Somatic Maturity and Physical Performance in Male Youth Players from a Professional Soccer Academy / Madurez Somática y Rendimiento Físico en Jugadores Juveniles Masculinos de una Academia de Fútbol Profesional

SUMMARY: The aim was to analyze the relationship between somatic maturation and physical performance in male youth soccer players belonging to a professional Mexican academy. In 121 male soccer aged 11 to 16 years from a professional academy the peak height velocity (PHV), percentage of adult height (PAS), jump capacity, sprint, intermittent speed and muscle mass were estimated. ANOVA was conducted to compare performance variables among maturity somatic categories and percentiles were calculated based on maturity offset using LMS method. Furthermore, a general linear model was employed to determine the explanatory variables for performance. Post-PHV soccer players demonstrated superior physical performance across several tests compared to Pre-PHV (p<0.001) and Circa-PHV (p<0.001) players. The smoothed percentile values of performance tests, based on somatic maturation, indicated progressive performance enhancement as individuals approached PHV (-2 to 2 years from PHV) (p<0.005). PHV was associated with jump capacity (p<0.001) and intermittent speed (p=0.007) while PAS was associated with time in sprint (p=.0004). In conclusion PHV and PAS explained better performance than chronological age, body composition characteristics, injuries, or training factors.

El objetivo fue analizar la relación entre la maduración somática y el rendimiento físico en futbolistas juveniles masculinos pertenecientes a una academia profesional mexicana. Métodos. En 121 futbolistas masculinos de 11 a 16 años de una academia profesional se estimó la velocidad máxima en altura (VPH), porcentaje de altura adulta (PAS), capacidad de salto, sprint, velocidad intermitente y masa muscular. Se realizó ANOVA para comparar variables de desempeño entre categorías somáticas de madurez y se calcularon percentiles en función de la compensación de madurez utilizando el método LMS. Además, se empleó un modelo lineal general para determinar las variables explicativas del desempeño. Los jugadores de fútbol post-PHV demostraron un rendimiento físico superior en varias pruebas en comparación con los jugadores Pre-PHV (p<0,001) y Circa-PHV (p<0,001). Los valores percentiles suavizados de las pruebas de rendimiento, basados en la maduración somática, indicaron una mejora progresiva del rendimiento a medida que los individuos se acercaban al PHV (-2 a 2 años desde el PHV) (p<0,005). PHV se asoció con la capacidad de salto (p<0,001) y velocidad intermitente (p=0,007) mientras que PAS se asoció con el tiempo en sprint (p=0,0004). En conclusión PHV y PEA explicaron un mejor rendimiento que la edad cronológica, las características de composición corporal, las lesiones o los factores de entrenamiento.

A comparison of modelled serum cTnT and cTnI kinetics after 60 min swimming.

Post-exercise elevations of cardiac troponin T (cTnT) and I (cTnI) are often used in isolation but interpreted interchangeably. Research suggests, however, that post-exercise cTn kinetic might differ with each isoform. In this cross-sectional observational study, we collected blood samples before, immediately after (5 minutes), and at 1-, 3-, 6-, 12-, and 24-hour post-exercise in a mixed cohort of 56 participants after a distance-trial of 60 min continuous swimming (age range from 14 to 22, 57.1% female). Cardiac troponin kinetics were modelled using Bayesian mixed-effects models to estimate time to peak (TTP) and peak concentration (PC) for each isoform, while controlling for participants sex, tanner stage and average relative heart rate during the test. Exercise induced an elevation of cTnT and cTnI in 93% and 75% of the participants, respectively. Cardiac troponin T peaked earlier, at 2.9 h (CI: 2.6 - 3.2 h) post-exercise, whereas cTnI peaked later, at 4.5 h (CI: 4.2 - 4.9 h). Peak concentrations for cTnT and cTnI were 2.5 ng/L, CI: 0 - 11.2 ng/L and 2.16 ng/L, CI: 0 - 22.7 ng/L, respectively. Additionally, we did not observe a systematic effect of sex and maturational status mediating cTn responses.

Exercise-Induced Release of Cardiac Troponins in Adolescent vs. Adult Swimmers.

To examine the exercise-induced release of cardiac troponin T (cTnT) in adolescent and adult swimmers. Thirty-two trained male (18 adolescents, 14 adults) swam at maximal pace in a 45 min distance trial, and blood samples were drawn before, immediately and 3 h after exercise for subsequent cTnT analysis and comparison. Having comparable training experience and baseline values of cTnT (p = 0.78 and p = 0.13), adults exercised at lower absolute and relative intensity (p < 0.001 and p < 0.001, respectively), but presented higher immediate cTnT after exercise than adolescents (p < 0.001). Despite that, peak concentrations were observed at 3 h post exercise and peak elevations were comparable between groups (p = 0.074). Fourteen (44%) apparently healthy subjects exceeded the cutoff value for myocardial infarction (MI). Adolescents presented a delayed elevation of cTnT compared with adults, but achieved similar peak values.

Cardiac Biomarker Release After Exercise in Healthy Children and Adolescents: A Systematic Review and Meta-Analysis.

PURPOSE: The authors evaluated the impact of acute exercise and 24-hour recovery on serum concentration of cardiac troponins T and I (cTnT and cTnI) and N-terminal fragment of the prohormone brain natriuretic peptide (NT-proBNP) in healthy children and adolescents. The authors also determined the proportion of participants exceeding the upper reference limits and acute myocardial infarction cutoff for each assay. METHOD: Web of Science, SPORTDiscus, MEDLINE, ScienceDirect, and Scopus databases were systematically searched up to November 2017. Studies were screened and quality-assessed; the data was systematically extracted and analyzed. RESULTS: From 751 studies initially identified, 14 met the inclusion criteria for data extraction. All 3 biomarkers were increased significantly after exercise. A decrease from postexercise to 24 hours was noted in cTnT and cTnI, although this decrease was only statistically significant for cTnT. The upper reference limit was exceeded by 76% of participants for cTnT, a 51% for cTnI, and a 13% for NT-proBNP. Furthermore, the cutoff value for acute myocardial infarction was exceeded by 39% for cTnT and a 11% for cTnI. Postexercise peak values of cTnT were associated with duration and intensity (Q(3) = 28.3, P < .001) while NT-proBNP peak values were associated with duration (Q(2) = 11.9, P = .003). CONCLUSION: Exercise results in the appearance of elevated levels of cTnT, cTnI, and NT-proBNP in children and adolescents. Postexercise elevations of cTnT and NT-proBNP are associated with exercise duration and intensity.

The impact of exercise intensity on the release of cardiac biomarkers in marathon runners.

We sought to determine the influence of exercise intensity on the release of cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in amateur marathon runners. Fourteen runners completed three exercise trials of the same duration but at exercise intensities corresponding to: (a) a competitive marathon [mean ± SD: heart rate 159 ± 7 beat min(-1), finish time 202 ± 14 min]; (b) 95% of individual anaerobic threshold [heart rate 144 ± 6 beat min(-1)] and; (c) 85% of individual anaerobic threshold [heart rate 129 ± 5 beat min(-1)]. cTnI and NT-proBNP were assayed from blood samples collected before, 30 min and 3 h post-exercise for each trial. cTnI and NT-proBNP were not different at baseline before each trial. After exercise at 85% of individual anaerobic threshold cTnI was not significantly elevated. Conversely, cTnI was elevated after exercise at 95% of individual anaerobic threshold (0.016 µg L(-1)) and to an even greater extent after exercise at competition intensity (0.054 µg L(-1)). Peak post-exercise values of NT-proBNP were elevated to a similar extent after all exercise trials (P < 0.05). The upper reference limit for cTnI (0.04 µg L(-1)) was exceeded in six subjects at competition intensity. No data for NT-proBNP surpassed its upper reference limit. Peak post-exercise values for cTnI and NT-proBNP were correlated with their respective baseline values. These data suggest exercise intensity influences the release of cTnI, but not NT-proBNP, and that competitive marathon running intensity is required for cTnI to be elevated over its upper reference limit.

Cardiac biomarkers and exercise duration and intensity during a cycle-touring event.

OBJECTIVE: To determine the influence of age, training status, race time, and exercise intensity on the appearance of cardiac biomarkers after a cycle-touring event. DESIGN: Pre-post exercise measurements. SETTING: University of Zaragoza, Zaragoza, Spain. PARTICIPANTS: Ninety-one amateur cyclists. INTERVENTION: The 2005 Quebrantahuesos cycle-touring event (distance: 206 km; altitude difference: 3800 m). MAIN OUTCOME MEASURES: Cardiac troponin I (cTnI) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) were measured the day before and immediately after the race. Heart rate (HR) monitoring was performed on 55 cyclists during the race to evaluate exercise intensity. RESULTS: cTnI and NT-pro-BNP were significantly elevated immediately post race, with 43% of participants exhibiting cTnI levels greater than 0.04 microg/L and 65% of the participants measuring NT-pro-BNP levels greater than 125 ng/L. The cTnI increase was significantly associated with mean exercise intensity HR (r = 0.36, P < 0.01) but was not associated with age, training status, or race time. The increase in NT-pro-BNP correlated with race time (r = 0.40, P < 0.001) and training status (r = -0.36, P < 0.001) but was not associated with age or exercise intensity HR measures. CONCLUSIONS: These results suggest that, in part, exercise intensity (HR) is responsible for the cTnI increase and that race time is responsible for the increase in NT-pro-BNP. Future standardized endurance exercise trials are recommended to further elucidate the potentially differential effects of training status, exercise time, and intensity on post-exercise increases in cTnI and NT-pro-BNP.