The purpose of this study was to investigate the effects of high‐volume endurance training on the development of maximal oxygen uptake (VO2max) in physically active boys and girls between the ages of 12 and 15 years, using a longitudinal design. The children participated in organized training in sports clubs for an average of 7‐10 hours per week, with one group undertaking a high volume of endurance training (~7 hours per week; End boys, n = 23 and End girls, n = 17) and the other group having a primary focus on technical and tactical skill development, undertaking low volumes of endurance training (~1.6 hours per week; non‐End boys, n = 29 and non‐End girls, n = 9). VO2max and anthropometrics were assessed at age 12, 13, and 15. At age 12, VO2max was 58.9 (5.6), 65.5 (7.2), 56.5 (6.5), and 58.8 (7.9) mL·kg−1·min−1 in End girls, End boys, non‐End girls, and non‐End boys, respectively. Over the three years, there was no difference between the training groups in the development of VO2max independent of scaling. In boys, VO2max relative to body mass (BM) did not change from age 12 to 15, while VO2max tended to decrease relative to fat‐free mass (FFM). In girls, VO2max relative to BM decreased slightly from age 12 to 15, with no changes over the years relative to FFM. The present longitudinal study suggests that in growing active children during puberty, high volumes of systematic endurance training do not have an additional effect on VO2max compared with similar volume of training mainly aiming at developing motor skills.
BackgroundAthlete’s heart is a condition of exercise-induced cardiac remodelling. Adult male endurance athletes more often remodel beyond reference values. The impact of sex on remodelling through adolescence remains unclear. Paediatric reference values do not account for patient sex or exercise history. We aimed to study the effect of sex on cardiac remodelling throughout adolescence.MethodsWe recruited 76 male (M) and female (F) 12-year-old cross-country skiers in a longitudinal cohort study. Echocardiography was performed and analysed according to guidelines at age 12 (48 M, 28 F), 15 (34 M, 14 F) and 18 (23 M, 11 F). Repeated echocardiographic measurements were analysed by linear mixed model regression.ResultsMales displayed greater indexed left ventricular end-diastolic volumes (LV EDVi) from age 12 (M 81±7 vs F 76±7, mL/m², p≤0.01), and progressed further until follow-up at age 18 (M 2.3±9.7 vs F −3.9±4.5 ΔmL/m², p≤0.01). LV EDVi remained above adult upper reference values in both groups. Males increased LV Mass Index from age 12 to 18 (M 33±27 vs F 4±19, Δg/m², p≤0.01). Males displayed LV mass above paediatric reference values at ages 15 and 18. A subset of males (35%) and females (25%) displayed wall thickness above paediatric reference values at age 12. Cardiac function was normal. There was no sex difference in exercise hours.ConclusionSex-related differences in athlete’s heart were evident from age 12, and progressed throughout adolescence. Remodelling beyond reference values was more frequent than previously reported, particularly affecting males. Age, sex and exercise history may assist clinicians in distinguishing exercise-induced remodelling from pathology in adolescents.
Background Cardiac remodelling beyond reference values is well-known in adult athlete's heart. Male endurance athletes are more prone to develop cardiac chambers and wall thickness above reference values. Cardiac remodelling is also described in adolescent athletes, but considered to be moderate compared to adults. However, few studies evaluate adolescent athlete's heart by paediatric echocardiographic reference values. Current paediatric reference values are sex-unspecific and do not include exercise data. The impact of sex and exercise on remodelling in adolescent athlete's heart remains unclear. Purpose We aimed to study the development of cardiac remodelling and potential sex differences in adolescent athletes. We hypothesized that male adolescent athletes would display greater degree of remodelling compared to female adolescent athletes. Methods Male (M) and female (F) adolescent cross-country skiers were recruited in a longitudinal cohort study. They were examined with echocardiography at age 12, 15 and 18. Data on exercise was collected at all examinations. We evaluated echocardiographic parameters by paediatric reference values (Z-score: number of standard deviations above estimated mean in the given body surface area). Echocardiographic measures were considered above upper reference value if Z-score was ≥2. Results Seventy-six athletes were examined at age 12 (48 M, 28 F), 48 at age 15 (34 M, 14 F) and 34 at age 18 (23 M, 11 F). Although Z-scores were within reference values at age 12 (Table 1), a subset of athletes displayed Z-scores ≥2 for end-diastolic intraventricular septum diameter (IVSd, M 13/48=27%, F 5/28=18%) and left ventricular posterior wall thickness (LVPWd, M 6/48=13%, F 2/28=14%). The male group demonstrated enlarged left ventricular mass (LVM) from age 15 (Figure 1). Males had greater left ventricular end-diastolic volume (LV EDV) from age 12. Additional sex differences were evident from age 15 for IVSd, LVPWd and LVM (Table 1). There was no sex difference in exercise hours. Both groups had normal myocardial function through the study period. Conclusion Cardiac remodelling beyond reference values was observed in athletes of both sexes from early adolescent age. Sex differences were evident from age 12 with further progression. Pathological values for LVM were more frequent in males. These findings suggest that sex differences in exercise-induced cardiac remodelling is more prominent in adolescents than previously reported. Sex and exercise history should be considered in questions of pathology. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): The South-Eastern Norway Regional Health AuthorityCentre for Children and Youth Sport, Norwegian School of Sport Sciences
Funding Acknowledgements Type of funding sources: Public Institution(s). Main funding source(s): MF: The South-Eastern Norway Regional Health Authority [grant number 2017207]. KHH, MKS: Norwegian Research Council [grant number 309762 ProCardio]. Background Distinguishing athlete´s heart from hypertrophic cardiomyopathy (HCM) can be challenging. There is a lack of data describing physiological and pathological remodelling in adolescents. Purpose The purpose of this study was to compare development of left ventricular (LV) hypertrophy in adolescent athletes to HCM genotype positive adolescents. Methods Athletes and age- and sex-matched HCM genotype positive adolescents underwent echocardiography at baseline and at follow-up, minimum two years later. Echocardiographic parameters were evaluated by pediatric reference values (Z-scores). LV hypertrophy was defined as Z-score >2 for intraventricular septum diameter (IVSd) or posterior wall thickness (LVPWd). Results Seventy-six athletes were compared to 63 (1 proband, 62 family members) HCM genotype positive adolescents (37% vs 44% female, p = 0.36, mean age baseline 12.1±0.2 vs 12.4±1.4 years, p = 0.10). Mean follow-up-time was alike by protocol (3.1±0.2 vs 3.2±1.3 years, p = 0.59). LV hypertrophy was found in a similar proportion of athletes and HCM genotype positive adolescents (28% vs 30% at baseline, p = 0.75, 30% vs 32% at follow-up, p = 0.80). Compared with athletes, interventricular septum was thicker in HCM genotype positive adolescents at baseline (Z IVSd 1.4±0.9 vs 2.7±5.2, p = 0.03). Left ventricular volumes were greater in athletes (Z LVEDV 1.0±0.6 vs −0.1±0.9, p<0.001). Septum thickness increased only in HCM genotype positive adolescents (Z IVSd progression rate −0.17(SE0.05), p = 0.001 vs 0.54(SE0.16), p = 0.001, p for interaction <0.001). There was no difference in LVPWd (0.6±1.3 vs 0.8±0.8, p = 0.13). Conclusions LV hypertrophy was observed in nearly 1/3 of both athletes and HCM genotype positive adolescents in the first longitudinal study comparing these populations. We found a significant difference in progression of LV hypertrophy, with increasing septum thickness only in the HCM genotype positive adolescents. These findings highlight the importance of repeated examinations to distinguish physiological from pathological remodelling.
A navegação consulta e descarregamento dos títulos inseridos nas Bibliotecas Digitais UC Digitalis, UC Pombalina e UC Impactum, pressupõem a aceitação plena e sem reservas dos Termos e Condições de Uso destas Bibliotecas Digitais, disponíveis em https://digitalis.uc.pt/pt-pt/termos.Conforme exposto nos referidos Termos e Condições de Uso, o descarregamento de títulos de acesso restrito requer uma licença válida de autorização devendo o utilizador aceder ao(s) documento(s) a partir de um endereço de IP da instituição detentora da supramencionada licença.Ao utilizador é apenas permitido o descarregamento para uso pessoal, pelo que o emprego do(s) título(s) descarregado(s) para outro fim, designadamente comercial, carece de autorização do respetivo autor ou editor da obra. Na medida em que todas as obras da UC Digitalis se encontram protegidas pelo Código do Direito de Autor e Direitos Conexos e demais legislação aplicável, toda a cópia, parcial ou total, deste documento, nos casos em que é legalmente admitida, deverá conter ou fazer-se acompanhar por este aviso.Hemoglobin mass (Hb-mass), blood volume (BV) and maximum oxygen uptake (VO2max) in 12 years old endurance athletes Autor(es):Landgraff, Hege WilsonPublicado por: Imprensa da Universidade de Coimbra
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