In daily activities, hand use is dominated by individuated thumb and finger movements, and by grasping. This thesis focused on the level of ???independence??? of the digits and its relationship to hand grasps, from the level of the motor units to the level of synergistic grasping forces. Four major studies were conducted in healthy adult volunteers. First, spike-triggered averages of forces produced by single motor units in flexor pollicis longus (FPL) in a grasp posture showed small but significant loading of the index, but not other fingers. This reflected a neural rather than anatomical coupling, as intramuscular stimulation produced minimal effect in any finger. Also, FPL had a surprisingly large number of low-force motor units and this may account for the thumb???s exceptional dexterity and force stability compared with the fingers. Second, independent control of extensor digitorum (ED) was more limited than flexor digitorum profundus (FDP), as more ED motor units of a ???test??? finger were recruited inadvertently by extension than by flexion of adjacent digits. Third, ???force enslavement??? in maximal voluntary tasks was greater in digit extension than flexion. The distribution of force enslavement (and deficits) matched the pattern of daily use of the digits (alone and in combination), and reveals a neural control system which preferentially lifts fingers together from an object by extension but allows an individual digit to flex to contact an object so the finger pads can engage in exploration and grasping. Finally, during grasping, irrespective of whether a digit had been lifted from the object, coherence among forces generated by the digits was similar. In addition, the coherence between finger forces was independent of any contraction of the thumb, was stable over 2 months, and required no learning. The pattern of coherence between digital grasping forces may be closely related to the level of digit independence and daily use. Overall, the grasp synergy was remarkably invariant over the various tasks and over time. In summary, this thesis demonstrates novel aspects of the properties of FPL, the lack of complete independence of the digits, and robustness in the production of flexion forces in hand grasps.

Made available in DSpace on 2016-12-06T17:07:26Z (GMT). No. of bitstreams: 1 DISSERTACAO PRONTA.pdf: 1254266 bytes, checksum: f6cd46c7547dc4db63544d5dade63617 (MD5) Previous issue date: 2011-03-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The anterior knee laxity has been described as a risk factor for anterior cruciate ligament injuries of the knee. During exercise it has been verified an increase in knee laxity due to cyclic loading. This increase can alter the neuromuscular control and also decrease the joint dynamic stability. Thus, this study aimed to evaluate the neuromuscular response during jump landing after incresing anterior knee laxity. Nineteen male subjects were evaluated (mean age 27,47 ±4,56 years; mean body mass 73 ±9,41 kg; mean height 1,75 ±0,05 m). Neuromuscular response was verified through semitendinosus, biceps femoris, vastus medialis and vastus lateralis muscular activation. In order to evaluate joint dynamic stability, the co-activation index between medialis and lateralis muscles was also verified. Subjects performed five trials of unipodal jumps from a 30 cm height. The subject s knee was submitted to cyclic passive anterior traction for 15 min, with 0,1 Hz frequency. Traction load was normalized for 40% of body mass to induce increase laxity. The knee was positioned at 30 degrees of flexion, and a cable was fixed right below the tuberosity of the tibia. After cyclic loads, subjects were revaluated. The jump was divided in three windows: 100ms before landing, 100ms after landing and 200ms after landing. Paired t test was used to compare muscle activities before and after inducing anterior knee laxity. The results showed a decrease in semitendinosus activity during 100ms after landing, as well as decrease in vastus lateralis in 100ms before and after landing. However, vastus medialis, biceps femoris and co-activation index were not affected by anterior knee laxity. The results show that increased anterior knee laxity can change the neuromuscular control. However, this alteration may not be sufficient to reduce the dynamic joint stability / A lassidão anterior do joelho tem sido descrita como um dos fatores de risco para as lesões do ligamento cruzado anterior do joelho. Tem-se verificado que cargas cíclicas durante o exercício provocam o aumento dessa lassidão. Esse aumento pode alterar o controle neuromuscular e diminuir a estabilidade articular dinâmica. Dessa forma este estudo teve por objetivo avaliar a resposta neuromuscular durante o salto após o aumento da lassidão anterior do joelho. Para isso foram avaliados 19 sujeitos do sexo masculino, com idade média de 27,47 anos (±4,56), massa corporal de 73 kg (±9,41), e estatura de 1,75 m (±0,05). Para a avaliação da resposta neuromuscular foi mensurada a atividade muscular dos músculos semitendíneo, bíceps femoral, vasto medial, e vasto lateral. Para a avaliação da estabilidade articular dinâmica foi obtido ainda o índice de co-ativação entre os músculos mediais e laterais da coxa. Estas variáveis foram obtidas em 5 saltos unipodais, realizados de uma altura de 30 cm. Em seguida, o aumento da lassidão foi provocado por meio de uma força de tração anterior cíclica passiva aplicada à tíbia por 15 min., a uma freqüência de 0,1 Hz, com a magnitude da força correspondente a 40% da massa corporal do sujeito. Para a aplicação da carga o joelho foi posicionado a 30 ° de flexão e um cabo fixado abaixo da tuberosidade da tíbia. Para a avaliação da atividade muscular o salto foi dividido em três instantes: 100ms pré-aterrissagem, 100ms pós-aterrissagem e 200ms pós-aterrissagem.Em cada instante do salto analisado a atividade muscular foi comparada estatisticamente nas situações pré e pós-aumento da lassidão por meio de teste t de student para medidas repetidas. O resultado do teste t demonstrou que houve diminuição significativa na ativação do músculo semitendíneo no instante 100ms pós-aterrissagem, e do músculo vasto lateral no instante 100ms pré-aterrissagem e 100ms pós-aterrissagem. Nos demais músculos e no índice de co-ativação não foram observados alterações. A partir dos resultados concluiu-se que o aumento da lassidão anterior do joelho pode alterar o controle neuromuscular. Todavia, estas alterações podem não ser suficientes para alterar a estabilidade articular dinâmica

La reconstruction chirurgicale est le traitement préconisé après rupture du Ligament Croisé Antérieur (LCA) chez les patients sportifs. Cette opération est suivie d'une longue période de rééducation et les résultats en termes de reprise du sport et de récidive ne sont pas totalement satisfaisants. Ainsi ce travail s'articule autour de deux objectifs : l'amélioration de la récupération après lésion du LCA et la prévention des primo-ruptures. Dans un premier temps, nous avons évalué les altérations cinématiques et dynamiques présentes chez les patients, lors d'un mouvement de saut, 7 mois après reconstruction du LCA. Les études conduites mettent en évidence des performances plus faibles et des asymétries plus importantes chez les patients, notamment pour le travail mécanique articulaire total. La jambe opérée présente des déficits au niveau du genou, de la hanche et de la cheville sur des paramètres tels que les amplitudes articulaires, les moments et puissances articulaires. Des altérations ont également été retrouvées sur la jambe non-opérée. Elles se traduisent par une modification des angles de la cheville, du genou, et un plus faible moment articulaire total. Dans un deuxième temps, nous nous sommes intéressés aux possibilités de prévention des ruptures du LCA chez les athlètes féminines. Nos résultats démontrent qu'il est possible de détecter et de diminuer les facteurs de risque neuromusculaires, dont le « valgus dynamique », tout en augmentant la performance de saut chez de jeunes basketteuses. En conclusion, l'amélioration des résultats après lésion du LCA requiert, dans le protocole de rééducation et le suivi des patients, une attention particulière à la qualité d'exécution des mouvements pluriarticulaires, sur chacun des deux membres inférieurs. En parallèle, la détection et la prise en charge des facteurs de risque neuromusculaires devraient être systématisées dans les pratiques ou les publics à risque afin de prévenir les ruptures du LCA / Surgical reconstruction is the common treatment after Anterior Cruciate Ligament (ACL) injury in athletes. It usually requires a long period of rehabilitation and the results in terms of return to sport and re-injury rates are not fully satisfactory. The present work has two aims: the enhancement of recovery after ACL tear and the prevention of initial injury. Firstly, we assessed the kinematic and kinetic alterations during a jump task in patients 7 months after ACL reconstruction. Our findings highlight both a lower jumping performance, and greater asymmetries in patients, particularly considering the total joint mechanical work. The operated leg presents deficits at the knee, hip and ankle joints on parameters such as joint range of motion, joint moments and powers. In addition, changes are also found on the non-operated leg, characterized by a modification of the knee and ankle joint angles, and by a lower total joint moment. Secondly, we focused on ACL injury prevention in female athletes. We determinate a way to detect and reduce the neuromuscular risk factors, including “dynamic valgus”, while increasing jumping performance in young basketball female players. In conclusion, maximizing the recovery after ACL tear requires, in the rehabilitation protocol and the patients follow-up, a particular emphasis on the quality of execution of multi-joint task, on each of both lower limbs. Moreover, the detection and management of the neuromuscular risk factors should be systematized in sports or public at risk in order to prevent ACL injury

Low back pain (LBP) remains the most prevalent and costly work-related disability worldwide and is directly associated with "physical" risk factors prevalent in manual material handling (MMH) tasks. Back-support exoskeletons (BSEs) are a promising ergonomic intervention to mitigate LBP risk, by reducing muscular exertion and spine loading. The purpose of this work was to help better understand both the "intended" and "unintended" consequences of BSE use on physical risk factors for LBP, as an essential prerequisite for the safe and effective implementation of this technology in actual workplaces. The first study assessed the effects of using two BSEs on objective and subjective responses during repetitive lifting involving symmetric and asymmetric postures. Wearing both BSEs significantly reduced peak levels of trunk extensor muscle activity and reduced energy expenditure. Such reductions, though, were more pronounced in the symmetric conditions and differed between the two BSEs tested. The second study quantified the assistive torque profiles of two passive BSEs using a computerized dynamometer, with both human subjects and a mannequin. Clear differences in torque magnitudes were evident between the BSEs, though both generated more assistive torques during flexion than extension. The third study estimated the effects of BSE use on lumbosacral compressive and shear forces during repetitive lifting using an optimization-based model. Using both BSEs reduced peak compression and anteroposterior shear forces, but these effects differed between tasks and BSE designs. Reductions in composite measures of trunk muscle activity did not correspond consistently with changes in spine forces when using a BSE. The fourth study quantified the effects of two passive BSEs on trunk stability and movement coordination during repetitive lifting. Some adverse effects on stability were evident for pelvis and thorax movements and coupling of these body segments, suggesting that caution is needed in selecting a BSE for a given MMH task. Overall, we found that the efficacy of BSEs is design- and task-specific. Important safety features of the exoskeletons were also identified, providing insights on their performance boundaries. Overall, the BSEs tested were more effective and safer in tasks closer to the mid-sagittal plane and with moderate degrees of trunk flexion. / Doctor of Philosophy / Low back pain (LBP) remains the most prevalent and costly work-related disability worldwide, and the risk of LBP is related to "physical" risk factors common in manual material handling (MMH) tasks. Back-support exoskeletons (BSEs) are a new ergonomic intervention that may reduce the risk of occupational LBP, by reducing muscular efforts and loads on the spine. For the safe use of BSEs, though, it is critical to better understand both the "intended" and "unintended" consequences of this emerging technology. In this dissertation, such consequences of BSE use were evaluated in the context of repetitive lifting tasks. The first study assessed the efficacy of two BSEs in terms of physical demands during repetitive lifting tasks involving a range of torso bending and twisting. Wearing both BSEs reduced the physical demands on back muscles and decreased energy consumption. Larger reductions, though, were observed in forward bending and such reductions differed between the two BSEs tested. The second study measured the amount of support provided by two BSEs using a new measurement method, which was examined for both human subjects and a mannequin. Clear differences in the BSE support were evident between the BSEs, and both devices generated more support during torso forward bending than returning upright. The third study estimated the effects of BSE use on low back loadings during repetitive lifting using a computational model. Using both BSEs reduced loads on the low back region, though such reductions were task-specific and depended on the BSE design. The fourth study quantified the effects of the BSE use on torso stability and movement patterns during repetitive lifting. Some adverse effects on stability were evident for lower and upper torso, suggesting that caution is needed in selecting a BSE for a given MMH task. Findings from this work show the potential benefits of BSEs for use in MMH tasks, yet such benefits can depend on the BSE design and the MMH task they are used for. Further, BSE use can lead to adverse effects, especially with tasks involving extreme working postures.

El control neuromuscular ha estat descrit com un important factor per a l'èxit en el rendiment esportiu. De la mateixa manera, també s'ha identificat com a clau en la prevenció i readaptació de les lesions esportives. El principal objectiu d'aquesta tesi doctoral és avaluar l'eficàcia de diferents tipus d'entrenament neuromuscular en esportistes.S'ha utilitzat una mostra de 81 esportistes sans entre els diferents estudis que s'hi presenten. Les diferents avaluacions realitzades han registrat els següents ítems: dolor (escala visual analògica), incidència de lesions esportives, estabilitat postural estàtica i dinàmica (estabilometria i salt unipodal) i força explosiva de l'extremitat inferior (salt amb contramoviment). Els dos mètodes d'entrenament neuromuscular utilitzats són l'anomenat TRAL (Teràpia Reequilibradora de l'Aparell Locomotor) i les VCS (vibracions de cos sencer). La primera part d'aquesta tesi (Estudis I i II) va tenir l'objectiu de valorar l'eficàcia del mètode TRAL. Aquest va produir una reducció significant del dolor de turmell independentment del gènere registrat, mentre que en el cas del dolor de genoll només hi van haver diferències en les noies estudiades. Un dels altres efectes registrats importants a destacar va ser la reducció significant de l'àrea de desviació del centre de pressions en el cas de les noies, el que representa una millora de l'estabilitat postural. Aquesta dada també va ser positiva en una de les proves registrades en el grup de nois. La segona part d'aquest treball (Estudi III) es va centrar en donar fiabilitat a una bateria de tests d'equilibri mesurats amb un estabilòmetre, tenint com a objectiu valorar l'estabilitat estàtica i dinàmica de l'extremitat inferior. Es va obtenir una correlació de bona a excel·lent en totes les variables de la millor amplitud promig en el test unipodal d'ulls oberts i tancats. Aquests resultats suggereixen una bona fiabilitat per a la distinció entre grups de subjectes. En el cas del test més dinàmic i proper a la realitat de l'esportista, el salt unipodal, la correlació va ser baixa.Com a continuació d'aquesta segona part, l'estudi IV va comparar de forma transversal les diferències de l'estabilitat postural estàtica i dinàmica segons sexe i cama dominant. El test d'equilibri unipodal d'ulls oberts no va mostrar diferències significatives en la desviació del centre de pressions entre homes i dones. D'altra banda, el sexe femení va mostrar un major equilibri en els tests més dinàmics (UT i S) en comparació amb el sexe masculí. En relació a les diferències entre cama dominant - no dominant, només es van trobar diferències significatives en les dones en la recepció del salt unipodal, mostrant-se un millor control quan la recepció s'efectuava amb la cama dominant.La següent línia de treball es va iniciar amb l'estudi V, que va consistir en una revisió sistemàtica sobre els efectes de l'entrenament vibratori sobre el rendiment esportiu en persones físicament actives. Els resultats van mostrar una gran heterogeneïtat clínica i una baixa qualitat metodològica dels treballs analitzats fins la data cercada. Malgrat no poder extreure conclusions clares, existeix una tendència a la millora de la força explosiva. També podem establir un rang segur dels paràmetres d'aplicació de vibracions mecàniques sobre la població d'estudi. Aquest es troba entre 1,7-11mm d'amplitud i entre 20-44 Hz de freqüència, aplicant-se tant en exercicis estàtics com dinàmics i fins a un màxim de 18 minuts de durada per sessió.Per últim, es va realitzar un assaig clínic controlat aleatori (Estudi VI) amb l'objectiu de valorar l'eficàcia de l'entrenament mitjançant vibracions de cos sencer sobre la força explosiva i el control postural en joves jugadores de bàsquet. Els resultats van mostrar un increment significatiu del salt amb contramoviment, del salt unipodal i de l'equilibri amb ulls tancats a les 8 i 15 setmanes d'entrenament en el grup experimental. És destacable el fet que no es trobessin diferències significatives entre els tests realitzats a les 8 i les 15 setmanes d'entrenament en cap de les variables. D'altra banda, el grup control no va experimentar canvis respecte les valoracions preintervenció. Amb aquests resultats podem afirmar que l'entrenament vibratori possibilita la millora dels paràmetres analitzats, repercutint favorablement en el rendiment esportiu i, també, de forma indirecta, en la prevenció de lesions en esportistes d'alt risc.A forma de síntesi, els estudis d'aquesta tesi emfatitzen la importància del control neuromuscular sobre el rendiment i prevenció de lesions esportives. És necessari destacar la importància de continuar investigant sobre noves eines que mesurin els paràmetres associats al control neuromuscular, així com seguir estudiant l'eficàcia dels diferents mètodes d'entrenament neuromuscular per a la seva optimització. / El control neuromuscular ha sido descrito como un importante factor para el éxito en el rendimiento deportivo. Del mismo modo, también se ha identificado como clave en la prevención y readaptación de las lesiones deportivas. El principal objetivo de esta tesis doctoral ha sido evaluar la eficacia de diferentes tipos de entrenamiento neuromuscular en deportistas.Se ha utilizado una muestra de 81 deportistas sanos entre los diferentes estudios que se presentan. Las diferentes evaluaciones realizadas han registrado los siguientes ítems: dolor (escala visual analógica), incidencia de lesiones deportivas, estabilidad postural estática y dinámica (estabilometría y salto unipodal) y fuerza explosiva de la extremidad inferior (salto con contramovimiento). Los métodos de entrenamiento neuromuscular utilizados fueron el llamado TRAL (Terapia reequilibradora del Aparato Locomotor) y las VCE (vibraciones de cuerpo entero).La primera parte de esta tesis (Estudios I y II) tuvo el objetivo de valorar la eficacia del método TRAL. Este produjo una reducción significativa del dolor de tobillo independientemente del género registrado, mientras que en el caso del dolor de rodilla sólo hubo diferencias en las chicas estudiadas. Otro de los efectos registrados importantes a destacar fue la reducción significativa del área de desviación del centro de presiones en el caso de las chicas, lo que representa una mejora de la estabilidad postural. Este dato también fue positivo en una de las pruebas de equilibrio registradas en el grupo de chicos. La segunda parte de este trabajo (Estudio III) se centró en dar fiabilidad a una batería de tests de equilibrio medidos con un estabilómetro, teniendo como objetivo valorar la estabilidad estática y dinámica de la extremidad inferior. Se obtuvo una correlación de buena a excelente en todas las variables de la mejor amplitud media en el test unipodal de ojos abiertos y cerrados. Estos resultados sugieren una buena fiabilidad para la distinción entre grupos de sujetos. En el caso del test más dinámico y cercano a la realidad del deportista, el salto unipodal, la correlación fue baja. Como continuación de esta segunda parte, el estudio IV comparó de forma transversal las diferencias de la estabilidad postural estática y dinámica según sexo y pierna dominante. El test de equilibrio unipodal de ojos abiertos no mostró diferencias significativas en la desviación del centro de presiones entre hombres y mujeres. Por otro lado, el sexo femenino mostró un mayor equilibrio en los tests más dinámicos (UT y S) en comparación con el sexo masculino. En relación a las diferencias entre pierna dominante - no dominante, sólo se encontraron diferencias significativas en las mujeres en la recepción del salto unipodal, mostrándose un mejor control cuando la recepción se efectuaba con la pierna dominante.La siguiente línea de trabajo se inició con el estudio V, que consistió en una revisión sistemática sobre los efectos del entrenamiento vibratorio sobre el rendimiento deportivo en personas físicamente activas. Los resultados mostraron una gran heterogeneidad clínica y una baja calidad metodológica de los trabajos analizados hasta la fecha buscada. A pesar de no poder extraer conclusiones claras, existe una tendencia a la mejora de la fuerza explosiva. También podemos establecer un rango seguro de los parámetros de aplicación de vibraciones mecánicas sobre la población de estudio. Este se encuentra entre 1,7-11mm de amplitud y entre 20-44 Hz de frecuencia, aplicándose tanto en ejercicios estáticos como dinámicos y hasta un máximo de 18 minutos de duración.Por último, se realizó un ensayo clínico controlado aleatorio (Estudio VI) con el objetivo de valorar la eficacia del entrenamiento mediante vibraciones de cuerpo entero sobre la fuerza explosiva y el control postural en jóvenes jugadoras de baloncesto. Los resultados mostraron un incremento significativo del salto con contramovimiento, del salto unipodal y del equilibrio con ojos cerrados a las 8 y 15 semanas de entrenamiento en el grupo experimental. Es destacable el hecho de que no se encontraran diferencias significativas entre los tests realizados a las 8 y las 15 semanas de entrenamiento en ninguna de las variables. Por otra parte, el grupo control no experimentó cambios respecto a las valoraciones preintervención. Con estos resultados podemos afirmar que el entrenamiento vibratorio posibilita la mejora de los parámetros analizados, repercutiendo favorablemente en el rendimiento deportivo y, también, de forma indirecta, en la prevención de lesiones en deportistas de alto riesgo.En forma de síntesis, los estudios de esta tesis enfatizan la importancia del control neuromuscular sobre el rendimiento y prevención de lesiones deportivas. Es necesario destacar la importancia de continuar investigando sobre nuevas herramientas que midan los parámetros asociados al control neuromuscular, así como seguir estudiando la eficacia de los diferentes métodos de entrenamiento neuromuscular para su optimización. / Neuromuscular control is believed to be an important factor for success in athletic performance. Similarly, it has also been identified as a key to prevention and rehabilitation of sports injuries. The main objective of this thesis is to evaluate the effectiveness of different types of neuromuscular training in athletes.A total of 81 healthy athletes were used for the purpose of the study. The evaluations performed have resulted in the following items: pain (visual analogue scale), incidence of sports injuries, static and dynamic postural stability (stabilometry and one-leg hop test) and explosive strength of the lower extremity (countermovement jump). Neuromuscular training methods used were TRAL (Locomotive rebalancing therapy) and WBV (whole body vibration).The first part of this thesis (Studies I and II) aims to assess the efficacy of TRAL. The training period showed a significant reduction of ankle pain recorded regardless of gender, whereas in the case of knee pain only differences in the girls studied were found. Another important effect to highlight that contributes to an improvement of stability in body position in women is the significant reduction of movements of the centre of pressure, while there was only a significant reduction in one of the men tests. The aim in the second part (Study III) is to assess the static and dynamic stability of the lower extremities focusing on battery of tests reliability measured with a stabilometer. Correlation obtained in single leg stance test of open and closed eyes was found in the range between good to excellent, in all variables of t he best average amplitude. These results suggest a good reliability for the distinction between subject groups. Regarding a more dynamic and closer to athlete's reality test, the one-leg hop test, poor correlation was obtained. Continuing in the second part, study IV compares differences between static and dynamic position stability, by sex and leg dominance. The one leg stance with open eyes test showed no significant difference in the deviation of center of pressure between men and women. Moreover, females showed more balance in higher dynamics tests (UT and S) compared with males. The differences regarding dominant - non dominant leg, were found only in girls in receiving one leg jump, showing a better control where the reception took place with the dominant leg.The next topic begins with study V, which consists of a systematic review on the effects of vibration training in physically active people. The results demonstrate a high clinical --heterogeneity and low methodological quality of previous studies performed prior to the date of our study. Even if we cannot provide a specific result, there is a tendency to improve explosive strength. Also, we can certainly establish a safe range of parameters for vibration training to be applied on a physically active population. This range goes from 1.7-11mm amplitude, 20-44 Hz frequency, both in static and dynamic exercises, and up to 18 minutes working with vibration.In the last topic, we conduct a randomized controlled trial (Study VI) aimed to assess the effectiveness of whole body vibration training on explosive strength and postural control in young basketball players. The results showed a significant increase in countermovement jump, one-leg hop test and balance with closed eyes at 8 and 15 weeks of training with the experimental group. It is noteworthy that no significant differences were found between tests performed at 8 and 15 weeks of training in any of the variables. Moreover, the control group experienced no changes from pre-intervention assessments. Based on these results we can state that vibration training enables the improvement of the analyzed parameters, impacting positively on athletic performance, and indirectly prevents injuries in high-risk athletes.In conclusion, this thesis emphasizes the importance of neuromuscular control on sports performance and prevention of injuries. It is necessary to stress the importance of continuing the research on new tools to measure parameters associated with neuromuscular control, and further studying the effectiveness of different methods of neuromuscular training for its optimization.

Introduction : L’évaluation clinique du contrôle neuromusculaire des muscles du tronc est criante en réhabilitation et en entraînement. L’objectif principal de cette étude a été d’évaluer la reproductibilité intra et inter-évaluateur d’un test clinique le soulèvement actif de la jambe tendue (SAJT) chez une population active et saine. Méthode : Chaque sujet (18 joueurs de tennis) a été testé à deux reprises par 2 physiothérapeutes avec le SAJT. Résultats : La reproductibilité intra-évaluateur s’est avérée élevée à très élevée (ICC = 0.81 à 0.93) tandis la reproductibilité inter-évaluateur s’est avérée cliniquement non viable. Conclusion : À notre connaissance, le SAJT est le premier test clinique reproductible évaluant le contrôle neuromusculaire du tronc avec des compensations musculaires et cinétiques chez des sujets actifs et sains. Une formation plus importante des évaluateurs aurait certainement amélioré la reproductibilité inter-évaluateur. / Introduction: The clinical assessment of the trunk muscles neuromuscular control is lacking in rehabilitation and in conditioning. The main goal of this study was to assess the intra and inter-rater reliability of a clinical test, the active straight leg raise (ASLR), on an active and healthy population. Method: Each subject (18 tennis players) was tested twice by 2 physiotherapists with the ASLR. Results: The intra-rater reliability turned out to be high to very high (ICC = 0.81 à 0.93) while the inter-rater reliability came out clinically unsustainable. Conclusion: To our knowledge, the ASLR is the first reliable clinical test to assess the core neuromuscular control based on muscular and kinetic compensation observations with active and healthy subjects. A more exhaustive training of the assessors would definitely improve the inter-rater reliability.

Introduction : L’évaluation clinique du contrôle neuromusculaire des muscles du tronc est criante en réhabilitation et en entraînement. L’objectif principal de cette étude a été d’évaluer la reproductibilité intra et inter-évaluateur d’un test clinique le soulèvement actif de la jambe tendue (SAJT) chez une population active et saine. Méthode : Chaque sujet (18 joueurs de tennis) a été testé à deux reprises par 2 physiothérapeutes avec le SAJT. Résultats : La reproductibilité intra-évaluateur s’est avérée élevée à très élevée (ICC = 0.81 à 0.93) tandis la reproductibilité inter-évaluateur s’est avérée cliniquement non viable. Conclusion : À notre connaissance, le SAJT est le premier test clinique reproductible évaluant le contrôle neuromusculaire du tronc avec des compensations musculaires et cinétiques chez des sujets actifs et sains. Une formation plus importante des évaluateurs aurait certainement amélioré la reproductibilité inter-évaluateur. / Introduction: The clinical assessment of the trunk muscles neuromuscular control is lacking in rehabilitation and in conditioning. The main goal of this study was to assess the intra and inter-rater reliability of a clinical test, the active straight leg raise (ASLR), on an active and healthy population. Method: Each subject (18 tennis players) was tested twice by 2 physiotherapists with the ASLR. Results: The intra-rater reliability turned out to be high to very high (ICC = 0.81 à 0.93) while the inter-rater reliability came out clinically unsustainable. Conclusion: To our knowledge, the ASLR is the first reliable clinical test to assess the core neuromuscular control based on muscular and kinetic compensation observations with active and healthy subjects. A more exhaustive training of the assessors would definitely improve the inter-rater reliability.

A digital twin of the human neuromuscular system can substantially improve the prediction of injury risks and the evaluation of the readiness to return to sport. Reinforcement learning (RL) algorithms already learn physical quantities unmeasurable in biomechanics, and hence can contribute to the development of the digital twin. Our preliminary results confirm the potential of RL algorithms to estimate the muscle activations of an athlete’s moves. / Ein digitaler Zwilling des menschlichen neuromuskulären Systems kann die Vorhersage von Verletzungsrisiken und die Bewertung der Bereitschaft zur Rückkehr in den Sport erheblich verbessern. Algorithmen des bestärkenden Lernens (Reinforcement Learning, RL) lernen bereits physikalische Größen, die in der Biomechanik nicht messbar sind, und können daher zur Entwicklung des digitalen Zwillings beitragen. Unsere vorläufigen Ergebnisse bestätigen das Potenzial von RL-Algorithmen zur Schätzung der Muskelaktivierung bei den Bewegungen eines Sportlers.