Effects of Post-Exercise Protein Intake on Muscle Mass and Strength During Resistance Training: is There an Optimal Ratio Between Fast and Slow Proteins?

While effects of the two classes of proteins found in milk (i.e. soluble proteins, including whey, and casein) on muscle protein synthesis have been well investigated after a single bout of resistance exercise (RE), the combined effects of these two proteins on the muscle responses to resistance training (RT) have not yet been investigated. Therefore, the aim of this study was to examine the effects of protein supplementation varying by the ratio between milk soluble proteins (fast-digested protein) and casein (slow-digested protein) on the muscle to a 9-week RT program. In a double-blind protocol, 31 resistance-trained men, were assigned to 3 groups receiving a drink containing 20g of protein comprising either 100% of fast protein (FP(100), n=10), 50% of fast and 50% of slow proteins (FP(50), n=11) or 20% of fast protein and 80% of casein (FP(20), n=10) at the end of training bouts. Body composition (DXA), and maximal strength in dynamic and isometric were analyzed before and after RT. Moreover, blood plasma aminoacidemia kinetic after RE was measured. The results showed a higher leucine bioavailability after ingestion of FP(100) and FP(50) drinks, when compared with FP(20) (p<0.05). However, the RT-induced changes in lean body mass (p<0.01), dynamic (p<0.01), and isometric muscle strength (p<0.05) increased similarly in all experimental groups. To conclude, compared to the FP(20) group, the higher rise in plasma amino acids following the ingestion of FP(100) and FP(50) did not lead to higher muscle long-term adaptations

Collateral Health Issues Derived from the Covid-19 Pandemic.

At the end of 2019, a new coronavirus (Covid-19) outbreak occurred in Wuhan, China, and spread throughout the world despite efforts to contain the virus. At the end of January 2020, the General Director of the World Health Organization (WHO) declared a Public Health Emergency of International Concern, and by mid-May 2020, the worldwide number of known Covid-19 cases had surpassed 4.4 million including more than 300,000 deaths..

Medical encounters (including injury and illness) at mass community-based endurance sports events: an international consensus statement on definitions and methods of data recording and reporting

Mass participation endurance sports events are popular but a large number of participants are older and may be at risk of medical complications during events. Medical encounters (defined fully in the statement) include those traditionally considered 'musculoskeletal' (eg, strains) and those due to 'illness' (eg, cardiac, respiratory, endocrine). The rate of sudden death during mass endurance events (running, cycling and triathlon) is between 0.4 and 3.3 per 100 000 entrants. The rate of other serious medical encounters (eg, exertional heat stroke, hyponatraemia) is rarely reported; in runners it can be up to 100 times higher than that of sudden death, that is, between 16 and 155 per 100 000 race entrants. This consensus statement has two goals. It (1) defines terms for injury and illness-related medical encounters, severity and timing of medical encounters, and diagnostic categories of medical encounters, and (2) describes the methods for recording data at mass participation endurance sports events and reporting results to authorities and for publication. This unifying consensus statement will allow data from various events to be compared and aggregated. This will inform athlete/patient management, and thus make endurance events safer

Letter to the editor entitled “fairness and scientific correctness is needed in the debate on transgender athletes”

editorial reviewe

Union Cycliste Internationale (UCI) cycling pregnancy and postpartum guidanceGuide de l’Union Cycliste Internationale (UCI) sur la pratique du cyclisme pendant la grossesse et en post-partum

ObjectivesPractical information is needed on the extent to which elite and competitive female athletes can continue to train and compete safely during pregnancy, without risk for themselves or their child, as well as advice for the postpartum period, including breast-feeding. Such information is also needed to recommend cycling for non-athlete women who wish to exercise. For this reason, the International Cycling Union (UCI) has produced this guide to provide information for all those who participate in recreational cycling activities and UCI sanctioned competitions during pregnancy.MethodsThis policy has been developed utilising the AGREE II instrument and has had input from elite female cyclists, including those who have came back to compete following pregnancy.ResultsSupported by clinical evidence, the UCI encourages women to continue cycling throughout their pregnancy. Although cycling exercise is generally safe during pregnancy, some general principles are required for women, especially when cycling in the heat. No competitive cycling events included in the UCI calendar are possible beyond the 1st trimester of pregnancy, mainly to prevent the risk of trauma to the uterus and foetus in the event of an accident. However, the UCI encourages pregnant women to participate in recreational/leisure cycling as a form of physical activity throughout their pregnancy; but the ability to participate in organised recreational activities is only possible up to the end of the 1st trimester. Exercise, and especially cycling exercise, should be viewed as an important component to improve women's psychological health and common complaints during the postpartum period. Breast-feeding is highly recommended when women return to exercise and there is no impact of exercise on the quantity and quality of breast-milk.ConclusionsThere are no significant disadvantages with regard to foetal and/or maternal conditions with high-intensity training programmes when they are subjectively tolerated and carefully monitored, at least during the first trimester of pregnancy. For the global population, exercises at moderate-intensity during pregnancy have many positive effects for both the mothers and their unborn children. That is why it is highly recommended that pregnant women begin or continue biking at moderate-intensity at least 150 minutes a week with at least 3 sessions of a duration longer than 30 minutes each

Sodium citrate ingestion and muscle performance in acute hypobaric hypoxia

International audienc

Modélisation de l'enchaînement natation-cyclisme d'un triathlon en laboratoire. Influence sur la cinétique de la lactatémie

International audienceThis study, which simulates the swimming-cycling transition of a triathlon, compares the kinetics of blood lactate and aerobic capacity during one exercise that only involves lower limbs (similar to cycling) and during one exercise that involves first upper limbs, then lower limbs (similar to swimming and cycling). Male competitor triathletes performed two groups of exercises (fig 1): the first consisted in incremental bicycle exercises to maximal intensity, with (T2) or without (T1) prior upper limb exercise; the second consisted in bicycle exercises at a constant intensity at approximately 80% VO2 max, with (R2) or without (R1) prior upper limb exercise. The results show enhanced lactic acid clearance produced by a lower limb exercise, when it occurs after an upper limb exercise (p < 0.05). This reduction may be due either to an increase in lactate oxidation or a participation in the intramuscular glyconeogenesis in the upper limbs partially depleted in glycogen. The free fatty acid concentration increased after upper limb exercise (T2: 0.51 ± 0.12 mM vs 0.17t 0.03 mM; R2: 0.37 ± 0.04 mM vs 0.13 ± 0.02 mM). Moreover, the respiratory exchange ratios calculated at 60%, 85% and 100% V02 max are significantly lower during T2 exercise thon during T1 exercise (p < 0.05). These results suggest that the use of lipid substrates, stimulated by upper limb exercise does not affect performance during lower limb exercise (maximal aerobic power and maximal oxygen uptake: VO2 max).Cette étude, en modélisant l'enchaînement natation-cyclisme d'un triathlon, vise à apprécier les modifications de la cinétique de la lactatémie et de l'aptitude aérobie chez des sujets réalisant d'une part un exercice des membres inférieurs seuls (de type cyclisme) et d'autre part un exercice impliquant successivement membres supérieurs puis membres inférieurs (de type natation + cyclisme). Les sujets, masculins, triathlètes compétiteurs, sont soumis à deux groupes d'épreuves : le premier est constitué d'exercices d'intensité croissante par palier sur les membres inférieurs (exercices triangulaires précédés (T2) ou non (T1) d'un exercice au niveau des membres supérieurs), le deuxième étant constitué d'exercices d'intensité constante (80% de VO2max) sur les membres inférieurs (exercices rectangulaires précédés (R2) ou non (R1) d'un exercice au niveau des membres supérieurs). Les résultats montrent que la lactatémie mesurée au cours et après un exercice réalisé avec les membres inférieurs est plus basse quand celui-ci a été précédé d'un exercice des membres supérieurs (p < 0,05). Cette diminution peut être due aussi bien à une augmentation de l'oxydation du lactate qu'à une participation de celui-ci à la néoglucogenèse intramusculaire au niveau des membres supérieurs partiellement déplétés en glycogène. La concentration plasmatique des acides gras libres a augmenté après l'exercice de pédalage des membres supérieurs (T2 : 0,51 ± 0,12 mM vs 0,17 ± 0,03 mM ; R2 : 0,37 ± 0,04 mM vs 0,13 ± 0,02 mM). Par ailleurs, les quotients respiratoires calculés au cours des paliers correspondant à 60%, 85% et 100% de VO2 max de l'épreuve T2 sont significativement plus bas que ceux calculés au cours de l'épreuve T1 (p < 0,05). Ces résultats permettent de suggérer que l'utilisation de substrats lipidiques, stimulée par l'exercice des membres supérieurs, ne pénalise pas les performances réalisées au cours de l'exercice intéressant les membres inférieurs en termes de puissance maximale aérobie (PMA) et de consommation maximale d'oxygène (VO2max)

Effets de la supplémentation en créatine sur la cinétique de régénérescence du muscle squelettique après lésion étendue

Résumé Objectif. – Il s'agit ici d'étudier, sur modèle animal, les effets d'une supplémentation prolongée avec de la créatine sur la cinétique de récupération d'un muscle lent et oxydatif, le soléaire, après induction d'une dégénérescence étendue (par infiltration de notexine). Résultats et Discussion. – Que les animaux aient été ou non supplémentés en créatine, les résultats suivants ont été obtenus : 1) La masse du muscle soléaire est récupérée 35 jours après la lésion. 2) Le profil d'expression des isoformes de MHC est similaire à celui d'un muscle soléaire intact 28 jours après la lésion. 3) L'activité de la CS est récupérée 14 jours après la lésion, tandis que l'activité spécifique H-LDH reste légèrement inférieure à celle du muscle intact. 4) La myogénine a un pic d'expression à trois jours. Conclusion. – Contrairement à l'hypothèse initiale, proposée après des études in vitro, la supplémentation en créatine n'a pas d'effet bénéfique sur la cinétique de récupération du muscle squelettique évaluée in vivo après lésion par un myotoxique. Abstract Objective. – The aim of the experiment was to study, in rats, the effects of Cr supplementation on the time course of recovery of the soleus, a slow-twitch oxidative muscle, after a notexin-induced injury. Results and Discussion. – Whether or not animals have been supplemented with oral creatine, we observed: 1) soleus muscle mass was recovered at day 35 following injury. 2) MHC profile of regenerated muscles was similar to that of intact muscles at day 28. 3) A full recovery of the CS activity was observed from day 14, while the specific H-LDH activity remained slightly lower than in intact muscles. 4) Myogenin expression peaked at day 3. Conclusion. – In contrast with our hypothesis resulting from in vitro experiments, creatine supplementation failed to show any beneficial effect on the time course of recovery of skeletal muscle assessed in vivo after a myotoxic-induced injury