Rowland Thomas W, Garrard Max, Marwood Simon, Guerra Miriam E, Roche Denise, Unnithan Viswanath B
Department of Pediatrics, Baystate Medical Center, Springfield, MA, USA.
Med Sci Sports Exerc. 2009 Sep;41(9):1721-8. doi: 10.1249/MSS.0b013e3181a06cb5.
The extent that enhanced ventricular function contributes to superior aerobic fitness of trained athletes is unclear. This study compared cardiovascular responses to progressive cycle exercise in 12 adolescent soccer players and 10 untrained boys with assessment of ventricular inotropic and relaxation properties by Doppler ultrasound techniques.
Resting cardiac dimensions were measured by M-mode echocardiography. Stroke volume was estimated by the Doppler technique, and systolic function by peak aortic flow velocity and ejection flow rate. Diastolic transmitral pressure gradient was assessed by pulse wave peak E-wave velocity, ventricular relaxation properties by tissue Doppler imaging (E' velocity, adjusted for ventricular size), and ventricular filling pressure by E/E' ratio.
Size-adjusted cardiac dimensions were significantly greater in the athletes. Peak V O2 values for the athletes and nonathletes were 57.4 +/- 4.8 and 44.4 +/- 6.6 mL.kg.min, respectively. Maximal cardiac index and stroke index were greater in the athletes (11.10+/- 1.52 vs 9.02 +/- 2.05 L.min.m; 59 +/- 8 vs 46 +/- 10 mL.m). Athletes and nonathletes demonstrated similar maximal peak aortic velocity (231 +/- 20 and 208 +/- 45 cm.s, respectively) and ejection rate (13.3 +/- 1.0 and 12.5 +/- 2.8 mL.s.cm x 10, respectively). No significant group differences were observed in Emax (155 +/- 17 and 149 +/- 23 cm.s for athletes and nonathletes, respectively), adjusted E'max (5.9 +/- 1.2 and 5.8 +/- 1.2 cm.s.mm for athletes and nonathletes, respectively), and E/E'max (265 +/- 40 and 262 +/- 56 for athletes and nonathletes, respectively).
This study revealed no differences between young trained athletes and nonathletes in myocardial functional responses to progressive exercise, implying that greater aerobic fitness in these athletes reflected volume expansion of the cardiovascular system without contribution of enhanced systolic or diastolic ventricular function. Such findings should be considered limited to the context of young athletes with limited duration of athletic training.
增强的心室功能对训练有素的运动员卓越的有氧适能的贡献程度尚不清楚。本研究比较了12名青少年足球运动员和10名未经训练的男孩在进行渐进性自行车运动时的心血管反应，并通过多普勒超声技术评估心室的变力性和舒张特性。
通过M型超声心动图测量静息时的心脏大小。用多普勒技术估计每搏输出量，用主动脉峰值流速和射血流速评估收缩功能。通过脉冲波E峰峰值速度评估舒张期二尖瓣压力梯度，通过组织多普勒成像（E'速度，根据心室大小进行调整）评估心室舒张特性，通过E/E'比值评估心室充盈压。
经大小调整后的心脏大小在运动员中显著更大。运动员和非运动员的峰值摄氧量分别为57.4±4.8和44.4±6.6 mL.kg.min。运动员的最大心脏指数和每搏指数更大（分别为11.10±1.52与9.02±2.05 L.min.m²；59±8与46±10 mL.m²）。运动员和非运动员的最大主动脉峰值流速（分别为231±20和208±45 cm/s）和射血速率（分别为13.3±1.0和12.5±2.8 mL.s.cm⁻²×10）相似。在Emax（运动员和非运动员分别为155±17和149±23 cm/s）、调整后的E'max（运动员和非运动员分别为5.9±1.2和5.8±1.2 cm.s.mm⁻¹）以及E/E'max（运动员和非运动员分别为265±40和262±56）方面未观察到显著的组间差异。
本研究显示，年轻的训练有素的运动员和非运动员在对渐进性运动的心肌功能反应方面没有差异，这意味着这些运动员更高的有氧适能反映了心血管系统的容量扩张，而不是心室收缩或舒张功能增强的贡献。这些发现应仅限于运动训练时间有限的年轻运动员的情况。
