L’OPTIMISATION DE LA PERFORMANCE ECONOMIQUE PEUT-ELLE ETRE DANGEREUSE POUR L’ENTREPRISE ?

A l'heure où les entreprises des pays industriels sont contraintes d'innover sans cesse et d'adopter des stratégies de différenciation qui leur permettent de contrebalancer le poids de leur main d'œuvre élevée, l'amélioration de la performance globale devient encore plus l'obsession des dirigeants. Ne leur est-il pas en effet demandé de garantir non seulement la performance économique de leurs entreprises mais aussi leurs performances sociales ?economic performnace, corporate social responsability

Formation of high-valent iron-oxo species in superoxide reductase: characterization by resonance Raman spectroscopy.

International audienceSuperoxide reductase (SOR), a non-heme mononuclear iron protein that is involved in superoxide detoxification in microorganisms, can be used as an unprecedented model to study the mechanisms of O2 activation and of the formation of high-valent iron-oxo species in metalloenzymes. By using resonance Raman spectroscopy, it was shown that the mutation of two residues in the second coordination sphere of the SOR iron active site, K48 and I118, led to the formation of a high-valent iron-oxo species when the mutant proteins were reacted with H2O2. These data demonstrate that these residues in the second coordination sphere tightly control the evolution and the cleavage of the O-O bond of the ferric iron hydroperoxide intermediate that is formed in the SOR active site

Effets d'une complémentation en acides aminés essentiels sur les microlésions musculaires suite à une séance d'entraînement excentrique à charge lourde

Aim. — Unaccustomed physical exercise, particularly repeated eccentric muscle contractions,induces muscle soreness and alterations on muscle cellular structure. An increase in myofibrillarprotein accretion can occur in the early post-exercise period and be potentiated by essentialamino acid ingestion. We hypothesized that essential amino acid supplementation could reducethe efflux of indirect markers of muscle damage and delay the onset of muscular soreness inthe week following a heavy-load eccentric training session.Methods. — Twenty-three randomly assigned young males performed a bench press exerciseunder eccentric condition. They were subdivided into a placebo group (n = 11) and an essential amino acids group (n = 12). The effect of the training session was assessed by analysingtwo indirect markers of muscle damage, namely plasma concentrations of creatine kinase andmyoglobin measured before, immediately after, and post-workout day 1, 2, 3, 4 and 7. Musclesoreness was evaluated by a visual analogy scale at the same time point as the markers ofmuscle damage.info:eu-repo/semantics/publishe

Audit social et qualité de vie au travail

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Effect of essential amino acid and carbohydrate supplementation on muscle torque and hypertrophy following resistance training in young men

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β‑Alanine supplementation slightly enhances repeated plyometric performance after high‑intensity training in humans

β-Alanine (BA) supplementation has become an ergogenic aid amongst competitive athletes to augment intramuscular carnosine content, leading to higher buffer capacity and exercise performance. We investigated 27 regularly trained young males and females who were randomly allocated either to placebo (PL) or BA ingestion for 8 weeks. Every single day, BA or PL (4.0–5.6 g day−1) supplements were ingested by participants and associated with a strong plyometric high-intensity training (two sessions per week during the 8 weeks). Before and after training, maximal jump heights were recorded during squat jump (SJ) and countermovement jump (CMJ) and an index of fatigue was recorded as a mean height of 45 consecutive CMJ. Blood lactate was measured at rest, after completing the fatigue test and every 5 min thereafter up to 30 min recovery. After plyometric training, SJ and CMJ were increased, respectively, by 8.8 and 6.4 % in PL groupand 9.9 and 11.0 % in BA group (p < 0.01, no difference between groups). Blood lactate reached a maximal value of 9.4 ± 1.6 mmol l−1 in PL group, and 10.3 ± 1.3 mmol l−1 in BA group, with a slight better performance in the fatigue test (+8.6 %, p ≤ 0.01) for BA group as compared to PL group. To conclude, 2-month β-alanine supplementation resulted in a slight improvement of explosive force after 45maximal consecutive jumps in young athletes. However, the practical adequacy of supplementation remains questionable in an active and healthy population.info:eu-repo/semantics/publishe

Effect of Rhodiola Rosea supplementation on physical performance following en durance training

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Impact of an essential amino acid rich in leucine/carbohydrate supplementation on muscle mass following resistance training in young men

info:eu-repo/semantics/publishe