Efectos del alpinismo de altitud en la composición corporal: revisión sistemática

High altitude mountaineering is characterized by high energetic requirements due to the environment in which the activity is developed: negative energy balance, extreme cold, high altitude and the assumption of potential risks can be found during the practice of this sport. High altitude mountaineering, as a result of the previous factors, induces changes in body composition which have never been studied previously in a systematic review. A search within four different databases (PubMed, SportDiscus, Scopus and Medline) was performed using the thesaurus terms “Mountaineering” and “Body composition”. A second search was performed using the following terms “Altitude” and “Body composition”. The selection criteria included studies with healthy adults which evaluated the effects of at least 14 days of uninterrupted stays at altitudes above 4,000 m. The studies included in the review assessed body composition through different methods such as anthropometry, bioimpedance, dual energy x-ray absorptiometry, hydrostatic weighing and air displacement plethysmography. The search was performed up to and including December 1st 2018. Eleven observational studies met the inclusion criteria. All studies reported weight loss, of which five reported significant reductions in lean mass and six reported reductions in fat mass. Also, three studies reported reductions in both fat mass and lean mass. Current evidence is limited to observational studies with important confounding factors affecting the final conclusions. Longitudinal studies with a better methodological design and control groups are needed in order to verify these results.El alpinismo a grandes altitudes se caracteriza por elevados requerimientos energéticos debido al ambiente en el que se desarrolla la actividad: los balances energéticos negativos, el frío extremo, la exposición a la altitud o niveles de estrés elevados se pueden observar en la práctica de este deporte. Debido a estos factores, el alpinismo de altitud induce cambios en la composición corporal que no se han estudiado previamente en una revisión sistemática. Se realizó una búsqueda en cuatro bases de datos (PubMed, SportDiscus, Scopus and Medline) con los términos Mesh “Mountaineering” y “Body composition”. Una segunda búsqueda se realizó usando los términos “Altitude” y “Body composition”. Los criterios de selección incluyeron estudios con adultos sanos que evaluaron los efectos de estancias de al menos 14 días ininterrumpidos en altitudes superiores a los 4.000 m. La composición corporal se analizó con diferentes métodos como antropometría, bioimpedancia, absorciometría dual de rayos x, pesada hidrostática y pletismografía por desplazamiento de aire. La búsqueda se realizó incluyendo estudios fechados hasta el 1 de diciembre de 2018. Once estudios observacionales cumplieron con los criterios de inclusión. Todos los estudios reportaron pérdida de peso, de los cuales cinco reportaron reducciones en masa magra; seis, reducciones en masa grasa; y tres, reducciones en ambas. La evidencia actual se limita a estudios observacionales con factores de confusión importantes que afectan a los resultados finales. Se necesitan estudios longitudinales con mejor diseño metodológico y grupo control para verificar estos resultados

Effects of a low-carbohydrate diet on performance and body composition in trained cyclists

Introduction: Previous evidence suggests that low-carbohydrate diets may improve body composition and performance relative to body weight in endurance athletes. This has been the first study that has attempted to evaluate the utility of low-carbohydrate diets in a sample of eleven trained and experienced road cyclists who consumed 10% of their caloric intake in the form of carbohydrates during four weeks while maintaining a neutral energy balance (50 kcal/kg/day). Body composition was evaluated through an electrical impedance assessment before and after the intervention while maximal power output (5 and 20 min) was measured on a bike trainer by following a standardized protocol and in the same room conditions for all the participants. The study was performed during the preseason, when the subjects could abstain from performing high-intensity workouts. The participants, eleven men aged 31 ± 5 years, performed four weekly 150 min training sessions at submaximal intensities and received nutritional support from a certified sport nutritionist. The intervention resulted in reduced total weight (-2.51 kg) and body fat percentage (2.42%), and improved relative power (+0.2 w/kg for 20 min and +0.25 w/kg for 5 min) values while absolute power remained unchanged. The results suggest that low-carbohydrate diets could be used in order to induce changes in body composition and improve relative power during the preseason. However, future research with larger sample sizes and a control group is needed in order to validate the results.Introducción: La evidencia científica previa sugiere que las dietas bajas en hidratos de carbono pueden mejorar la composición corporal y el rendimiento relativo al peso en deportistas de resistencia. Este ha sido el primer estudio que ha intentado evaluar la utilidad de este tipo de dieta en una muestra de once ciclistas de carretera entrenados y experimentados que consumieron un 10% de sus calorías diarias en forma de hidratos de carbono durante cuatro semanas mientras mantenían un balance energético neutro (50 kcal/kg/día). La composición corporal se evaluó con bioimpedancia eléctrica antes y después de la intervención mientras que la potencia máxima (5 y 20 min) se evaluó siguiendo un protocolo estandarizado sobre un rodillo de ciclismo en las mismas condiciones ambientales para todos los participantes. El estudio se realizó en la pretemporada, cuando todos los sujetos podían abstenerse de realizar entrenamientos de alta intensidad. Los participantes, once hombres con edades de 31 ± 5 años, realizaron cuatro sesiones de entrenamiento de 150 minutos de duración semanales y recibieron apoyo de un nutricionista deportivo titulado. La intervención resultó en una disminución del peso (-2, 51 kg) y el porcentaje de grasa corporal (-2, 42%), así como en un aumento de la potencia relativa (+0, 2 w/kg en potencia 20 min y +0, 25 w/kg en potencia 5 min) mientras que los valores de potencia absoluta no se modificaron. Los resultados sugieren que las dietas bajas en hidratos de carbono podrían utilizarse durante la pretemporada para inducir cambios en la composición corporal y mejorar la potencia relativa. Sin embargo, hacen falta estudios con una muestra más grande y un grupo de control para poder validar estos resultados

Mining Urban Performance: Scale-Independent Classification of Cities Based on Individual Economic Transactions

Intensive development of urban systems creates a number of challenges for urban planners and policy makers in order to maintain sustainable growth. Running efficient urban policies requires meaningful urban metrics, which could quantify important urban characteristics including various aspects of an actual human behavior. Since a city size is known to have a major, yet often nonlinear, impact on the human activity, it also becomes important to develop scale-free metrics that capture qualitative city properties, beyond the effects of scale. Recent availability of extensive datasets created by human activity involving digital technologies creates new opportunities in this area. In this paper we propose a novel approach of city scoring and classification based on quantitative scale-free metrics related to economic activity of city residents, as well as domestic and foreign visitors. It is demonstrated on the example of Spain, but the proposed methodology is of a general character. We employ a new source of large-scale ubiquitous data, which consists of anonymized countrywide records of bank card transactions collected by one of the largest Spanish banks. Different aspects of the classification reveal important properties of Spanish cities, which significantly complement the pattern that might be discovered with the official socioeconomic statistics.Comment: 10 pages, 7 figures, to be published in the proceedings of ASE BigDataScience 2014 conferenc

Escalada deportiva: un deporte con explicación poli factorial del rendimiento

La escalada deportiva es un deporte cada vez más popular y practicado. Esta popularidad se ha visto refrendada en la incorporación de esta disciplina deportiva a los Juegos Olímpicos de Tokio 2020. Hasta la fecha, ningún estudio ha analizado los factores que determinan el rendimiento en esta disciplina deportiva, hecho que podría facilitar la preparación física de los deportistas así como simplificar el trabajo de los entrenadores de esta disciplina. En este estudio hemos analizado uno por uno los principales factores técnicos, tácticos, físicos y psicológicos que inciden en el rendimiento de esta disciplina deportiva intermitente y compleja

Niveles de ansiedad precompetitiva en ciclistas profesionales

El ciclismo de carretera es un deporte con un gran seguimiento y un impacto económico importante. Los ciclistas profesionales se ven sometidos a una gran presión por conseguir resultados para prolongar sus contratos y aumentar sus ganancias. Por otra parte, las pruebas cicloturistas como la Quebrantahuesos pueden llegar a ser extremadamente competitivas y conllevar unos niveles importantes de ansiedad en los participantes. En este estudio se ha comprobado, mediante el uso de un cuestionario validado, que los ciclistas profesionales sufren unos niveles de ansiedad precompetitiva superiores a los vistos en los participantes en las pruebas cicloturistas comúnmente disputadas como la Quebrantahueso

Power Assessment in Road Cycling: A Narrative Review

Nowadays, the evaluation of physiological characteristics and training load quantification in road cycling is frequently performed through power meter data analyses, but the scientific evidence behind this tool is scarce and often contradictory. The aim of this paper is to review the literature related to power profiling, functional threshold testing, and performance assessment based on power meter data. A literature search was conducted following preferred reporting items for review statement (PRISMA) on the topic of {"cyclist" OR "cycling" AND "functional threshold" OR "power meter"}. The reviewed evidence provided important insights regarding power meter-based training: (a) functional threshold testing is closely related to laboratory markers of steady state; (b) the 20-min protocol represents the most researched option for functional threshold testing, although shorter durations may be used if verified on an individual basis; (c) power profiling obtained through the recovery of recorded power outputs allows the categorization and assessment of the cyclist''s fitness level; and (d) power meters represent an alternative to laboratory tests for the assessment of the relationship between power output and cadence. This review elucidates the increasing amount of studies related to power profiling, functional threshold testing, and performance assessment based on power meter data, highlighting the opportunity for the expanding knowledge that power meters have brought in the road cycling field

Los escaladores de alto nivel sufren mayor ansiedad precompetitiva que los escaladores aficionados

La escalada deportiva es un deporte con escaso arraigo competitivo: los premios otorgados son de escaso valor, la popularidad del deporte es relativamente baja y apenas una franja de todos los practicantes compite en esta disciplina deportiva. En el presente estudio comprobamos, mediante un cuestionario validado, que a pesar de todo lo anterior, los escaladores de alto nivel presentan niveles de ansiedad más elevados que los escaladores aficionados durante las competiciones. Los resultados de este estudio pueden permitir elaborar estrategias para la prevención del exceso de ansiedad en escaladores de alto nivel

Anthropometric Characteristics of Road Cyclists of Different Performance Levels

Road cycling is an endurance sport characterized by several anthropometric performance factors, such as reduced body mass and body fat percentage. As the power to weight ratio is considered one of the most important markers of performance in this sport discipline, it is speculated that anthropometric factors could relate to the physiological parameters found in road cyclists of different performance levels. The current study aimed to describe the anthropometric differences across road cyclists of different performance levels and to assess whether anthropometric values could relate to physiological markers that are commonly used to classify road cyclists, according to their performance level. We classified 46 cyclists as recreationally trained, trained, well trained and professional, according to their VO2max, and performed graded exercise tests and complete anthropometric assessments. The results showed that there were no significant anthropometric differences between trained, well trained and professional cyclists, with only recreationally trained cyclists exhibiting larger perimeters and skinfolds than professional cyclists. Further, although physiological performance, such as VO2max and respiratory compensation point, correlated negatively with several skinfolds and perimeters, these correlations remained restrained and did not distinguish between cyclists of different specialties