No description available.

Musicians can develop and suffer from playing-related musculoskeletal disorders (PRMDs) with pianists being a group of instrumentalists that experience a higher occurrence of PRMDs in comparison with other musicians. One cause of PRMDs is posture. The Alexander Technique (AT) is a popular somatic method among musicians that purports to alter its students’ postural and movement behaviour. Such changes may be beneficial in improving music performance. However, there is a lack of quantitative research to offer support for the effectiveness of the AT in altering posture in musicians, especially in pianists. To address this issue, four studies were conducted. The first study addressed the AT alone to determine what postural changes could be expected following lessons in the AT. Findings of this study showed that changes include a larger craniovertebral angle, head tilt, and head-neck-trunk angle as well as smaller trunk, thoracic, and thoracolumbar angles. The second study addressed variability in individual pianists’ postures and its implications for intervention studies. The results of this study demonstrated that within-person variability is present in posture between performances but does not vary widely enough to exhibit inconsistent posture across measurements. The third study examined the effects of 10 AT lessons on pianists’ postures. Findings showed that, in comparison with their pre-lesson measurements, pianists demonstrate a postural pattern of larger craniovertebral and head-neck-trunk angles as well as smaller trunk, thoracic, and thoracolumbar angles in both the post-test and follow-up tests. The fourth study explored the relationship between pianists’ perceptions of their posture and their application of the AT with quantitatively measured changes in their posture. The results of this study showed that participant perception and reported application of the AT does not necessarily always reflect the postural changes that have occurred.

No description available.

Suspension of the body in the head-down posture (90° below the horizontal) for traction and added resistance to exercise has generated considerable interest in recent years. However, recent investigators of inversion have cautioned individuals not to participate in such activities until further research could be performed on the effects of exercise in the head-down position. The purpose of this investigation was to examine the acute metabolic and hemodynamic responses of men at rest and during exercise in the inverted posture (90° head-down tilt) versus the supine and standing postures. The parameters investigated were oxygen consumption(V̇O₂), heart rate(HR), systolic blood pressure (SBP), and diastolic blood pressure(DBP). Eleven male recreational athletes underwent 6 sessions of postural change. The baseline posture was sitting and the critical positions were supine, standing, and inverted. The subjects were asked to remain in each of these postures for three minutes. In the first 2 sessions, oxygen consumption(V̇O₂), was measured at rest and during 45° hip-f1exion respectively, The V̇O₂ in the inverted posture at rest was found to be 1.7% greater than the V̇O₂ in the standing and the supine postures. V̇O₂ in the inverted posture during exercise was 7% and 36.5% greater than in the supine and standing postures, respective1y. A statistical significance in HR at rest in the standing posture versus the inverted and supine postures was observed. During 45° hip-flexion activity, the HR in the standing posture was found to be significantly faster than the supine posture. The HR in the inverted posture was significantly faster than the supine posture as well. At rest, there was no significant increase in SBP as re1ated to posture. During exercise, the SBP was significant1y greater; at rest in each of the postures. Both postural and exercise factors significantly affected the DBP. The post-hoc analyses showed supine resting DBP was significantly lower than in the other two resting postures. During exercise, the standing BP was significantly greater than the supine and inverted DBP. These data demonstrate: A) V̇O₂ in the supine and inverted postures is significantly greater than in the standing postures. B) a statistically significant increase in HR occurs in the standing posture as compared to the supine and inverted postures; however, it does not appear to be clinically significant, C) with the arms maintained in the anatomical position for all postural changes, the SBP was not significantly affected by the change of posture, but was significantly increased with exercise. D) and DBP in the standing posture was statistically greater than in the other two postures and DBP in the inverted posture was significantly elevated above that found in the supine posture. / Master of Science

Of the studies that considered negatively sloped keyboards, results showed improved comfort and postural effects while typing on keyboards; however, few studies of negatively sloped keyboard angles and their resulting effects on objective physiological measures, psychological measures, and performance have been performed. The objective of this study was to quantify the effects of negative keyboard slopes on forearm muscle activity, wrist posture, key strike force, perceived discomfort, and performance to identify a negative keyboard angle or range of keyboard angles that minimizes exposure to hypothesized risk factors for hand/wrist work related musculoskeletal disorders. Ten experienced typists (4 males and 6 females) participated in a laboratory study to compare keyboard slopes ranging from 7° to -30°, at 10° increments from 0° to -30°, using an experimental wedge designed for use with QWERTY keyboards. Repeatability was examined by requiring participants to complete the experiment in two test sessions one week apart. Dependent variable data was collected during 10 minute test sessions. Wrist posture data revealed postural benefits for negative angles of 0° or greater compared to 7°. Specifically, the percentage of wrist movements within a neutral zone and percentage of wrist movements within ±5° and ±10° degrees increased as keyboard angle became more negative. EMG results were mixed with some variables supporting negative keyboard angles, while other results favored the standard keyboard configuration. Net typing speed supported the -10° keyboard angle, while other negative typing angles were comparable, if not better, than the standard. These findings showed that there was strong support for improved postural changes associated with negatively sloped keyboard wedges, though user perceptions favored the standard configuration. / Master of Science

An array of sauropod taxa coexisted in Late Jurassic North America. How so many giant genera coexisted without competing for food is puzzling considering their potential metabolic requirements. One aspect of this question is neck posture, which has been much contested, both in terms of the intrinsic curvature of the neck and the resultant elevation of the head. Neck curvature is characterized by the Osteological Neutral Pose (ONP), wherein the intervertebral joints are in an undeflected state. This pose is crucial to understanding neck posture. The articulated series of presacral vertebrae 2-19 of an exceptionally well-preserved apatosaurine, BYU 18531, are used to unravel its neck posture. This study utilized photogrammetry, digital bone repair, and CT segmentation to create virtual and physical vertebral models use to articulate the neck of this specimen, sans the atlas. To facilitate comparison with other models, dorsal vertebra 1 was set with the long axis of the centrum horizontal and at a height of 5 m above ground level. The wedge-shaped first dorsal marks the broad, U-shaped intersection between the low arched back and the neck. The neck is sinusoidal. Cervical vertebrae 15-10 are slightly arched, 9-5 droop markedly, and 4-2 are slightly dorsoflexed. This pose places the skull snout 1.5 m above the ground. The physical and virtual models were nearly identical except the neck curvature is smoother and more pronounced in the physical model. The similarity between this specimen and other apatosaurines, and possibly all diplodocids, suggests they had similar neck postures and feeding habits. This ONP, combined with dentition and the shape of the implies that this apatosaurine was "grazer". Understanding the biomechanics of this specimen provides some evidence for the larger problem of how so many coeval sauropods lived in Late Jurassic North America.

The purpose of this study was to evaluate metabolic, cardiorespiratory, and perceptual responses during recumbent cycle ergometry performed at various seat back angles and different work rates. Healthy college-aged men performed steady-state exercise at two work rates, 100 watts (n=46) and 150 watts (n=26), using five back seat angles, 90, 105, 120, 135, and 150 degrees. The results of this study suggest that recumbent seat back angles of 135 to 150 degrees are associated with lower metabolic and cardiorespiratory stress during rest and submaximal exercise than more upright positions. The reduced stress at these angles is accompanied by lower perceptions of exertion and improved seating comfort. The failure of the base-line correction for resting V0 2 to remove the effect of seat back angle implies that the reduced physiological stress associated with these positions is due to reasons other than attenuated resting metabolic costs. It is concluded that the selection of recumbent seat back angles between 135 and 150 degrees can result in improved efficiency, reduced physiological stress, diminished perceptions of exertion, and increased seating comfort.

Yes / To investigate the reliability and variability of Video Rasterstereography (VR) measurements of the spine and pelvis, for eight proposed standing postures, in order to help define an optimal standing position for erect pelvis radiography. Methods: Surface topography data were collected using the formetic 4D dynamic modelling (Diers) system. 61 healthy participants were recruited; each participant performed eight different standing positions. Four positions were performed with the feet shoulder width apart and parallel, and four positions were performed with the feet shoulder width apart and internally rotated. For the upper extremity, each of the (two sets of) four positions were performed with different arm positions (arms by the sides, arms crossed over the chest, arms 30° flexed and touching the medial end of the clavicle, arms 30° flexed with the hands holding a support). Three sets of surface topography were collected in the eight positions (n = 24). The variability was assessed by calculating standard error of the measurement (SEm) and the coefficient of variation (CV). Reliability was assessed using intra-class correlation coefficients (ICC ± 95% CI). Results: No significant differences in the SEm were found between the three paired measurements for all standing positions (P > 0.05). ICC values demonstrated excellent reliability for all measurements across the eight standing positions (range 0.879–1.00 [95% CI 0.813–1.00]). Conclusion: Evaluating eight standing positions radiographically would be unethical as it would involve repeat radiation exposures. Using the formetic 4D dynamic modelling (Diers) system, provides an alternative and has shown that there was only a minimal, non-statistically significant, differences between the eight different standing positions. / KA is supported by the Hashemite University/ Jordan.

Cette thèse porte sur l'importance de deux contraintes posturales soit la posture et l'obésité. Nous nous sommes plus particulièrement intéressés à l'impact de ces contraintes sur le contrôle de l'équilibre postural et le contrôle d'un mouvement de pointage nécessitant vitesse et précision. Ainsi, cinq grands thèmes ont été abordés dans cette thèse. La première étude porte sur l'influence du poids corporel sur la stabilité posturale. La deuxième étude porte sur l'influence d'une perte de poids sur la stabilité posturale. La troisième étude porte sur l'influence d'une modification du contrôle de l'équilibre créée par l'adoption d'une configuration posturale plus ou moins stable sur la production de mouvements de pointage rapide et précis. La quatrième étude porte sur l'effet de la diminution de stabilité posturale observée chez des individus souffrant d'obésité lors de l'exécution d'un mouvement de pointage rapide et précis. Finalement, la dernière étude porte sur les améliorations possibles que pourraient entraîner une perte de poids sur un mouvement de pointage rapide et précis effectué dans différents contextes de stabilité posturale. L'objectif de la première étude était d'évaluer l'effet du poids corporel sur la stabilité posturale. Pour réaliser cet objectif, 59 hommes avec des indices de masse corporelle variant entre 17.4 et 63.8 kg/m ont été évalués dans une tâche de posture statique à l'aide d'une plateforme de force. Les participants à cette étude étaient testés en condition yeux ouverts et yeux fermés. En vision, l'analyse de régression multiple a montré que le poids corporel était responsable de 52% de la variance associée à la stabilité posturale. Sans la vision ce pourcentage était de 54%. Ces résultats suggèrent que le poids corporel est un indicateur majeur de la stabilité posturale et que les individus plus lourds sont moins stables et plus à risque de chuter. L'objectif de la deuxième étude était d'investiguer l'effet d'une perte de poids chez des individus obèses et obèses morbides. Dans cette étude la stabilité posturale a été évaluée avant et après une perte de poids à l'aide d'une plate forme de force. Suite à la perte de poids une amélioration de pratiquement tous les paramètres posturaux a été observée. De plus, une forte relation entre la quantité de poids perdue et les améliorations posturales a été notée. En résumé, les résultats de cette étude montrent que la perte de poids améliore la stabilité posturale et cette amélioration est fonction de la quantité de poids perdue. L'objectif de la troisième étude était d'examiner l'interaction entre le contrôle de l'équilibre postural et l'exécution d'un mouvement de pointage. Afin de d'évaluer l'effet du contrôle de l'équilibre postural, les sujets devaient pointer à une cible en posture assise ou en posture debout. Différentes largeurs de cible ont été utilisées afin de varier la difficulté de la tâche (0.5, 1.0, 2.5, et 5.0 cm). Les résultats de cette étude montrent que lorsque les sujets pointent à la plus petite cible, l'augmentation du temps de mouvement est plus importante en posture debout qu'en posture assise. Ce résultat suggère que le degré de difficulté de la tâche ne peut pas être uniquement déterminé par la largeur de la cible. Comparativement à la posture assise, la tâche de pointage en posture debout crée une contrainte supplémentaire lorsque le degré de précision requis est grand (la plus petite cible). L'objectif de la quatrième étude consistait à examiner si l'obésité par une contrainte posturale additionnelle pourrait limiter la relation vitesse-précision avec laquelle un mouvement du membre supérieur peut être accompli. Dans cette étude, la tâche de pointage était effectuée uniquement en posture debout. Huit sujets ayant un indice de masse corporelle normal (IMC) (IMC entre 20.9 et 25 kg/m2 ) et neuf sujets obèses en santé (IMC entre 30.5 et 48.6 kg/m2 ) devaient pointer en position debout à une cible située face à eux. Différentes largeurs de cible étaient utilisées afin de varier la difficulté de la tâche (0.5, 1.0, 2.5, et 5.0 cm). Conformément à la relation vitesse-précision, les deux groupes ont montré une augmentation du temps de mouvement avec la diminution de la largeur de la cible. Toutefois, l'augmentation du temps de mouvement est plus grande pour les sujets obèses que ceux avec un IMC normal pour les deux cibles les plus petites. Les temps de mouvements pour atteindre ces deux cibles étaient en moyenne 115 et 145 ms plus lent pour le groupe obèse. Ces résultats suggèrent que l'obésité impose une contrainte posturale additionnelle qui limite la vitesse à laquelle un mouvement de pointage précis peut être réalisé. Pour terminer, l'objectif de la cinquième étude est d'examiner si une perte de poids chez des sujets obèses permet l'amélioration de la relation vitesse-précision lors d'un mouvement de pointage. Dans cette étude, la tâche étaient effectuée en posture assise et debout. Dix sujets obèses ont exécuté des mouvements de pointage dans deux postures différentes. Différentes largeurs de cible étaient utilisées afin de varier la difficulté de la tâche (0.5, 1.0, 2.5, et 5.0 cm). L'ensemble des sujets fut évalué avant et après un programme de perte de poids. Avant la perte de poids, le temps de mouvement et la durée de la phase de décélération étaient plus longs lorsque les sujets pointaient en posture debout qu'en posture assise. Après la perte de poids, les sujets montraient un temps de mouvement et une durée de la phase de décélération similaires pour les deux postures. Suite à la perte de poids, la performance dans la tâche de pointage en posture debout s'est améliorée. Cette amélioration de la performance résulterait probablement de l'augmentation de la stabilité posturale permettant un meilleur contrôle lors de l'exécution du mouvement. En conclusion, en comparant des mouvements de pointage nécessitant vitesse et précision effectués en posture assise ou posture debout, on remarque que le contrôle postural, plus important en posture debout, ajoute une contrainte supplémentaire l'exécution du mouvement focal. Toutefois, cette différence est notable seulement lorsque la difficulté de la tâche de pointage est élevée (index de difficulté de 6.9). De plus, l'obésité, par son effet sur le contrôle de l'équilibre postural, ajoute également une contrainte sur la performance d'un mouvement de pointage nécessitant vitesse et précision. En effet, les temps de mouvement sont plus longs pour les sujets obèses que ceux de poids normal suggérant que l'obésité ajoute une contrainte posturale qui limite la vitesse à laquelle un mouvement précis peut être effectué. Suite à un programme de perte de poids, une amélioration dans la performance d'un mouvement de pointage en posture debout est observée. L'augmentation de la stabilité posturale qui est amenée par la perte de poids favoriserait un meilleur contrôle lors de l'exécution du mouvement. Ces résultats renforcent l'importance de la perte de poids chez les individus obèses ou avec un surplus de poids afin de réduire les risques potentiels de blessures au travail impliquant le contrôle de l'équilibre postural et la production de mouvements du membre supérieur. Hypothétiquement, les individus obèses pourraient être plus à risque de se blesser lorsqu'ils exécutent en posture debout des mouvements de pointage qui nécessitent vitesse et un haut degré de précision. / This thesis sought to examine if obesity and posture impose an additional balance control constraint limiting the speed and accuracy of an upper limb goal-directed movement. In the fïrst study, the aim was to détermine the contribution of body weight to predict balance stability. In the second study, the objective was to investigate the effect of weight loss on balance control in obese and morbid obese men. In a longitudinal and clinical intervention study, postural stability was measured with a force platform before and after weight loss in men. In the third study, we examined the interaction between the control of posture and an aiming movement by having subjects reaching target from a seated or a standing position. In the fourth study, based on our fïrst two researches we examined the potentially négative impact of obesity on the control of upper limb movements by comparing obese to normal weight individuals when pointing to targets of various sizes from a standing'posture. Finally, we examined if a weight loss program could improve the speed and accuracy of goal-directed aiming movements of obese individuals and compared their performance when movements were produced from a seated or upright posture. In the fïrst study the aim was to détermine the contribution of body weight to predict balance stability. The balance stability of 59 maie subjects with BMI ranging from 17.4 to 63.8 kg/m2 was assessed using a force platform. The subjects were tested with and without vision. A stepwise multiple régression analysis was used to détermine the independent effect of body weight, âge, body height and foot length on balance stability (Le., mean speed of the center of foot pressure). With vision, the stepwise multiple régression revealed that body weight accounted for 52% of the variance of balance stability. The addition of âge contributed a further 3% to explain balance control. Without vision, body weight accounted for 54% of the variance and the addition of âge and body height added a further 8% and 1% to explain the total variance, respectively. The final model explained 63% of the variance. A decrease in balance stability is strongly correlated to an increase in body weight. In the second study, the objective was to investigate the effect of weight loss on balance control in obese and morbid obese men. In a longitudinal and clinical intervention study, postural stability was measured with a force platform before and after weight loss in men. Weight loss was obtained in obese men (mean body mass index (BMI) = 33.0 kg/m2) by hypocaloric diet until resistance and in morbid obese men (mean BMI = 50.5 kg/m2) by bariatric surgery. Morbid obese men were tested before surgery, and 3 and 12 months after surgery when they had lost 20 and nearly 50% of initial body weight, respectively. Normal weight individuals (mean BMI = 22.7 kg/m2) were tested twice within a 6- to 12-month period to serve as control. Weight loss averaged 12.3 kg after dieting and 71.3 kg after surgery. Body weight remained unchanged in the control group. After weight loss, nearly ail measures of postural stability were improved with and without vision (i.e., CP speed and range in antero-posterior and medio-lateral axes). A strong linear relationship was observed between weight loss and improvement in balance control measured from CP speed (adjusted R2 = 0.65, P<0.001). Weight loss improves balance control in obese men and the extent of the improvement is directly related to the amount of weight loss. In the third study we examined the interaction between the control of posture and an aiming movement. Balance control was varied by having subjects aim at a target from a seated or a standing position. The difficulty of the task was varied by using different target sizes (0.5, 1.0, 2.5 and 5.0cm width). For the smallest target width, the increased MT was greater when subjects were standing than when they were seated suggesting that the difficulty of the aiming task could not be determined solely by the target size. Compared to a seated position, aiming from a standing position added constraints on the movement but only when the accuracy requirements were important (smaller target). The fourth study sought to examine if obesity imposes an additional balance control constraint limiting the speed and accuracy with which an upper limb goal-directed movement performed from an upright standing position can be executed. Eight healthy lean subjects (body mass index (BMI) between 20.9 and 25.0 kg/m2) and nine healthy obese subjects (BMI between 30.5 and 48.6 kg/m2) pointed to a target located in front of them from an upright standing posture. The difficulty of the task was varied by using different target sizes (0.5, 1.0, 2.5 and 5.0cm width). For both groups, MT increased with a decreasing target size. Compared to the normal BMI group, this effect was exacerbated for the obese group. For the two smallest targets, movements were on average 115 and 145 ms slower for the obese than for the normal BMI group suggesting that obesity added a balance constraint and limited the speed with which an accurate movement could be done. Based on the previous results, in the fifth study, we examined if a weight loss program could improve the speed and accuracy of goal-directed aiming movements of obese individuals. Ten obese subjects performed aiming movements from two different postures, standing and seated. Ail participants were evaluated before and after a weight loss program when they were experiencing resistance to weight loss (resistance). Before weight loss, movement times and the duration of declaration phases were longer when subjects were standing than when they were seated. This effect vanished after weight loss and subjects showed declaration phases of similar durations for both postural conditions. After the weight loss program, there was an improvement of goal-directed aiming movements performed from a standing posture (i.e., movement time decreased). In conclusion, a decrease in balance stability is strongly correlated to an increase in body weight. Weight loss improves balance control in obese men and the extent of the improvement is directly related to the amount of weight loss. Compared to a seated position, aiming from a standing position adds constraints on upper limb goal-directed movements but only when the accuracy requirements are important. Similarly, obesity, presumably because of its effects on the control of balance, also imposes constraints on goal-directed movements. Movements are slower for the obese than for the normal weight group suggesting that obesity added a balance constraint and limited the speed with which an accurate movement could be performed. After a weight loss program, there is an improvement of goal-directed aiming movements executed from a standing posture. This improvement presumably resulted from a more stable postural platform allowing a better control of the upper-limb movements. These results strengthen the importance of weight loss for health benefits and possibly to reduce work-related injuries involving balance control during standing and upper arm movements. Obese individual could be at greater risk of injury when, from a standing position, they perform an aiming task requiring a high degree of accuracy and speed.

Le roman négro-africain de dénonciation que nous appelons « roman subversif » et que d'aucuns insèrent dans la catégorie dite roman de la rupture, en tant que macro-acte de langage, comporte bien une visée illocutoire subversive. Cela est vrai même si le discours littéraire négro-africain d'après les indépendances, à l'instar de tout discours, reste contraint, c'est-à-dire en grande partie déterminé par le contexte sociopolitique, mais également le champ littéraire francophone où entrent en concurrence divers « positionnements » et « postures » d'auteurs. Nous montrons dans ce travail que cette visée qui est une entreprise de dévoilement des dérives des nouveaux régimes politiques et/ou religieux, résultante de l'intrication du contexte non verbal négro-africain et de l'intérieur des romans, et qui se traduit par la construction littéraire de divers ethos individuels et collectifs, peut s'étudier, entre autres, au moyen de la méthode d'analyse du discours. En reliant extérieu r et intérieur du texte littéraire, ce qui écarte l'immanence structuraliste, nous abordons le roman négro-africain d'après les indépendance comme un dispositif d'énonciation dont le centre déictique et modal est le garant du discours, à savoir le narrateur principal qui est le plus souvent « homodiégétique » dans notre corpus à l'exception de Perpétue où il est « extradiégétique ». Ainsi, la thèse ruine la conception romantique qui distingue le moi social de l'écrivain et le moi créateur. Nous considérons donc que les romans de notre corpus sont des activités sociales s'insérant dans les pratiques discursives d'une société, ce qui consacre définitivement la relation texte et société en mettant en branle des notions de la problématique de l'énonciation à grande portée socioculturelle comme la « scénographie », la « scène générique », la « scène validée », la « paratopie », etc. Nous confirmons donc la possibilité d'un enrichissement des approches de la littéraire négro-afric aine considérant l'histoire littéraire composée de trois entités séparées (l' « homme », l' « uvre » et le « milieu ») et qui sont restées plus ou moins classiques, c'est-à-dire thématiques, souvent sociologiques. En recourant systématiquement aux outils de la linguistique de l'énonciation, de la pragmatique, de la linguistique textuelle, de l'argumentation, de la linguistique interactionniste, etc., nous appliquons à quelques romans négro-africains d'après les indépendances et à plusieurs séquences textuelles que nous avons sélectionnées et tirées de ce corpus, la méthode de l'analyse du discours telle qu'elle est théorisée dans la sphère européenne par des chercheurs tels que Dominique Maingueneau et Patrick Chareaudeau, mais également d'autres qui ont développé des problématiques linguistiques proches ou similaires : Jean Michel Adam, Ruth Amossy, Emile Benveniste, Catherine Kerbrat-Orecchioni, Oswald Ducrot, etc., pour ne citer que ceux-là. L'étude de la polyphonie pour la détermination des voix en présence dans les romans nous conduit à l'étude, d'une part, de la double énonciation qui se traduit par les dialogues en tant que modalité narrative où plusieurs énonciateurs sont mis en scène, de l'autre, de tous les types de discours rapporté, mais également de la manifestation verbale du peuple négro-africain. Ces voix définissent des identités énonciatives, celles des camps opposés, à savoir le pouvoir politique et/ou religieux et les opposants qui sont sans cesse en conflit dans les romans. Bannissant l' « authenticité » qui était la visée des conceptions identitaires négro-africaines comme la Négritude, les auteurs du corpus utilisent le discours rapporté et la double énonciation non pour restituer la réalité crue, comme dans le roman à thèse, mais pour dénoncer en dictant, en creux, au lecteur modèle ce qu'il faut penser ou croire. La tourmente politique et/ou religieuse est décriée par la présentation au lecteur de « patrons discursif » et d'un code langagier qui s'insérèrent dans l' « interdiscours » et qui montrent différents ethos populaires ou individuels fonctionnant comme des repoussoirs utilisés pour la dénonciation. Le lecteur modèle arrive à produire l'effet discursif attaché aux textes par l'activité d'« incorporation » de ces ethos qui se manifestent par une certaine corporalité et une vocalité précise.Mots clés :Énonciation, polyphonie, « scène d'énonciation », genre, dialogue, interaction, argumentation, « posture », « paratopie », ethos, discours, texte, contexte. / The black African novel of denunciation which is called the subversive novel and which some insert in the category said to be the novel of rupture, as a macro act of language, does involve a subversive and illocutory aim. That is true even if the post independence black African literary discourse, like any discourse, remains under constraint, that is to say, determined to a large extent, by the socio-political context, but also, the literary field where various positionings and postures of authors are in competition. In this work, we endeavour to show that this aim which is an attempt to reveal the awkwardness of the new political and/or religions systems, a result of the relationship between a non verbal black African context and the internal side of novels and results in literary construction of various individual and collective ethos, can be studied through the discourse analysis method. By linking the external and inner side of the literary text, which moves aside the str ucturalist immanence. We tackle the post independence black African novel as a system of enunciation whose deistic and modal centre vouches for the discourse, that is to say the principal narrator who is the most often homodiectic in our corpus except Perpetue where he is extradiegetic. So, the thesis ruins the romantic conception which distinguishes the social self from the creative self. We hence consider that the novels of our corpus are social activities involved in discursive practices of a society, which definitely settles the relationship between a text and society raising the notions of the enunciation issue with a broad socio cultural scope like the scenography, the generic scene, the validated scene, the paratopy,… we hence confirm the possibility of a rupture in the black African literary approaches considering literary history made up of three separate different entries(Man, his work and the environment) which have remained more or less classical, that is to say thematic, often sociological. In resorting systematically to the linguistic tool of enunciation, of pragmatism, of textual linguistic, of the argument of interaction linguistic, … we apply to a few post independence black African novels and to several textual sequences which we have selected and drawn from that corpus, the discourse analysis method as theoretized in the European area by researchers such as Dominique Maingueneau and Patric Chareaudeau, but also others who have developed similar linguistic issues : Jean Michel Adam, Ruth Amossy, Emile Benveniste, Catherine Kerbrat-Orecchioni, Oswald Ducrot,… to name but a few. The study of polygamy to determine voices which are found in the novels lead us to the study, on the one hand, of the double enunciation which are turned out into dialogues as narrative modality where several enunciators are brought to the stage, on the other hand, of all the type of reported speeches, but also of the verbal manifestation of the black Af rican people. These voices define enunciative identities, those of opposed positions, namely the political and/or religions power and the opponents who are always in conflict in the novels. Rejecting authenticity which was always the aim of black African; identity conceptions like Negritude, the authors of the corpus use the reported speech and the double enunciation not to restore the plain reality, like the thesis novel, but denounce by telling, in bias, the standard reader, what to think or believe. The political and/or religions upheaval is disparaged by the presentation to the reader of discursive patrons and of a language code which are integrated into the interdiscourse and which show different popular or individual ethos functioning as a foil used for denunciation. The standard reader manages to produce the discursive effect connected to the texts through the incorporation activity of these ethos which are shown through some corporality and precise vocality.Keywords:Enunciation, polyphony, enunciation scene gender, dialogue, interaction, argument, posture, paratopy, ethos, discourse, text, context.