title: Modeling of Longitudinal Changes in Left Ventricular Dimensions among Female Adolescent Runners.
abstract: OBJECTIVE
  Left ventricular (LV) enlargement has been linked to sudden cardiac death among young athletes. This study aimed to model the effect of long-term incessant endurance training on LV dimensions in female adolescent runners.
  
  
  METHODS
  Japanese female adolescent competitive distance runners (n = 36, age: 15 years, height: 158.1 ± 4.6 cm, weight: 44.7 ± 6.1 kg, percent body fat: 17.0 ± 5.2%) underwent echocardiography and underwater weighing every 6 months for 3 years. Since the measurement occasions varied across subjects, multilevel analysis was used for curvilinear modeling of changes in running performance (velocities in 1500 m and 3000 m track race), maximal oxygen uptake (VO2max), body composition, and LV dimensions.
  
  
  RESULTS
  Initially, LV end-diastolic dimension (LVEDd) and LV mass were 47.0 ± 3.0 mm and 122.6 ± 15.7 g, respectively. Running performance and VO2max improved along with the training duration. The trends of changes in fat-free mass (FFM) and LVEDd were similarly best described by quadratic polynomials. LVEDd did not change over time in the model including FFM as a covariate. Increases in LV wall thicknesses were minimal and independent of FFM. LV mass increased according to a quadratic polynomial trend even after adjusting for FFM.
  
  
  CONCLUSIONS
  FFM was an important factor determining changes in LVEDd and LV mass. Although running performance and VO2max were improved by continued endurance training, further LV cavity enlargement hardly occurred beyond FFM gain in these adolescent female runners, who already demonstrated a large LVEDd.
authors.affiliation: Faculty of Sports and Health Studies, Hosei University, Machida, Tokyo, Japan.
authors.forename: Norimitsu
authors.initials: N
authors.lastname: Kinoshita
authors.affiliation: Sports Medicine Research Center, Keio University, Yokohama, Kanagawa, Japan.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Katsukawa
authors.affiliation: Sports Medicine Research Center, Keio University, Yokohama, Kanagawa, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Yamazaki
mesh_terms: D000293:Adolescent; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging*; D006801:Humans; D007564:Japan; D008953:Models, Anatomic; D009929:Organ Size; D011446:Prospective Studies; D014142:Track and Field / Q000502:physiology*; D014463:Ultrasonography; D016277:Ventricular Function, Left