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Cuenca Garcia Eduardo - One of the best experts on this subject based on the ideXlab platform.

  • Efecto de la suplementación aguda con zumo de remolacha en el rendimiento aeróbico y anaeróbico
    'Edicions de la Universitat de Barcelona', 2021
    Co-Authors: Cuenca Garcia Eduardo
    Abstract:

    Esta tesis doctoral esta consta de la publicación de 4 artículos en Journal Citation Reports de primer cuartil, una revisen y tres intervenciones. El principal objetivo es comprobar los efectos de la suplementación aguda con zumo de remolacha en el rendimiento de esfuerzos anaeróbicos de alta intensidad y en el rendimiento cardiorrespiratorio de esfuerzos mayoritariamente aeróbicos prolongados, en diferentes deportistas. El zumo de remolacha es considerado una ayuda ergonutricional de alta evidencia científica. Es rico en nitrato inorgánico que tras su metabolización se convierte en óxido nítrico. Este presenta numerosas funciones fisiológicas: mejoras hemodinámicas y metabólicas, dilatación vascular, aumento del flujo sanguíneo muscular, mejora en la perfusión sanguínea y en la funcionalidad de las unidades motoras tipo II. Lo que se puede traducir en un aumento de la capacidad de producción de fuerza muscular por parte de las unidades motoras tipo II. La controversia existente, junto con la poca literatura sobre la suplementación con zumo de remolacha en esfuerzos de alta intensidad o en deportes de resistencia, hacen que se tenga que profundizar en su estudio, para ampliar más información sobre sus efectos. Durante esta tesis doctoral se han desarrollado los siguientes objetivos específicos: Analizar las evidencias científicas relacionadas con la suplementación con zumo de remolacha y su posible efecto ergogénico en esfuerzos de alta intensidad. Estudiar los efectos de la suplementación aguda con zumo de remolacha sobre el rendimiento cardiorrespiratorio en triatletas mediante un protocolo, en condiciones de laboratorio, a una intensidad de carga equivalente al primer y segundo umbral ventilatorio. Examinar los efectos de la suplementación aguda con zumo de remolacha en el rendimiento anaeróbico en sujetos entrenados, así como la fatiga metabólica y muscular mediante un test de Wingate. Respecto a los resultados, en la revisión anaeróbica solo encontramos 9 artículos que reúnan los criterios de exclusión, existiendo pocos estudios. Durante la primera intervención en triatletas no hubo mejoras significativas, aunque si se mejoró el tiempo en el segundo umbral, pero no de forma significativa. Durante la segunda y tercera intervención hubo mejoras en los valores de pico de potencia, potencia media, niveles de lactato y ninguna mejora en la fatiga mecánica. Tras los estudios realizados anteriores podemos concluir: No hay mejoras significativas en las variables cardiorrespiratorias en atletas entrenados en deportes de resistencia aeróbica, sin embargo, las mejoras leves (no significativas) observadas en las variables de rendimiento, plantean numerosos interrogantes, ya que los mecanismos mecánicos y fisiológicos analizados hasta ahora siguen siendo poco conocidos. La suplementación con zumo de remolacha tiene un efecto ergogénico sobre el rendimiento en un esfuerzo de alta intensidad. Estas mejoras podrían dar pie a interpretar un incremento en el rendimiento en modalidades de alta intensidad, así como de aquellas que requieran aplicar máximos niveles de potencia o aceleración, debido a las posibles mejoras específicas sobre la producción de fuerza y perfusión de las unidades motoras tipo II. La suplementación con ZR no tiene ningún efecto ergogénico sobre la fatiga mecánica durante un esfuerzo de alta intensidad. Existe controversia sobre los efectos positivos del ZR en esfuerzos de alta intensidad. Las recomendaciones para la ingesta aguda de ZR para esfuerzos de alta intensidad se sitúan entre 2-3 horas antes de actividad, siendo la dosis recomendada entre 6,4 y 12 mmol en función de la condición física de los deportistas.This PhD thesis sought to gain insight into the effects of acute supplementation with beetroot juice (BJ) on high intensity anaerobic performance and on cardiorespiratory performance when executing prolonged, mostly aerobic, efforts in different sports. The high inorganic nitrate content of BJ makes this supplement a nutritional Ergogenic Aid aimed at enhancing performance and backed by high scientific evidence. Once metabolized in the organism, nitrate is converted into nitric oxide with its numerous physiological functions. After several reviews and experimental studies we found the following results. When reviewing the impacts of BJ on anaerobic performance, we only identified 9 studies that met the exclusion criteria highlighting the lack of studies examining the effects of this supplement on high intensity efforts in fairly well-trained athletes. During our first experimental intervention in triathletes, no significant improvement was observed in the cardiorespiratory variables examined, although there was improvement in the second ventilatory threshold (VT2) time but the difference lacked significance. In a second and third study in which we assessed high-intensity anaerobic efforts, improvements were noted in peak power, average power and lactate levels while no effects were detected on muscular fatigue. In conclusion, BJ supplementation did not improve performance in prolonged aerobic efforts in highly trained triathletes. However, the slight non-significant improvement noted in VT2 time raises several questions, as the mechanical and physiological mechanisms addressed so far are still poorly understood. The acute intake of BJ supplements had an Ergogenic effect on performance in a high-intensity anaerobic effort. These improvements could indicate greater performance in high-intensity modalities and those requiring maximal power or acceleration levels due to possible specific beneficial effects on power output and blood flow produced in type II motor units. In contrast, BJ was not able to diminish muscular fatigue during a high-intensity effort. There is controversy in the scientific literature over the beneficial effects of BJ in high-intensity efforts. Recommendations for BJ supplementation are its acute intake 2-3 hours before the exercise activity at a dose between 6.4 and 12 mmol depending on the athletes' physical condition

  • Efecto de la suplementación aguda con zumo de remolacha en el rendimiento aeróbico y anaeróbico
    'Edicions de la Universitat de Barcelona', 2021
    Co-Authors: Cuenca Garcia Eduardo
    Abstract:

    [spa] Esta tesis doctoral esta consta de la publicación de 4 artículos en Journal Citation Reports de primer cuartil, una revisen y tres intervenciones. El principal objetivo es comprobar los efectos de la suplementación aguda con zumo de remolacha en el rendimiento de esfuerzos anaeróbicos de alta intensidad y en el rendimiento cardiorrespiratorio de esfuerzos mayoritariamente aeróbicos prolongados, en diferentes deportistas. El zumo de remolacha es considerado una ayuda ergonutricional de alta evidencia científica. Es rico en nitrato inorgánico que tras su metabolización se convierte en óxido nítrico. Este presenta numerosas funciones fisiológicas: mejoras hemodinámicas y metabólicas, dilatación vascular, aumento del flujo sanguíneo muscular, mejora en la perfusión sanguínea y en la funcionalidad de las unidades motoras tipo II. Lo que se puede traducir en un aumento de la capacidad de producción de fuerza muscular por parte de las unidades motoras tipo II. La controversia existente, junto con la poca literatura sobre la suplementación con zumo de remolacha en esfuerzos de alta intensidad o en deportes de resistencia, hacen que se tenga que profundizar en su estudio, para ampliar más información sobre sus efectos. Durante esta tesis doctoral se han desarrollado los siguientes objetivos específicos: Analizar las evidencias científicas relacionadas con la suplementación con zumo de remolacha y su posible efecto ergogénico en esfuerzos de alta intensidad. Estudiar los efectos de la suplementación aguda con zumo de remolacha sobre el rendimiento cardiorrespiratorio en triatletas mediante un protocolo, en condiciones de laboratorio, a una intensidad de carga equivalente al primer y segundo umbral ventilatorio. Examinar los efectos de la suplementación aguda con zumo de remolacha en el rendimiento anaeróbico en sujetos entrenados, así como la fatiga metabólica y muscular mediante un test de Wingate. Respecto a los resultados, en la revisión anaeróbica solo encontramos 9 artículos que reúnan los criterios de exclusión, existiendo pocos estudios. Durante la primera intervención en triatletas no hubo mejoras significativas, aunque si se mejoró el tiempo en el segundo umbral, pero no de forma significativa. Durante la segunda y tercera intervención hubo mejoras en los valores de pico de potencia, potencia media, niveles de lactato y ninguna mejora en la fatiga mecánica. Tras los estudios realizados anteriores podemos concluir: No hay mejoras significativas en las variables cardiorrespiratorias en atletas entrenados en deportes de resistencia aeróbica, sin embargo, las mejoras leves (no significativas) observadas en las variables de rendimiento, plantean numerosos interrogantes, ya que los mecanismos mecánicos y fisiológicos analizados hasta ahora siguen siendo poco conocidos. La suplementación con zumo de remolacha tiene un efecto ergogénico sobre el rendimiento en un esfuerzo de alta intensidad. Estas mejoras podrían dar pie a interpretar un incremento en el rendimiento en modalidades de alta intensidad, así como de aquellas que requieran aplicar máximos niveles de potencia o aceleración, debido a las posibles mejoras específicas sobre la producción de fuerza y perfusión de las unidades motoras tipo II. La suplementación con ZR no tiene ningún efecto ergogénico sobre la fatiga mecánica durante un esfuerzo de alta intensidad. Existe controversia sobre los efectos positivos del ZR en esfuerzos de alta intensidad. Las recomendaciones para la ingesta aguda de ZR para esfuerzos de alta intensidad se sitúan entre 2-3 horas antes de actividad, siendo la dosis recomendada entre 6,4 y 12 mmol en función de la condición física de los deportistas.[eng] This PhD thesis sought to gain insight into the effects of acute supplementation with beetroot juice (BJ) on high intensity anaerobic performance and on cardiorespiratory performance when executing prolonged, mostly aerobic, efforts in different sports. The high inorganic nitrate content of BJ makes this supplement a nutritional Ergogenic Aid aimed at enhancing performance and backed by high scientific evidence. Once metabolized in the organism, nitrate is converted into nitric oxide with its numerous physiological functions. After several reviews and experimental studies we found the following results. When reviewing the impacts of BJ on anaerobic performance, we only identified 9 studies that met the exclusion criteria highlighting the lack of studies examining the effects of this supplement on high intensity efforts in fairly well-trained athletes. During our first experimental intervention in triathletes, no significant improvement was observed in the cardiorespiratory variables examined, although there was improvement in the second ventilatory threshold (VT2) time but the difference lacked significance. In a second and third study in which we assessed high-intensity anaerobic efforts, improvements were noted in peak power, average power and lactate levels while no effects were detected on muscular fatigue. In conclusion, BJ supplementation did not improve performance in prolonged aerobic efforts in highly trained triathletes. However, the slight non-significant improvement noted in VT2 time raises several questions, as the mechanical and physiological mechanisms addressed so far are still poorly understood. The acute intake of BJ supplements had an Ergogenic effect on performance in a high-intensity anaerobic effort. These improvements could indicate greater performance in high-intensity modalities and those requiring maximal power or acceleration levels due to possible specific beneficial effects on power output and blood flow produced in type II motor units. In contrast, BJ was not able to diminish muscular fatigue during a high-intensity effort. There is controversy in the scientific literature over the beneficial effects of BJ in high-intensity efforts. Recommendations for BJ supplementation are its acute intake 2-3 hours before the exercise activity at a dose between 6.4 and 12 mmol depending on the athletes' physical condition

Gemma Milligan - One of the best experts on this subject based on the ideXlab platform.

  • Do Ergogenic Aids Alter Lower Extremity Joint Alignment During a Functional Movement Lunge Prior to and Following an Exercise Bout?
    2016
    Co-Authors: Chris Mills, James Knight, Gemma Milligan
    Abstract:

    Ergogenic Aids have been used to alter joint kinematics in an attempt to minimise injury risk, yet the effectiveness of these Aids may be compromised following a bout of exercise. This preliminary study aimed to measure the effect of compression garments and Kinesio Tape ® on lower extremity joint alignment prior to and following an exercise bout. Eight male athletes (age = 24.1 ± 3.0 years, body height = 177.4 ± 5.2 cm, body mass = 72.3 ± 7.2 kg) volunteered to participant in this study. Joint kinematics were recorded whilst all participants performed three rotational lunges, in three conditions (control, compression garment, Kinesio Tape®), prior to and following a 10 minute exercise bout. Frontal plane kinematics (lateral pelvic tilt, knee valgus, ankle inversion/eversion) were used to assess Ergogenic Aid effectiveness during the lunge. Participants exhibited no significant differences in joint kinematics between Ergogenic Aid conditions prior to the exercise bout. Following exercise the only significant difference occurred within the Kinesio Tape ® condition where maximum knee valgus angle significantly increased from 6.5 ° prior to exercise, to 7.7 ° following the exercise bout. The results of this study suggest joint kinematics are not affected by the Ergogenic Aids in this study prior to an exercise bout. However, there is evidence to suggest that the application of Kinesio Tape ® may allow an increase in knee valgus angle following a bout of exercise, yet, compression garments are effective at maintaining joint alignment following a bout of exercise. Key words: tape, injury, stability

  • Do Ergogenic Aids Alter Lower Extremity Joint Alignment During a Functional Movement Lunge Prior to and Following an Exercise Bout
    Journal of Human Kinetics, 2015
    Co-Authors: Chris Mills, James Knight, Gemma Milligan
    Abstract:

    Ergogenic Aids have been used to alter joint kinematics in an attempt to minimise injury risk, yet the effectiveness of these Aids may be compromised following a bout of exercise. This preliminary study aimed to measure the effect of compression garments and Kinesio Tape® on lower extremity joint alignment prior to and following an exercise bout. Eight male athletes (age = 24.1 ± 3.0 years, body height = 177.4 ± 5.2 cm, body mass = 72.3 ± 7.2 kg) volunteered to participant in this study. Joint kinematics were recorded whilst all participants performed three rotational lunges, in three conditions (control, compression garment, Kinesio Tape®), prior to and following a 10 minute exercise bout. Frontal plane kinematics (lateral pelvic tilt, knee valgus, ankle inversion/eversion) were used to assess Ergogenic Aid effectiveness during the lunge. Participants exhibited no significant differences in joint kinematics between Ergogenic Aid conditions prior to the exercise bout. Following exercise the only significant difference occurred within the Kinesio Tape® condition where maximum knee valgus angle significantly increased from 6.5° prior to exercise, to 7.7° following the exercise bout. The results of this study suggest joint kinematics are not affected by the Ergogenic Aids in this study prior to an exercise bout. However, there is evidence to suggest that the application of Kinesio Tape® may allow an increase in knee valgus angle following a bout of exercise, yet, compression garments are effective at maintaining joint alignment following a bout of exercise.

Lawrence L Spriet - One of the best experts on this subject based on the ideXlab platform.

  • no effect of beetroot juice supplementation on exercise economy and performance in recreationally active females despite increased torque production
    Physiological Reports, 2019
    Co-Authors: Kate A Wickham, Devin G Mccarthy, Jamie M Pereira, Daniel T Cervone, Lex B Verdijk, Luc J C Van Loon, Geoffrey A Power, Lawrence L Spriet
    Abstract:

    This study investigated the effects of acute and chronic beetroot juice (BRJ) supplementation on submaximal exercise oxygen uptake (VO2 ), time trial (TT) performance, and contractile properties of the plantar flexors in females. Study 1: Using a double blind, randomized, crossover design, 12 recreationally active females using hormonal contraceptives supplemented acutely (2.5 h) and chronically (8 days) with 280 mL BRJ/d (~26 mmoles nitrate [ NO 3 - ]) or a NO 3 - -free placebo (PLA). On days 1 and 8, participants cycled for 10 min at 50% and 70% VO2peak and completed a 4 kJ/kg body mass TT. Plasma [ NO 3 - ] and nitrite ([NO2 - ]) increased significantly following BRJ supplementation versus PLA. There was no effect of BRJ supplementation on VO2 at 50% or 70% VO2peak , or TT performance. Study 2: 12 recreationally active females (n = 7 from Study 1) using hormonal contraceptives participated in a baseline visit and were supplemented acutely (2.5 h) and chronically (8 days) with 280 mL BRJ/d. Maximum voluntary strength (MVC) of the plantar flexors was assessed and a torque-frequency curve performed. BRJ had no effect on MVC, voluntary activation, peak twitch torque, time to peak torque, or half relaxation time. Following both acute (46.6 ± 4.9% of 100 Hz torque) and chronic (47.2 ± 4.4%) supplementation, 10 Hz torque was significantly greater compared to baseline (32.9 ± 2.6%). In summary, BRJ may not be an effective Ergogenic Aid in recreationally active females as it did not reduce submaximal exercise VO2 or improve aerobic TT performance despite increasing low frequency torque production.

  • beetroot juice supplementation does not improve performance of elite 1500 m runners
    Medicine and Science in Sports and Exercise, 2014
    Co-Authors: Robert K Boorsma, Jamie Whitfield, Lawrence L Spriet
    Abstract:

    AB Purpose: Dietary nitrate supplementation with beetroot juice (BR) has received widespread attention as an Ergogenic Aid. However, recent evidence in well-trained cyclists has not consistently reported improved cycling economy or performance. The present study examined the effects of acute and chronic BR supplementation on V[spacing dot above]O2 during submaximal running and 1500-m time trial (TT) performance of elite distance runners. Methods: Eight male 1500-m runners (V[spacing dot above]O2peak, 80 +/- 5 mL[middle dot]kg-1[middle dot]min-1; 1500-m personal best, 3:56 +/- 9 s) participated in this study. In a randomized, double-blind, crossover design, subjects supplemented with BR or a nitrate-free BR placebo (PL) for 8 d separated by at least 1 wk. On days 1 (acute) and 8 (chronic), subjects ingested 210 mL of BR (19.5-mmol nitrate) or PL and completed a submaximal treadmill run and 1500-m TT on an indoor 200-m track. Results: Plasma nitrate increased from 37 +/- 15 to 615 +/- 151 [mu]M (acute) and 870 +/- 259 [mu]M (chronic) after BR supplementation. There were no V[spacing dot above]O2 differences between conditions at 50%, 65%, and 80% V[spacing dot above]O2peak (acute PL, 4194 +/- 90 mL[middle dot]min-1; chronic PL, 4216 +/- 95 mL[middle dot]min-1; acute BR, 4192 +/- 113 mL[middle dot]min-1; chronic BR, 4299 +/- 92 mL[middle dot]min-1). The 1500-m TT was unaffected by acute or chronic BR supplementation (acute PL, 4:10.4 min:s +/- 2.5 s; chronic PL, 4:11.4 min:s +/- 2.7 s; acute BR, 4:10.7 min:s +/- 1.5 s; chronic BR, 4:10.5 min:s +/- 2.2 s). However, two subjects improved their TT performance after acute (5.8 and 5.0 s) and chronic BR supplementation (7.0 and 0.5 s). Conclusions: Acute and chronic BR supplementation did not reduce running V[spacing dot above]O2 or improve 1500-m TT performance of a group of elite distance runners, but two responders to BR were identified

Chris Mills - One of the best experts on this subject based on the ideXlab platform.

  • Do Ergogenic Aids Alter Lower Extremity Joint Alignment During a Functional Movement Lunge Prior to and Following an Exercise Bout?
    2016
    Co-Authors: Chris Mills, James Knight, Gemma Milligan
    Abstract:

    Ergogenic Aids have been used to alter joint kinematics in an attempt to minimise injury risk, yet the effectiveness of these Aids may be compromised following a bout of exercise. This preliminary study aimed to measure the effect of compression garments and Kinesio Tape ® on lower extremity joint alignment prior to and following an exercise bout. Eight male athletes (age = 24.1 ± 3.0 years, body height = 177.4 ± 5.2 cm, body mass = 72.3 ± 7.2 kg) volunteered to participant in this study. Joint kinematics were recorded whilst all participants performed three rotational lunges, in three conditions (control, compression garment, Kinesio Tape®), prior to and following a 10 minute exercise bout. Frontal plane kinematics (lateral pelvic tilt, knee valgus, ankle inversion/eversion) were used to assess Ergogenic Aid effectiveness during the lunge. Participants exhibited no significant differences in joint kinematics between Ergogenic Aid conditions prior to the exercise bout. Following exercise the only significant difference occurred within the Kinesio Tape ® condition where maximum knee valgus angle significantly increased from 6.5 ° prior to exercise, to 7.7 ° following the exercise bout. The results of this study suggest joint kinematics are not affected by the Ergogenic Aids in this study prior to an exercise bout. However, there is evidence to suggest that the application of Kinesio Tape ® may allow an increase in knee valgus angle following a bout of exercise, yet, compression garments are effective at maintaining joint alignment following a bout of exercise. Key words: tape, injury, stability

  • Do Ergogenic Aids Alter Lower Extremity Joint Alignment During a Functional Movement Lunge Prior to and Following an Exercise Bout
    Journal of Human Kinetics, 2015
    Co-Authors: Chris Mills, James Knight, Gemma Milligan
    Abstract:

    Ergogenic Aids have been used to alter joint kinematics in an attempt to minimise injury risk, yet the effectiveness of these Aids may be compromised following a bout of exercise. This preliminary study aimed to measure the effect of compression garments and Kinesio Tape® on lower extremity joint alignment prior to and following an exercise bout. Eight male athletes (age = 24.1 ± 3.0 years, body height = 177.4 ± 5.2 cm, body mass = 72.3 ± 7.2 kg) volunteered to participant in this study. Joint kinematics were recorded whilst all participants performed three rotational lunges, in three conditions (control, compression garment, Kinesio Tape®), prior to and following a 10 minute exercise bout. Frontal plane kinematics (lateral pelvic tilt, knee valgus, ankle inversion/eversion) were used to assess Ergogenic Aid effectiveness during the lunge. Participants exhibited no significant differences in joint kinematics between Ergogenic Aid conditions prior to the exercise bout. Following exercise the only significant difference occurred within the Kinesio Tape® condition where maximum knee valgus angle significantly increased from 6.5° prior to exercise, to 7.7° following the exercise bout. The results of this study suggest joint kinematics are not affected by the Ergogenic Aids in this study prior to an exercise bout. However, there is evidence to suggest that the application of Kinesio Tape® may allow an increase in knee valgus angle following a bout of exercise, yet, compression garments are effective at maintaining joint alignment following a bout of exercise.

Muñoz Moreno Alejandro - One of the best experts on this subject based on the ideXlab platform.

  • Suplementación Deportiva en Balonmano: Efecto de la Cafeína e Influencia del CYP1A2 y ADORA2A en el Rendimiento Deportivo en Jugadores de Élite de Balonmano
    'Universidad Politecnica de Madrid - University Library', 2021
    Co-Authors: Muñoz Moreno Alejandro
    Abstract:

    El balonmano es una modalidad deportiva de carácter intermitente y de alta intensidad, donde las acciones explosivas son determinantes en el resultado final. Fruto de ello, la nutrición ha adquirido un papel imprescindible con el objetivo de maximizar las adaptaciones físicas y fisiológicas derivadas de los entrenamientos y competiciones, siendo cada vez más frecuente que los jugadores de balonmano recurran a la ingesta de suplementos deportivos con el objetivo de maximizar esas mejoras obtenidas a través del entrenamiento. Entre las ayudas ergogénicas que han demostrado una fuerte evidencia para mejorar el rendimiento deportivo podemos mencionar la cafeína; mostrando que su ingesta de forma aguda en dosis moderadas y bajas (2-6 mg·kg-1) repercute en un mayor rendimiento deportivo. Sin embargo, aunque esta ayuda ergogénica presenta una gran evidencia científica en otros deportes de carácter intermitente, esta se encuentra de manera escasa en el balonmano. La presente Tesis Doctoral busca evaluar y analizar los patrones de uso de los suplementos deportivos más consumidos en el balonmano. Además, de determinar los efectos de la ingesta aguda de la cafeína en el rendimiento deportivo en el balonmano en jugadoras de élite femeninas y analizar si el efecto de la cafeína puede estar mediado por los diferentes polimorfismos de dos genes implicados en el metabolismo de la cafeína como son el CYP1A2 y el ADORA2A. Para la consecución de estos objetivos se plantearon 3 estudios. En el estudio 1 se analizaron los patrones de uso de los suplementos deportivos en jugadores de balonmano en función del género y el nivel competitivo. Se seleccionó una muestra de 187 jugadores de balonmano (112 hombres y 75 mujeres) los cuales completaron un cuestionario autoadministrado y validado previamente sobre el uso de suplementos deportivos. La muestra se dividió en dos grupos: uno compuesto por 81 jugadores profesionales (1º división) y un segundo, formado por 106 jugadores amateurs (2º y 3º división). Los suplementos deportivos se clasificaron de acuerdo con la clasificación elaborada por el Instituto Australiano del Deporte (AIS). El análisis de los cuestionarios mostró que los jugadores de balonmano informaron de un uso moderado de suplementos deportivos (59,9 %). Respecto a la prevalencia en el uso de suplementos deportivos se encontraron mínimas diferencias en función del género y de los niveles competitivos de los jugadores. Además, los suplementos deportivos más consumidos por los jugadores de balonmano fueron: bebidas deportivas, barritas energéticas, cafeína, proteína de suero y creatina. Una vez constatado que la cafeína era uno de los suplementos deportivos más consumidos, en el estudio 2 se analizó el efecto agudo que provoca la ingesta de 3 mg·kg-1 de cafeína en los factores físicos determinantes del rendimiento deportivo en balonmano y su efecto durante un partido simulado en 15 jugadoras de élite de balonmano (1º División). Además, se analizaron los efectos secundarios derivados de la dosis de cafeína administrada. El análisis de los resultados mostró que la ingesta aguda de 3 mg·kg-1 de cafeína mejoró la capacidad de salto, la velocidad en sprint en distancias cortas, la fuerza isométrica manual de la mano dominante y la velocidad de lanzamiento. Con respecto al partido simulado, se observó que la ingesta de cafeína mejoraba la capacidad de realizar aceleraciones, desaceleraciones e impactos corporales con respecto a la situación placebo. Habiendo quedado demostrada la efectividad de la ingesta aguda de cafeína sobre el rendimiento deportivo en el balonmano, en el estudio 3 se analizó la influencia que tienen los genes CYP1A2 y ADORA2A relacionados con el metabolismo de la cafeína sobre el rendimiento en balonmano. Para ello, se realizó un estudio con tamaño muestral de 31 jugadores de balonmano (16 de categoría masculina y 15 de categoría femenina) de un equipo de élite (1º División). Los resultados mostraron que los jugadores de balonmano de élite obtuvieron beneficios similares con la ingesta aguda de 3 mg·kg-1 de cafeína independientemente de los genotipos del CYP1A2 y ADORA2A. Adicionalmente, los portadores de alelos C en CYP1A2 y los homocigotos TT en ADORA2A, reportaron efectos secundarios como insomnio, diuresis. En conclusión, los resultados derivados de los tres estudios que componen esta Tesis Doctoral sugieren que la cafeína es uno de los suplementos deportivos más consumidos y que puede tener una repercusión positiva sobre el rendimiento en el balonmano con independencia del genotipo del jugador. ----------ABSTRACT---------- Handball is an intermittent and high intensity sport modality, where explosive actions are crucial in the final result. As a result, nutrition has acquired an essential role in order to maximize the physical and physiological adaptations caused by training and competitions, being more and more frequent that handball players take sports supplements in order to maximize those improvements obtained through training. Among the Ergogenic Aids that have shown strong evidence to improve sports performance we can mention caffeine; showing that its acute intake in moderate and low doses (2-6 mg·kg-1) has an impact on greater sports performance. However, although this Ergogenic Aid presents great scientific evidence in other intermittent sports, it is scarcely found in handball. This Doctoral Thesis seeks to evaluate and analyze the patterns of the use of the most consumed sports supplements in handball. In addition, to determine the effects of acute caffeine ingestion on sports performance in handball in elite female players and to analyze whether the effect of caffeine may be mediated by the different polymorphisms of two genes involved in caffeine metabolism such as CYP1A2 and ADORA2A. To achieve these objectives, 3 studies were proposed. In study 1, the patterns of the use of sports supplements in handball players were analyzed according to gender and competitive level. A sample of 187 handball players (112 men and 75 women) was selected who completed a self-administered and previously validated questionnaire on the use of sports supplements. The sample is divided into two groups: one made up of 81 professional players (1st division) and a second one, made up of 106 amateur players (2nd and 3rd division). Sports supplements are classified according to the classification developed by the Australian Institute of Sport (AIS). Analysis of the questionnaires showed that handball players reported moderate use of sports supplements (59.9%). Regarding the prevalence in the use of sports supplements, minimal differences were found based on gender and the competitive levels of the players. In addition, the most consumed sports supplements by handball players were sports drinks, energy bars, caffeine, whey protein and creatine. Once it was verified that caffeine was one of the most consumed sports supplements, in study 2 the acute effect caused by the ingestion of 3 mg·kg-1 of caffeine on the physical determinants of sports performance in handball and its effect was analyzed during a simulated match in 15 elite handball players (1st Division). In addition, the side effects derived from the dose of caffeine administered were analyzed. The analysis of the results showed that the acute intake of 3 mg·kg-1 of caffeine improved jumping capacity, sprinting speed over short distances, manual isometric strength of the dominant hand and throwing speed. With regards to the simulated game, it is realized that caffeine intake improved the ability to perform accelerations, decelerations, and bodily impacts with respect to the placebo situation. Having demonstrated the effectiveness of acute caffeine ingestion on sports performance in handball, study 3 analyzed the influence of CYP1A2 and ADORA2A genes related to caffeine metabolism on handball performance. For this, a study was carried out with a sample size of 31 handball players (16 in the male category and 15 in the female category) from an elite team (1st Division). The results show that elite handball players obtained similar benefits with the acute intake of 3 mg·kg-1 of caffeine regardless of CYP1A2 and ADORA2A genotypes. In addition, carriers of alleles C in CYP1A2 and homozygous TT in ADORA2A, reported side effects such as insomnia and diuresis. In conclusion, the results derived from the three studies that make up this Doctoral Thesis suggest that caffeine is one of the most consumed sports supplements and that it can have a positive impact on handball performance regardless of the player's genotype