Diferença entre os géneros na análise cinemática e eletromiográfica do membro superior durante uma atividade diária de beber

As diferenças entre os géneros parecem surgir desde a origem da humanidade, quando a função do homem era caçar e da mulher fornecer cuidados às crianças e realizar trabalhos de cariz manual. O membro superior apresenta um papel primordial na execução da maioria das atividades relevantes para o ser humano, sendo pertinente a realização de avaliações mais objetivas do mesmo. Com a realização deste estudo pretendemos verificar se existem diferenças entre os géneros nos parâmetros eletromiográficos e cinemáticos do movimento durante uma atividade diária; perceber se os valores da eletromiografia e da cinemática do membro superior são dependentes do género à medida que a distância do objeto é alterada e ainda, levar a cabo a análise da atividade de beber. Para tal foram avaliados parâmetros de qualidade de movimento e parâmetros de recrutamento muscular em 15 indivíduos do género feminino e 15 indivíduos do género masculino com idades compreendidas entre os 18 e os 30 anos numa atividade de beber em três momentos diferentes. Para a análise cinemática foi utilizado o software Qualysis Motion Capture e para a análise eletromiográfica o software AcqKnowledge Analysis. Com os resultados obtidos constatamos que a percentagem de ativação muscular e os ângulos de flexão do ombro e flexão do cotovelo apresentam diferenças estatisticamente significativas (p<0.05) entre os géneros, sendo o grupo feminino a apresentar valores superiores. Aferiu-se também que a percentagem de ativação do músculo Deltoide Anterior parece ser influenciado pelo género (p<0.05) ao longo das três distâncias em estudo, sendo novamente o grupo feminino a apresentar valores superiores. Para além disto, aquando do movimento de alcançar, verificaram-se evidências estatísticas (p<0.05) do envolvimento do tronco em todas as distâncias de alcance do objeto, inclusive numa distância inferior ao comprimento do braço. Este estudo permitiu a descrição detalhada da eletromiografia e cinemática do movimento do membro superior de alcançar e transportar numa atividade diária, bem como uma comparação da mesma entre o grupo masculino e grupo feminino.

Reorganização dos ajustes posturais antecipatórios do tibial anterior e do solear no início da marcha, em pacientes com AVE, face a uma intervenção de fisioterapia baseada no conceito de Bobath

Introdução: os APA´s ocorrem imediatamente antes do movimento e preparam-no tornando-o mais harmonioso e eficiente. Os pacientes com lesão do SNC apresentam frequentemente alterações no sistema de controlo postural interferindo significativamente nas suas AVD´s, como no início da marcha. Objetivo: descrever as alterações no tempo de ativação e sequência de ativação muscular do TA e do SOL no início da marcha em pacientes com AVE, face a uma intervenção em fisioterapia. Metodologia: A avaliação realizou-se antes e após um programa de intervenção, segundo a abordagem do Conceito de Bobath, através da electromiografia, plataforma de forças e máquina fotográfica para a avaliação do tempo de ativação muscular do tibial anterior e do solear no início da marcha. Recorreu-se também à Classificação Internacional de Funcionalidade e à Fulg-Mayer Assessment of Motor Recovery after Stroke. Resultados: Obteve-se uma diminuição dos valores registados pela EMG nos tempos de ativação muscular do TA e do SOL bilateralmente, e alterações na sequência de ativação. Verificaram-se modificações nos resultados da Classificação Internacional de Funcionalidade e da Fulg-Mayer Assessment of Motor Recovery after Stroke. Conclusão: O programa de intervenção segundo o Conceito de Bobath, induziu mudanças nos tempos de ativação muscular e na sequência de ativação dos músculos TA e SOL no início da marcha em pacientes com AVE.

Efeitos imediatos da mobilização com movimento na dor, Amplitude de movimento e actividade electromiográfica dos músculos da cintura escapular em indivíduos com síndrome do conflito subacromial

Introdução: A síndrome do conflito subacromial (SCSA) é a causa mais frequente de dor no ombro. Alterações na cinemática escapuloumeral e na activação dos músculos escapulares têm sido identificadas em pessoas com SCSA. A mobilização com movimento (MWM) é uma técnica de terapia manual, desenvolvida por Mulligan, que visa normalizar a cinemática articular. Objectivos: Determinar os efeitos imediatos da MWM na dor, na amplitude de movimento (ADM) de abdução no plano da escápula (APE), e na amplitude do sinal electromiográfico (EMG) do trapézio e grande dentado (GD), em pessoas com SCSA. Métodos: Foram incluídas no estudo 24 pessoas com SCSA, divididas de forma aleatória em 2 grupos de 12, MWM e Placebo. As medidas de resultados avaliadas foram: a dor nos testes de Neer e Hawkins-Kennedy; o limiar de dor à pressão; a ADM de APE até ao início da dor; e a percentagem da contracção isométrica voluntária máxima dos músculos trapézio (superior, médio e inferior) e GD. Resultados: A aplicação da MWM resultou numa significativa diferença, com redução da dor, no teste de Hawkins-Kennedy (p=0,028), num aumento do limiar de dor à pressão (p=0,002) e da ADM de APE até ao início da dor (p=0,010), e numa diminuição da actividade EMG do trapézio superior (TS), na fase concêntrica, abaixo dos 90˚ (p=0,028), comparativamente ao grupo Placebo. Foi, ainda, identificada uma diminuição estatisticamente significativa da actividade EMG do TS, nas restantes fases do movimento (p<0,05), um aumento do limiar de dor à pressão (p<0,001) e da ADM até ao início da dor (p=0,006) entre, antes e após a intervenção com MWM. Conclusão: A MWM poderá ser uma técnica efectiva em indivíduos com SCSA, pelos seus efeitos na redução de dor, aumento de ADM até ao início da dor e diminuição da actividade EMG do TS.

A biosignal embedded system for physiological computing

Thesis submitted in the fulfilment of the requirements for the Degree of Master in Electronic and Telecomunications Engineering

Estudo comparativo entre criança com e sem joelhos valgos praticantes de hóquei em patins utilizando diferentes sistemas de análise

O presente estudo tem como objetivo comparar experimentalmente duas crianças praticantes de Hóquei em Patins, uma normal e uma com a patologia dos joelhos valgos, avaliando qualitativamente as diferenças posturais, estáticas e dinâmicas, decorrentes da utilização dos patins específicos desta modalidade, através do sistema de análise da Força de Reação do Solo (FRS), de Eletromiografia (EMG), de captura de movimento, e de modelação e simulação. Para atingir o objetivo definiu-se um protocolo de ensaios com as seguintes tarefas: repouso com e sem patins, marcha, corrida, deslizar com os dois pés apoiados e deslizar com o pé esquerdo levantado. No repouso avaliou-se a variação do ponto de aplicação da FRS da criança normal e patológica, com e sem patins. Ainda na tarefa de repouso avaliou-se também as componentes médio-lateral, antero-posterior individualmente e a componente vertical da FRS, juntamente com a atividade muscular dos músculos Gastrocnémio Medial (GM), Recto Femoral (RF), Vasto Medial (VM), Vasto Lateral (VL), Bicípete Femoral (BF), Semitendinoso (ST), Tensor da Fascia Lata (TFL), Gastrocnémio Lateral (GL), de forma a comparar os valores de intensidade de FRS e da atividade muscular dos diferentes instantes de tempo desta tarefa. Para as restantes tarefas apenas se avaliou individualmente as componentes médio-lateral e antero-posterior da FRS e a componente vertical da FRS juntamente com a atividade muscular dos referidos músculos, salientando as diferenças evidentes entre as curvas da criança normal e as curvas da criança patológica durante os diferentes instantes do movimento. Todas as tarefas referidas, exceto a tarefa de repouso com patins, foram ainda simuladas recorrendo a modelos músculo-esqueléticos. A partir destas simulações do movimento obtiveram-se os ângulos articulares e efetuou-se a respetiva análise. No final dos resultados obtidos apresentou-se uma tabela de resumo com o cálculo dos coeficientes de variação de cada grandeza, exceto nos gráficos da posição no espaço da FRS, onde se constatou que existe uma grande variabilidade inter-individuo em cada tarefa. A análise dos resultados de cada tarefa permite concluir que a utilização de patins pode trazer uma maior ativação muscular para a criança patológica, embora se verifique instabilidade articular. Apesar dessa instabilidade pode-se inferir que, uma maior ativação muscular decorrente da utilização de patins, tal como acontece na prática do hóquei em patins, pode trazer uma melhoria, a longo prazo, na estabilidade da articulação do joelho e na sustentação corporal, proporcionada pelo fortalecimento muscular.

Anti-vibration gloves and the forearm efforts during tools operations

The objective of this paper is to analyze the forearm muscular contraction levels associated to the use of anti-vibration gloves, by comparing the contraction levels with gloves and without gloves. Two different vibration tools were used in a simulated work environment: (1) A compact Duty Multi-Cutter Bosch and (2) and a Percussion Drill with a drill bit Ø20 mm. Standard operations were performed by each subject in the following materials: (1) Performing cross- sectional cuts in 80x40 mm pine section and (2) performing 20 mm diameter holes in a concrete slab 2 x 2 m, 70 mm thick. The forearm contraction level were measured by surface electromyography in four different muscles: Flexor Digitorum Superficialis (FDS), Flexor Carpi Ulnaris (FCU), Extensor Carpi Radialis Longus (ECRL) e Extensor Carpi Ulnaris (ECU). For the flexor muscles (FDS, FCU), an increase tendency in muscular contraction was observed when the operations are performed without gloves (2-5% MVE increase in the FDS and 3-9% MVE increase in the FCU). For the extensor muscles ECU a decrease tendency in muscular contraction was observed when the operations are performed without gloves (1-10% MVE decrease). Any tendency was found in the ECRL muscle. ECU was the muscle with the highest contraction level for 79% and 71% of the operators, during the operations respectively with the multi-cutter (P50= 27-30%MVE) and with the percussion drill (P50=46-55%MVE). As a final conclusion from this study, anti- vibration gloves may increase the forearm fatigue in the posterior region of the forearm (ECU muscle) during operations with the mentioned tools

Ajustes Posturais dos músculos da tibiotársica em indivíduos com Doença de Parkinson durante o sit-to-stand

Introdução: Os ajustes posturais antecipatórios (APAs) são essenciais para o movimento típico, estando alterados nas doenças neuro degenerativas como a doença de Parkinson (DP) Objectivo(s): Estudar os early postural adjustments e os APAs em indivíduos com DP durante o sentar para levantar (STS), com e sem dupla tarefa. Métodos: Foi recolhida a atividade eletromiográfica (EMG) dos músculos tibial anterior, solear e gastrocnémio medial, em indivíduos com e sem DP (9 em cada grupo), durante o STS. Este foi determinado pelo deslocamento antero posterior do centro de pressão através da plataforma de forças, sendo a tarefa cognitiva dada pelo stroop colour word interference test. Os ajustes posturais foram avaliados pelo tempo de ativação e pela atividade EMG relativa, bem como pela análise da co ativação agonista/antagonista. Resultados: Não foram encontradas diferenças estatisticamente significativas entre o grupo de controlo e o grupo com DP em nenhuma das variáveis analisadas Há uma tendência para o grupo com DP apresentar APAs mais cedo na tarefa simples, mantendo atividade muscular durante mais tempo e com maior atividade EMG relativa que o grupo controlo. Na dupla tarefa mantém-se essa tendência, exceto o tempo de ativação ser mais próximo do levante. Conclusão: Os défices posturais decorrentes da doença de Parkinson parecem não ser evidenciados na primeira fase do sit-to-stand.

Subclinical femoral neuropathy after anterior cruciate ligament reconstruction

Background and aim of the study: Patients with anterior cruciate ligament (ACL) reconstruction and femoral catheter analgesia may develop quadriceps amyotrophy. We aimed to determine whether this amyotrophy might be related to a femoral neuropathy. Material and method: After Ethical Committee approval and patients' written informed consent, 17 patients ASA I and II scheduled to undergo ACL reconstruction were recruited. An electromyography (EMG) was performed before the operation in order to exclude a femoral neuropathy. A femoral nerve catheter was inserted before the surgery with the aid of a nerve stimulator, and 20 ml of 0.5% ropivacaine was injected. The operation was done under spinal or general anaesthesia. Postoperative analgesia was provided with 0.2% ropivacaine for 72 hours, in association with oxycodone, paracetamol and ibuprofen. A second EMG was performed 4 weeks after the ACL repair. A femoral neuropathy was defined as a reduction of the surface of the motor response of more than 20%, compared to the first EMG. A third EMG was performed at 6 months if a neuropathy was present. Results: Mean age of this group of patients was 27 years old (range 18-38 y.). Among the 17 patients, 4 developed a transient femoral neuropathy (incidence of 24%) without clinical complain. Conclusion: In this study, the incidence of subclinical femoral neuropathy after ACL reconstruction is high. This lesion may be caused by the femoral catheter (mechanical damage, toxicity of local anaesthesia) or by the Tourniquet. Further studies are needed to investigate the incidence of subclinical neuropathy, according to the type of analgesia (epidural analgesia, PCA) and surgery.

Ecology and neurophysiology of sleep in two wild sloth species

Study Objectives: Interspecific variation in sleep measured in captivity correlates with various physiological and environmental factors, including estimates of predation risk in the wild. However, it remains unclear whether prior comparative studies have been confounded by the captive recording environment. Herein we examine the impact of predation pressure on sleep in sloths living in the wild. Design: Comparison of two closely related sloth species, one exposed to predation and one free from predation. Setting: Panamanian mainland rainforest (predators present) and island mangrove (predators absent). Participants: Mainland (Bradypus variegatus, 5 males and 4 females) and island (Bradypus pygmaeus, 6 males) sloths. Interventions: None. Measurements and Results: EEG and EMG activity were recorded using a miniature data logger. Although both species spent between 9 and 10 hours per day sleeping, the mainland sloths showed a preference for sleeping at night, whereas island sloths showed no preference for sleeping during the day or night. EEG activity during NREM sleep showed lower low-frequency power, and increased spindle and higher frequency power in island sloths when compared to mainland sloths. Conclusions: In sloths sleeping in the wild, predation pressure influenced the timing of sleep, but not the amount of time spent asleep. The preference for sleeping at night in mainland sloths may be a strategy to avoid detection by nocturnal cats. The pronounced differences in the NREM sleep EEG spectrum remain unexplained, but might be related to genetic or environmental factors.

Controlled study of 50-Hz repetitive transcranial magnetic stimulation for the treatment of Parkinson disease.

OBJECTIVE: To investigate the safety and efficacy of 50-Hz repetitive transcranial magnetic stimulation (rTMS) in the treatment of motor symptoms in Parkinson disease (PD). BACKGROUND: Progression of PD is characterized by the emergence of motor deficits that gradually respond less to dopaminergic therapy. rTMS has shown promising results in improving gait, a major cause of disability, and may provide a therapeutic alternative. Prior controlled studies suggest that an increase in stimulation frequency might enhance therapeutic efficacy. METHODS: In this randomized, double blind, sham-controlled study, the authors investigated the safety and efficacy of 50-Hz rTMS of the motor cortices in 8 sessions over 2 weeks. Assessment of safety and clinical efficacy over a 1-month period included timed tests of gait and bradykinesia, Unified Parkinson's Disease Rating Scale (UPDRS), and additional clinical, neurophysiological, and neuropsychological parameters. In addition, the safety of 50-Hz rTMS was tested with electromyography-electroencephalogram (EMG-EEG) monitoring during and after stimulation. RESULTS: The authors investigated 26 patients with mild to moderate PD: 13 received 50-Hz rTMS and 13 sham stimulation. The 50-Hz rTMS did not improve gait, bradykinesia, and global and motor UPDRS, but there appeared a short-lived "on"-state improvement in activities of daily living (UPDRS II). The 50-Hz rTMS lengthened the cortical silent period, but other neurophysiological and neuropsychological measures remained unchanged. EMG/EEG recorded no pathological increase of cortical excitability or epileptic activity. There were no adverse effects. CONCLUSION: It appears that 50-Hz rTMS of the motor cortices is safe, but it fails to improve motor performance and functional status in PD. Prolonged stimulation or other techniques with rTMS might be more efficacious but need to be established in future research.

High Altitude Increases Alteration in Maximal Torque but Not in Rapid Torque Development in Knee Extensors after Repeated Treadmill Sprinting.

We assessed knee extensor neuromuscular adjustments following repeated treadmill sprints in different normobaric hypoxia conditions, with special reference to rapid muscle torque production capacity. Thirteen team- and racquet-sport athletes undertook 8 × 5-s "all-out" sprints (passive recovery = 25 s) on a non-motorized treadmill in normoxia (NM; FiO2 = 20.9%), at low (LA; FiO2 = 16.8%) and high (HA; FiO2 = 13.3%) normobaric hypoxia (simulated altitudes of ~1800 m and ~3600 m, respectively). Explosive (~1 s; "fast" instruction) and maximal (~5 s; "hard" instruction) voluntary isometric contractions (MVC) of the knee extensors (KE), with concurrent electromyographic (EMG) activity recordings of the vastus lateralis (VL) and rectus femoris (RF) muscles, were performed before and 1-min post-exercise. Rate of torque development (RTD) and EMG (i.e., Root Mean Square or RMS) rise from 0 to 30, -50, -100, and -200 ms were recorded, and were also normalized to maximal torque and EMG values, respectively. Distance covered during the first 5-s sprint was similar (P > 0.05) in all conditions. A larger (P < 0.05) sprint decrement score and a shorter (P < 0.05) cumulated distance covered over the eight sprints occurred in HA (-8 ± 4% and 178 ± 11 m) but not in LA (-7 ± 3% and 181 ± 10 m) compared to NM (-5 ± 2% and 183 ± 9 m). Compared to NM (-9 ± 7%), a larger (P < 0.05) reduction in MVC torque occurred post-exercise in HA (-14 ± 9%) but not in LA (-12 ± 7%), with no difference between NM and LA (P > 0.05). Irrespectively of condition (P > 0.05), peak RTD (-6 ± 11%; P < 0.05), and normalized peak RMS activity for VL (-8 ± 11%; P = 0.07) and RF (-14 ± 11%; P < 0.01) muscles were reduced post-exercise, whereas reductions (P < 0.05) in absolute RTD occurred within the 0-100 (-8 ± 9%) and 0-200 ms (-10 ± 8%) epochs after contraction onset. After normalization to MVC torque, there was no difference in RTD values. Additionally, the EMG rise for VL muscle was similar (P > 0.05), whereas it increased (P < 0.05) for RF muscle during all epochs post-exercise, independently of the conditions. In summary, alteration in repeated-sprint ability and post-exercise MVC decrease were greater at high altitude than in normoxia or at low altitude. However, the post-exercise alterations in RTD were similar between normoxia and low-to-high hypoxia.

The surface electromyography-force relationship during isometric dorsiflexion in males and females

This study evaluated sex-related differences in the tibialis anterior (TA) surface electromyography (EMG) to force relationship. One-hundred participants (50 males and 50 females) performed three isometric contractions at 20, 40, 60, 80, and 100% of maximal voluntary contraction (MVC) in an apparatus designed to isolate the action of the dorsiflexors. The surface EMG signal was amplified (lOOOx), band-pass filtered (10-500Hz), and sampled at 2048 Hz. The load cell signal was low-passed filtered at 100 Hz and sampled at the same rate. Males were stronger than females {P <0.05). However, there was no significant difference in root-mean-square (RMS) values between sexes {P <0.05). Both sexes exhibited a quadratic increase in RMS across force levels (P <0.05). The mean power frequency (MNF) for males was greater than for females {P <0.05). Males and females exhibited a linear increase in both frequency measures up to 80% of MVC (P <0.05). Between 80 and 100% MVC, the frequency values for the females plateaued while males showed a decrease {P <0.05). The magnitude of the difference in MNF between males and females was consistent with sex-specific TA physiology. In general, the pattern of means for RMS and MNF between males and females revealed no sex-related differences in the surface EMG/force relationship. We therefore conclude that there are no sex-related differences in the gradation of muscle force.

3D movement and muscle activity patterns in a violin bowing task

Objective: Overuse injuries in violinists are a problem that has been primarily analyzed through the use of questionnaires. Simultaneous 3D motion analysis and EMG to measure muscle activity has been suggested as a quantitative technique to explore this problem by identifying movement patterns and muscular demands which may predispose violinists to overuse injuries. This multi-disciplinary analysis technique has, so far, had limited use in the music world. The purpose of this study was to use it to characterize the demands of a violin bowing task. Subjects: Twelve injury-free violinists volunteered for the study. The subjects were assigned to a novice or expert group based on playing experience, as determined by questionnaire. Design and Settings: Muscle activity and movement patterns were assessed while violinists played five bowing cycles (one bowing cycle = one down-bow + one up-bow) on each string (G, D, A, E), at a pulse of 4 beats per bow and 100 beats per minute. Measurements: An upper extremity model created using coordinate data from markers placed on the right acromion process, lateral epicondyle of the humerus and ulnar styloid was used to determine minimum and maximum joint angles, ranges of motion (ROM) and angular velocities at the shoulder and elbow of the bowing arm. Muscle activity in right anterior deltoid, biceps brachii and triceps brachii was assessed during maximal voluntary contractions (MVC) and during the playing task. Data were analysed for significant differences across the strings and between experience groups. Results: Elbow flexion/extension ROM was similar across strings for both groups. Shoulder flexion/extension ROM increaslarger for the experts. Angular velocity changes mirrored changes in ROM. Deltoid was the most active of the muscles assessed (20% MVC) and displayed a pattern of constant activation to maintain shoulder abduction. Biceps and triceps were less active (4 - 12% MVC) and showed a more periodic 'on and off pattern. Novices' muscle activity was higher in all cases. Experts' muscle activity showed a consistent pattern across strings, whereas the novices were more irregular. The agonist-antagonist roles of biceps and triceps during the bowing motion were clearly defined in the expert group, but not as apparent in the novice group. Conclusions: Bowing movement appears to be controlled by the shoulder rather than the elbow as shoulder ROM changed across strings while elbow ROM remained the same. Shoulder injuries are probably due to repetition as the muscle activity required for the movement is small. Experts require a smaller amount of muscle activity to perform the movement, possibly due to more efficient muscle activation patterns as a result of practice. This quantitative multidisciplinary approach to analysing violinists' movements can contribute to fuller understanding of both playing demands and injury mechanisms .

A comparison of electrophysiological changes during the sleep onset period of psychophysiological insomniacs, psychiatric insomniacs and normal sleepers

The EEG of the sleep onset period of psychophysiological insomniacs, psychiatric insomniacs and controls was compared using power spectral analysis (FFT). Eighteen drug-free subjects were equally divided into three groups according to their responses in the Brock Sleep and Insomnia Questionnaire, the Minnesota Multiphasic Personality Inventory and the Sleep Disorders Questionnaire. Group 1 consisted of psychophysiological insomniacs, group 2 included insomniacs with an indication of psychiatric disturbances, and group 3 was a control group. EEG, EOG and EMG were recorded for two consecutive nights. Power spectral analysis (FFT) of EEG at C4 from the sleep onset period (defined as lights out to the first five minutes of stage 2) was performed on all standard frequency bands, delta: .5-4 Hz; theta: 4-8 Hz; alpha: 8-12 Hz; sigma: 12-15 Hz beta: 15-25 Hz. Psychophysiological insomniacs had less alpha during wakefulness than the other two groups and did not show the dramatic drop in alpha across the sleep onset period, which characterizes normal sleep. They also had less delta, especially during stage 2 on night 2. They also showed less delta in the last quartile of the chronological analysis of the sleep onset period. Psychiatric insomniacs showed lower relative beta power values overall while psychophysiological insomniacs showed higher relative beta power values during wakefulness. This microanalysis 11 confirms that the sleep onset period is generally similar for psychiatric insomniacs and normal sleepers. This may be due to the sample of psychiatric insomniacs being heterogeneous or may reflect a sleep onset system that is essentially intact. Psychophysiological insomniacs have higher cortical arousal during the sleep onset period than do the psychiatric insomniacs and the controls. Clear differences in the sleep onset period of psychophysiological insomniacs exist. The dramatic changes in power values in these two groups are not seen in the psychophysiological insomniacs, which may make the discrimination between wakefulness and sleep more difficult.

Neuromuscular adaptations in endurance-trained boys and men

Competitive sports participation in youth is becoming increasingly more common in the Western world. It is widely accepted that sports participation, specifically endurance training, is beneficial for physical, psychomotor, and social development of children. The research on the effect of endurance training in children has focused mainly on healthrelated benefits and physiological adaptations, particularly on maximal oxygen uptake. However, corresponding research on neuromuscular adaptations to endurance training and the latter's possible effects on muscle strength in youth is lacking. In children and adults, resistance training can enhance strength and mcrease muscle activation. However, data on the effect of endurance training on strength and neuromuscular adaptations are limited. While some evidence exists demonstrating increased muscle activation and possibly increased strength in endurance athletes compared with untrained adults, the neuromuscular adaptations to endurance training in children have not been examined. Thus, the purpose of this study was to examine maximal isometric torque and rate of torque development (RID), along with the pattern of muscle activation during elbow and knee flexion and extension in muscle-endurancetrained and untrained men and boys. Subjects included 65 males: untrained boys (n=18), endurance-trained boys (n=12), untrained men (n=20) and endurance-trained men (n=15). Maximal isometric torque and rate of torque development were measured using an isokinetic dynamometer (Biodex III), and neuromuscular activation was assessed using surface electromyography (SEMG). Muscle strength and activation were assessed in the dominant arm and leg, in a cross-balanced fashion during elbow and knee flexion and extension. The main variables included peak torque (T), RTD, rate of muscle activation (Q30), Electro-mechanical delay (EMD), time to peak RTD and co-activation index. Age differences in T, RTD, electro-mechanical delay (EMD) and rate of muscle activation (Q30) were consistently observed in the four contractions tested. Additionally, Q30, nonnalized for peak EMG amplitude, was consistently higher in the endurancetrained men compared with untrained men. Co-activation index was generally low in all contractions. For example, during maximal voluntary isometric knee extension, men were stronger, had higher RTD and Q30, whether absolute or nonnalized values were used. Moreover, boys exhibited longer EMD (64.8 ± 18.5 ms vs. 56.6 ± 15.3 ms, for boys and men respectively) and time to peak RTD (112.4 ± 33.4 ms vs. 100.8 ± 39.1 ms for boys and men, respectively). In addition, endurance-trained men had lower T compared with untrained men, yet they also exhibited significantly higher nonnalized Q30 (1.9 ± 1.2 vs. 1.1 ± 0.7 for endurance-trained men and untrained men, respectively). No training effect was apparent in the boys. In conclusion, the findings demonstrate muscle strength and activation to be lower in children compared with adults, regardless of training status. The higher Q30 of the endurance-trained men suggests neural adaptations, similar to those expected in response to resistance training. The lower peak torque may su9gest a higher relative involvement oftype I muscle fibres in the endurance-trained athletes. Future research is required to better understand the effect of growth and development on muscle strength and activation patterns during dynamic and sub-maximal isometric contractions. Furthennore, training intervention studies could reveal the effects of endurance training during different developmental stages, as well as in different muscle groups.