title: Indirect and direct relations between aerobic fitness, physical activity, and academic achievement in elementary school students.
abstract: BACKGROUND
  There is evidence to suggest that increasing physical activity (PA) improves academic achievement (AA) in children and that aerobic fitness is associated with both cognitive function and AA. However, it is not known how these variables are interrelated and analyses with adequate control for socioeconomic variables are needed. It was hypothesized that PA would not directly affect AA but would have an indirect effect on AA through its effect on aerobic fitness. The purpose of this study was to test this hypothesized mediation using path analysis.
  
  
  METHODS
  Cross-sectional data including AA, aerobic fitness, and daily PA assessed through accelerometry were collected from a large sample (N= 687) of 2ndand 3rdgrade students. Demographic data were assessed via parent self-report.
  
  
  RESULTS
  A total of 401 students wore the accelerometer for at least 10 hours on 3 days or more and were included in the final path analysis to evaluate potential relations among PA (predictor), aerobic fitness (mediator), and WIAT-III subtest standard scores (outcomes; i.e., reading, spelling, and mathematics). Findings showed a direct effect of PA on aerobic fitness (b= 0.009,p< 0.001) and an indirect effect (mediation) of PA via fitness on math achievement (b= 0.003,p< 0.01) after controlling for student's grade, gender, body mass index, mother's education level, and household income, as well as intraclass correlations among classes and schools. Neither PA nor aerobic fitness were correlated with WIAT-III reading or spelling scores.
  
  
  CONCLUSIONS
  Mediation analysis indicated that PA exerted an influence on math achievement through its effects on aerobic fitness but was not associated with reading or spelling achievement scores.
authors.affiliation: Internal Medicine, Cardiovascular Research Institute, Center for Physical Activity and Weight Management, The University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, Kansas, 66160, USA. Katel@ku.edu.
authors.forename: K
authors.initials: K
authors.lastname: Lambourne
authors.affiliation: Department of Psychology and Research in Education, The University of Kansas, 1122 West Campus Road, Lawrence, KS, 66045 USA. dhansen1@ku.edu.
authors.forename: D M
authors.initials: DM
authors.lastname: Hansen
authors.affiliation: Internal Medicine, Cardiovascular Research Institute, Center for Physical Activity and Weight Management, The University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, Kansas, 66160, USA. aszabo@ku.edu.
authors.forename: A N
authors.initials: AN
authors.lastname: Szabo
authors.affiliation: Center for Research Methods and Data Analysis, The University of Kansas, 1425 Jayhawk Boulevard, Watson RM 470, Lawrence, KS 66045 USA. jaehoon@ku.edu.
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.affiliation: Internal Medicine, Cardiovascular Research Institute, Center for Physical Activity and Weight Management, The University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, Kansas, 66160, USA. sherrmann@ku.edu.
authors.forename: S D
authors.initials: SD
authors.lastname: Herrmann
authors.affiliation: Internal Medicine, Cardiovascular Research Institute, Center for Physical Activity and Weight Management, The University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, Kansas, 66160, USA. jdonnelly@ku.edu.
authors.forename: J E
authors.initials: JE
authors.lastname: Donnelly
keywords: Path analysis; Progressive Aerobic Cardiovascular Endurance Run; Weschler Individual Achievement Test-III; mediation