Kinoshita Norimitsu, Katsukawa Fuminori, Yamazaki Hajime
Faculty of Sports and Health Studies, Hosei University, Machida, Tokyo, Japan.
Sports Medicine Research Center, Keio University, Yokohama, Kanagawa, Japan.
PLoS One. 2015 Oct 15;10(10):e0140573. doi: 10.1371/journal.pone.0140573. eCollection 2015.
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.
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.
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.
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.
左心室（LV）扩大与年轻运动员的心源性猝死有关。本研究旨在模拟长期持续耐力训练对女性青少年跑步运动员左心室尺寸的影响。
36名日本女性青少年竞技长跑运动员（年龄：15岁，身高：158.1±4.6厘米，体重：44.7±6.1千克，体脂百分比：17.0±5.2%）在3年时间里每6个月接受一次超声心动图检查和水下称重。由于测量时间因受试者而异，因此采用多水平分析对跑步成绩（1500米和3000米田径比赛速度）、最大摄氧量（VO2max）、身体成分和左心室尺寸的变化进行曲线建模。
最初，左心室舒张末期内径（LVEDd）和左心室质量分别为47.0±3.0毫米和122.6±15.7克。跑步成绩和VO2max随着训练时间的延长而提高。无脂肪质量（FFM）和LVEDd的变化趋势同样最好用二次多项式来描述。在将FFM作为协变量的模型中，LVEDd并未随时间变化。左心室壁厚度的增加极小且与FFM无关。即使在调整FFM后，左心室质量仍按照二次多项式趋势增加。
FFM是决定LVEDd和左心室质量变化的重要因素。尽管持续的耐力训练提高了跑步成绩和VO2max，但在这些已经表现出较大LVEDd的青少年女性跑步运动员中，除了FFM增加外，左心室腔进一步扩大的情况几乎没有发生。
