Cette étude a pour but de tester si l’ajout de variables biomécaniques, telles que celles associées à la morphologie, la posture et l’équilibre, permet d’améliorer l’efficacité à dissocier 29 sujets ayant une scoliose progressive de 45 sujets ayant une scoliose non progressive. Dans une étude rétrospective, un groupe d’apprentissage (Cobb: 27,1±10,6°) a été utilisé avec cinq modèles faisant intervenir des variables cliniques, morphologiques, posturales et d’équilibre et la progression de la scoliose. Un groupe test (Cobb: 14,2±8,3°) a ensuite servit à évaluer les modèles dans une étude prospective. Afin d’établir l’efficacité de l’ajout de variables biomécaniques, le modèle de Lonstein et Carlson (1984) a été utilisé à titre d’étalon de mesures. Le groupe d’apprentissage a été utilisé pour développer quatre modèles de classification. Le modèle sans réduction fut composé de 35 variables tirées de la littérature. Dans le modèle avec réduction, une ANCOVA a servit de méthode de réduction pour passer de 35 à 8 variables et l’analyse par composantes principales a été utilisée pour passer de 35 à 7 variables. Le modèle expert fut composé de huit variables sélectionnées d’après l’expérience clinque. L’analyse discriminante, la régression logistique et l’analyse par composantes principales ont été appliquées afin de classer les sujets comme progressifs ou non progressifs. La régression logistique utilisée avec le modèle sans réduction a présenté l’efficience la plus élevée (0,94), tandis que l’analyse discriminante utilisée avec le modèle expert a montré l’efficience la plus faible (0,87). Ces résultats montrent un lien direct entre un ensemble de paramètres cliniques et biomécaniques et la progression de la scoliose idiopathique. Le groupe test a été utilisé pour appliquer les modèles développés à partir du groupe d’apprentissage. L’efficience la plus élevée (0,89) fut obtenue en utilisant l’analyse discriminante et la régression logistique avec le modèle sans réduction, alors que la plus faible (0,78) fut obtenue en utilisant le modèle de Lonstein et Carlson (1984). Ces valeurs permettent d’avancer que l’ajout de variables biomécaniques aux données cliniques améliore l’efficacité de la dissociation entre des sujets scoliotiques progressifs et non progressifs. Afin de vérifier la précision des modèles, les aires sous les courbes ROC ont été calculées. L’aire sous la courbe ROC la plus importante (0,93) fut obtenue avec l’analyse discriminante utilisée avec le modèle sans réduction, tandis que la plus faible (0,63) fut obtenue avec le modèle de Lonstein et Carlson (1984). Le modèle de Lonstein et Carlson (1984) n’a pu séparer les cas positifs des cas négatifs avec autant de précision que les modèles biomécaniques. L’ajout de variables biomécaniques aux données cliniques a permit d’améliorer l’efficacité de la dissociation entre des sujets scoliotiques progressifs et non progressifs. Ces résultats permettent d’avancer qu’il existe d’autres facteurs que les paramètres cliniques pour identifier les patients à risque de progresser. Une approche basée sur plusieurs types de paramètres tient compte de la nature multifactorielle de la scoliose idiopathique et s’avère probablement mieux adaptée pour en prédire la progression. / The purpose of this study is to examine whether the addition of biomechanical variables, such as variables associated with morphology, posture and balance, produce an increase in dissociation efficiency of 29 subjects with progressive scoliosis from 45 subjects with non progressive scoliosis. In a retrospective study, a learning group (Cobb: 27,1±10,6°) was used with five models comprising clinical, morphological, postural and balance variables and scoliosis progression. A testing group (Cobb: 14,2±8,3°) was then used to evaluate the models in a prospective study. In order to establish the efficiency of the addition of biomechanical variables, Lonstein and Carlson’s (1984) model was used as a reference. The learning group was used to develop four classification models. The model without reduction was composed of 35 variables taken from the literature. In the model with reduction, an ANCOVA served as a reduction method to go from 35 to 8 variables and principal component analysis was used to go from 35 to 7 variables. The expert model was composed of eight variables selected according to clinical experience. Discriminant analysis, logistic regression and principal component analysis were applied in order to classify the subjects as progressive or non progressive. Logistic regression used with the model without reduction presented the highest efficiency (0,94), whereas discriminant analysis used with the expert model showed the lowest efficiency (0,87). These results show a direct relation between a group of clinical and biomechanical parameters and idiopathic scoliosis progression. The testing group was used to apply the models developed from the learning group. The highest efficiency (0,89) was obtained with the use of discriminant analysis and logistic regression and the model without reduction, as the lowest (0,78) was obtained with the use of Lonstein and Carlson’s (1984) model. These values suggest that the addition of biomechanical variables to clinical data increases dissociation efficiency between progressive and non progressive scoliotic subjects. In order to verify the precision of the models, the area under the ROC curve was calculated. The largest area under the ROC curve (0,93) was obtained with the discriminant analysis used with the model without reduction, whereas the lowest (0,63) was obtained with Lonstein and Carlson’s (1984) model. Lonstein and Carlson’s (1984) model could not separate the positive cases from the negative cases with the same amount of precision compared with the biomechanical models. The addition of biomechanical variables to clinical data allowed increasing dissociation efficiency between progressive and non progressive scoliotic subjects. These results suggest that factors other than clinical parameters can identify patients at risk of progression. An approach based on many types of parameters takes into account the multi-factorial nature of idiopathic scoliosis and appears to be better adapted to predict it’s progression.

The theoretical part of this Diploma Thesis is attend to matter of body posture and diagnose of it, problematic of body balance and possibilities of preventive medical equalize excercising. The Research part of this Diploma Thesis is attended to physical testing of the body posture and body balance. The tests results are proving the rightness of the Excercising Plan, which has as an object to affect the right body posture of pre-school children and also improve their body balance by regular Excercising on a Balance balls as an important sphere of the right body posture. Key words Body Posture Body Balance Posture system Balance Ball Pre-school age

Les mouvements volontaires sont accompagnés par des ajustements posturaux anticipateurs (APAs). Leur rôle consiste à prévenir et à compenser de possibles perturbations du corps provoquées par l’exécution du mouvement. Des études antérieures ont montré que la coordination posture / mouvement est modifiée selon que le mouvement est exécuté le plus rapidement possible en réponse à un signal externe (réactif :TRS), ou que le mouvement est auto-initié (prédictif :AI). L’objectif de ce travail est d’examiner le mode de coordination posture / mouvement impliqué dans une situation d’anticipation-coïncidence (AC) lors de l’exécution de mouvements simples et complexes, et ensuite, comparer ce mode aux modes TRS et AI. Trois études expérimentales ont été menées pour vérifier si : (1) les modes de coordination, obtenus sur des gestes simples, s’étendent à des mouvements complexes ; (2) le mode de coordination en AC dépend des caractéristiques temporelles du mobile utilisé dans la tâche ; (3) les commandes impliquant les APAs et le mouvement focal sont associées ou dissociées en fonctions des contraintes temporelles TRS et AC. Ainsi, nous avons démontré que : (1) les stratégies de coordination posture / mouvement s’appliquent sur les mouvements complexes ; (2) la prédictibilité du moment de déclenchement dans la condition AC rapproche celle-ci de la situation AI ; (3) les différences de coordination entre les conditions réactive (TRS) et prédictives (AC, AI) sont liées à des différences dans les mécanismes de préparation consistant à dissocier les commandes posturales et focales en situation prédictive et à associer ces commandes dans la situation réactive. Les implications théoriques qui émergent de ces résultats sont discutées. / Voluntary movements are generally accompanied by anticipatory postural adjustments (APAs). They are centrally generated as a feedforward mechanism to counteract the mechanical effects of predicted balance perturbations. Previous studies showed that the coordination between posture and movement is modified depending on whether the movement is performed in a reactive temporal pressure (TRS) or in a self-initiated (AI) manner. The aim of this thesis is to examine the coordination of posture and movement in anticipation-coincidence (AC) timing tasks in simple and complex movements, and then to compare this mode to the TRS and AI modes. Three experiments was achieved to verify : (1) whether simple movement coordination modes can be extended to complex movements ; (2) whether the temporal characteristics of the mobile used in the task modifies the coordination in AC condition ; (3) to which extent the motor commands of APAs and the focal movement are coupled in response to the TRS and AC temporal pressures. Results show that: (1) the different strategies of coordination between posture and movement are extended to the complex tasks; (2) the predictable timing of movement execution in the AC condition generates behaviours closer to those observed in AI condition; (3) the differences in the coordination between the reactive (TRS) and the predictive (AC, AI) conditions are related to the difference in the preparatory processes which consists on the dissociation of postural and focal commands in the predictive situations, and the association of this motor commands in the reactive situation. Theoretical implications emerging from these results are discussed.

Abstract title: Postural deviations and their compensations of blind cyclist Thesis objective: The objective of this thesis is to create a compensatory motional program for a visually impaired client. Compensatory motional program deals with the positive influence of defective body posture and pain alleviation of relevant muscular areas, particularly in the areas of cervical, thoracic and lumbar spine. Method: The research method is qualitative examinations by usage of pretest and posttest designs. The thesis is conceived as the case report of a 31-year-old patient with acquired handicap. Exercise in fitness center was selected as part of compensatory motional program with the application of stretching, relaxing and work-out exercise. Additionally, hippotherapy was practiced to improve the stability of individual body areas, as well as to generally enhance the body posture. The testing methods for defective body postures by Jaroš and Lomíček, Matthiase; as well as testing method by Janda, were applied for the verification of program effect. The HHT motor test was applied for the verification of hippotherapy. Results: Compensatory motional program positively influenced the body posture of the clients already after three months of exercise. The integral part of hippotherapy was also the influence of...

No description available.

Cette étude a pour but de tester si l’ajout de variables biomécaniques, telles que celles associées à la morphologie, la posture et l’équilibre, permet d’améliorer l’efficacité à dissocier 29 sujets ayant une scoliose progressive de 45 sujets ayant une scoliose non progressive. Dans une étude rétrospective, un groupe d’apprentissage (Cobb: 27,1±10,6°) a été utilisé avec cinq modèles faisant intervenir des variables cliniques, morphologiques, posturales et d’équilibre et la progression de la scoliose. Un groupe test (Cobb: 14,2±8,3°) a ensuite servit à évaluer les modèles dans une étude prospective. Afin d’établir l’efficacité de l’ajout de variables biomécaniques, le modèle de Lonstein et Carlson (1984) a été utilisé à titre d’étalon de mesures. Le groupe d’apprentissage a été utilisé pour développer quatre modèles de classification. Le modèle sans réduction fut composé de 35 variables tirées de la littérature. Dans le modèle avec réduction, une ANCOVA a servit de méthode de réduction pour passer de 35 à 8 variables et l’analyse par composantes principales a été utilisée pour passer de 35 à 7 variables. Le modèle expert fut composé de huit variables sélectionnées d’après l’expérience clinque. L’analyse discriminante, la régression logistique et l’analyse par composantes principales ont été appliquées afin de classer les sujets comme progressifs ou non progressifs. La régression logistique utilisée avec le modèle sans réduction a présenté l’efficience la plus élevée (0,94), tandis que l’analyse discriminante utilisée avec le modèle expert a montré l’efficience la plus faible (0,87). Ces résultats montrent un lien direct entre un ensemble de paramètres cliniques et biomécaniques et la progression de la scoliose idiopathique. Le groupe test a été utilisé pour appliquer les modèles développés à partir du groupe d’apprentissage. L’efficience la plus élevée (0,89) fut obtenue en utilisant l’analyse discriminante et la régression logistique avec le modèle sans réduction, alors que la plus faible (0,78) fut obtenue en utilisant le modèle de Lonstein et Carlson (1984). Ces valeurs permettent d’avancer que l’ajout de variables biomécaniques aux données cliniques améliore l’efficacité de la dissociation entre des sujets scoliotiques progressifs et non progressifs. Afin de vérifier la précision des modèles, les aires sous les courbes ROC ont été calculées. L’aire sous la courbe ROC la plus importante (0,93) fut obtenue avec l’analyse discriminante utilisée avec le modèle sans réduction, tandis que la plus faible (0,63) fut obtenue avec le modèle de Lonstein et Carlson (1984). Le modèle de Lonstein et Carlson (1984) n’a pu séparer les cas positifs des cas négatifs avec autant de précision que les modèles biomécaniques. L’ajout de variables biomécaniques aux données cliniques a permit d’améliorer l’efficacité de la dissociation entre des sujets scoliotiques progressifs et non progressifs. Ces résultats permettent d’avancer qu’il existe d’autres facteurs que les paramètres cliniques pour identifier les patients à risque de progresser. Une approche basée sur plusieurs types de paramètres tient compte de la nature multifactorielle de la scoliose idiopathique et s’avère probablement mieux adaptée pour en prédire la progression. / The purpose of this study is to examine whether the addition of biomechanical variables, such as variables associated with morphology, posture and balance, produce an increase in dissociation efficiency of 29 subjects with progressive scoliosis from 45 subjects with non progressive scoliosis. In a retrospective study, a learning group (Cobb: 27,1±10,6°) was used with five models comprising clinical, morphological, postural and balance variables and scoliosis progression. A testing group (Cobb: 14,2±8,3°) was then used to evaluate the models in a prospective study. In order to establish the efficiency of the addition of biomechanical variables, Lonstein and Carlson’s (1984) model was used as a reference. The learning group was used to develop four classification models. The model without reduction was composed of 35 variables taken from the literature. In the model with reduction, an ANCOVA served as a reduction method to go from 35 to 8 variables and principal component analysis was used to go from 35 to 7 variables. The expert model was composed of eight variables selected according to clinical experience. Discriminant analysis, logistic regression and principal component analysis were applied in order to classify the subjects as progressive or non progressive. Logistic regression used with the model without reduction presented the highest efficiency (0,94), whereas discriminant analysis used with the expert model showed the lowest efficiency (0,87). These results show a direct relation between a group of clinical and biomechanical parameters and idiopathic scoliosis progression. The testing group was used to apply the models developed from the learning group. The highest efficiency (0,89) was obtained with the use of discriminant analysis and logistic regression and the model without reduction, as the lowest (0,78) was obtained with the use of Lonstein and Carlson’s (1984) model. These values suggest that the addition of biomechanical variables to clinical data increases dissociation efficiency between progressive and non progressive scoliotic subjects. In order to verify the precision of the models, the area under the ROC curve was calculated. The largest area under the ROC curve (0,93) was obtained with the discriminant analysis used with the model without reduction, whereas the lowest (0,63) was obtained with Lonstein and Carlson’s (1984) model. Lonstein and Carlson’s (1984) model could not separate the positive cases from the negative cases with the same amount of precision compared with the biomechanical models. The addition of biomechanical variables to clinical data allowed increasing dissociation efficiency between progressive and non progressive scoliotic subjects. These results suggest that factors other than clinical parameters can identify patients at risk of progression. An approach based on many types of parameters takes into account the multi-factorial nature of idiopathic scoliosis and appears to be better adapted to predict it’s progression.

The neural and sensory mechanisms underlying appropriate muscle recruitment in response to balance challenges remains elusive. We asked whether the decerebrate cat preparation might be employed for further investigation of postural mechanisms. First, we evaluated the muscular activation patterns and three-dimensional whole limb forces generated by a modified premammillary decerebrated cat. We hypothesized that directionally appropriate muscle activation does not require the cerebral cortices. Furthermore, we hypothesized that the muscle responses would generate functionally appropriate and constrained force responses similar to those reported in the intact animal. Data confirmed both of our hypotheses and suggested important roles for the brainstem and spinal cord in mediating directionally appropriate muscular activation. Second, we investigated how individual muscle activation is translated to functional ground reaction forces. We hypothesized that muscles are selectively activated based upon their potential counteractive endpoint force. Data demonstrated that the endpoint force generated by each muscle through stimulation was directed oppositely to the principal direction of each muscle's EMG tuning curve. Further, muscles that have variable tuning curves were found to have variable endpoint forces in the XY plane. We further hypothesized that the biomechanical constraints of individual muscle actions generate the constrained ground reaction forces created in response to support surface perturbations. We found that there was a lack of muscles with strong medial-lateral actions in the XY plane. This was further exaggerated at long stance conditions, which corresponds to the increased force constraint present in the intact animal under the same conditions. Third, we investigated how loss of cutaneous feedback from the footpads affects the muscle recruitment in response to support surface perturbations. We utilized our decerebrate cat model as it allows 1) isolation of the proprioceptive system (cutaneous and muscle receptor) and 2) observation of the cutaneous loss before significant compensation by the animal. We hypothesized that muscle spindles drive directionally sensitive muscle activation during postural disturbances. Therefore, we expected that loss of cutaneous feedback from the foot soles would not alter the directional properties of muscle activation. While background activity was significantly diminished, the directionally sensitive muscular activation remained intact. Due to fixation of the head, the decerebrate cat additionally does not have access to vestibular or visual inputs. Therefore, this result strongly implicates muscle receptors as the primary source of directional feedback. Finally to confirm that muscle receptors, specifically muscle spindles, are capable of generating feedback to drive the directionally tuning, we investigated the response properties of muscle spindles to horizontal support surface perturbations in the anesthetized cat. As previously stated, we hypothesized that muscle spindles provide the feedback necessary for properly directed muscular responses. We further hypothesized that muscle spindles can relay feedback about the perturbation parameters such as velocity and the initial stance condtion. Results confirmed that muscle spindle generate activation patterns remarkably similar to muscular activation patterns generated in the intact cat. This information, along the knowledge that cutaneous feedback does not substantially eliminate directional tuning, strongly suggests that muscle spindles contribute the critical directional feedback to drive muscular activation in response to support surface perturbations.

La collaboration entre artistes et scientifiques accompagne, depuis le XVIe siècle, une évolution des représentations d’un corps de plus en plus morcelé. La théorie de la plasticité neuronale, aussi révolutionnaire pour certains que celle de Copernic ou de Darwin, a esquissé les lignes de nouveaux paradigmes scientifiques, mais aussi philosophiques et sociaux, sur lesquels les artistes contemporains s’appuient de manière poétique, parfois ironique et dénonciatrice. De la fétichisation de la science à la manipulation des concepts et protocoles récents, certains modes d’expression plastiques s’appuient aussi sur l’avancée spectaculaire et stimulante des biotechnologies. Les questions de déformation, d’impermanence et d’interaction accompagnent celle de plasticité, qu’elle soit neuronale, physique ou qu’elle concerne les matériaux. Cette thèse analyse, à partir des éléments de ce contexte, les enjeux de démarches d’artistes aux prises avec ces plasticités à l’œuvre. Prenant en considération le rapport d’influence réciproque qui existe entre plasticité cérébrale et corporelle, j’analyse aussi l’impact d’une pratique méditative ou énergétique sur toute démarche humaine, et plus précisément sur celle de l’artiste par l’élargissement de ses champs perceptifs et créatifs. Je questionne ainsi l’impact du shintaïdo, art martial japonais, sur ma poïèse. L’usage de la cire, matériau plastique à la fois modeste et sacré, est confronté à celui de la toile brute, extirpant de la matière cérébrale mais aussi corporelle des cartographies à la syntaxe mystérieuse, telles des errances nomades telluriques devenues aujourd’hui plus aériennes / Since the 16th century, the collaboration between artists and scientists has gone along with an evolution of representations of a more and more fragmented body. The neuroplasticity theory, as revolutionary for some people as the one of Copernicus or of Darwin, has made a start on the lines of new scientific, but also philosophical and social paradigms, on which contemporary artists rely in a poetic, sometimes ironic and denunciatory way. From the high value given to science to the recent protocols and concepts manipulation, some artistic techniques also rely on the spectacular and stimulating breakthrough of biotechnologies. The questions linked to distortion, impermanence and interaction come with those of plasticity, being neuronal, physical or in connection with materials. From these context elements, this thesis analyzes the issues linked to the approaches from artists grappling with these plasticities at work. Taking into consideration the mutual influence relationship existing between brain and body plasticity, I also analyze the impact of Shintaido, a Japanese martial art, on my poïesis. The use of wax, a both modest and sacred plastic material, is confronted to the use of raw canvas, dragging out maps with a mysterious syntax from brain and body matter, like telluric nomadic wanderings that have become more ethereal today.

Despite extensive research into musculoskeletal disorders (MSDs) they continue to plague workers. Manual materials handling (MMH), in particular the concurrence of load manipulation and awkward body posture, has been identified as a key factor in the onset of MSDs. Only a few studies have looked at the interaction between manipulation tasks and working posture during assembly tasks and as a result their relationship has not been widely explored. Assessing the stresses resulting from individual task factors and body posture in isolation and adding them together may be too simplified to estimate an overall risk profile, since this does not take into account that there may be a non-linear interaction in strain responses when manipulation task and body posture interact. Therefore, the present study investigated biophysical, physiological and psychophysical responses to combined tasks, rather than individual tasks of body posture and manipulative tasks. The objective of the research was to establish the interactive effects of constrained body postures and manipulative tasks and to identify whether a cumulative or compensatory reaction occurs during this interaction. Nine conditions were assessed in a laboratory setting, which included combinations of three working postures (standing, sitting and stooping) and three assembly tasks (torque wrenching, precision and no task). Thirty-six subjects were required to complete all nine conditions, with each condition lasting ninety seconds. Muscle activity was recorded for seven muscles from the upper extremity, trunk and lower extremity regions and was complemented by physiological (heart rate, tidal volume, minute ventilation, oxygen consumption, energy expenditure and breathing frequency) and psychophysical (body discomfort) data. At the completion of all nine conditions subjects completed a retrospective psychophysical rating questionnaire pertaining to discomfort felt during the conditions. Responses obtained for the different task and posture combinations revealed compensatory reactions (additive > combined) for most of the conditions assessed for the biomechanical and physiological responses. In the majority of cases for muscle activity, no significant differences were found between the combined and the additive effects (p < 0.05), while for the physiological responses there were mostly significant differences observed. Psychophysical responses indicated that there was a significant difference overall between the additive and combined effects. The results of this study demonstrate that in order to identify risk areas, manipulation tasks and constrained working postures may be considered either in isolation and added together (additive) or as a combined task, since there were very few significant differences observed between these two effects. Further studies are required, however, to provide conclusive evidence.

La fonction d’anticipation programmant l'action et ses conséquences sur la posture s’appuie sur les représentations sensorimotrice. L’adolescence étant caractérisée par des modifications du corps et du cerveau, cette thése évalue les liens qui unissent anticipation, représentations sensorimotrices et maturation cérébrale. La tâche bimanuelle de délestage met en jeu l’utilisation d’un bras postural, supportant le poids, et d’un bras manipulateur, qui le déleste. Dans cette tâche, l'anticipation s'exprime par les ajustements posturaux anticipés (APA), annulant la déstabilisation posturale causée par l'action. Des enregistrements cinématiques, EMG et EEG ont été utilisés. Bien qu’une stabilisation posturale stable soit reportée, les APAs à l’adolescence se caractérisent par une amélioration de la latence de l’inhibition des fléchisseurs. Chez l’adulte, les APA s’expriment par une désynchronisation du rythme mu et une onde positive au dessus de M1 impliqué dans la posture. Les caractéristiques temporelles de ces signatures varient à l’adolescence. L’apprentissage d’un nouveau contrôle postural est caractérisé par une amélioration rapide puis plus lente de la stabilisation posturale. Plus tardive à l'adolescence, cette acquisition repose sur la maitrise du réglage temporel de l’inhibition des fléchisseurs. Une intégration des retours proprioceptifs issus de l’action permettrait la construction d’une représentation sensorimotrice. Exprimée par la maitrise des paramètres temporels, la réactualisation des représentations sensorimotrice à l’adolescence passerait par une meilleure intégration des retours proprioceptifs. La maturation des régions cérébrales serait aussi capitale. / Voluntary action requires an anticipation, which predicts the consequence of action on posture. Anticipation rests on action and body representations. Adolescence is characterized by body modifications and cerebral maturation. This thesis explored the link between the anticipatory function, action and body representations, and the cerebral maturation. The bimanual load-lifting task engages a postural arm, supporting the load, and a motor arm, lifting the load. In this task, the anticipation, expressed by anticipatory postural adjustments (APA) cancelled the destabilizing effect of movement on the posture. Kinematics, EMG and EEG were recorded. Although performances of postural stabilization were stable, APAs at the adolescence were characterized by an earlier latency of inhibition on the postural flexors. In adults, APA are expressed by a mu rhythm desynchronization and a positive wave over M1involved in posture, which presented different temporal characteristics in adolescents. Thus, the improvement of APA would be underlain by a maturation of these EEG activities. Learning a new postural control was characterized by a rapid followed by a slow improvement of the postural stabilisation. This acquisition rested on the mastering of the temporal parameters of the flexors inhibition, which took more time at the adolescence. Integration of proprioceptive feedback coming from action allowed an update of sensorimotor representation. Expressed by the mastering of the temporal parameters, the update of body and action representations at adolescence would imply an enhancement of the integration of proprioceptive information. Maturation of the cerebral areas would be a key element.