Stroke Steadiness as a Determinant Factor of Performance in 100 m Freestyle in Young Swimmers.

The classical kinematic variables in swimming are based on the calculation of mean values. Stroke steadiness determines the relationship between the duration of all consecutive strokes throughout a test. The aims of the current investigation were to examine differences in stroke-to-stroke steadiness according to swimmers' performance level on both body sides (breathing and non-breathing) and to analyse the interrelationship with kinematics during a 100 m front-crawl test. Thirty-two young, experienced swimmers voluntarily participated in the present study and were divided into two groups, national level (n = 15) and local level (n = 17), according to their competitive status within the national age-rankings. All participants performed a 100 m maximal test in a 50 m pool where they were laterally recorded. Kinematic variables such as mean velocity, stroke rate, stroke length, and stroke index, as well as long-term steadiness and short-term steadiness, were calculated. The two 50 m sections were analysed independently. Significant differences were observed between the two groups in the classical kinematic variables and in stroke steadiness (p < 0.05). In addition, stroke steadiness showed moderately high correlations with velocity (r = [-0.61-(-0.749)]) and stroke index (r = [-0.356-(-0.582)]). Maintaining a more stable inter-stroke period appears to be a determinant of performance in young, high-level national swimmers.

Assessment of Intercostal Muscle Near-Infrared Spectroscopy for Estimating Respiratory Compensation Point in Trained Endurance Athletes.

This study aimed to assess the reliability and validity of estimating the respiratory compensation point (RCP) in trained endurance athletes by analyzing intercostal muscles' NIRS-derived tissue oxygenation dynamics. Seventeen experienced trail runners underwent an incremental treadmill protocol on two separate occasions, with a 7-day gap between assessments. Gas exchange and muscle oxygenation data were collected, and the oxygen saturation breakpoint (SmO2BP) measured in the intercostal muscles was compared to the RCP, which was identified by the increase in the VE/V.CO2 slope and the point at which the PetCO2 started to decrease. No statistically significant differences were observed between the two methods for any of the variables analyzed. Bland-Altman analysis showed significant agreement between the NIRS and gas analyzer methods for speed (r = 0.96, p < 0.05), HR (r = 0.98, p < 0.05), V.O2 relative to body mass (r = 0.99, p < 0.05), and %SmO2 (r = 0.98, p < 0.05). The interclass correlation coefficient values showed moderate to good reliability (0.60 to 0.86), and test-retest analysis revealed mean differences within the confidence intervals for all variables. These findings suggest that the SmO2BP measured using a portable NIRS device in the intercostal muscles is a reliable and valid tool for estimating the RCP for experienced trail runners and might be useful for coaches and athletes to monitor endurance training.

Synbiotic Supplementation Improves Quality of Life and Inmunoneuroendocrine Response in Patients with Fibromyalgia: Influence of Codiagnosis with Chronic Fatigue Syndrome.

Fibromyalgia (FM) and chronic fatigue syndrome (CFS) are two medical conditions in which pain, fatigue, immune/inflammatory dysregulation, as well as various mental health disorders predominate in the diagnosis, without evidence of a clear consensus on the treatment of FM and CFS. The main aim of this research was to analyse the possible effects of a synbiotic (Synbiotic, Gasteel Plus® (Heel España S.A.U.), through the study of pro-inflammatory/anti-inflammatory cytokines (IL-8/IL-10) and neuroendocrine biomarkers (cortisol and DHEA), in order to evaluate the interaction between inflammatory and stress responses mediated by the cytokine-HPA (hypothalamic-pituitary-adrenal) axis, as well as mental and physical health using body composition analysis, accelerometry and previously validated questionnaires. The participants were women diagnosed with FM with or without a diagnostic of CFS. Each participant was evaluated at baseline and after the intervention, which lasted one month. Synbiotic intervention decreased levels of perceived stress, anxiety and depression, as well as improved quality of life during daily activities. In addition, the synbiotic generated an activation of HPA axis (physiological cortisol release) that can compensate the increased inflammatory status (elevated IL-8) observed at baseline in FM patients. There were no detrimental changes in body composition or sleep parameters, as well as in the most of the activity/sedentarism-related parameters studied by accelerometry. It is concluded that synbiotic nutritional supplements can improve the dysregulated immunoneuroendocrine interaction involving inflammatory and stress responses in women diagnosed with FM, particularly in those without a previous CFS diagnostic; as well as their perceived of levels stress, anxiety, depression and quality of life.

The Consumption of a Synbiotic Does Not Affect the Immune, Inflammatory, and Sympathovagal Parameters in Athletes and Sedentary Individuals: A Triple-Blinded, Randomized, Place-bo-Controlled Pilot Study.

This investigation aimed to identify the effect of a synbiotic in athletes and sedentary people, and their potential varying responses regarding the immune system, autonomic regulation and body composition. Twenty-seven participants were involved in the protocol: 14 sedentary and 13 semi-professional soccer players. Both groups were randomly divided into an experimental and control group. A synbiotic (Gasteel Plus®, Heel España S.A.U.) comprising a blend of probiotic strains, including Bifidobacterium lactis CBP-001010, Lactobacillus rhamnosus CNCM I-4036, and Bifidobacterium longum ES1, was administered to the experimental group, and a placebo was given to the control group for 30 days. Heart rate variability, body composition, and immune/inflammatory cytokines were determined. Statistically significant differences were observed between sedentary individuals and athletes in heart rate variability but not between the experimental and control groups. A difference between the athletic and sedentary group is observed with the influence of training on the effects of the synbiotic on the levels of fat mass and body-fold sum. No significant differences were shown in cytokines after the protocol study. No changes occur with the synbiotic treatment between the athlete and sedentary groups, while no negative effect was produced. Further research will be necessary to see chronic effects in the analyzed biomarkers.

Accidental doping. Prevention strategies / Dopaje accidental. Estrategias de prevención

There is growing consumption of nutritional supplements aimed at improving performance because the number of athletes, mainly amateurs, is growing very significantly. This great demand supposes a market of huge proportions, supposing an economic activity that in Spain reached 920 million Euros in the year 2018.This consumption occurs at all levels of sport, from 13% in global numbers, to 100% in some groups of professional sportsmen and women. However, the use of these substances in very few circumstances is done under the advice of a professional, and the athlete takes them on their own. This fact, with the possibility that the product to be taken may contain prohibited substances that do not appear on the labeling, means that an adverse analytical finding can occur in a doping control through so-called accidental doping, which is the use of adulterated or contaminated nutritional supplements containing substances prohibited in sport that have not been declared on the labeling. Between 11.6% and 25.8% of nutritional supplements contaminated with anabolic androgenic steroids have been found to exist. This paper describes the various causes of accidental doping, the substances most frequently used, paying particular attention to the ways of preventing this type of doping based on information and education, product certification and information, the form of prescription, criteria for use and safety of the origin of the products, and precautions followed in case of consumption

Hay un consumo creciente de suplementos nutricionales destinados a mejorar el rendimiento porque el número de deportistas, fundamentalmente aficionados, está creciendo de forma muy importante. Esta gran demanda supone un mercado de proporciones gigantescas, suponiendo un actividad económica que en España alcanzó los 920 millones de euros en el año 2018.Este consume se produce en todos los niveles deportivos, desde el 13 % en cifras globales, hasta el 100 % en algunos grupos de deportistas profesionales. Sin embargo, el uso de estas sustancias en muy pocas circunstancias se realiza bajo al asesoramiento de un profesional y el deportista los toma por su cuenta. Este hecho, junto a la posibilidad de que el producto que se vaya a tomar pueda contener sustancias prohibidas que no figuran en el etiquetado supone que se pueda producir un hallazgo analítico adverso en un control de dopaje a través del denominado dopaje accidental que consiste el que se produce por consumir suplementos nutricionales adulterados o contaminados que contienen sustancias prohibidas en el deporte que no se han declarado en el etiquetado. Se ha comprobado que existe entre el 11,6 y el 25,8% de suplementos nutricionales contaminados con esteroides androgénicos anabolizantes. En este trabajo se describen las diversas causas de dopaje accidental, las sustancias más frecuentemente utilizadas prestando una especial atención a las formas de prevención de este tipo de dopaje que se basan en la información y educación, en la certificación e información de los productos, en la forma de prescripción, en los criterios de uso y seguridad del origen de los productos y en las precauciones que se deben tomar en caso de consumirlos

Acute effects of heat on health variables during continuous exercise and their comparison with normal and cold conditions: A systematic review / Efectos agudos del calor sobre variables de salud durante el ejercicio continuo en comparación con condiciones normales y frías: una revisión sistemática

Background: There has been an increasing number of running practitioners in the last years. Although running activity involves several benefits for practitioners, it might also induce health problems when practicing under heat conditions. Purpose: The main aim of this systematic review was to evaluate how high temperatures affect runner's health during continuous exercise. Search strategy: The search for articles for this study was carried out in two different databases, Web of Science and Pubmed.Study selection: The inclusion criteria were a) Studies that investigated the effects of endurance exercise, at least at 27º, on health variables, determining exercise intensity, indicating total time for exercise and presenting pre- and post-test results or compare with normal or cold conditions. Results: 1336 articles were identified after the searching process. 333 runners were evaluated in fifteen articles that were included in the qualitative synthesis. High increases in heart rate, body and skin temperature, some urine and blood markers, blood pH, ventilation, rate of perceived exertion and sweat rate were identified during continuous activity under heat conditions, and also when comparing with normal or cold conditions. Lower values were found in body mass, eosinophil than those observed before the running activity. Lower values for oxygen consumption and plasma lactate may occur in hot conditions when comparing with normal conditions. Conclusions: Studies analyzed conclude that an uncontrolled long-term activity in hot conditions may induce health problems related to high body and skin temperatures. Cooling strategies should be assessed after continuous exercise under hot conditions. In addition exercise in hot conditions produces greater increases in immune functions, heart rate, breathing stress, metabolic responses and rate of perceived exertion, also compared with normal and cold conditions

Introducción: El número de corredores ha incrementado en los últimos años. Aunque la actividad de correr implica varios beneficios para los practicantes, también puede provocar problemas de salud cuando se practica en condiciones de calor. Propósito: El objetivo de esta revisión fue evaluar cómo las altas temperaturas afectan la salud del corredor. Estrategia de búsqueda: La búsqueda de artículos para este estudio se llevó a cabo en Web of Science y Pubmed. Selección de estudios: Los criterios de inclusión fueron estudios que investigaron los efectos del ejercicio de resistencia, al menos a 27º, sobre variables de salud, determinando la intensidad y duración del ejercicio y se presentaron resultados previos y posteriores a la prueba o compararon con condiciones normales o frías. Resultados: 1336 artículos fueron identificados después del proceso de búsqueda. 333 corredores fueron evaluados en quince artículos que fueron incluidos en la síntesis cualitativa. Durante la actividad en condiciones de calor, se identificaron incrementos elevados en la frecuencia cardíaca, la temperatura corporal y de la piel, algunos marcadores de orina y sangre, el pH sanguíneo, la ventilación, el esfuerzo percibido y la sudoración. Se encontraron valores más bajos de masa corporal y eosinófilos que los observados antes de la actividad de carrera. Valores más bajos de consumo de oxígeno y lactato aparecen en condiciones de calor cuando se comparan con las condiciones normales. Conclusiones: Los estudios analizados concluyen que una actividad no controlada a largo plazo en condiciones de calor puede inducir problemas de salud relacionados con altas temperaturas corporales y de la piel. Además, el ejercicio en condiciones de calor produce mayores incrementos en las funciones inmunitarias, la frecuencia cardíaca, el estrés respiratorio, las respuestas metabólicas y el esfuerzo percibido, también en comparación con las condiciones normales y frías