Effects of oral creatine supplementation on high intensity, intermittent exercise performance in competitive squash players

The purpose of this study was to determine the effects of oral creatine supplementation on high intensity, intermittent exercise performance in competitive squash players. Nine squash players (mean ± SEM V˙O2max = 61.9 ± 2.1ml · kg-1 · min-1; body mass = 73 ± 3 kg) performed an on-court “ghosting” routine that involved 10 sets of 2 repetitions of simulated positional play, each set interspersed with 30 s passive recovery. A double blind, crossover design was utilised whereby experimental and control groups supplemented 4 times daily for 5 d with 0.075 g · kg-1 body mass of creatine monohydrate and maltodextrine, respectively, and a 4 wk washout period separated the crossover of treatments. The experimental group improved mean set sprint time by 3.2 ± 0.8 % over and above the changes noted for the control group (P = 0.004 and 95 % Cl = 1.4 to 5.1 %). Sets 2 to 10 were completed in a significantly shorter time following creatine supplementation compared to the placebo condition (P < 0.05). In conclusion, these data support existing evidence that creatine supplementation improves high intensity, intermittent exercise performance. In addition, the present study provides new evidence that oral creatine supplementation improves exercise performance in competitive squash players

Los carbohidratos durante el ejercicio: la investigación de los últimos 10 años. Nuevas recomendaciones

Durante los últimos años se han producido cambios significativos en la comprensión del papel que juegan los carbohidratos durante el ejercicio, y esto permite realizar un asesoramiento más específico y más individualizado en cuanto a la ingestión de carbohidratos durante el ejercicio. Las nuevas directrices propuestas tienen en cuenta la duración (y la intensidad) del ejercicio y el asesoramiento no se limita a la cantidad de carbohidratos, sino que también propone el tipo de estos. La ingesta recomendada de carbohidratos se puede lograr consumiendo bebidas, geles con pocas grasas o alimentos sólidos bajos en proteínas y en fibra (barritas) y la elección debe basarse en las preferencias personales. Debe tenerse en cuenta que la mayoría de estudios se basan en descubrimientos realizados con corredores y ciclistas, por lo que es necesario investigar más para establecer los efectos y los mecanismos subyacentes de la ingestión de carbohidratos en los componentes de habilidad de deportes intermitentes de equipo.Durante los últimos años se han producido cambios significativos en la comprensión del papel que juegan los carbohidratos durante el ejercicio, y esto permite realizar un asesoramiento más específico y más individualizado en cuanto a la ingestión de carbohidratos durante el ejercicio. Las nuevas directrices propuestas tienen en cuenta la duración (y la intensidad) del ejercicio y el asesoramiento no se limita a la cantidad de carbohidratos, sino que también propone el tipo de estos. La ingesta recomendada de carbohidratos se puede lograr consumiendo bebidas, geles con pocas grasas o alimentos sólidos bajos en proteínas y en fibra (barritas) y la elección debe basarse en las preferencias personales. Debe tenerse en cuenta que la mayoría de estudios se basan en descubrimientos realizados con corredores y ciclistas, por lo que es necesario investigar más para establecer los efectos y los mecanismos subyacentes de la ingestión de carbohidratos en los componentes de habilidad de deportes intermitentes de equipo

Els carbohidrats durant l’exercici: la recerca dels darrers 10 anys. Noves recomanacions

Durant els darrers anys s’han produït canvis significatius en la manera d’entendre el paper que juguen els carbohidrats durant l’exercici, i això permet realitzar un assessorament més específic i més individualitzat pel que fa a la ingestió de carbohidrats durant l’exercici. Les noves directrius proposades tenen en compte la durada (i la intensitat) de l’exercici i l’assessorament no es limita a la quantitat de carbohidrats, sinó que també en proposa el tipus. La ingesta recomanada de carbohidrats es pot assolir consumint begudes, gels amb pocs greixos o aliments sòlids baixos en proteïnes i en fibra (barretes) i l’elecció s’ha de basar en les preferències personals. Cal tenir en compte que la majoria d’estudis es basen en descobriments realitzats amb corredors i ciclistes, per la qual cosa cal investigar més per establir els efectes i els mecanismes subjacents de la ingestió de carbohidrats en els components d’habilitat d’esports intermitents d’equip

Mouth Rinsing With Carbohydrate Solutions at the Postprandial State Fail to Improve Performance During Simulated Cycling Time Trials.

Mouth-rinsing with carbohydrate solutions during cycling time trials results in performance enhancements, however the majority of studies have utilised ∼6% carbohydrate solutions. Therefore, the purpose of this study was to compare the effectiveness of mouth-rinsing with 4%, 6%, and 8% carbohydrate (CHO) solutions on 1-h simulated cycling time trial performance. On four occasions, seven trained male cyclists completed at the postprandial period, a set amount of work as fast as possible in a randomised, counterbalanced order. The subjects mouth rinsed for 5-s, upon completion of each 12.5% of the trial, with 25 mL of a non-CHO placebo, 4%, 6%, and 8% CHO solutions. No additional fluids were consumed during the time trial. Heart rate (HR), ratings of perceived exertion (RPE), thirst (TH) and subjective feelings (SF) were recorded after each rinse. Further, blood samples were drawn every 25% of the trial to measure blood glucose (BG) and blood lactate (BG) concentrations, whilst whole body carbohydrate oxidation was monitored continuously. Time to completion was not significant between conditions with the placebo, 4%, 6%, and 8% conditions completing the trials in 62.0 ± 3.0, 62.8 ± 4.0, 63.4 ± 3.4, and 63 ±4.0 minutes respectively. There were no significant differences between conditions in any of the variables mentioned above however significant time effects were observed for HR, RPE, TH, and SF. Post-hoc analysis showed that TH and SF of subjects in the CHO conditions but not in the placebo were significantly increased by completion of the time trial. In conclusion, mouth-rinsing with CHO solutions did not impact 1-h cycling performance in the postprandial period and in the absence of fluid intake. Our findings suggest that there is scope for further research to explore the activation regions of the brain and whether they are receptive to CHO dose, before specific recommendations for athletic populations are established. Consequently mouth-rinsing as a practical strategy for coaches and athletes is questionable under specific conditions and should be carefully considered before its inclusion. The emphasis should be focused on appropriate dietary and fluid strategies during training and competition

Effect of Mouth Rinsing and Ingestion of Carbohydrate Solutions on Mood and Perceptual Responses During Exercise

Background: The aim of this study was to investigate whether mouth rinsing or ingesting carbohydrate (CHO) solutions impact on perceptual responses during exercise. Methods: Nine moderately trained male cyclists underwent a 90-min glycogen-reducing exercise, and consumed a low CHO meal, prior to completing an overnight fast. A 1-h cycle time trial was performed the following morning. Four trials, each separated by 7days, were conducted in a randomized, counterbalanced study design: 15% CHO mouth rinse (CHOR), 7.5% CHO ingestion (CHOI), placebo mouth rinse (PLAR) and placebo ingestion (PLAI). Solution volumes (1.5ml·g-1 ingestion trials and 0.33ml·kg-1 rinsing trials) were provided after every 12.5% of completed exercise. Perceptual scales were used to assess affective valence (feeling scale, FS), arousal (felt arousal scale, FAS), exertion (ratings of perceived exertion, RPE) and mood (profile of mood states, POMS) before, during and immediately after exercise. Results: There was no difference in RPE (CHOI, 14.0±9; CHOR, 14.2±.7; PLAI, 14.6±1.8; PLAR, 14.6±2.0; P=0.35), FS (CHOI, 0.0±1.7; CHOR, -0.2±1.5; PLAI, -0.8±1.4; PLAR, -0.8±1.6; P0.15), or FAS (CHOI, 3.6±1.1; CHOR, 3.5±1.0; PLAI, 3.4±1.4; PLAR, 3.3±1.3; P=725) scores between trials. While overall POMS score did not appear to differ between trials, the 'vigour' subscale indicated that CHOI may facilitate the maintenance of 'vigour' scores over time, in comparison to the steady decline witnessed in other trials (P=0.04). There was no difference in time trial performance between trials (CHOI, 65.3±4.8min; CHOR, 68.4±3.9min; PLAI, 68.7±5.3min; PLAR, 68.3±5.2min; P=0.21) but power output was higher in CHOI (231.0±33.2 W) relative to other trials (221-223.6 W; Plt0.01). Conclusions: In a CHO-reduced state, mouth rinsing with a CHO solution did not impact on perceptual responses during high-intensity exercise in trained cyclists and triathletes. On the other hand CHO ingestion improved perceived ratings of vigour and increased power output during exercise

Nutrition Strategies for Triathlon

Contemporary sports nutrition guidelines recommend that each athlete develop a personalised, periodised and practical approach to eating that allows him or her to train hard, recover and adapt optimally, stay free of illness and injury and compete at their best at peak races. Competitive triathletes undertake a heavy training programme to prepare for three different sports while undertaking races varying in duration from 20 min to 10 h. The everyday diet should be adequate in energy availability, provide CHO in varying amounts and timing around workouts according to the benefits of training with low or high CHO availability and spread high-quality protein over the day to maximise the adaptive response to each session. Race nutrition requires a targeted and well-practised plan that maintains fuel and hydration goals over the duration of the specific event, according to the opportunities provided by the race and other challenges, such as a hot environment. Supplements and sports foods can make a small contribution to a sports nutrition plan, when medical supplements are used under supervision to prevent/treat nutrient deficiencies (e.g. iron or vitamin D) or when sports foods provide a convenient source of nutrients when it is impractical to eat whole foods. Finally, a few evidence-based performance supplements may contribute to optimal race performance when used according to best practice protocols to suit the triathlete’s goals and individual responsiveness

The effect of pre-exercise galactose and glucose ingestion on high-intensity endurance cycling.

This study evaluated the effects of the pre-exercise (30 minutes) ingestion of galactose (Gal) or glucose (Glu) on endurance capacity as well as glycemic and insulinemic responses. Ten trained male cyclists completed 3 randomized high-intensity cycling endurance tests. Thirty minutes before each trial, cyclists ingested 1 L of either 40 g of glucose, 40 g of galactose, or a placebo in a double-blind manner. The protocol comprised 20 minutes of progressive incremental exercise (70-85% maximal power output [Wmax]); ten 90-second bouts at 90% Wmax, separated by 180 seconds at 55% Wmax; and 90% Wmax until exhaustion. Blood samples were drawn throughout the protocol. Times to exhaustion were longer with Gal (68.7 ± 10.2 minutes, p = 0.005) compared with Glu (58.5 ± 24.9 minutes), with neither being different to placebo (63.9 ± 16.2 minutes). Twenty-eight minutes after Glu consumption, plasma glucose and serum insulin concentrations were higher than with Gal and placebo (p < 0.001). After the initial 20 minutes of exercise, plasma glucose concentrations increased to a relative hyperglycemia during the Gal and placebo, compared with Glu condition. Higher plasma glucose concentrations during exercise, and the attenuated serum insulin response at rest, may explain the significantly longer times to exhaustion produced by Gal compared with Glu. However, neither carbohydrate treatment produced significantly longer times to exhaustion than placebo, suggesting that the pre-exercise ingestion of galactose and glucose alone is not sufficient to support this type of endurance performance

The thermic effect of sugar-free Red Bull: Do the non-caffeine bioactive ingredients in energy drinks play a role?

Objective: Consumption of energy drinks is increasing amongst athletes and the general public. By virtue of their bioactive ingredients (including caffeine, taurine, glucuronolactone, and B-group vitamins) and paucity of calories, sugar-free “diet” versions of these drinks could be a useful aid for weight maintenance. Yet little is known about the acute influence of these drinks, and specifically the role of the cocktail of non-caffeine ingredients, on resting energy expenditure (REE) and substrate oxidation. Therefore, the metabolic impact of sugar-free Red Bull (sfRB) to a comparable amount of caffeine was compared.Methods: REE and respiratory quotient (RQ) were measured in eight healthy young men by ventilated-hood indirect calorimetry for 30 min baseline and 2 h following ingestion of 355 ml of either: sfRB +  placebo, water + 120 mg caffeine, or water + placebo, according to a randomized cross-over design.Results: sfRB and water + caffeine both increased REE to the same degree (+4%). Additionally, sfRB briefly increased RQ. Water + caffeine had no effect on RQ relative to water + placebo.Conclusions: sfRB enhanced thermogenesis and marginally shifted RQ to favor carbohydrate oxidation. The stimulatory effects of sfRB on REE are mimicked by water + caffeine, indicating that the auxiliary ingredients do not influence this thermic effect. The metabolic effects of sfRB are primarily due to caffeine alone

Placebo in sports nutrition: a proof-of-principle study involving caffeine supplementation

We investigated the effects of supplement identification on exercise performance with caffeine supplementation. Forty-two trained cyclists (age 37 ± 8 years, body mass [BM] 74.3 ± 8.4 kg, height 1.76 ± 0.06 m, maximum oxygen uptake 50.0 ± 6.8 mL/kg/min) performed a ~30 min cycling time-trial 1 h following either 6 mg/kgBM caffeine (CAF) or placebo (PLA) supplementation and one control (CON) session without supplementation. Participants identified which supplement they believed they had ingested (“caffeine”, “placebo”, “don't know”) pre- and post-exercise. Subsequently, participants were allocated to subgroups for analysis according to their identifications. Overall and subgroup analyses were performed using mixed-model and magnitude-based inference analyses. Caffeine improved performance vs PLA and CON (P ≤ 0.001). Correct pre- and post-exercise identification of caffeine in CAF improved exercise performance (+4.8 and +6.5%) vs CON, with slightly greater relative increases than the overall effect of caffeine (+4.1%). Performance was not different between PLA and CON within subgroups (all P > 0.05), although there was a tendency toward improved performance when participants believed they had ingested caffeine post-exercise (P = 0.06; 87% likely beneficial). Participants who correctly identified placebo in PLA showed possible harmful effects on performance compared to CON. Supplement identification appeared to influence exercise outcome and may be a source of bias in sports nutrition