaining MVPA was spent in IS (15.5%) and ISA (2.3%).It takes most of the waking day for preschoolers to attain their PA. They engage in short spurts of small duration, in four common MVPA patterns. Utilizing this method could better characterize preschooler physical activity needs in practice and policy guidelines.

    View details for DOI 10.1002/oby.20560

    View details for Web of Science ID 000326637400006

    View details for PubMedID 24136917

    View details for PubMedCentralID PMC3947437

  • The Relationship Between Hispanic Parents and Their Preschool-Aged Children's Physical Activity PEDIATRICS Ruiz, R., Gesell, S. B., Buchowski, M. S., Lambert, W., Barkin, S. L. 2011; 127 (5): 888–95


    The goal of this study was to examine activity pattern associations between Hispanic parents and their preschool-aged children.We examined baseline data collected as part of a randomized controlled trial. Self-defined Hispanic parents with children aged 3 to 5 years were randomly assigned to either a weekly healthy lifestyle group (intervention) or a monthly school-readiness group (control) for 3 months. There were no weight eligibility criteria. All participants were instructed to wear an accelerometer for up to 7 consecutive days to measure physical activity.Of the 106 dyads enrolled in the study, 80 children and 85 parents provided useable actigraphy data. Mean percentage of time spent in sedentary behaviors was 82.0% (SD: 10.4) for parents and 69.8% (SD: 18.5) for preschool-aged children. Percentage of awake time per day spent in sedentary behavior was strongly correlated for parents and children (r = 0.597; P < .001). Correlations between activity level were large (r = 0.895 and 0.739 for low and moderate activity levels, respectively), except for vigorous activity level, for which the parent-child correlation was nonsignificant (P = .64) because of a near-0 level of vigorous parental activity. Child's age (P = .81) and gender (P = .43) were nonsignificant predictors of child activity levels.These results suggest that parental activity levels are a powerful explanation of preschool-aged child activity levels, except for vigorous activity, which children do on their own without parental participation. Hispanic parents play a critical role in setting physical activity patterns in their children.

    View details for DOI 10.1542/peds.2010-1712

    View details for Web of Science ID 000290097800049

    View details for PubMedID 21482607

    View details for PubMedCentralID PMC3387864