Dynamics of Gut Microbiota and Short-Chain Fatty Acids during a Cycling Grand Tour Are Related to Exercise Performance and Modulated by Dietary Intake.

BACKGROUND: Regular exercise has been described to modify both the diversity and the relative abundance of certain bacterial taxa. To our knowledge, the effect of a cycling stage race, which entails extreme physiological and metabolic demands, on the gut microbiota composition and its metabolic activity has not been analysed. OBJECTIVE: The aim of this cohort study was to analyse the dynamics of faecal microbiota composition and short-chain fatty acids (SCFAs) content of professional cyclists over a Grand Tour and their relationship with performance and dietary intake. METHODS: 16 professional cyclists competing in La Vuelta 2019 were recruited. Faecal samples were collected at four time points: the day before the first stage (A); after 9 stages (B); after 15 stages (C); and on the last stage (D). Faecal microbiota populations and SCFA content were analysed using 16S rRNA sequencing and gas chromatography, respectively. A principal component analysis (PCA) followed by Generalised Estimating Equation (GEE) models were carried out to explore the dynamics of microbiota and SCFAs and their relationship with performance. RESULTS: Bifidobacteriaceae, Coriobacteriaceae, Erysipelotrichaceae, and Sutterellaceae dynamics showed a strong final performance predictive value (r = 0.83, ranking, and r = 0.81, accumulated time). Positive correlations were observed between Coriobacteriaceae with acetate (r = 0.530) and isovalerate (r = 0.664) and between Bifidobacteriaceae with isobutyrate (r = 0.682). No relationship was observed between SCFAs and performance. The abundance of Erysipelotrichaceae at the beginning of La Vuelta was directly related to the previous intake of complex-carbohydrate-rich foods (r = 0.956), while during the competition, the abundance of Bifidobacteriaceae was negatively affected by the intake of simple carbohydrates from supplements (r = -0.650). CONCLUSIONS: An ecological perspective represents more realistically the relationship between gut microbiota composition and performance compared to single-taxon approaches. The composition and periodisation of diet and supplementation during a Grand Tour, particularly carbohydrates, could be designed to modulate gut microbiota composition to allow better performance.

One Season in Professional Cycling Is Enough to Negatively Affect Bone Health.

Cycling is a very popular sport worldwide, and several studies have already indicated that cycling at various levels has a negative impact on bone health. This is of concern to both performance and health managers of many cycling teams at different levels because of its economic and social impact. Based on the scientific literature, we hypothesize that a single season at the professional level can negatively affect bone health status. The aim of this study was to assess how professional cycling affects bone health markers after one season. Densitometry was used to measure the bone mineral density (BMD), bone mineral content (BMC), bone area (BA), fat mass (FM), fat-free mass (FFM), T-score and Z-score in professional cyclists after one season. After one season at the professional level, cyclists' BMD decreased significantly in the legs, trunk, ribs and pelvis (p ≤ 0.05). BMC decreased in the arms and spine (p ≤ 0.05). BA decreased significantly in the arms and spine (p ≤ 0.05). In addition, a significant decrease in Z-score (p ≤ 0.05) and a decreasing trend in T-score and total BMD (p = 0.06) were observed. One season of professional cycling is enough to negatively affect bone health status.

Professional cyclists have lower levels of bone markers than amateurs. Is there a risk of osteoporosis in cyclist?

Currently, there is a greater number of amateurs that practice cycling. However, there is no clear evidence regarding bone health in amateur cyclists compared to professional cyclists, as the latter has shown to have lower bone mineral content and density. Therefore, the aim of this study was to identify the differences in bone variables between professional (PRO) and amateur (AMA) road cyclists, and to see if these differences were related to differences in cycling performance. A parallel trial was carried out with 15 AMA and 10 PRO cyclists. All cyclists visited the laboratory twice: 1) in a fasted state, body composition measured by dual-energy X-ray absorptiometry (DXA) and 2) physiological variables measured using an incremental test until exhaustion. Significantly lower values were found in bone mineral density, bone mineral content and fat free mass in PRO compared to AMA (p < 0.05). In addition, significantly higher power was produced in ventilatory thresholds 1 and 2 (VT1 and VT2) and VO2MAX in PRO compared to AMA (p < 0.05). Overall, PRO cyclists had lower values in bone health and muscle mass but better results in performance compared to AMA.

Methods for epidemiological studies in competitive cycling: an extension of the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sport 2020.

In 2020, the IOC released a consensus statement that provides overall guidelines for the recording and reporting of epidemiological data on injury and illness in sport. Some aspects of this statement need to be further specified on a sport-by-sport basis. To extend the IOC consensus statement on methods for recording and reporting of epidemiological data on injury and illness in sports and to meet the sport-specific requirements of all cycling disciplines regulated by the Union Cycliste Internationale (UCI). A panel of 20 experts, all with experience in cycling or cycling medicine, participated in the drafting of this cycling-specific extension of the IOC consensus statement. In preparation, panel members were sent the IOC consensus statement, the first draft of this manuscript and a list of topics to be discussed. The expert panel met in July 2020 for a 1-day video conference to discuss the manuscript and specific topics. The final manuscript was developed in an iterative process involving all panel members. This paper extends the IOC consensus statement to provide cycling-specific recommendations on health problem definitions, mode of onset, injury mechanisms and circumstances, diagnosis classifications, exposure, study population characteristics and data collection methods. Recommendations apply to all UCI cycling disciplines, for both able-bodied cyclists and para-cyclists. The recommendations presented in this consensus statement will improve the consistency and accuracy of future epidemiological studies of injury and illness in cycling.

Differences between Professional and Amateur Cyclists in Endogenous Antioxidant System Profile.

Currently, no studies have examined the differences in endogenous antioxidant enzymes in professional and amateur cyclists and how these can influence sports performance. The aim of this study was to identify differences in endogenous antioxidants enzymes and hemogram between competitive levels of cycling and to see if differences found in these parameters could explain differences in performance. A comparative trial was carried out with 11 professional (PRO) and 15 amateur (AMA) cyclists. All cyclists performed an endogenous antioxidants analysis in the fasted state (visit 1) and an incremental test until exhaustion (visit 2). Higher values in catalase (CAT), oxidized glutathione (GSSG) and GSSG/GSH ratio and lower values in superoxide dismutase (SOD) were found in PRO compared to AMA (p < 0.05). Furthermore, an inverse correlation was found between power produced at ventilation thresholds 1 and 2 and GSSG/GSH (r = -0.657 and r = -0.635; p < 0.05, respectively) in PRO. Therefore, there is no well-defined endogenous antioxidant enzyme profile between the two competitive levels of cyclists. However, there was a relationship between GSSG/GSH ratio levels and moderate and submaximal exercise performance in the PRO cohort.

Variacion genetica del sistema renina-angiotensina y deporte de resistencia: relacion con el rendimiento y la prevencion de patologias / Genetic variation in the renin angiotensin system and endurance performance. Its relationship with performance and prevention of pathology

Algunos estudios recientes relacionan factores genéticos con patologías asociadas al ejercicio físico. El desarrollo de la enfermedad coronaria (infarto) y la hipertrofia ventricular han sido asociadas a la variación (polimorfismos) en el gen de la Enzima Convertidora de la Angiotensina (ECA). Los individuos homocigotos DD para el polimorfismo I/D de la ECA muestran un incremento significativo de la masa ventricular izquierda en respuesta al entrenamiento, comparados con sujetos con los genotipos II e ID. Los individuos II e ID, que, tienen unos niveles mas bajos de ECA en plasma, tendrían una mayor respuesta anabólica al ejercicio. En este sentido, se ha descrito un aumento de la frecuencia del alelo I entre remeros y alpinistas de elite. Considerando los antecedentes descritos, el objetivo de este trabajo es comparar la distribución de los genotipos dé los polimorfismos de los componentes del sistema renina angiotensina en sujetos sanos y en deportistas de alto nivel, analizando también la relación entre el genotipo y los niveles sanguíneos del enzima. Amplificando el ADN mediante la reacción en cadena de la polimerasa (PCR), determinamos el genotipo de cuarenta y cinco deportistas de élite (25 ciclistas y 20 corredores de fondo) y 400 controles sanos para el polimorfismo del gen de la ECA. El alelo I de la ECA presentaba una frecuencia significativamente mayor (p=0,0029) en los deportistas que en los controles sanos. Los niveles plasmáticos de ECA mostraron una fuerte correlación con el genotipo I/D en nuestra población. En conclusión, por su relación con el desarrollo de patologias cardíacas y con el rendimiento fisico, él polimorfismo de la ECA es un factor genético de interés para el deporte de alto rendimiento. El análisis de este marcador genético podría ser útil en la mejora del rendimiento físico y en la prevención de las patologías asociadas a la práctica deportiva (AU)