L'amputation du membre supérieur, dont la prévalence est comparable à celle des maladies orphelines, induit chez les patients une perte considérable d'autonomie dans la majorité des tâches simples de la vie quotidienne. Pour pallier ces difficultés, les prothèses myoélectriques actuelles proposent une multitude de mouvements possibles. Cependant, leur contrôle non intuitif et lourd cognitivement requiert un apprentissage long et difficile, qui pousse une proportion importante de patients amputés à l'abandon de la prothèse. Dans cette thèse, nous avons cherché à identifier l'origine des difficultés et les manques du contrôle myoélectrique en comparaison au contrôle sensorimoteur naturel, dans le but à terme de proposer de meilleures solutions de restitution et de suppléance. Pour cela, nous avons manipulé diverses conditions expérimentales dans un contexte d'interface homme-machine simplifié où des sujets non amputés contrôlent un curseur sur un écran à partir de contractions isométriques, i.e. des contractions qui n'engendrent pas de mouvement. Cette condition isométrique nous a permis de nous approcher de la condition de la personne amputée contrôlant sa prothèse à partir de l'activité électrique (EMG) de ses muscles résiduels, en absence de mouvement articulaire. Durant une tâche d'atteinte de cible, nous avons entre autre démontré le bénéfice d'une adaptation conjointe du décodeur qui traduit les activités EMG en mouvement du curseur, venant s'ajouter à la propre adaptation du plan de mouvement des sujets en réponse à des perturbations orientées. De plus, il a été mis en évidence que ce bénéfice est d'autant plus important que la dynamique d'adaptation artificielle du décodeur s'inspire de celle de l'Homme. Dans des tâches d'acquisition et de poursuite de cible, impliquant davantage les mécanismes de régulation en ligne du mouvement, nous avons mis en évidence l'importance d'une congruence immédiate entre les informations sensorimotrices et la position du curseur à l'écran pour permettre des corrections rapides et efficaces. Dans une condition où le niveau de bruit du système est relativement faible, comme avec l'utilisation du signal de forces plus stable que l'habituel signal EMG, cette congruence explique, en partie, la supériorité d'un contrôle d'ordre 0 (i.e. position) sur un contrôle d'ordre 1 (i.e.} vitesse). Cependant, dès lors que le niveau de bruit est trop important, ce qui est le cas avec le signal EMG, le filtrage induit par l'intégration nécessaire au contrôle vitesse fait que celui-ci devient plus performant que le contrôle position. L'ensemble de ces résultats suggèrent qu'un décodeur adaptatif et intuitif, respectant et suppléant au mieux les boucles du contrôle sensorimoteur naturel, est le plus à même de faciliter le contrôle des futures prothèses. / Upper limb amputation, although quite rare, induces enormous loss of autonomy for patients in most daily life activities. To overcome this loss, current myoelectric prosthesis offers a multitude of possible movements. However, current controls of these movements are typically non-intuitive and cognitively demanding, leading to a high abandon rate in response to the long and tedious learning involved. In this thesis, we aimed at identifying difficulties and gaps associated with myoelectric controls when compared to natural sensorimotor control, with the long term goal of informing the design of better solutions for prosthesis control. To do so, we manipulated several experimental conditions in a simplified human-machine interface, where non-amputated subjects controlled a cursor on a computer screen from isometric contractions, i.e. muscle contractions produced in the absence of joint movement. This isometric condition was designed to get closer to a situation in which an amputee controls a myoelectric prosthesis using electrical activity (EMG) of his/her residual muscles, without movement of the missing limb. During aiming movements, we demonstrated the benefits of adapting the decoder that translate muscle activities into cursor movement in conjunction with the own subject’s adaptation of the planned movement direction in response to oriented perturbations. Furthermore, these benefits were showed to be even more important as the artificial decoder adaptation was inspired by the modeled adaptation of a human. In reaching and tracking movements toward fixed and moving targets, which increasingly involve online movement regulations, we revealed the importance of an immediate congruency between sensorimotor information and the cursor position on the screen for timely and efficient corrections. For conditions in which the level of noise associated with the control signal is relatively low, such as when using force that is more stable than the usual EMG signal used, this congruency partly explains the better performance obtained with zero order control (i.e. position) when compared to first order control (i.e. velocity). However, when the noise level increases, as is the case with EMG signals, the filtering property associated with the integration involved in a velocity control elicits better performances than with a position control. Taken together, these results suggest that intuitive and adaptive decoder, that supplies and judiciously complements natural sensorimotor feedback loops, is promising to facilitate future prosthesis controls.

L’objectif général de la présente thèse était d’étudier les effets et les facteurs d’influence des exercices et des programmes d’entraînement consistant en la co-contraction maximale isométrique volontaire (CCMIV) de l’articulation du coude : effet de l’entraînement en CCMIV sur la force explosive (Etude A), influence de l’heure habituelle d’entraînement (Etude B) et de charges additionnelles pendant les CCMIV (Etude C). Les résultats ont montré que 6 semaines d’entraînement en CCMIV peuvent améliorer simultanément la force maximale volontaire des muscles sans altération de la force explosive (Etude A et B) et indépendamment de l’heure habituelle d’entraînement (Etude B). Ces gains de force s’accompagnaient d’une augmentation de l’activité électromyographique des muscles agonistes (Etude A et B). Cependant, les résultats de l’étude B suggèrent que l’entraînement le matin s’accompagne d’un meilleur gain de la force musculaire, masquant ainsi les différences de force entre le matin et le soir. Par ailleurs, l’étude C a montré qu’une charge additionnelle (50% FMV) associée à une CCMIV modifie le pattern d’activation des muscles agonistes-antagonistes : augmentation du niveau d’activation des muscles agonistes et diminution de celui des antagonistes. Par conséquent, un programme d’entraînement en CCMIV avec charge additionnelle devrait comprendre des exercices avec charge pour les fléchisseurs et les extenseurs. De plus, les résultats de l’étude C suggèrent que le concept du fléchisseur équivalent pourrait être appliqué non seulement quand les fléchisseurs agissent comme agonistes mais aussi quand ils agissent comme antagonistes. / The aim of the present thesis was to study the effects and the influencing factors during the elbow joint maximal isometric voluntary co-contractions (MIVCC) exercises and training program: effect of the MIVCC training on the explosive force (Study A), influence of the time-of-day at which training was scheduled (Study B) and additional load during MIVCC (Study C). The results showed that six weeks of MIVCC training can simultaneously improve the maximum voluntary force, without altering the explosive force (Study A and B) and independently of the time-of-day at which training was scheduled (Study B). These improvements were accompanied by an increase in electromyography activity of agonist muscles (Study A and B). However, the results of study B suggest that morning training is accompanied by a higher strength improvement, by masking the strength differences between the morning and evening. Furthermore, the study C showed that additional load (50% MVF) associated with MIVCC modifies the activation pattern of the agonist-antagonist muscles: by increasing the activation level of the agonist muscles and decreasing the co-activation level of the antagonist muscles. Therefore, MIVCC training program with additional load should include exercises with load for flexor and extensor muscles. In addition, the results of the study C suggest that the concept of “flexor equivalent” may be applied not only when the flexor muscles acting as agonist but also when they acting as antagonist muscles.

No description available.

Tyrimo objektas: rankų ir kojų raumenų izometrinio susitraukimo variabilumo pokyčiai. Tyrimo problema: įvykus insultui, priklausomai nuo pažeidimo laipsnio, sutrinka ne tik dinaminės, bet ir kinematinės judesių savybės (pvz., tikslaus judesio trajektorija). Galvos smegenys reaguoja į pažeidimą kaip visuma, todėl sutrinka ne vienas, bet daugelis judesių (Skurvydas, 2008). Kadangi po insulto atsiranda apsitarnavimo problemos, ir yra ribojama kasdieninė veikla, norėjome ištirti ligonius, baigusius reabilitaciją, su nežymiais liekamaisiais reiškiniais bei nustatyti galūnių izometrinio susitraukimo variabilumo dydį, kuris atspindi atliekamo veiksmo stabilumą. Tyrimo tikslas: nustatyti rankų ir kojų raumenų izometrinio susitraukimo variabilumo pokyčius po galvos smegenų insulto rezidualiniu periodu. Tyrimo uždaviniai: 1. Nustatyti ir palyginti tiriamosios bei kontrolinės grupės tiriamųjų dilbį lenkiančių ir blauzdą tiesiančių raumenų maksimalią valingą jėgą. 2. Nustatyti ir palyginti tiriamosios bei kontrolinės grupės tiriamųjų rankų ir kojų raumenų izometrinio susitraukimo variabilumo pokyčius. 3. Nustatyti grįžtamojo ryšio įtaką izometrinio raumens susitraukimo variabilumui. Tyrimo hipotezė: galvos smegenų insultą patyrusių žmonių rezidualiniu periodu rankų ir kojų raumenų izometrinio susitraukimo variabilumas yra didesnis negu nepatyrusių galvos smegenų insulto. Tyrimo metodai ir organizavimas: tyrimas buvo atliktas LKKA Žmogaus motorikos laboratorijoje 2010 – 2011 metais... [toliau žr. visą tekstą] / Research object: changes of variability of the upper and lower extremities muscles isometric contraction. Research question: Subject to the degree of lesion, both dynamic and kinematic properties of motions (e.c., pathway of an accurate motion) can be disturbed after stroke. The cerebral brain reacts to lesion as whole, therefore disturbs not only one but many motinos (Skurvydas, 2008). Patient gets self-service problems after stroke and it limits daily activities, and it is the reason why we wanted to investigate patients who have inappreciable residual appearances after rehabilitation as well as we wanted to establish the value of variability of extremities isometric contraction, which reflects stability of movemt. Research purpose: to assess the changes of isometric contraction of upper and lower extremities muscles of residual post-stroke periode. Research goals: 1.To assess and compare the experimental and control group maximum voluntary strength of the forearm flexors and calf extensors; 2.To assess and compare the experimental and control group alterations of variability of the upper and lower extremities muscle isometric contraction; 3.To assess the influence of feedback on the muscle contraction variability. Research hypothesis: people at residual post-stroke periode have a higher variability of isometric contraction of the upper and lower extremities muscles than people people who did not undergo cerebral brain stroke. Research methods and organization: the... [to full text]

Aim The purpose of this study was to compare resistance-trained (RT) and non-trained (NT) males regarding mechanisms for neural activation during isometric muscle contractions of the soleus muscle. Further the plantar flexor strength of the two groups were compared. Method Ten males that had been resistance training for at least 3 years (RT) and 10 who did not train regularly (NT) participated in the study. The participants performed isometric contractions of their right plantar flexors against an isokinetic dynamometer at 15, 25, 50, 80 and 100% of maximal voluntary contraction. Five contractions were performed for each level in two different conditions; one where the participants were stimulated using transcranial magnetic stimulation over the left motor cortex and one in which they were stimulated electrically over the tibial nerve. Stimulations were also delivered at rest. The resulting soleus muscle motor evoked potentials (MEPs) and V-waves were normalized to a maximal M-wave (Mmax). Plantar flexor strength was measured and voluntary activation estimated using the twitch interpolation technique. Results No significant difference was found between the RT and the NT group for voluntary activation, V/Mmax ratio or MEP/Mmax at any level of maximal voluntary contraction (MVC). The RT group was significantly stronger than the NT group. Conclusions The study showed that the RT group was stronger than the NT group. Despite the difference in strength there was no significant group difference between the two groups in MEPs, V/Mmax or voluntary activation. This indicates that there is no, or a very small difference in corticospinal excitability of the soleus muscle between the chronic RT males and the NT males.

Made available in DSpace on 2016-06-02T20:19:12Z (GMT). No. of bitstreams: 1 2579.pdf: 1151605 bytes, checksum: bbdba1904bf51bc08fc113ee84d13c12 (MD5) Previous issue date: 2009-06-10 / Financiadora de Estudos e Projetos / Cardiovascular responses to different isometric contractions were evaluated in 12 patients (63 ± 11,6 years, mean ± dp) with coronary artery disease and/or risk factors, participants in the cardiac rehabilitation phase III. Heart rate variation (&#916;HR) was evaluated during maximum (CVM, five and ten seconds in duration) and submaximal (CVSM, 30 and 60% of CVM-5, until muscle exhaustion) voluntary contraction, using a handgrip dynamometer. Additionally, the RMSSD (representative index of vagal modulation) was calculated at rest (precontraction), at the last 30 seconds of CVSM and recovery (post-contraction). &#916;HR showed higher values in CVM CVM-10 vs-5 (17 ± 5,5 vs 12 ± 4,2 bpm, p <0.05) and the CVSM-60 vs CVSM -30 (19 ± 5,8 vs 15 ± 5,1 bpm, p <0.05). However, results for CVM-10 showed similar &#916;HR compared to results for CVSM (p> 0.05). RMSSD at rest decreased (p <0.05) during CVSM-30 (30% = 28 ± 17 vs 13 ± 8 ms) and CVSM-60 (60% = 26 ± 18 vs 10 ± 4 ms), but returned to baseline values as the contraction was interrupted. In in patients with coronary artery disease and/or risk factors, low intensity isometric contraction, maintained over long periods of time, presents the same effect on the responses of HR, compared to a briefly high intensity or maximal isometric effort. / As respostas da frequência cardíaca frente à diferentes percentuais de contração isométrica foram avaliadas em 12 pacientes (63 ± 11,6 anos; média±dp) com doença da artéria coronária e/ou fatores de risco para a mesma e participantes de um programa de reabilitação cardíaca fase III. A variação da frequência cardíaca (&#916;FC) foi avaliada durante a contração voluntária máxima (CVM; cinco e dez segundos de duração) e submáximas (CVSM; 30 e 60% da CVM-5, até exaustão muscular) de preensão palmar, utilizando-se um dinamômetro (hand grip). Adicionalmente, o RMSSD dos iR-R em ms (índice representativo da modulação vagal no nó sino atrial) foi calculado em repouso (pré-contração), nos últimos 30 segundos da CVSM e na recuperação (pós-contração). A &#916;FC apresentou maiores valores em CVM-10 vs CVM-5(17 ± 5,5 vs 12 ± 4,2 bpm, p<0,05) e no CVSM-60 vs CVSM -30 (19 ± 5,8 vs 15 ± 5,1 bpm, p<0,05). No entanto, os resultados para CVM-10 mostrou &#916;FC similar quando comparado aos resultados obtidos para CVSM (p>0,05). RMSSD de repouso reduziu (p<0,05) durante a CVSM-30 (30% = 28 ± 17 vs 13 ± 8 ms) e CVSM-60 (60% = 26 ± 18 vs 10 ± 4 ms), mas retornou aos valores basais quando a contração foi interrompida. Em pacientes com doença da artéria coronária e/ou fatores de risco para a mesma, a contração isométrica de baixa intensidade mantida por longos períodos de tempo, apresenta os mesmos efeitos sobre as respostas da FC, quando comparada à atividade isométrica de alta intensidade ou ao esforço isométrico máximo.

Made available in DSpace on 2016-06-02T20:19:23Z (GMT). No. of bitstreams: 1 5764.pdf: 2262686 bytes, checksum: 19925e290e86a08608b11073c73bac3f (MD5) Previous issue date: 2014-02-25 / Universidade Federal de Minas Gerais / To prevent and treat pelvic floor muscle (PFM) dysfunctions, level A of evidence proposes isometric contractions to strengthen these muscles. In literature, there are studies regarding the cardiovascular effects of isometric exercises and the cardiac autonomic regulation in response to these exercises. However, currently there are no studies regarding the cardiovascular response to PFM exercises and the effects of these responses to sympathetic and parasympathetic cardiac modulations. Therefore, the objective of this dissertation was to analyze heart rate (HR) response to a protocol of PFM contractions and the acute effect of the PFM contractions in blood pressure (BP) and sympathetic and parasympathetic cardiac modulations responses and compare these variables to rest conditions before and after the PFM contractions. We evaluated eutrophic women aged between 18 and 80 years, divided in groups according to age. They underwent two protocols; each one containing a series of PFM contractions with monitoring of the PFM contraction pressure, HR, BP and R-R intervals. Both series contained 10 PFM contractions, one series contained contractions lasting 5 seconds with 5 seconds of rest between each contraction and the other series contained contractions lasting 10 seconds with 10 seconds of rest between each contraction. We observed an increase in HR during PFM contractions and an increase in systolic BP immediately after the contractions in the evaluated groups. Regarding the cardiac autonomic regulation, we performed the time domain (RMSSD and SDNN indexes) and frequency domain (low and high frequency spectral components in absolute values) analysis. We observed increase in SDNN and RMSSD indexes during PFM contractions; after frequency domain analysis we observed predominance of vagal modulation in the group containing young women after the series of PFM contractions with 10 seconds and the group consisting of adult and elderly women showed a higher prevalence of sympathetic modulation after series of PFM contraction lasting 5 seconds. The observed variables were within the normal values and returned to basal values as soon as the contractions ended. In conclusion, the proposed protocol of PFM contractions might not represent a cardiovascular risk for healthy women. Moreover, the applied protocol did not changed positively or negatively the cardiac autonomic modulation. / Para a prevenção e tratamento de disfunções dos músculos do assoalho pélvico (MAP) é proposto, com nível de evidência A, a realização de contrações isométricas para fortalecimento desta musculatura. Os efeitos cardiovasculares de exercícios isométricos bem como a modulação autonômica cardíaca em resposta a esses exercícios têm sido estudados na literatura. No entanto, atualmente não existem estudos que avaliem a resposta cardiovascular aos exercícios de contração dos MAP e os efeitos dessas respostas sobre as modulações simpática e parassimpática cardíacas. Sendo assim, os objetivos dessa dissertação foram avaliar a resposta da frequência cardíaca (FC) durante um protocolo de exercícios de contração dos MAP e efeito agudo da contração dos MAP na resposta da pressão arterial (PA) e sobre as modulações simpática e parassimpática cardíacas e comparar estas variáveis às condições de repouso antes e após as contrações. Foram avaliadas mulheres eutróficas com idade entre 18 e 80 anos, divididas em grupos de acordo com a idade. As participantes foram submetidas a dois protocolos, cada um contendo uma série de exercícios de contração dos MAP com registro da pressão de contração da MAP, PA, FC e intervalos R-R. As séries continham 10 contrações dos MAP, uma série conteve 10 contrações com duração de 5 segundos e 5 segundos de repouso entre cada contração e a outra era composta por 10 contrações sustentadas por 10 segundos e 10 segundos de repouso entre cada contração. Foram observados valores maiores de FC durante as contrações dos MAP e de PA sistólica imediatamente após os exercícios nos grupos avaliados. Em relação à modulação autonômica, foram realizadas as análises no domínio do tempo (índices RMSSD e SDNN) e no domínio da frequência (componentes espectrais absolutos de alta e baixa frequência). Observou-se aumento dos índices SDNN e RMSSD durante as contrações dos MAP; após a análise no domínio da frequência foi observada maior predominância da modulação vagal no grupo composto por mulheres jovens após a série de contrações dos MAP com duração de 10 segundos e o grupo constituído de mulheres adultas e idosas apresentou maior predominância da modulação simpática após a série de contração dos MAP com duração de 5 segundos. Os valores observados se mantiveram dentro dos padrões de normalidade e retornaram aos valores basais logo após as contrações. Conclui-se que o protocolo de contrações dos MAP proposto parece não apresentar risco cardiovascular para mulheres saudáveis. Além disso, o protocolo aplicado não alterou positiva ou negativamente a modulação autonômica.

Made available in DSpace on 2016-06-02T20:19:25Z (GMT). No. of bitstreams: 1 6272.pdf: 943725 bytes, checksum: fe22255b4e68c17bf799b7fcb6c4e5d4 (MD5) Previous issue date: 2014-02-26 / Financiadora de Estudos e Projetos / Traumatic anterior glenohumeral instability makes the humeral head unable to remain centered on the glenoid fossa and alters the arthrokinematics and the strength of the shoulder rotators. The rotator cuff muscles depend on a good performance of the scapular muscles and their strengthening has been recommended at different levels for subjects with traumatic anterior glenohumeral instability. On the other hand, poor scapular performance is not well described in this population. Therefore, the aim of this thesis was to investigate muscle performance during protraction and retraction of the scapula in the sagittal and scapular planes in subjects with traumatic anterior glenohumeral instability. The study included 40 volunteers of both sexes, divided into two groups: control group (n = 20) and patients with traumatic anterior glenohumeral instability (n = 20). Muscle performance during protraction and retraction was assessed using Biodex System III isokinetic dynamometer in the isometric mode, with three repetitions, and in the concentric isokinetic mode, at the speeds of 12.2 cm/s and 36.6 cm/s, with 5 and 10 repetitions, respectively. The evaluations were performed with the shoulder flexed at 90° in the sagittal plane and elevated at 90° in the scapular plane. The mean peak force, total work and the total range of motion (ROM) were the variables of interest. The variables were compared using analysis of variance with two factors (ANOVA - Two Way), considering plans as the withinsubject factor and group as the between-subject factor, at a significance level of 5%. There was difference between subjects in the average peak force at isometric protraction and retraction and also at protraction during isokinetic evaluation at 36 cm/s (p <0.05). For intra-subject analysis (scapular plane vs sagittal plane), differences were found for mean peak force during isometric protraction, isokinetic protraction at 12.2 cm/s and isokinetic protraction at 36.6 cm/s. There was an interaction for the total work in retraction at 12.2 cm / s, total work in retraction at 36.6 cm / s for ROM. This dissertation shows that subjects with traumatic anterior glenohumeral instability have decreased strength in protraction and in isometric retraction and also in isokinetic contraction. Average peak force, total work and ROM in the sagittal plane are higher than in the scapular plane. / A instabilidade glenoumeral traumática anterior torna a cabeça umeral incapaz de manter-se centralizada na fossa glenoidal. Essa disfunção altera a artrocinemática e a força dos rotadores do ombro. Os músculos do manguito rotador dependem de um bom desempenho dos músculos escapulares e, assim, seu fortalecimento tem sido recomendado em planos diferentes, em sujeitos com instabilidade glenoumeral traumática anterior. Por outro lado, o comprometimento do desempenho escapular não está claro nessa população. Diante disso, o objetivo desta dissertação foi investigar o desempenho muscular de protração e retração da escápula no plano sagital e escapular em sujeitos com instabilidade glenoumeral traumática anterior. Participaram deste estudo 40 voluntários de ambos os sexos, divididos em dois grupos: grupo controle (n=20) e grupo com instabilidade glenoumeral traumática anterior (n=20). O desempenho muscular de protração e retração foi avaliado por meio do dinamômetro isocinético Biodex System III, no modo isométrico, com 3 repetições, e no modo isocinético concêntrico, nas velocidades 12,2 cm/s e 36,6 cm/s, com 5 e 10 repetições, respectivamente. As avaliações foram realizadas com o ombro posicionado a 90° de flexão no plano sagital e a 90º de elevação no plano da escápula. A média dos picos de força, o trabalho total e a amplitude total de movimento (ADM) foram as variáveis de interesse. As variáveis foram comparadas, utilizando-se a análise de variância com dois fatores (ANOVA Two Way), com os planos como fator intrassujeitos e grupo como fator entressujeitos, a um nível de significância de 5%. Houve diferença entressujeitos para a média dos picos de força em protração e retração isométrica e também em protração durante a avaliação isocinética a 36 cm/s (p<0.05). Para a análise intrassujeitos (Plano escapular vs Plano sagital), as diferenças foram encontradas para a média dos picos de força durante a protração isométrica, protração isocinética a 12,2 cm/s e protração isocinética a 36,6 cm/s. Houve interação para o trabalho total em retração a 12,2 cm/s, trabalho total em retração a 36,6 cm/s e para a ADM. Esta dissertação permite concluir que sujeitos com instabilidade glenoumeral traumática anterior apresentam diminuição de força em protração e retração isométrica e em retração isocinética. A média dos picos de força, o trabalho total e a ADM no plano sagital são maiores do que no plano escapular.

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No. of bitstreams: 1 DissJPF.pdf: 6779665 bytes, checksum: 3ac5f7c32c06f0d6fc7fe8b5f43a53e9 (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Contextualization: The Diabetes Mellitus (DM) is an epidemic disease in the world and stay associated with right index of morbidity and mortality and about 90% of cases of DM are type 2 (DM2). DM2 develop by inflammatory mechanisms carrying the insulin resistance and consecutively blond hyperglycemia. Believes that in chronic stages the diabetes causes musculoskeletal dysfunctions can be related to inflammatory and metabolic alterations of the DM2 or with diabetic polyneuropathy. Some studies identified the musculoskeletal alteration in diabetic subjects. However not is clearly if the polyneuropathy cause muscle alteration proportionality sensitive alterations. Also weren’t observed studies that analyzed the torque in subjects with DM2, considering others factors that could influence the muscle torque production and also not were observed studies analyzing the torque in diabetic subjects during different types of contractions (concentric, eccentric and isometric). Objectives: The aim of the present study were analyze the torque at concentric eccentric and isometric muscle contractions in diabetic subject with and without polyneuropathy comparing with a control groups. Methods: The peak torques of flexion and extension were acquired using an isokinetic dynamometer, in sitting position. During concentric and eccentric contractions, the joint speed was set at 60°/s. Five maximal voluntary contractions were acquired for concentric and eccentric and 2 for isometric, with a rest interval of 1.5 minutes. The sequence of the tests was randomized and verbal and visual feedback were standardized and delivered to all subjects by the same person. Three groups of adult males were selected for this study (1) Control group (healthy non-diabetic patients, n=33), (2) Diabetic group (patients with diabetes mellitus without polyneuropathy, n=31), (3) Neuropathic group (patients with diabetic polyneuropathy, n=28). The Neuropathic group was defined according to a fuzzy model of signs and symptoms. Differences between groups were calculated with one way ANOVA for parametric knee variables (α of 5%) and Mann Whitney and Willcoxon for non-parametric ankle variables (adjusted α of 1.6%). To describe effect sizes, Hedges’ g was calculated. Results: Irrespective of polyneuropathy, both diabetic groups presented lower peak torques of knee and ankle, both for isometric contraction and for concentric flexion and extension. Other factors beside the polyneuropathy and early in the diabetes onset, may be influencing in the muscle strength production. The eccentric contraction was not different between any groups. / Contextualização: A Diabetes Mellitus (DM) se tornou uma doença epidêmica em todo mundo, e também está associada a altos índices de morbidade e mortalidade. Cerca de 90% dos casos são de DM do tipo 2, que desenvolve por meio de mecanismos inflamatórios que levam à resistência à insulina e consecutivamente à hiperglicemia sanguínea. Acredita-se que em estágios avançados a DM2 cause disfunções musculoesqueléticas, que podem estar relacionadas às alterações inflamatórias e metabólicas dessa doença ou à polineuropatia diabética (PND). Alguns estudos já identificaram alterações musculoesqueléticas em diabéticos. No entanto, ainda não está claro, se a polineuropatia acomete o sistema musculoesquelético, na mesma proporção que o sistema sensorial é acometido. Também não se observa na literatura, estudos que tenham analisado o torque de DM2, considerando outros fatores que podem influenciar a produção de torque e estudos que tenham analisado o torque nos três tipos de contrações (concêntrica, excêntrica e isométrica). Objetivo: O objetivo do presente estudo foi analisar o torque nas contrações concêntrica, excêntrica e isométrica em indivíduos com DM2, com e sem polineuropatia, comparados a um grupo controle sem DM. Métodos: Foram analisados três grupos de homens adultos (total 92), similares na distribuição de sexo, idade e características antropométricas: Controles não diabéticos (n=33); DM2 (n=31); PND (n=28). A PND foi avaliada por meio de um modelo Fuzzy. O pico de torque nas contrações concêntrica, excêntrica e isométrica foi avaliado com um dinamômetro isocinético de cadeira durante a flexão e extensão do joelho e dorsiflexão e flexão plantar do tornozelo. As diferenças entre os grupos foram calculadas com ANOVA one way, para as variáveis paramétricas de joelho (α of 5%) e Mann Whitney e Willcoxon para dados não paramétricos das variáveis do tornozelo (α ajustado de 1.6%). O tamanho de efeito foi calculado usando Hedges’ g. Resultados: Independente da polineuropatia, ambos os grupos diabéticos apresentaram menor torque concêntrico e isométrico de joelho e tornozelo, comparados aos Controles, mas sem diferença entre si. Para o torque excêntrico não houve diferença entre os três grupos em todos os movimentos e articulações avaliadas. Conclusão: A diminuição do torque concêntrico e isométrico em DM2 ocorre mesmo antes da instalação da PND, em tornozelo e joelho, enquanto o torque excêntrico permanece preservado nesses movimentos em diabéticos, independentemente da PND. Observa-se acometimento proximal e distal, com tamanhos de efeito maiores para os movimentos do joelho.

O objetivo desse estudo foi verificar a relação da aptidão aeróbia e de fatores neuromusculares com o desempenho em SR em tenistas com diferentes níveis de jogo. Um grupo de dez tenistas profissionais (GP) e um grupo de dez tenistas amadores (GA) foram submetidos a quatro sessões experimentais, a saber: 1) medidas antropométricas, familiarização com o teste de drop jump (DJ) e com o teste de contração voluntária isométrica máxima (CVIM) para membros inferiores, e um teste progressivo até a exaustão; 2) um teste de DJ e um teste de carga constante para avaliar a cinética on e off do consumo de oxigênio (VO2); 3) um teste de CVIM para membros inferiores, outro teste de carga constante para avaliar a cinética on e off do VO2 e familiarização com o teste de SR; 4) um teste composto por dez SR. O GP apresentou valores significativamente menores para o tempo do melhor sprint (SRmelhor) e para a média dos tempos de todos os sprints (SRmédio) em relação ao GA (p < 0,05). O percentual de aumento do tempo ao longo dos sprints (SR%aumento) do GP não foi significativamente menor em comparação ao GA (p = 0,102), porém a chance dessa variável ser menor para o GP foi considerada \"provável\". Para o GP, a única correlação significativa observada foi entre o SRmédio e o tempo de contato obtido no teste de DJ (r = 0,641, p < 0,05). Em relação ao GA, foram observadas correlações significativas da velocidade pico obtida no teste progressivo até a exaustão com o SRmelhor (r = -0,680, p < 0,05) e SRmédio (r = -0,744, p < 0,05), assim como da amplitude da fase lenta da cinética off do VO2 com o SRmelhor (r = -0,756, p < 0,05) e SRmédio (r = -0,794, p < 0,05). Portanto, esses dados sugerem que tenistas profissionais possuem um melhor desempenho em SR em comparação aos tenistas amadores. Entretanto, não está clara a importância de fatores da aptidão aeróbia e neuromusculares no desempenho dessa atividade / The objective of this study was to verify the relationship of aerobic fitness and neuromuscular factors with RS performance in tennis players with different playing level. A group of ten professional (PG) and ten amateur (AG) tennis players were submitted to four experimental sessions, to know: 1) anthropometric measurements, familiarization with the drop jump (DJ) test and the maximal voluntary isometric contraction (MVIC) test for the lower limbs, and a progressive test until exhaustion; 2) a DJ test and a constant load test for on and off oxygen consumption (VO2) kinetics measurement; 3) a MVIC test for the lower limbs, another constant load test for on and off VO2 kinetics measurement, and familiarization with the RS test; 4) a test of ten RS. The PG presented significant lower values for the best sprint time (RSbest) and mean time of all sprints (RSmean) in relation to the AG (p < 0.05). The percentage increase in time over all sprints (RSincrease) of the PG was not significantly lower in comparison to the AG (p = 0.102), however the chance of this variable to be lower for the PG was considered \"probable\". For the PG the only significant correlation observed was between RSmean and the contact time obtained in the DJ test (r = 0.641, p < 0.05). In relation to the AG, significant correlations were observed for the peak speed obtained on the progressive test until exhaustion with the RSbest (r = -0.680, p < 0.05) and RSmean (r = -0.744, p < 0.05), likewise for the amplitude of the slow phase in oxygen uptake off-kinetics with the RSbest (r = -0.756, p < 0.05) and RSmean (r = -0.794, p < 0.05). Thus, these data suggest that professional tennis players have a better performance in RS compared to amateur tennis players. However, it is not clear the importance of aerobic fitness and neuromuscular factors in the performance of this activity