Effect of long-term soccer training on changes in cardiac function during exercise in elite youth soccer players.

Abstract

It is unclear what the effect of long-term, high-volume soccer training has on left ventricular (LV) function during exercise in youth soccer players. This study evaluated changes in LV function during submaximal exercise in a group of highly trained male soccer players (SP) as they transitioned over a three-year period from pre-adolescent to adolescent athletes. Data were compared to age- and sex-matched recreationally active controls (CON) over the same time period. Twenty-two SP from two professional English Premier League youth soccer academies (age: 12.0±0.3years at start of the study) and 15 CON (age: 11.7±0.3years) were recruited. Two-dimensional echocardiography was used to quantify LV function during exercise at the same submaximal metabolic load (approx. 45%VO2peak ) across the 3years. After controlling for growth and maturation, there were training-induced changes and superiority (p<0.001) in cardiac index (QIndex) from year 1 in the SP compared to CON. SP (year 1: 6.13±0.76; year 2: 6.94±1.31; and year 3: 7.20±1.81 L/min/m2 ) compared to CON (year 1: 5.15±1.12; year 2: 4.67±1.04; and year 3: 5.49±1.06 L/min/m2 ). Similar training-induced increases were noted for mitral inflow velocity (E): SP (year 1: 129±12; year 2: 143±16; and year 3: 135±18cm/s) compared to CON (year 1: 113±10; year 2: 111±12; and year 3: 121±9cm/s). This study indicated that there was evidence of yearly, training-induced increases in left ventricular function during submaximal exercise independent from the influence of growth and maturation in elite youth SP.