Athlete's heart in prepubertal male swimmers

Abstract

To determine the cardiac response to intensive endurance training during prepuberty, we studied 22 male prebubertal swimmers who had been trained for at least 3 years, with a mean of 3.91 years and a standard deviation of 1.10 years, and 8 hours per week, the mean being 10.0 hours and the standard deviation 1.7 hours. The control group consisted of 21 boys of similar age, height and weight (p is more than 0.05 for all), who were not participating regularly in sporting activities. Left ventricular dimensions and systolic function were examined with M-Mode; velocities and durations of transmitral flow were measured with pulsed wave Doppler; and tissue Doppler velocities and durations were measured with pulsed wave tissue Doppler echocardiography. We determined the regional velocities of the lateral mitral annulus in four-chamber position, the left ventricular posterolateral wall, and the midseptum in long-axis position. Interventricular septal thickness, left ventricular posterior wall thickness, left ventricular mass and relative wall thickness were increased in swimmers (p is less than 0.05). All the tissue Doppler measurements were similar in both groups, except the septal isovolumic relaxation time. We observed that the left ventricular wall thickness had increased concentrically in prepubertal swimmers compared to controls, without a significant change in the left ventricular diastolic diameter. This finding is contrary to the previous studies on adult swimmers. Whether the structural changes observed in our study reflect the unique cardiac adaptation of the hearts of children to exercise will only be disclosed by longitudinal studies of prepubertal athletes.

Two months of endurance training does not alter diastolic function evaluated by TDI in 9–11-year-old boys and girls

“…Indeed, Nottin et al 6 established higher wall motion at the LV inferior, posterior and septal walls in 12–13-year old child cyclists who had been training 5–9 h per week for at least 5 years than in untrained counterparts. However, Ayabakan et al 15 did not report differences in tissue Doppler measurements at the LV lateral, posterior and septal walls between prepubertal boy swimmers who had been training 8 h per week for at least 3 years and age and sex-matched inactive controls. Maturation could be involved to explain this apparent blunted response to training.…”

“…Although this is controversial, TDI has been suggested to be less load-dependent than Doppler flow measures 13 14. To our knowledge, only two studies6 15 have examined TDI indexes in trained children. When compared with age-matched inactive children, highly trained cyclists demonstrated higher early wall motion velocities,6 whereas similar values were obtained in well-trained swimmers 15.…”

“…To our knowledge, only two studies6 15 have examined TDI indexes in trained children. When compared with age-matched inactive children, highly trained cyclists demonstrated higher early wall motion velocities,6 whereas similar values were obtained in well-trained swimmers 15. Whether conventional exercise training is able to improve myocardial function and especially regional diastolic function in healthy children remains currently unknown.…”

Influence of training status and exercise modality on pulmonary O2 uptake kinetics in pubertal girls

“…A higher peak _ VO 2 in trained children is largely attributable to an enhanced peak cardiac output consequent solely to an enhanced stroke volume as peak heart rates do not differ. The mechanistic basis of the higher peak stroke volume in trained children remains equivocal, with evidence to suggest both morphological (Ayabakan et al 2006;Nottin et al 2004;Obert et al 2009;Rowland et al 2009) and/or functional (Rowland et al 1998) differences according to training status. In the current study, the trained swimmers' peak _ VO 2 was 21 and 28% higher than the untrained girls during cycle and upper body ergometry, respectively.…”

Morfologia do ventrículo esquerdo em adolescentes: comparação entre atletas e não atletas

“…Paralelamente, alguns estudos têm focado sobre a avaliação das diferenças entre atletas e não atletas, relativamente à função e estrutura do coração 3,7,8 . Embora existam investigações sobre a morfologia e função do VE e demais parâmetros cardíacos em atletas adolescentes 2,4,5,9,10 , a variação inter-individual associada ao tamanho corporal não tem sido controlada. Considerando que as dimensões da estrutura cardíaca em crianças e jovens são diretamente proporcionais à estatura 11 , a comparação entre atletas e não atletas não deve desprezar o controle desta variável.…”