RESUMEN
AIM: To quantify the physiological demands and impact of muscle function t of the Fran workout, one of the most popular CrossFit benchmarks. METHODS: Twenty experienced CrossFitters-16 male: 29 (6) years old and 4 female: 26 (5) years old- performed 3 rounds (with 30-s rests in between) of 21-21, 15-15, and 9-9 front squats to overhead press plus pull-up repetitions. Oxygen uptake and heart rate were measured at baseline, during the workout, and in the recovery period. Rating of perceived exertion, blood lactate, and glucose concentrations were assessed at rest, during the intervals, and in the recovery period. Muscular fatigue was also monitored at rest and at 5 minutes, 30 minutes, and 24 hours postexercise. Repeated-measures analysis of variance was performed to compare time points. RESULTS: Aerobic (52%-29%) and anaerobic alactic (30%-23%) energy contributions decreased and the anaerobic lactic contribution increased (18%-48%) across the 3 rounds of the Fran workout. Countermovement jump height decreased by 8% (-12 to -3) mean change (95% CI), flight duration by 14% (-19 to -7), maximum velocity by 3% (-5 to -0.1), peak force 4% (-7 to -0.1), and physical performance (plank prone 47% [-54 to -38]) were observed. CONCLUSIONS: It appears that the Fran workout is a physically demanding activity that recruits energy from both aerobic and anaerobic systems. This severe-intensity workout evokes substantial postexercise fatigue and corresponding reduction in muscle function.
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Fatiga Muscular , Niño , Preescolar , Femenino , Humanos , Masculino , Metabolismo Energético , Frecuencia Cardíaca/fisiología , Fatiga Muscular/fisiologíaRESUMEN
Athletes often experience sleep disturbances and poor sleep as a consequence of extended travel, the timing of training and competition (i.e., early morning or evening), and muscle soreness. Nutrition plays a vital role in sports performance and recovery, and a variety of foods, beverages, and supplements purportedly have the capacity to improve sleep quality and quantity. Here, we review and discuss relevant studies regarding nutrition, foods, supplements, and beverages that may improve sleep quality and quantity. Our narrative review was supported by a semi-systematic approach to article searching, and specific inclusion and exclusion criteria, such that articles reviewed were relevant to athletes and sporting environments. Six databases-PubMed, Scopus, CINAHL, EMBASE, SPORTDiscus, and Google Scholar-were searched for initial studies of interest from inception to November 2020. Given the paucity of sleep nutrition research in the athlete population, we expanded our inclusion criteria to include studies that reported the outcomes of nutritional interventions to improve sleep in otherwise healthy adults. Carbohydrate ingestion to improve sleep parameters is inconclusive, although high glycemic index foods appear to have small benefits. Tart cherry juice can promote sleep quantity, herbal supplements can enhance sleep quality, while kiwifruit and protein interventions have been shown to improve both sleep quality and quantity. Nutritional interventions are an effective way to improve sleep quality and quantity, although further research is needed to determine the appropriate dose, source, and timing in relation to training, travel, and competition requirements.
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Atletas , Dieta , Sueño , Rendimiento Atlético , Bases de Datos Factuales , Carbohidratos de la Dieta/administración & dosificación , Proteínas en la Dieta/administración & dosificación , Suplementos Dietéticos , Frutas , Jugos de Frutas y Vegetales , Humanos , Mialgia/dietoterapia , Estudios Observacionales como Asunto , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
Gastrointestinal disturbances are one of the most common issues for endurance athletes during training and competition in the heat. The relationship between typical dietary intake or nutritional interventions and perturbations in or maintenance of gut integrity is unclear. Twelve well-trained male endurance athletes (peak oxygen consumption = 61.4 ± 7.0 ml·kg-1·min-1) completed two trials in a randomized order in 35 °C (heat) and 21 °C (thermoneutral) conditions and kept a detailed nutritional diary for eight consecutive days between the two trials. The treadmill running trials consisted of 15 min at 60% peak oxygen consumption, 15 min at 75% peak oxygen consumption, followed by 8 × 1-min high-intensity efforts. Venous blood samples were taken at the baseline, at the end of each of the three exercise stages, and 1 hr postexercise to measure gut integrity and the permeability biomarker concentration for intestinal fatty-acid-binding protein, lipopolysaccharide, and lipopolysaccharide-binding protein. The runners self-reported gut symptoms 1 hr postexercise and 3 days postexercise. The heat condition induced large (45-370%) increases in intestinal fatty-acid-binding protein, lipopolysaccharide-binding protein, and lipopolysaccharide concentrations compared with the baseline, but induced mild gastrointestinal symptoms. Carbohydrate and polyunsaturated fat intake 24 hr preexercise were associated with less lipopolysaccharide translocation. Protein, carbohydrate, total fat, and polyunsaturated fat intake (8 days) were positively associated with the percentage increase of intestinal fatty-acid-binding protein in both conditions (range of correlations, 95% confidence interval = .62-.93 [.02, .98]). Typical nutrition intake partly explained increases in biomarkers and the attenuation of symptoms induced by moderate- and high-intensity exercise under both heat and thermoneutral conditions.
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Ingestión de Alimentos , Tracto Gastrointestinal/fisiología , Calor , Esfuerzo Físico/fisiología , Carrera/fisiología , Adulto , Biomarcadores/sangre , Intervalos de Confianza , Estudios Cruzados , Registros de Dieta , Carbohidratos de la Dieta/administración & dosificación , Grasas de la Dieta/administración & dosificación , Ingestión de Energía , Proteínas de Unión a Ácidos Grasos/sangre , Ácidos Grasos Insaturados/administración & dosificación , Humanos , Lipopolisacáridos/sangre , Masculino , Consumo de Oxígeno , Acondicionamiento Físico Humano/fisiología , Resistencia Física , Fenómenos Fisiológicos en la Nutrición Deportiva , Factores de TiempoRESUMEN
Probiotic supplementation may offer team sport athletes a range of benefits beyond the immune and gastrointestinal systems. OBJECTIVES: To examine the effects of a probiotic formulation on perceptual markers of sleep quality and quantity, and muscle soreness, leg heaviness and motivation in elite rugby union athletes. METHODS: A double-blind randomised controlled trial involving 19 elite male rugby athletes was conducted over 17 weeks encompassing both domestic and international competition. Psychometric variables and salivary biomarkers were assessed twice a week. Athletes were assigned either a daily probiotic (Ultrabiotic 60™) and Saccharomyces boulardii (during international competition) or a placebo. Associations between psychometric scores for perceptual and salivary biomarkers of sleep (melatonin) and inflammation C-reactive protein (CRP) were investigated. RESULTS: Muscle soreness was â¼0.5 units lower (F(1, 343)=42.646, p<0.0001) and leg heaviness scores â¼0.7 units lower (F(1, 334)=28.990, p<0.0001) in the probiotic group compared to the placebo group. Across both groups, as self-reported muscle soreness scores and salivary CRP concentrations increased, sleep quantity, quality and motivation scores decreased. Conversely as muscle soreness scores and CRP decreased, sleep quantity and quality, and motivation scores improved. CONCLUSIONS: A long-term programme of probiotic supplementation in international-level rugby union players may yield favourable effects on self-reported muscle soreness and sleep quality associated with muscle soreness during training and competitions.
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Rendimiento Atlético/fisiología , Fútbol Americano/fisiología , Mialgia/prevención & control , Probióticos/administración & dosificación , Sueño/fisiología , Adulto , Rendimiento Atlético/psicología , Biomarcadores/metabolismo , Proteína C-Reactiva/metabolismo , Conducta Competitiva/fisiología , Método Doble Ciego , Fútbol Americano/lesiones , Fútbol Americano/psicología , Humanos , Pierna/fisiología , Masculino , Melatonina/metabolismo , Motivación , Psicometría , Saliva/metabolismo , Autoinforme , Adulto JovenRESUMEN
Heat waves represent a public health risk to elderly people, and typically result in an increased rate of hospital admissions and deaths. Studies of thermoregulation in this cohort have generally focused on single elements such as sweating capacity. Sweating capacity and skin blood flow reduce with age, reducing ability to dissipate heat. Perception of effort during heat exposure is emerging as an area that needs further investigation as the elderly appear to lack the ability to adequately perceive increased physiological strain during heat exposure. The role of the gut and endotoxemia in heat stress has received attention in young adults, while the elderly population has been neglected. This shortcoming offers another potential avenue for identifying effective integrated health interventions to reduce heat illnesses. Increasing numbers of elderly individuals in populations worldwide are likely to increase the incidence of heat wave-induced deaths if adequate interventions are not developed, evaluated, and implemented. In this narrative-style review we identify and discuss health-related interventions for reducing the impact of heat illnesses in the elderly.
RESUMEN
Upper respiratory symptoms remain the most common illness in athletes. Upper respiratory symptoms during heavy training and competition may impair performance. Preventing illness is the primary reason for the use of supplements, such as probiotics and prebiotics, for maintaining or promoting gut health and immune function. While exercise-induced perturbations in the immune system may increase susceptibility to illness and infection, growing evidence indicates that upper respiratory symptoms are related to a breakdown in the homeostatic regulation of the mucosal immune system of the airways. Balancing protection of the respiratory tract with normal physiological functioning requires dynamic orchestration between a wide array of immune parameters. The intestinal microbiota regulates extra-intestinal immunity via the common mucosal immune system and new evidence implicates the microbiota of the nose, mouth and respiratory tract in upper respiratory symptoms. Omics' approaches now facilitate comprehensive profiling at the molecular and proteomic levels to reveal new pathways and molecules of immune regulation. New targets may provide for personalised nutritional and training interventions to maintain athlete health.
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Atletas , Inmunidad Mucosa , Proteómica , Infecciones del Sistema Respiratorio/prevención & control , Suplementos Dietéticos , Ejercicio Físico/fisiología , Humanos , Probióticos , Fenómenos Fisiológicos en la Nutrición DeportivaRESUMEN
BACKGROUND: Given the likely influence that high training loads, contact-induced hemolysis and female-specific requirements have on the incidence of iron deficiency, characterizing the direction and magnitude of fluctuations in iron status over an international season is important for managing player health and physical performance in rugby sevens. METHODS: Australian national male (N.=27) and female (N.=23) rugby sevens players undertook blood tests at pre-season, mid-season, and end-season. Hemoglobin (Hb), hematocrit (Hct), ferritin, transferrin and transferrin saturation were quantified. Female athletes also reported oral contraceptive use and a subset (N.=7) provided 7-day food diaries to quantify iron intake. RESULTS: Male players typically had a three-fold higher ferritin concentration than females. Pre-season ferritin concentrations in male (151±66 µg/L) and female (51±24 µg/L) players declined substantially (~20%) by mid-season but recovered by end-season. Over the season 23% of female players were classified as iron deficient (ferritin <30 µg/L) and prescribed supplementation. The greatest incidence of iron deficiency in female players occurred mid-season (30%). Oral contraception and dietary iron intake had an unclear influence on female players' ferritin concentration, while age was largely positively correlated (r=0.66±~0.33). CONCLUSIONS: Given the relatively low ferritin concentrations evident in female rugby sevens players, and the potential for a further decline midway through a season when physical load may be at its highest, 6-monthly hematological reviews are suggested in combination with dietary management. Annual screening may be beneficial for male players, with further monitoring only when clinically indicated.
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Fútbol Americano , Hierro/sangre , Fenómenos Fisiológicos en la Nutrición Deportiva , Adulto , Atletas , Australia , Femenino , Ferritinas/análisis , Hematócrito , Hemoglobinas/análisis , Humanos , Deficiencias de Hierro , Estudios Longitudinales , Masculino , Factores de Tiempo , Transferrina/análisis , Adulto JovenAsunto(s)
Probióticos/administración & dosificación , Linfocitos T Reguladores/efectos de los fármacos , Adulto , Linfocitos T CD4-Positivos/efectos de los fármacos , Suplementos Dietéticos , Método Doble Ciego , Femenino , Humanos , Masculino , Infecciones del Sistema Respiratorio/tratamiento farmacológicoRESUMEN
Heat and hypoxia exacerbate central nervous system (CNS) fatigue. We therefore investigated whether essential amino acid (EAA) and caffeine ingestion attenuates CNS fatigue in a simulated team sport-specific running protocol in a hot, hypoxic environment. Subelite male team sport athletes (n = 8) performed a repeat sprint running protocol on a nonmotorized treadmill in an extreme environment on 4 separate occasions. Participants ingested one of four supplements: a double placebo, 3 mg.kg-1 body mass of caffeine + placebo, 2 x 7 g EAA (Musashi Create)+placebo, or caffeine + EAA before each exercise session using a randomized, double-blind crossover design. Electromyography (EMG) activity and quadriceps evoked responses to magnetic stimulation were assessed from the dominant leg at preexercise, halftime, and postexercise. Central activation ratio (CAR) was used to quantify completeness of quadriceps activation. Oxygenation of the prefrontal cortex was measured via near-infrared spectroscopy. Mean sprint work was higher (M = 174 J, 95% CI [23, 324], p < .05, d = 0.30; effect size, likely beneficial) in the caffeine + EAA condition versus EAAs alone. The decline in EMG activity was less (M = 13%, 95% CI [0, 26]; p < .01, d = 0.58, likely beneficial) in caffeine + EAA versus EAA alone. Similarly, the pre- to postexercise decrement in CAR was significantly less (M = -2.7%, 95% CI [0.4, 5.4]; p < .05, d = 0.50, likely beneficial) when caffeine + EAA were ingested compared with placebo. Cerebral oxygenation was lower (M = -5.6%, 95% CI [1.0, 10.1]; p < .01, d = 0.60, very likely beneficial) in the caffeine + EAA condition compared with LNAA alone. Co-ingestion of caffeine and EAA appears to maintain muscle activation and central drive, with a small improvement in running performance.
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Aminoácidos/administración & dosificación , Rendimiento Atlético/fisiología , Cafeína/administración & dosificación , Músculo Cuádriceps/efectos de los fármacos , Carrera/fisiología , Fenómenos Fisiológicos en la Nutrición Deportiva , Aminoácidos/sangre , Atletas , Cafeína/sangre , Estudios Cruzados , Suplementos Dietéticos , Método Doble Ciego , Electromiografía , Prueba de Esfuerzo , Fútbol Americano , Calor , Humanos , Masculino , Fatiga Muscular/efectos de los fármacos , Músculo Cuádriceps/fisiología , Adulto JovenRESUMEN
Upper respiratory illness is the most common reason for non-injury-related presentation to a sports medicine clinic, accounting for 35-65% of illness presentations. Recurrent or persistent respiratory illness can have a negative impact on health and performance of athletes undertaking high levels of strenuous exercise. The cause of upper respiratory symptoms (URS) in athletes can be uncertain but the majority of cases are related to common respiratory viruses, viral reactivation, allergic responses to aeroallergens and exercise-related trauma to the integrity of respiratory epithelial membranes. Bacterial respiratory infections are uncommon in athletes. Undiagnosed or inappropriately treated asthma and/or allergy are common findings in clinical assessments of elite athletes experiencing recurrent URS. High-performance athletes with recurrent episodes of URS should undergo a thorough clinical assessment to exclude underlying treatable conditions of respiratory inflammation. Identifying athletes at risk of recurrent URS is important in order to prescribe preventative clinical, training and lifestyle strategies. Monitoring secretion rates and falling concentrations of salivary IgA can identify athletes at risk of URS. Therapeutic interventions are limited by the uncertainty of the underlying cause of inflammation. Topical anti-inflammatory sprays can be beneficial for some athletes. Dietary supplementation with bovine colostrum, probiotics and selected antioxidants can reduce the incidence or severity of URS in some athletes. Preliminary studies on athletes prone to URS indicate a genetic predisposition to a pro-inflammatory response and a dysregulated anti-inflammatory cytokine response to intense exercise as a possible mechanism of respiratory inflammation. This review focuses on respiratory infections and inflammation in elite/professional athletes.
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Asma Inducida por Ejercicio/inmunología , Atletas , Rendimiento Atlético , Ejercicio Físico , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/inmunología , Animales , Antiinflamatorios/uso terapéutico , Antioxidantes/uso terapéutico , Asma Inducida por Ejercicio/terapia , Suplementos Dietéticos , Ejercicio Físico/fisiología , Humanos , Inflamación/epidemiología , Inflamación/inmunología , Inflamación/terapia , Probióticos/uso terapéutico , Infecciones del Sistema Respiratorio/terapiaRESUMEN
Probiotic supplementation has traditionally focused on gut health. However, in recent years, the clinical applications of probiotics have broadened to allergic, metabolic, inflammatory, gastrointestinal and respiratory conditions. Gastrointestinal health is important for regulating adaptation to exercise and physical activity. Symptoms such as nausea, bloating, cramping, pain, diarrhoea and bleeding occur in some athletes, particularly during prolonged exhaustive events. Several studies conducted since 2006 examining probiotic supplementation in athletes or highly active individuals indicate modest clinical benefits in terms of reduced frequency, severity and/or duration of respiratory and gastrointestinal illness. The likely mechanisms of action for probiotics include direct interaction with the gut microbiota, interaction with the mucosal immune system and immune signalling to a variety of organs and systems. Practical issues to consider include medical and dietary screening of athletes, sourcing of recommended probiotics and formulations, dose-response requirements for different probiotic strains, storage, handling and transport of supplements and timing of supplementation in relation to travel and competition.
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Atletas , Suplementos Dietéticos , Probióticos , Fenómenos Fisiológicos en la Nutrición Deportiva/fisiología , Adolescente , Adulto , Anciano , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
In this review, we outline key principles for prevention of injury and illness in aquatic sports, detail the epidemiology of injury and illness in aquatic athletes at major international competitions and in training, and examine the relevant scientific evidence on nutrients for reducing the risk of illness and injury. Aquatic athletes are encouraged to consume a well-planned diet with sufficient calories, macronutrients (particularly carbohydrate and protein), and micronutrients (particularly iron, zinc, and vitamins A, D, E, B6, and B12) to maintain health and performance. Ingesting carbohydrate via sports drinks, gels, or sports foods during prolonged training sessions is beneficial in maintaining energy availability. Studies of foods or supplements containing plant polyphenols and selected strains of probiotic species are promising, but further research is required. In terms of injury, intake of vitamin D, protein, and total caloric intake, in combination with treatment and resistance training, promotes recovery back to full health and training.
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Traumatismos en Atletas/prevención & control , Dieta , Salud , Necesidades Nutricionales , Estado Nutricional , Natación , Humanos , Micronutrientes/uso terapéutico , Polifenoles/uso terapéutico , DeportesRESUMEN
Elite athletes who compete in aquatic sports face the constant challenge of arduous training and competition schedules in difficult and changing environmental conditions. The huge range of water temperatures to which swimmers and other aquatic athletes are often exposed (16-31 °C for open-water swimming), coupled with altered aquatic thermoregulatory responses as compared with terrestrial athletes, can challenge the health, safety, and performance of these athletes. Other environmental concerns include air and water pollution, altitude, and jetlag and travel fatigue. However, these challenging environments provide the potential for several nutritional interventions that can mitigate the negative effects and enhance adaptation and performance. These interventions include providing adequate hydration and carbohydrate and iron intake while at altitude; optimizing body composition and fluid and carbohydrate intake when training or competing in varying water temperatures; and maximizing fluid and food hygiene when traveling. There is also emerging information on nutritional interventions to manage jetlag and travel fatigue, such as the timing of food intake and the strategic use of caffeine or melatonin. Aquatic athletes often undertake their major global competitions where accommodations feature cafeteria-style buffet eating. These environments can often lead to inappropriate choices in the type and quantity of food intake, which is of particular concern to divers and synchronized swimmers who compete in physique-specific sports, as well as swimmers who have a vastly reduced energy expenditure during their taper. Taken together, planned nutrition and hydration interventions can have a favorable impact on aquatic athletes facing varying environmental challenges.
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Adaptación Fisiológica , Dieta , Ambiente , Conducta Alimentaria , Fenómenos Fisiológicos en la Nutrición Deportiva , Estrés Fisiológico , Natación , Altitud , Composición Corporal , Deshidratación/prevención & control , Suplementos Dietéticos , Fatiga/prevención & control , Humanos , Síndrome Jet Lag , Deportes , Temperatura , Viaje , AguaRESUMEN
BACKGROUND & AIMS: To examine the effect of supplementation with probiotics on respiratory and gastrointestinal illness in healthy active men and women. METHODS: A randomised double-blind placebo-controlled trial was conducted. Four hundred and sixty five participants (241 males; age 35 ± 12 y (mean ± SD) and 224 females; age 36 ± 12 y) were assigned to one of three groups: Group 1 - Bifidobacterium animalis subsp. lactis Bl-04 (Bl-04) 2.0 × 10(9)colony forming units per day, CFU per day, Group 2 - Lactobacillus acidophilus NCFM and Bifidobacterium animalis subsp. lactis Bi-07 (NCFM & Bi-07) 5 × 10(9) CFU each per day) or Group 3 - placebo mixed in a drink. RESULTS: The risk of an upper respiratory illness episode was significantly lower in the Bl-04 group (hazard ratio 0.73; 95% confidence interval 0.55-0.95; P = 0.022) compared to placebo. There was no significant difference in illness risk between the NCFM & Bi-07 group (hazard ratio 0.81; 0.62-1.08; P = 0.15) and the placebo group. There was a 0.7 and 0.9 month delay in the median time to an illness episode in the Bl-04 and NCFM & Bi-07 groups respectively compared to placebo (placebo 2.5 months; Bl-04 3.2 months; NCFM & Bi-07 3.4 months). There were insufficient GI illness episodes for analysis. The NCFM & Bi-07 group but not the Bl-04 group undertook significantly more physical activity (8.5%; 6.7%-10%; P < 0.003) than the placebo group. CONCLUSION: The probiotic Bl-04 appears to be a useful nutritional supplement in reducing the risk of URTI in healthy physically-active adults. TRIAL REGISTRATION: Australia New Zealand Clinical Trials Registry: Number ACTRN12611000130965.
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Suplementos Dietéticos , Enfermedades Gastrointestinales/terapia , Probióticos/administración & dosificación , Adulto , Bifidobacterium , Índice de Masa Corporal , Método Doble Ciego , Femenino , Voluntarios Sanos , Humanos , Lactobacillus acidophilus , Masculino , Persona de Mediana Edad , Actividad Motora , Nueva Zelanda , Adulto JovenRESUMEN
BACKGROUND: Butyrate delivery to the large bowel may positively modulate commensal microbiota and enhance immunity. OBJECTIVE: To determine the effects of increasing large bowel butyrate concentration through ingestion of butyrylated high amylose maize starch (HAMSB) on faecal biochemistry and microbiota, and markers of immunity in healthy active individuals. DESIGN: Male and female volunteers were assigned randomly to consume either two doses of 20 g HAMSB (n = 23; age 37.9 +/- 7.8 y; mean +/- SD) or a low amylose maize starch (LAMS) (n = 18; age 36.9 = 9.5 y) twice daily for 28 days. Samples were collected on days 0, 10 and 28 for assessment of faecal bacterial groups, faecal biochemistry, serum cytokines and salivary antimicrobial proteins. RESULTS: HAMSB led to relative increases in faecal free (45%; 12-86%; mean; 90% confidence interval; P = 0.02), bound (950%; 563-1564%; P < 0.01) and total butyrate (260%; 174-373%; P < 0.01) and faecal propionate (41%; 12-77%; P = 0.02) from day 0 to day 28 compared to LAMS. HAMSB was also associated with a relative 1.6-fold (1.2- to 2.0-fold; P < 0.01) and 2.5-fold (1.4- to 4.4-fold; P = 0.01) increase in plasma IL-10 and TNF-alpha but did not alter other indices of immunity. There were relative greater increases in faecal P. distasonis (81-fold (28- to 237-fold; P < 0.01) and F. prausnitzii (5.1-fold (2.1- to 12-fold; P < 0.01) in the HAMSB group. CONCLUSIONS: HAMSB supplementation in healthy active individuals promotes the growth of bacteria that may improve bowel health and has only limited effects on plasma cytokines.
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Butiratos/farmacología , Colon/efectos de los fármacos , Colon/microbiología , Citocinas/biosíntesis , Almidón/farmacología , Adulto , Butiratos/inmunología , Colon/inmunología , Fibras de la Dieta/administración & dosificación , Suplementos Dietéticos , Método Doble Ciego , Heces/química , Femenino , Humanos , Masculino , Reacción en Cadena en Tiempo Real de la Polimerasa , Saliva/química , Saliva/inmunología , Almidón/inmunologíaRESUMEN
Although some laboratory-based studies show an ergogenic effect with beta-alanine supplementation, there is a lack of field-based research in training and competition settings. Elite/Sub-elite swimmers (n = 23 males and 18 females, age = 21.7 ± 2.8 years; mean ± SD) were supplemented with either beta-alanine (4 weeks loading phase of 4.8 g/day and 3.2 g/day thereafter) or placebo for 10 weeks. Competition performance times were log-transformed, then evaluated before (National Championships) and after (international or national selection meet) supplementation. Swimmers also completed three standardized training sets at baseline, 4 and 10 weeks of supplementation. Capillary blood was analyzed for pH, bicarbonate and lactate concentration in both competition and training. There was an unclear effect (0.4%; ± 0.8%, mean, ± 90% confidence limits) of beta-alanine on competition performance compared to placebo with no meaningful changes in blood chemistry. While there was a transient improvement on training performance after 4 weeks with beta-alanine (-1.3%; ± 1.0%), there was an unclear effect at ten weeks (-0.2%; ± 1.5%) and no meaningful changes in blood chemistry. Beta-alanine supplementation appears to have minimal effect on swimming performance in non-laboratory controlled real-world training and competition settings.
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Rendimiento Atlético , Estimulantes del Sistema Nervioso Central/farmacología , Conducta Competitiva/efectos de los fármacos , Suplementos Dietéticos , Educación y Entrenamiento Físico , Natación/fisiología , beta-Alanina/farmacología , Adulto , Atletas , Análisis Químico de la Sangre , Método Doble Ciego , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
Synbiotic supplements, which contain multiple functional ingredients, may enhance the immune system more than the use of individual ingredients alone. A double blind active controlled parallel trial over a 21 d exercise training period was conducted to evaluate the effect of Gut Balance™, which contains Lactobacillus paracasei subsp. paracasei (L. casei 431®), Bifidobacterium animalis ssp. lactis (BB-12®), Lactobacillus acidophilus (LA-5®), Lactobacillus rhamnosus (LGG®), two prebiotics (raftiline and raftilose) and bovine whey derived lactoferrin and immunoglobulins with acacia gum on fecal microbiota, short chain fatty acids (SCFA), gut permeability, salivary lactoferrin and serum cytokines. All subjects randomized were included in the analysis. There was a 9-fold (1.2-fold to 64-fold; 95% confidence intervals p = 0.03) greater increase in fecal L. paracasei numbers with Gut Balance™ compared with acacia gum supplementation. Gut Balance™ was associated with a 50% (-12% to 72%; p = 0.02) smaller increase in the concentration of serum IL-16 in comparison to acacia gum from pre- to post-study. No substantial effects of either supplement were evident in fecal SCFA concentrations, measures of mucosal immunity or GI permeability. Clinical studies are now required to determine whether Gut Balance™ may exert beneficial GI health effects by increasing the recovery of fecal L. paracasei. Both supplements had little effect on immunity. Twenty two healthy physically active male subjects (mean age = 33.9 ± 6.5y) were randomly allocated to either daily prebiotic or synbiotic supplementation for 21 d. Saliva, blood, urine and fecal samples were collected pre-, mid and post-intervention. Participants recorded patterns of physical activity on a self-reported questionnaire.
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Carga Bacteriana , Dieta/métodos , Tracto Gastrointestinal/microbiología , Tracto Gastrointestinal/fisiología , Lactobacillus/aislamiento & purificación , Simbióticos , Adulto , Citocinas/sangre , Método Doble Ciego , Ácidos Grasos/análisis , Heces/química , Heces/microbiología , Tracto Gastrointestinal/inmunología , Humanos , Lactoferrina/análisis , Masculino , Saliva/química , Suero/químicaRESUMEN
This study investigated the effects of high-dose large neutral amino acid (LNAA) supplementation on attenuating fatigue-induced decrements in exercise and motor skill performance in Australian Rules Football (ARF) players. Fifteen subelite ARF players participated in 3 testing sessions separated by 7 days. Players completed an initial control trial involving a reactive motor skills test (RMST) and a reactive agility test (RAT) carried out before and after fatiguing exercise. In the subsequent experimental trials, players ingested a serotonin-depleting or protein control (PC) LNAA mixture 3 h before testing, allocated in a double-blind randomized cross-over design. Blood samples were taken at presupplementation and pre- and postexercise for analysis of plasma amino acid, insulin, and metabolite concentrations. The effect of the LNAA was established as the difference in the change in the mean RMST and RAT test scores among the depleting, PC, and baseline (BL) trials. Mean overall repetition time of the RAT was moderately improved by -5.2% ± 3.4% (mean ± 90% confidence limits; effect size -0.45 ± 0.28) after ingestion of the serotonin-depleting mixture compared with the BL trial. Serotonin-depleting and PC supplements had a divergent effect on mean repetition time after fatiguing exercise in RMST: depleting serotonin elicited a small improvement (-3.0% ± 2.7%) in motor skill performance in contrast to a small decrement (2.4% ± 2.7%) after ingestion of the PC mixture, when compared to the BL. High-dose serotonin-"depleting" LNAA supplementation given 3 h prior to intermittent high-intensity exercise improved reactive motor skill and agility performance in ARF players.
Asunto(s)
Aminoácidos Neutros/uso terapéutico , Rendimiento Atlético , Cognición , Toma de Decisiones , Suplementos Dietéticos , Fatiga/prevención & control , Destreza Motora , Adulto , Aminoácidos Neutros/administración & dosificación , Aminoácidos Neutros/sangre , Atletas/psicología , Rendimiento Atlético/psicología , Australia , Estudios Cruzados , Proteínas en la Dieta/administración & dosificación , Proteínas en la Dieta/uso terapéutico , Método Doble Ciego , Fatiga/sangre , Fatiga/fisiopatología , Fatiga/psicología , Fútbol Americano , Humanos , Masculino , Resistencia Física , Antagonistas de la Serotonina/administración & dosificación , Antagonistas de la Serotonina/sangre , Antagonistas de la Serotonina/uso terapéutico , Triptófano/antagonistas & inhibidores , Triptófano/sangre , Adulto JovenRESUMEN
Bicarbonate loading is a popular ergogenic aid used primarily by athletes in short-duration, high-intensity sporting events and competitions. Controlled experimental trials have shown that small (worthwhile) benefits can obtained from acute doses of bicarbonate taken before exercise. Gastrointestinal problems encountered by some athletes limit the widespread use of this practice, however. The transfer of positive research findings to the competitive environment has proved problematic for some individuals. More recent applications involve serial ingestion of bicarbonate over several days before competition or during high-intensity training sessions over a few weeks. A number of research questions need to be addressed to enhance applications of bicarbonate loading in the elite sport environment. This commentary examines some of research and practical issues of bicarbonate loading used to enhance both training and competitive performance.