Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide ...up-to-date recommendations to optimise performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimise performance is to heat acclimatise. Heat acclimatisation should comprise repeated exercise-heat exposures over 1-2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimise dehydration during exercise. Following the development of commercial cooling systems (eg, cooling-vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organisers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimising the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events, for hydration and body cooling opportunities, when competitions are held in the heat.
Le but de cette étude est de vérifier la reproductibilité des mesures respiratoires au moyen du système métabolique Fitmate™, au cours d’un exercice de cyclisme sous maximal.
Vingt-et-une personnes ...ont effectué, lors de deux sessions, un exercice composé de trois fois cinq minutes de pédalage à des intensités sous maximales (16, 18 et 21km/h). La reproductibilité des mesures respiratoires était analysée entre les deux sessions.
Les coefficients de corrélation intraclasse (ICC) entre les deux sessions et pour les trois intensités varient de 0,61 à 0,71 pour VO2 et de 0,79 à 0,89 variant pour VE. Les coefficients de variation (CV) sont inférieurs à 10 % pour tous les paramètres et à toutes les vitesses. Ces résultats indiquent une bonne reproductibilité pour VE et une reproductibilité satisfaisante pour VO2 ou le rendement du pédalage.
Le système Fitmate™ apparaît comme un système reproductible pour la mesure de VE et VO2 à des intensités sous maximales et permet ainsi l’évaluation de la dépense énergétique de façon rapide et aisée dans un cadre d’évaluation clinique.
The purpose of this study was to test the reproducibility of the Fitmate™ metabolic system in measuring breathing gas during a cycling exercise.
Twenty-one participants performed during two sessions three 5-min exercises at submaximal intensities (16, 18 et 21km/h). The reproducibility of respiratory variables was assessed between the two sessions.
Intraclass correlation coefficient (ICC) between the two sessions and for all intensities ranged from 0.61 to 0.71 for VO2 and from 0.79 to 0.89 for VE. Coefficient of variation CV are always lower than 10% for all parameters and all speeds. These results indicate a good reproducibility for VE and a satisfactory reproducibility for VO2 and cycling efficiency.
The Fitmate™ portable metabolic analyzer provides reproducible measures of VO2 and VE during steady-state exercise that allows the assessment of energy expenditure in a simple manner in a clinical framework.
Le but de ce travail était d’étudier l’effet d’une stratégie de supplémentation en vitamines selon des doses et une composition correspondantes aux apports nutritionnels conseillés (ANC) pendant ...l’entraînement sur la variation de force maximale volontaire d’athlètes masters engagés dans un programme d’entraînement en force.
Vingt athlètes masters bien entraînés en endurance ont réalisé un programme d’entraînement en force des muscles extenseurs de la cuisse d’une durée de trois semaines. Avant et après la période d’entraînement, les marqueurs sanguins de l’inflammation musculaire ont été mesurés. Avant chaque séance d’entraînement, la force maximale volontaire isométrique était testée. Ces sujets étaient divisés selon une méthode en double insu en deux groupes expérimentaux avec (groupe supplémenté Ao) ou sans (groupe placebo Pl) apport nutritionnel en vitamines et micronutriments, Isoxan Force
®.
À la suite de la période d’entraînement, la force maximale volontaire des muscles extenseurs de la cuisse a augmenté dans les deux groupes, (+9,7 % pour le groupe Ao versus +6,3 % pour le groupe Pl). Dans le groupe Ao l’amélioration est supérieure à celle du groupe Pl et la récupération entre les séances est améliorée. Enfin, en fin d’entraînement, une différence significative des marqueurs sanguins des dommages et de l’inflammation musculaires est relevée entre les deux groupes.
Les résultats de cette étude confirment les bénéfices liés à une courte période d’entraînement en force sur la performance maximale musculaire chez des athlètes masters. Par ailleurs, l’apport micronutritionnel pendant l’entraînement s’accompagne de dommages musculaires moins importants suggérant un effet de potentialisation des bénéfices de l’entraînement en force avec une supplémentation en vitamines et minéraux.
The purpose of this study was to analyze the effectiveness of supplementation in vitamin on the maximal muscular performance in master athletes during a strength-training program.
Twenty well-trained master athletes took part in a 3 weeks strength-training program and in a same time in a micronutritional supplementation program. Before and after the training period, blood markers of muscle damages were assessed. Before each training sessions maximal voluntary isometric strength was recorded. They were divided in two groups either with supplementation (Isoxan Force
®, Ao) or without (placebo Pl).
After the training period, knee extensor's maximal voluntary strength significantly increased (+9,7% in Ao group versus +6,3% in Pl group) in both groups. However, this increase was more pronounced in Ao group than in Pl group and recovery between training sessions was improved. Moreover, significant difference in blood markers of muscle damages was found between groups at the end of the training program.
Results of this study confirm the benefits of a short period of strength training program on maximal muscular performance in master athletes. In all subjects, strength production capacity has significantly increased after the 3 weeks of training. Moreover, the micronutritional supplement is associated with a lower muscle inflammation suggesting an improvement of the beneficial effect of strength training with vitamin and mineral supplementation.
To determine if pre‐cooling (PC) following heat‐acclimatization (HA) can further improve self‐paced endurance performance in the heat, 13 male triathletes performed two 20‐km cycling time‐trials (TT) ...at 35 °C, 50% relative humidity, before and after an 8‐day training camp, each time with (PC) or without (control) ice vest PC. Pacing strategies, physiological and perceptual responses were assessed during each TT. PC and HA induced moderate (+10 ± 18 W; effect size ES 4.4 ± 4.6%) and very large (+28 ± 19 W; ES 11.7 ± 4.1%) increases in power output (PO), respectively. The overall PC effect became unclear after HA (+4 ± 14 W; ES 1.4 ± 3.0%). However, pacing analysis revealed that PC remained transiently beneficial post‐HA, i.e., during the first half of the TT. Both HA and PC pre‐HA were characterized by an enhanced PO without increased cardio‐thermoregulatory or perceptual disturbances, while post‐HA PC only improved thermal comfort. PC improved 20‐km TT performance in unacclimatized athletes, but an 8‐day HA period attenuated the magnitude of this effect. The respective converging physiological responses to HA and PC may explain the blunting of PC effectiveness. However, perceptual benefits from PC can still account for the small alterations to pacing noted post‐HA.
Elite synchronized swimmers follow high‐volume training regimen that result in elevated rates of exercise energy expenditure (ExEE). While adequate energy intake (EI) is important to optimize ...recovery, a number of sport‐specific constraints may lead to chronically low energy availability (EA = EI–ExEE). This study aimed to quantify changes in EA, endocrine markers of energy conservation, and perceived fatigue in synchronized swimmers, during a week of baseline training followed by 4 weeks of intensified training (IT). EI, ExEE, and body composition were measured in nine swimmers at Baseline, midpoint (ITWK2), and end of IT (ITWK4). Waking saliva samples were obtained to measure leptins, ghrelins, and cortisols. Fatigue ratings were provided daily. ExEE increased by 27% during IT. Swimmers increased EI from Baseline to ITWK2, but decreased it significantly from ITWK2 to ITWK4. EA, fat mass, and leptins decreased from Baseline to ITWK4, while ghrelins increased significantly. Fatigue at ITWK4 was inversely correlated with Baseline EI and EA. The significant decrease in EA was accompanied by endocrine signs of energy conservation in elite swimmers. As perceived fatigue was associated with low EA, particular attention should be paid to these athletes' energy intake during phases of heavy training.
Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide ...up‐to‐date recommendations to optimize performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimize performance is to heat acclimatize. Heat acclimatization should comprise repeated exercise‐heat exposures over 1–2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimize dehydration during exercise. Following the development of commercial cooling systems (e.g., cooling vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organizers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimizing the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events for hydration and body cooling opportunities when competitions are held in the heat.
As soluble intercellular adhesion molecule-1 (sICAM-1) was recently hypothesized to be a key player in the mechanisms involved in exercise-induced muscular damage (EIMD), we investigated its ...circulating concentration changes in athletes before and after EIMD with and without the use of whole-body cryostimulation (WBC; 3 min at −110 °C) at the exercise end and repeated once a day during 4 days.
We previously characterized plasma specimens from 11 endurance athletes who performed twice (randomized crossover design) strenuous running leading to EIMD, followed by passive recovery or WBC. Muscle soreness and inflammatory response were observed in both cases but the use of WBC induced a significant reduction in these responses (PlosOne 2011; 6:e22748). We now found that sICAM-1 concentration slightly increased in both circumstances and remained elevated for 24 h (p < 0.01). However, no significant WBC effect was observed concerning sICAM-1 changes indicating that this compound is not a major player both in EIMD and WBC physiological impacts.
Cette revue examine tout d’abord l’efficacité de la récupération musculaire par l’immersion en eau froide ou eau contrastée (chaud–froid) et détaille les différents protocoles scientifiques afin ...d’obtenir des applications pratiques pour les athlètes. Ensuite, cette revue propose une synthèse sur les effets de la cryothérapie en corps entier et les bénéfices ou non apportées par cette modalité relativement récente.
La multitude des protocoles ayant investigué les effets de la récupération par immersion en eau froide et/ou contrastée expliquent les résultats hétérogènes rapportés par les différents travaux menés sur les effets de cette technique sur la récupération musculaire. Cette méthode semble être préconisée largement après des exercices de musculation ou des exercices à forte contrainte énergétique, lorsqu’elle est programmée dans les 20
minutes qui succèdent l’exercice fatigant. L’immersion en eau chaude fait rarement l’unanimité scientifique, surtout si l’exercice préalable est à prédominance anaérobie ; seule la profondeur de l’immersion paraît vraiment essentielle, une immersion jusqu’au cou semble donner des résultats concluants. Pour ce qui est de la cryothérapie en corps entier, peu de données actuelles sont disponibles concernant la récupération avec cette modalité suite à un exercice. Cependant, la littérature scientifique nous donne des indications sur des effets bénéfiques de certains paramètres de l’inflammation lorsque cette pratique est réalisée, sur une possible augmentation du statut antioxydant, ainsi que sur une large augmentation de l’humeur et des syndromes dépressifs.
Il apparaît principalement que des études complémentaires davantage ciblées sur l’activité physique sont à mener pour nous renseigner sur la capacité ou non des athlètes à mieux récupérer en utilisant la cryothérapie en corps entier.
This review focuses first of all on the effects of the cold and/or contrast water immersion techniques on muscular recovery to determine practical implications for athletes. Then, the present review summarizes the effects of whole-body cryotherapy and its potential benefits.
The multitude of protocols concerning the cold water immersion technique and the contrast water technique explains the large variety of the results reported in the literature on this topic. This recovery strategy seems mainly recommended after strength training and anaerobic solicitations, when it is planed during the 20
min following the fatiguing task. Immersion in warm water is not supported by the literature; only the depth of the immersion looks essential, an immersion to the neck is associated with positive effects. Concerning the whole-body cryotherapy, few data are available about its benefits on recovery after exercise. Nevertheless, the literature reports interesting results on its positive impact relating to inflammatory factors, antioxidant status, mood and syndromes of depression.
Further studies are needed to investigate the potential positive effects of whole-body cryotherapy on recovery by athletes.
The aim of this study was two-fold: i) to analyse age-related declines in swimming, cycling, and running performances for Olympic and Ironman triathlons, and ii) to compare age-related changes in ...these three disciplines between the Olympic and Ironman triathlons. Swimming, cycling, running and total time performances of the top 10 males between 20 and 70 years of age (in 5 years intervals) were analysed for two consecutive world championships (2006 and 2007) for Olympic and Ironman distances. There was a lesser age-related decline in cycling performance (p<0.01) compared with running and swimming after 55 years of age for Olympic distance and after 50 years of age for Ironman distance. With advancing age, the performance decline was less pronounced (p<0.01) for Olympic than for Ironman triathlon in cycling (>55 years) and running (>50 years), respectively. In contrast, an age-related decline in swimming performance seemed independent of triathlon distance. The age-related decline in triathlon performance is specific to the discipline, with cycling showing less declines in performance with age than swimming and running. The magnitude of the declines in cycling and running performance at Ironman distance is greater than at Olympic distance, suggesting that task duration exerts an important influence on the magnitude of the age-associated changes in triathlon performance.
Tapering for competition: A review Le Meur, Y.; Hausswirth, C.; Mujika, I.
Science & sports,
04/2012, Letnik:
27, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The taper is a progressive nonlinear reduction of the training load during a variable period of time, in an attempt to reduce the physiological and psychological stress of daily training and optimize ...sports performance. Existing research has defined the taper, identified various forms used in contemporary sport, and examined the prescription of training volume, load, intensity, duration, and type (progressive or step). The current literature reveals that tapering strategies may be associated with a competition performance improvement of about 3% (usual range 0.5–6.0%). Particular attention given to nutrition, hydration and recovery strategies during the pre-event taper may help maximize its associated positive effects. Interactions between the taper and long-haul travel, heat, and altitude should be also taken into account with particular attention.
Future progress in sports science will play an important part in refining and developing existing tapering methodologies, particularly in the context of multiple peaking for team and racquet sports.
La période d’affûtage correspond à une réduction non linéaire de la charge d’entraînement lors de la période précompétitive, dont l’objectif est de réduire le stress physiologique et psychologique engendré par l’entraînement afin d’optimiser le niveau de performance. Les études scientifiques ont jusqu’à présent défini les différentes modalités d’affûtage, en caractérisant les pratiques adoptées par les entraîneurs et analysé l’influence des variations de volume d’entraînement, de charge de travail, d’intensité et de modalité de réduction de la charge (progressive ou par palier) sur la qualité de l’affûtage. La littérature actuelle révèle que les stratégies d’affûtage peuvent engendrer une amélioration du niveau de performance d’environ 3 % (intervalle compris généralement entre 0,5 et 6,0 %). Une attention particulière accordée à la nutrition, à l’hydratation et aux stratégies de récupération durant cette période semble indispensable pour optimiser les bénéfices de l’affûtage. De même, la gestion des voyages transméridiens, l’acclimatation à la chaleur et la planification des stages en altitude semblent devoir être prises en compte avec particulièrement d’attention.
Les prochaines recherches scientifiques devront aider à optimiser les stratégies existantes, voire en développer de nouvelles, particulièrement dans les sports exigeant une fréquence importante de compétitions lors de la saison sportive, comme les sports collectifs et les sports de raquette.
PDF
