A sportomics soccer investigation unveils an exercise-induced shift in tyrosine metabolism leading to hawkinsinuria.

Tyrosine metabolism has an intense role in the synthesis of neurotransmitters. Our study used an untargeted, sportomics-based analysis of urine samples to investigate changes in metabolism during a soccer match in 30 male junior professional soccer players. Samples were collected before and after the match and analyzed using liquid chromatography and mass spectrometry. Results showed significant changes in tyrosine metabolism. Exercise caused a downregulation of the homogentisate metabolites 4-maleylacetoacetate and succinylacetone to 20% (p = 4.69E-5) and 16% (p = 4.25E-14), respectively. 4-Hydroxyphenylpyruvate, a homogentisate precursor, was found to be upregulated by 26% (p = 7.20E-3). The concentration of hawkinsin and its metabolite 4-hydroxycyclohexyl acetate increased ~six-fold (p = 1.49E-6 and p = 9.81E-6, respectively). Different DOPA metabolism pathways were also affected by exercise. DOPA and dopaquinone increased four-to six-fold (p = 5.62E-14 and p = 4.98E-13, respectively). 3-Methoxytyrosine, indole-5,6-quinone, and melanin were downregulated from 1 to 25%, as were dopamine and tyramine (decreasing to up to 5% or 80%; p= 5.62E-14 and p = 2.47E-2, respectively). Blood TCO2 decreased as well as urinary glutathione and glutamate (40% and 10% respectively) associated with a two-fold increase in pyroglutamate. Our study found unexpected similarities between exercise-induced changes in metabolism and the inherited disorder Hawkinsinuria, suggesting a possible transient condition called exercise-induced hawkinsinuria (EIh). Additionally, our research suggests changes in DOPA pathways may be involved. Our findings suggest that soccer exercise could be used as a model to search for potential countermeasures in Hawkinsinuria and other tyrosine metabolism disorders.

Measuring Heart Rate During Exercise: From Artery Palpation to Monitors and Apps

The use of technology has increased tremendously, by means of more reliable, smaller, more accessible and specially more user-friendly devices, which provide a wider range of features, and promote significant benefits for the population and health professionals. It is in this context that monitors and apps for heart rate (HR) measurement have emerged. HR is a clinical vital sign of diagnostic and prognostic importance. In response to body movement, HR tends to increase, in a direct relationship with the intensity of exercise. HR was primarily measured by the count of arterial pulse, and recently, HR can be precisely measured by monitors, bracelets and smartphone apps capable to perform real-time measurements and storage of data. This paper aimed to make a brief and updated review on the theme, providing a broader view of advantages and limitations of these resources for HR measurement in exercise. HR monitors and apps use basically two types of technology, optical sensor (photoplethysmography) and electrical signal from the heart. In general, these devices have shown good accuracy in measuring HR and HR variability at rest, but there are differences between brands and models considering the type, mode and intensity of exercise. HR measurements by monitors and smartphone apps are simple, accessible and may help cardiologists in the monitoring of the intensity of aerobic exercise, focusing on health promotion and on primary and secondary prevention of cardiovascular diseases

Which parameters to use for sleep quality monitoring in team sport athletes? A systematic review and meta-analysis.

BACKGROUND: Sleep quality is an essential component of athlete's recovery. However, a better understanding of the parameters to adequately quantify sleep quality in team sport athletes is clearly warranted. OBJECTIVE: To identify which parameters to use for sleep quality monitoring in team sport athletes. METHODS: Systematic searches for articles reporting the qualitative markers related to sleep in team sport athletes were conducted in PubMed, Scopus, SPORTDiscus and Web of Science online databases. The systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. For the meta-analysis, effect sizes with 95% CI were calculated and heterogeneity was assessed using a random-effects model. The coefficient of variation (CV) with 95% CI was also calculated to assess the level of instability of each parameter. RESULTS: In general, 30 measuring instruments were used for monitoring sleep quality. A meta-analysis was undertaken on 15 of these parameters. Four objective parameters inferred by actigraphy had significant results (sleep efficiency with small CV and sleep latency, wake episodes and total wake episode duration with large CV). Six subjective parameters obtained from questionnaires and scales also had meaningful results (Pittsburgh Sleep Quality Index (sleep efficiency), Likert scale (Hooper), Likert scale (no reference), Liverpool Jet-Lag Questionnaire, Liverpool Jet-Lag Questionnaire (sleep rating) and RESTQ (sleep quality)). CONCLUSIONS: These data suggest that sleep efficiency using actigraphy, Pittsburgh Sleep Quality Index, Likert scale, Liverpool Jet-Lag Questionnaire and RESTQ are indicated to monitor sleep quality in team sport athletes. PROSPERO REGISTRATION NUMBER: CRD42018083941.

Ponto ótimo cardiorrespiratório em futebolistas profissionais: uma nova variável submáxima do exercício / Cardiorespiratory optimal point in professional soccer players: a novel submaximal variable during exercise

O consumo máximo de oxigênio (VO2 max) e o limiar anaeróbico (LA) obtidos no teste cardiopulmonar de exercício (TCPE) são utilizados na avaliação de atletas. Todavia, dificuldades na identificação e mensuração dessas variáveis dificultam sua utilização prática. O ponto ótimo cardiorrespiratório (POC) é uma variável submáxima do TCPE de mensuração objetiva e com significado clínico prognóstico. Contudo, é desconhecido o seu comportamento em atletas.Descrever o comportamento do POC em jogadores profissionais de futebol e sua associação com VO2 max e LA. Análise retrospectiva de 198 futebolistas submetidos a TCPE máximo em esteira rolante com protocolo em rampa, divididos pela posição em campo: goleiro, zagueiro, lateral, meio-campo e atacante. Foram determinados VO2max, LA e POC. O POC correspondeu ao menor valor de ventilação/consumo de oxigênio em um dado minuto do TCPE. Variáveis contínuas foram comparadas pelo teste t de Student não emparelhado ou ANOVA, ou teste de Mann-Whitney ou de Kruskal-Wallis dependendo na distribuição das mesmas, e variáveis categóricas foram comparadas pelo teste do qui-quadrado. A correlação de Pearson foi utilizada para testar a associação entre POC e outras variáveis ventilatórias. Adotou-se um nível de 5% para significância estatística. O POC (média ± desvio-padrão) foi de 18,2 ± 2,1 a uma velocidade 4,3 ± 1,4 km.h-1 menor do que a do LA. Enquanto o VO2 max (62,1 ± 6,2 mL.kg-1.min-1) tendeu a ser menor nos goleiros (p < 0,05), o POC não variou conforme a posição em campo (p = 0,41). Não houve associação significativa entre POC e VO2max (r = 0,032,p = 0,65) nem com LA (r = -0,003, p = 0,96).O POC pode ser facilmente determinado em exercício submáximo realizado com velocidades incrementais em futebolistas e não varia pela posição em campo. A ausência de associação com VO2max e LA indica que o POC traz uma informação distinta e complementar a essas variáveis. Estudos futuros são necessários para determinar implicações práticas do POC na avaliação de atletas

Maximal oxygen consumption (VO2max) and ventilatory threshold (VT) obtained during a cardiopulmonary exercise test (CPX) are used in the evaluation of athletes. However, the identification of these variables may sometimes be unreliable, which limits their use. In contrast, the cardiorespiratory optimal point (COP) is a submaximal variable derived from CPX with objective measurement and prognostic significance. However, its behavior in athletes is unknown. To describe the behavior of COP in professional soccer players and its association with VO2max and VT. VO2max, VT and COP were obtained retrospectively from 198 soccer players undergoing maximal treadmill CPX using ramp protocol. COP was defined as the lowest value of the ventilation/oxygen consumption ratio in a given minute of the CPX. The soccer players were stratified according to their field position: goalkeeper, center-defender, left/right-back, midfielder and forwarder. Continuous variables were compared using unpaired Student t test or ANOVA, or Mann-Whitney test or Kruskal-Wallis test depending on their distribution, and categorical variables were compared using chi-square test. Pearson correlation was used to test the association between COP and other ventilatory variables. A level of 5% was used for statistical significance. COP (mean ± SD) was 18.2 ± 2.1 and was achieved at a speed 4.3 ± 1.4 km.h-1 lower than that achieved at the VT. While VO2max (62.1 ± 6.2 mL.kg-1.min-1) tended to be lower in goalkeepers (p < 0.05), the COP did not vary according to field position (p = 0.41). No significant association was observed between COP and VO2max (r = 0.032, p = 0.65) or between COP and VT (r = -0.003, p = 0.96). COP can be easily determined during submaximal exercise performed with incremental speed in soccer players and does not vary according to the athlete's field position. The absence of association with VO2max and VT indicates that COP provides distinct and complementary information to these variables. Future studies are needed to determine the practical implications of COP in assessing athletes

Ponto Ótimo Cardiorrespiratório em Futebolistas Profissionais: Uma Nova Variável Submáxima do Exercício / Cardiorespiratory Optimal Point in Professional Soccer Players: A Novel Submaximal Variable During Exercise

O consumo máximo de oxigênio (VO2max) e o limiar anaeróbico (LA) obtidos no teste cardiopulmonar de exercício (TCPE) são utilizados na avaliação de atletas. Todavia, dificuldades na identificação e mensuração dessas variáveis dificultam sua utilização prática. O ponto ótimo cardiorrespiratório (POC) é uma variável submáxima do TCPE de mensuração objetiva e com significado clínico prognóstico. Contudo, é desconhecido o seu comportamento em atletas. Objetivo: Descrever o comportamento do POC em jogadores profissionais de futebol e sua associação com VO2max e LA. Materiais e Método: Análise retrospectiva de 198 futebolistas submetidos a TCPE máximo em esteira rolante com protocolo em rampa, divididos pela posição em campo: goleiro, zagueiro, lateral, meio-campo e atacante. Foram determinados VO2max, LA e POC. O POC correspondeu ao menor valor de ventilação/consumo de oxigênio em um dado minuto do TCPE. Variáveis contínuas foram comparadas pelo teste t de Student não emparelhado ou ANOVA, ou teste de Mann-Whitney ou de Kruskal-Wallis dependendo na distribuição das mesmas, e variáveis categóricas foram comparadas pelo teste do qui-quadrado. A correlação de Pearson foi utilizada para testar a associação entre POC e outras variáveis ventilatórias. Adotou-se um nível de 5% para significância estatística. Resultados: O POC (média ± desvio-padrão) foi de 18,2 ± 2,1 a uma velocidade 4,3 ± 1,4 km.h-1 menor do que a do LA. Enquanto o VO2max (62,1 ± 6,2 mL.kg-1.min-1) tendeu a ser menor nos goleiros (p < 0,05), o POC não variou conforme a posição em campo (p = 0,41). Não houve associação significativa entre POC e VO2max (r = 0,032, p = 0,65) nem com LA (r = -0,003, p = 0,96). Conclusão: O POC pode ser facilmente determinado em exercício submáximo realizado com velocidades incrementais em futebolistas e não varia pela posição em campo. A ausência de associação com VO2max e LA indica que o POC traz uma informação distinta e complementar a essas variáveis. Estudos futuros são necessários para determinar implicações práticas do POC na avaliação de atletas

Maximal oxygen consumption (VO2max) and ventilatory threshold (VT) obtained during a cardiopulmonary exercise test (CPX) are used in the evaluation of athletes. However, the identification of these variables may sometimes be unreliable, which limits their use. In contrast, the cardiorespiratory optimal point (COP) is a submaximal variable derived from CPX with objective measurement and prognostic significance. However, its behavior in athletes is unknown. Objective: To describe the behavior of COP in professional soccer players and its association with VO2max and VT. Methods: VO2max, VT and COP were obtained retrospectively from 198 soccer players undergoing maximal treadmill CPX using ramp protocol. COP was defined as the lowest value of the ventilation/oxygen consumption ratio in a given minute of the CPX. The soccer players were stratified according to their field position: goalkeeper, center-defender, left/right-back, midfielder and forwarder. Continuous variables were compared using unpaired Student t test or ANOVA, or Mann-Whitney test or Kruskal-Wallis test depending on their distribution, and categorical variables were compared using chi-square test. Pearson correlation was used to test the association between COP and other ventilatory variables. A level of 5% was used for statistical significance. Results: COP (mean ± SD) was 18.2 ± 2.1 and was achieved at a speed 4.3 ± 1.4 km.h-1 lower than that achieved at the VT. While VO2max (62.1 ± 6.2 mL.kg-1.min-1) tended to be lower in goalkeepers (p < 0.05), the COP did not vary according to field position (p = 0.41). No significant association was observed between COP and VO2max (r = 0.032, p = 0.65) or between COP and VT (r = -0.003, p = 0.96). Conclusion: COP can be easily determined during submaximal exercise performed with incremental speed in soccer players and does not vary according to the athlete's field position. The absence of association with VO2max and VT indicates that COP provides distinct and complementary information to these variables. Future studies are needed to determine the practical implications of COP in assessing athletes

Cardiac vagal index varies according to field position in male elite football players / índice vagal cardíaco varia com a posição em campo de jogadores da elite do futebol

BACKGROUND: Cardiac vagal index (CVI) is supposedly higher in athletes and may differ between sports and/or between field positions. OBJECTIVE: To compare CVI: a) between elite football players vs. non-athletes and b) according to five football positions. METHOD: 242 football players of the first Brazilian/Angolan division were divided in five positions (N): goalkeepers (17), defenders (44), wingers (34), midfielders (87) and forwarders (60) and compared with 303 age-matched healthy non-athletes. CVI was estimated from a 4-second exercise test by quantifying the ratio of two cardiac cycle durations, before and at the end of a fast unloaded cycling exercise. RESULTS: Football players had resting and maximal heart rates of, respectively, 59 and 190 bpm and measured VO2max of 62.2 mL/(kg.min). Players and non-athletes showed similar CVI results (median-[P25-P75]) - 1.63-[1.46-1.84] vs 1.61-[1.41-1.81] (p = 0.22). Wingers tended to have a higher CVI (1.84-[1.60-1.99]), especially when compared to defenders (1.53-[1.41-1.72] (p = 0.01). There was a modest non-physiologically relevant association between VO2max and CVI (r = 0.15). CONCLUSIONS: Football players did not differ from non-athletes in CVI; however, among players, wingers were more often vagotonic, which may represent a hemodynamic advantage for match situations, where rapid heart rate transitions and faster oxygen delivery to muscles are required.

FUNDAMENTOS: O índice vagal cardíaco (IVC) é supostamente maior em atletas e pode diferir entre esportes e dentro do mesmo esporte. OBJETIVO: Comparar o IVC: a) entre futebolistas e não atletas e b) de acordo com cinco posições do futebol. MÉTODO: 242 jogadores da primeira divisão brasileira/angolana foram divididos em cinco posições (N): goleiros (17), zagueiros (44), laterais (34), meio-campistas (87) e atacantes (60) e comparados com 303 não-atletas saudáveis da mesma idade. IVC foi estimado a partir do teste de exercício de 4 segundos, quantificando a relação entre as durações de dois ciclos cardíacos - antes e ao final de uma pedalada rápida e sem carga RESULTADOS: As frequências cardíacas de repouso e máxima dos futebolistas foram, respectivamente, 59 e 190 bpm e o VO2max de 62,2 mL/(kg.min). Futebolistas e não-atletas mostraram resultados semelhantes de IVC (mediana- [P25-P75]) - 1,63- [1,46-1,84] vs 1,61- [1,41-1,81] (p = 0,22). Os laterais tenderam a ter maior IVC (1,84- [1,60-1,99]), especialmente quando comparados aos defensores (1,53- [1,41-1,72] (p = 0,01). Houve uma modesta associação fisiologicamente irrelevante entre VO2max e IVC (r = 0,15). CONCLUSÕES: jogadores da elite do futebol não diferem de não-atletas em IVC; entretanto, entre eles, os alas se mostraram mais frequentemente vagotônicos, o que pode representar uma vantagem hemodinâmica para situações de jogo, onde são necessárias transições rápidas da frequência cardíaca e um aporte mais rápido de oxigênio para os músculos ativos.

Improving Sprint Performance in Soccer: Effectiveness of Jump Squat and Olympic Push Press Exercises.

Training at the optimum power load (OPL) is an effective way to improve neuromuscular abilities of highly trained athletes. The purpose of this study was to test the effects of training using the jump squat (JS) or Olympic push-press (OPP) exercises at the OPL during a short-term preseason on speed-power related abilities in high-level under-20 soccer players. The players were divided into two training groups: JS group (JSG) and OPP group (OPPG). Both groups undertook 12 power-oriented sessions, using solely JS or OPP exercises. Pre- and post-6 weeks of training, athletes performed squat jump (SJ), countermovement jump (CMJ), sprinting speed (5, 10, 20 and 30 m), change of direction (COD) and speed tests. To calculate the transfer effect coefficient (TEC) between JS and MPP OPP and the speed in 5, 10, 20, and 30 m, the ratio between the result gain (effect size [ES]) in the untrained exercise and result gain in the trained exercise was calculated. Magnitude based inference and ES were used to test the meaningful effects. The TEC between JS and VEL 5, 10, 20, and 30 m ranged from 0.77 to 1.29, while the only TEC which could be calculated between OPP and VEL 5 was rather low (0.2). In addition, the training effects of JS on jumping and speed related abilities were superior (ES ranging from small to large) to those caused by OPP (trivial ES). To conclude, the JS exercise is superior to the OPP for improving speed-power abilities in elite young soccer players.

Caffeine decreases systemic urea in elite soccer players during intermittent exercise.

PURPOSE: We investigated the effects of caffeine on the ammonia and amino acid metabolism of elite soccer players. METHODS: In this double-blind randomized study, athletes (n = 19) received 5 mg·kg caffeine or lactose (LEx, control) and performed 45 min of intermittent exercise followed by an intermittent recovery test (Yo-Yo IR2) until exhaustion. The caffeine-supplemented athletes were divided into two groups (CEx and SCEx) depending on their serum caffeine levels (<900% and >10,000%, respectively). Data were analyzed by ANOVA and Tukey post hoc test (P < 0.05 was considered to be statistically significant). RESULTS: Caffeine supplementation did not significantly affect the performance (LEx = 12.3 ± 0.3 km·h, 1449 ± 378 m; CEx = 12.2 ± 0.5 km·h, 1540 ± 630 m; SCEx = 12.3 ± 0.5 km·h, 1367 ± 330 m). Exercise changed the blood concentrations of several amino acids and increased the serum concentrations of ammonia, glucose, lactate, and insulin. The LEx group showed an exercise-induced increase in valine (∼29%), which was inhibited by caffeine. Higher serum caffeine levels abolished the exercise-induced increase (∼24%-27%) in glutamine but did not affect the exercise-induced increase in alanine (∼110%-160%) and glutamate (42%-61%). In response to exercise, the SCEx subjects did not exhibit an increase in uremia and showed a significantly lower increase in their serum arginine (15%), citrulline (16%), and ornithine (ND) concentrations. CONCLUSIONS: Our data suggest that caffeine might decrease systemic urea by decreasing the glutamine serum concentration, which decreases the transportation of ammonia to the liver and thus urea synthesis.

Effect of caffeine supplementation on haematological and biochemical variables in elite soccer players under physical stress conditions.

OBJECTIVE: To evaluate the effect of caffeine on white cell distribution and muscle injury markers in professional soccer players during exercise. METHODS: 22 male athletes completed a placebo controlled double blind test protocol to simulate a soccer match, followed by a Yo-Yo intermittent recovery test. RESULTS: Exercise caused an increase in packed cell volume that was enhanced by caffeine. Caffeine and exercise had a synergistic effect on the blood lymphocyte count, which increased by about 38% after exercise, and by an additional 35% when combined with caffeine. Caffeine promoted an exercise independent rise in circulating monocytes, and a synergistic action of exercise and caffeine was observed on segmented neutrophils. Caffeine promoted thrombocytosis. Plasma adenosine deaminase, aspartate aminotransferase, and lactate dehydrogenase concentrations were enhanced by exercise, and alanine transaminase concentration was enhanced in both groups, with a synergistic effect of caffeine. CONCLUSIONS: The pronounced increase in the white cell count in the group receiving caffeine appeared to be caused by greater muscle stress and consequently more intense endothelial and muscle cell injury. The use of caffeine may augment the risk of muscle damage in athletes.