Neuro-mechanical and metabolic adjustments to the repeated anaerobic sprint test in professional football players.

PURPOSE: This study aimed to determine the neuro-mechanical and metabolic adjustments in the lower limbs induced by the running anaerobic sprint test (the so-called RAST). METHODS: Eight professional football players performed 6 × 35 m sprints interspersed with 10 s of active recovery on artificial turf with their football shoes. Sprinting mechanics (plantar pressure insoles), root mean square activity of the vastus lateralis (VL), rectus femoris (RF), and biceps femoris (BF) muscles (surface electromyography, EMG) and VL muscle oxygenation (near-infrared spectroscopy) were monitored continuously. RESULTS: Sprint time, contact time and total stride duration increased from the first to the last repetition (+17.4, +20.0 and +16.6 %; all P < 0.05), while flight time and stride length remained constant. Stride frequency (-13.9 %; P < 0.001) and vertical stiffness decreased (-27.2 %; P < 0.001) across trials. Root mean square EMG activities of RF and BF (-18.7 and -18.1 %; P < 0.01 and 0.001, respectively), but not VL (-1.2 %; P > 0.05), decreased over sprint repetitions and were correlated with the increase in running time (r = -0.82 and -0.90; both P < 0.05). Together with a better maintenance of RF and BF muscles activation levels over sprint repetitions, players with a better repeated-sprint performance (lower cumulated times) also displayed faster muscle de- (during sprints) and re-oxygenation (during recovery) rates (r = -0.74 and -0.84; P < 0.05 and 0.01, respectively). CONCLUSION: The repeated anaerobic sprint test leads to substantial alterations in stride mechanics and leg-spring behaviour. Our results also strengthen the link between repeated-sprint ability and the change in neuromuscular activation as well as in muscle de- and re-oxygenation rates.

The contribution of individual and professional characteristics to general and work-related well-being

Cette thèse porte sur la contribution des caractéristiques individuelles et des situations professionnelles au bien-être. En combinant différentes perspectives théoriques, notamment la théorie de la construction de la carrière, la théorie de la justice organisationnelle, les modèles du bien-être au travail, et les conceptualisations de l'incivilité au travail, un certain nombre d'hypothèses sont proposées concernant le lien entre certaines caractéristiques individuelles et situationnelles et le bien-être général et professionnel. Les deux premières études se focalisent sur la validation d'une échelle d'adaptabilités de carrière et sur le rôle médiateur de cette adaptabilité dans la relation entre des dispositions et le bien-être. La troisième étude évolue l'hypothèse d'un possible effet de médiation de l'adaptabilité mais cette fois de la relation entre insécurité professionnelle et charge de travail d'une part et le bien-être d'autre part. La quatrième étude adopte une perspective longitudinale et analyse les associations entre les dimensions de la personnalité, l'adaptabilité de carrière et le bien-être dans quatre parcours professionnels différents. La cinquième étude porte sur une autre caractéristique individuelle, à savoir la croyance en un monde juste. Cette étude illustre comment la croyance en un monde juste influence les perceptions de justice organisationnelle une année après, qui ont une incidence importante sur le bien-être. Enfin, la dernière étude se concentre sur une population spécifique, les immigrants en Suisse, et souligne qu'être la cible d'incivilité sur le lieu de travail est généralement liée au pays d'origine. Globalement, cette thèse met en évidence que les caractéristiques individuelles ont des effets tant directs qu'indirects sur le bien-être et que ces mêmes caractéristiques explique en partie, les relations entre la situation professionnelle et le bien-être. Plus spécifiquement, des situations professionnelles peuvent influencer l'expression de certaines caractéristiques individuelles, soit en contribuant à leurs activations ou à leurs inhibitions. De plus, l'impact des caractéristiques individuelles sur le bien-être semble dépendre de la situation professionnelle. Il est donc important de considérer les influences simultanées et réciproques des caractéristiques individuelles et de la situation contextuelle et professionnelle pour rendre compte du bien-être général et professionnel. -- This thesis explores how individual characteristics and professional situations correspond to well-being. Drawing from various theoretical backgrounds, such as career construction theory, justice theory, models of job strain, and theories on subtle discrimination, a number of specific hypotheses are put forward pertaining to a selection of individual and professional aspects as well as general and work-related well-being. The six studies presented in this thesis focus on specific aspects and adopt different methodological and theoretical approaches. The first two studies concern the validation of the career adapt-abilities scale and test the potential of career adapt-abilities to mediate the relationship between dispositions and outcomes. The third study extends the hypothesis of career adapt-abilities as a mediator and finds that it mediates the effects of job insecurity and job strain on general and professional well-being. The fourth study adopts a longitudinal approach and tests the associations between personality traits and career adaptability and well-being in four different professional situations. Study five concerns another individual characteristic, belief in a just world, and illustrates how justice beliefs drive perceptions of organizational justice, which in turn impact, on well-being outcomes one year later. The final study focuses on the professional experiences of a specific population, immigrants in Switzerland, and confirms that being a target of incivilities is related to national origin. Globally, this thesis finds that individual characteristics have direct and indirect influences on well-being and that these characteristics may also mediate the associations between professional situations and outcomes. In particular, the professional situation may alter the display of individual characteristics, either by contributing to their activation or their depletion, and the ways in which individual factors influence well-being does seem to depend on the professional situation. It is thus necessary to adopt a "both...and" perspective when studying the impact of individual and professional characteristics as these factors mutually influence each other.

Professional trajectories, individual characteristics and staying satisfied and healthy

Staying satisfied and healthy in the face of a complex and uncertain professional world is a priority for individuals. This article examines the contribution of personality traits, career adaptability, and prior well-being as predictors of well-being over 1 year in four different professional trajectory groups: those who remained employed, those who experienced a professional change, those who moved from unemployment to employment, and those who remained unemployed. Results show meaningful differences between these groups in terms of well-being over 1 year. Employed individuals have higher life satisfaction and self-rated health than unemployed individuals. Regaining employment contributes to improved well-being. Different professional situations correspond to varying levels of career adaptability, suggesting it may be a precursor for career changes. Personality traits and career adaptability predict well-being over time, but the strongest predictor of future well-being is prior well-being. Results are discussed in light of career development, personality, and well-being theory.

CSR : a new governance approach for regulating professional sport ? : the case of french professionnal sports clubs

The purpose of this paper is to examine the CSR practices and their implementation in the context of French professional sports clubs. In doing so, it analyses the link between the governance of sports clubs and CSR, which is viewed as a component of governance expanded to stakeholders and contributing to the creation of shared value. Drawing on interview data with key stakeholders of four professional sport clubs (football and basketball) and secondary material, the study sheds light on the determinants, the implementation as well as the impact of CSR on the governance of the professional clubs under examination.

Animal modelling for inherited central vision loss.

Disease-causing variants of a large number of genes trigger inherited retinal degeneration leading to photoreceptor loss. Because cones are essential for daylight and central vision such as reading, mobility, and face recognition, this review focuses on a variety of animal models for cone diseases. The pertinence of using these models to reveal genotype/phenotype correlations and to evaluate new therapeutic strategies is discussed. Interestingly, several large animal models recapitulate human diseases and can serve as a strong base from which to study the biology of disease and to assess the scale-up of new therapies. Examples of innovative approaches will be presented such as lentiviral-based transgenesis in pigs and adeno-associated virus (AAV)-gene transfer into the monkey eye to investigate the neural circuitry plasticity of the visual system. The models reported herein permit the exploration of common mechanisms that exist between different species and the identification and highlighting of pathways that may be specific to primates, including humans.