No description available.

The purposes of this research were i) to compare skeletal muscle development, function and bone mineralization in girls with Turner's syndrome (TS) (n=7) and healthy control girls (n=13), and ii) to examine the effects of growth hormone (GH) and estrogen (E2) therapy on musculoskeletal variables using a case study approach in two TS girls and one healthy control. Anthropometric measurements included: height, body mass, percent fat, and muscle and bone cross-sectional areas and muscle density from computed axial tomography. Evoked peak twitch torque (TT), maximal voluntary strength (MVC), contractile properties and motor unit activation (MUA) were determined for the elbow flexors (EF), plantar flexors (PF) and the knee extensors (KE). Total body and segmental bone mineral content (BMC) and density (BMD) were measured with dual photon absorptiometry. Dietary intake and participation in physical activity were assessed from questionnaires. Absolute strength (TT and MVC) for the TS patients was lower than that of the control girls' for EF, PF and KE and could not be accounted for by differences in muscle density, contractile properties, MUA, diet or level of physical activity. There were no significant differences in evoked and voluntary strength corrected for muscle area and lever length between the TS and control girls. Total body, leg and trunk BMC were lower in the TS girls compared to the controls; however, when normalized for body mass and bone width, total body BMC (g/kg) and BMD respectively were comparable between the TS and control girls. Growth hormone therapy increased height and lean mass, and reduced adiposity. All measures of arm strength increased but leg strength (PF & KE) was reduced. These may reflect the lack of GH effects on the leg muscle or possibly a detraining effect from the subject's withdraw! from a skating program. Growth hormone therapy resulted in increased leg BMC which may reflect a lag time between bone growth and subsequent mineralization. Estrogen therapy resulted in increased muscle area, fat mass and strength at all 3 muscle groups. The latter may be due to the laying down of muscle proteins as a result of estrogen therapy. The lack of major changes in BMC or BMD probably reflects the short duration of the follow-up period. Further studies are required with larger numbers for longer treatment periods in order to make conclusive statements about the effects of hormonal therapy on muscle function and bone mineralization in Turner's patients. / Thesis / Master of Science (MS)

Based on the ‘free radical theory of aging,’ I hypothesized that hypoxia caused by the mammalian dive response induces free radical production which could modulate or accelerate cellular aging. On the other hand, to prevent free radical “stress” (pro- /antioxidant imbalance), divers could display elevated protective mechanisms. Additionally, the unusual connection between diving physiology and foraging ecology implies that aging physiology is significant to our understanding of ecology for divers. This study examines three aspects of aging in representative diving mammals. First, gracilis muscle morphology was analyzed for old/young shrews (water shrew, Sorex palustris (diver); short-tailed shrew, Blarina brevicauda (non-diver)). Extracellular space was elevated in old animals (10% diver, ~70% non-diver; P=0.021), which corresponded to a larger extracellular collagen component of old muscle (~60%; P=0.008). Muscle was dominated by Type I collagen, and the ratio of collagen Type I: III more than doubled with age (P=0.001). Second, oxidative stress markers, protective antioxidant enzymes and apoptosis were examined in muscle of the two shrew species. The activities of antioxidant enzymes catalase and glutathione peroxidase were statistically identical at each age in both species. The Cu,Zn superoxide dismutase isoform was, however, elevated in older animals (115% diver, 83% non-diver, P=0.054). Only one indicator of oxidative stress (lipid peroxidation) increased with age (P=0.009), whereas the other markers declined (4-hydroxynonenal content, P=0.008, dihydroethidium oxidation, P=0.025). Apoptosis occurred in <1% of myocytes, and did not change with age. On balance, diving water shrews did not have adaptations to combat oxidative stress, yet they do not display excessive oxidative tissue damage. Apoptosis was similar between species. The third study component was the development of a predictive simulation model for the energetics of old/young foraging Weddell seals, Leptonychotes weddellii. With advancing age, the model predicts declining net energy gain associated with a decrease in muscle contractile efficiency. The effects of age are exacerbated when good prey patches are scarce. In such cases, declines in old seal energy gain caused by increased buoyancy and decreased aerobic dive limit become apparent. The model also addresses the idea that behavioral plasticity may allow older animals to compensate for age-related performance constraints.

<p> It is known that high-resistance training induces morphological changes in skeletal muscle. Following a resistance training program, increases in maximum torque generating capacity are observed due to both neural adaptations and hypertrophic gains within the trained muscle. Although it has been established that a muscle hypertrophies due to the addition of myofibrillar proteins through increased protein synthesis, the exact mechanism which stimulates the hypertrophic response is unknown.</p> <p> Previous reports have shown that training in the absence of eccentric contractions generally produces less muscle growth and strength gains, as well as inflicting less damage to the muscle ultrastructure. Likewise, fast eccentric contractions have been shown to increase muscular strength to a greater extent than slow contractions. It has been hypothesized that fast eccentric contractions may maximize muscular damage, thus invoking a greater response of repair mechanisms, including satellite cell recruitment, which would allow an increased addition of contractile proteins to be added to the injured muscle, increasing muscle size and strength to a greater degree.</p> <p> The effect of fast and slow eccentric training was investigated using a bilateral, within subject model. Twelve men trained one arm fast (3.66 rad/s) and one arm slow (0.52 rad/s) for 8 weeks on an isokinetic training apparatus. Type I muscle fibre size increased with training by an average of 9.3±12.0% (P<0.05, main effect for time). Type II muscle fibres increased more in the subjects' fast trained arm when compared to the slow trained arm according to ATPase histochemical analysis (P<0.05, time x condition interaction). Likewise, whole arm cross-sectional area showed that the fast trained arms had an average increase of 6.8±5.5 % whereas the slow arms only had an average increase CSA of 5.1±5.7% (P=0.065, time x condition interaction). Maximum torque generating capacity was also increased to a greater degree (P<0.05, time x condition interaction) in the fast trained arm with an average of 10.3±16.4 Nm, whereas the slow trained arm increased only 7.3±15.0 Nm, across testing speeds. A decrease in the percentage of type IIx fibres was seen in both arms after training according to both ATPase histochemical staining and MHC gel electrophoresis; however, the percentage of type IIa fibre area increased in the fast trained arms (8.4±8.6%) more significantly (P<0.05, time x condition interaction) than the slow trained arms (1.7±10.9%).</p> <p> Seven males were trained in a similar manner to determine the extent of muscle damage which was evaluated by both Z-band streaming and force production decrements. After a single exercise bout of fast eccentric training in one arm and slow eccentric training in the other, it was determined that a 1.97±0.74 areas of moderate Z-band streaming per mm^2 of muscle in the fast exercised arm compared to 0.89±0.79 areas of moderate Z-band streaming per mm^2 of muscle in the slow trained arm (P<0.05). In conclusion, training using fast (3.66 rad/s) eccentric contractions causes a greater degree of muscle damage, hypertrophy, and strength gains than does training with slow (0.52 rad/s) eccentric contractions.</p> / Thesis / Master of Science (MSc)

Lower back injury remains the most important injury problem in professional cricket with lumbar stress fractures in fast bowlers accounting for the most lost playing time. Previous research has associated workload, paraspinal muscle asymmetry and technique factors with lower back injury in fast bowlers, however, preventative strategies such as workload directives and coaching guidelines have not reduced the incidence and prevalence of these injuries. Recent developments in medical imaging technology have improved diagnosis of pathologies such as lumbar posterior bony element (partes interarticulares and pedicles) stress fractures and intervertebral disc degeneration in athletes whilst also allowing quantification of other, potentially associated factors such as paraspinal muscle asymmetry. However, there is very little published research regarding the use of modalities such as magnetic resonance imaging (MRI) in the identification and prognosis of these types of injuries in fast bowlers. Similarly, advances in three-dimensional (3D) motion analysis has aided technique evaluation in a variety of sports, however, little remains known about the pathomechanics of lower back injury in fast bowling. Therefore, the aim of this doctoral research was to investigate relationships between lower back injury and; the MRI appearance of the lumbar posterior bony elements and intervertebral discs, MRI-derived lumbar muscle morphology and the three-dimensional (3D) trunk kinematics of professional fast bowlers in cricket. This was examined in a series of five studies. The first study undertaken was an investigation of the MRI appearance of the lumbar spines of 36 asymptomatic professional fast bowlers and 17 active controls. / It was identified that the fast bowlers had a high prevalence of multi-level, predominantly non-dominant side, acute and chronic stress changes in the posterior bony elements of the lumbar spine. Multiple level disc degeneration was also more advanced in the fast bowlers compared with the control - iv - participants. However, disc degeneration appeared not to be associated with lumbar stress injury. The second study investigated the reliability and accuracy of using MRI to determine the FCSA of the lumbar paraspinal muscles (psoas, quadratus lumborum, erector spinae and multifidus). The novel methodology developed in this study was determined to be both valid and highly reliable. In the third study, this technique was then used to describe the functional crosssectional area (FCSA) morphology of the paraspinal muscles in a group of 46 professional fast bowlers and the 17 control participants scanned in the first study. It reinforced that there was a higher prevalence of lumbar muscle asymmetry in the fast bowler group. Paraspinal muscle asymmetry, consistent with hypertrophy of the dominant side muscle, was most prevalent in the quadratus lumborum of fast bowlers, and was also evident in the lumbar multifidus in both groups of subjects. The aims of the fourth study of the thesis were to quantify the proportion of lower trunk motion utilised during the delivery stride of fast bowling and to investigate the relationship between the most accepted fast bowling action classification system and potentially injurious kinematics of the lower trunk. 3D kinematic data were collected from 50 male professional fast bowlers during fast bowling trials and these were normalised to each bowler’s standing lower trunk range of motion. A high percentage of the fast bowlers used a mixed bowling action attributable to having shoulder counter-rotation greater than 30°. / The greatest proportion of lower trunk extension (26%), contralateral side-flexion (129%) and ipsilateral rotation (79%) was utilised during the front foot contact phase of the fast bowling delivery stride. There was no significant difference between mixed and non-mixed bowlers in the range of motion used during fast bowling. It was concluded that fast bowling action characteristics currently used to identify potentially dangerous action types may not be directly related to the likely pathomechanics of contralateral side lumbar stress injuries. It is proposed that coupled lower trunk extension, ipsilateral rotation in addition to extreme contralateral side-flexion, during the early part of the front foot contact phase of the bowling action may be an important mechanical factor in the aetiology of this type of injury. In the final study, a combination of the factors described in earlier studies i.e. the lumbar MRI appearance of the partes interarticulares and intervertebral discs, paraspinal muscle asymmetry and selected bowling action and delivery stride trunk kinematic variables, were examined. Therefore, the aim of this study was to examine the relationship between fast bowler lower back injury occurrence (one season either side of testing) and the aforementioned factors that were measured when participants were asymptomatic and bowling competitively. The results of this study indicated that a high percentage of professional fast bowlers in the United Kingdom continue to sustain a high number of acute lumbar stress injuries and these result a significant amount of lost playing and training time. Fast bowling action classification and lower trunk kinematic variables were not conclusively linked to acute lumbar stress injury occurrence. However, further investigation of the effect of coupled lower trunk motion on nondominant side lumbar bone stress is indicated. / The presence of acute MRI stress changes (particularly acute stress changes such as bone marrow oedema, periostitis and acute fracture lines) in the non-dominant side lumbar posterior elements seem to have a relationship with acute stress injury occurrence. Regular lumbar MRI scanning may assist in identifying early acute stress changes prior to the onset of symptoms. Intervertebral disc degeneration was less prevalent amongst professional fast bowlers who suffered acute stress injuries than those who had no significant lower back injury. Finally, although fast bowlers have a high prevalence of quadratus lumborum and lumbar multifidus asymmetry (larger on the dominant side), there was no observed relationship between acute lumbar stress injury and these findings.

A Doença Renal Crônica (DRC) é caracterizada pela degeneração progressiva e irreversível das estruturas componentes do sistema renal. Em estágio avançado da DRC é indicado o tratamento substitutivo renal, também conhecido como Hemodiálise (HD). Este tratamento é acompanhado por comorbidades como desnutrição e fraqueza muscular, que apresentam forte associação com a diminuição da independência funcional. Neste sentido, este trabalho apresenta como objetivos: (1) Caracterizar a morfologia muscular de pacientes com doença renal crônica (DRC) que realizam HD, comparada a um grupo controle; (2) Avaliar a característica neuromecânica muscular dos membros inferiores de pacientes com doença renal crônica (DRC) que realizam HD, comparada ao grupo controle (3) Investigar a influência das características morfológicas e neuromecânicas dos membros inferiores dos pacientes com DRC no desempenho do teste de caminhada de seis minutos (TC6’). Participaram da pesquisa 17 pacientes com DRC e 17 sujeitos controle, pareados por idade e características antropométricas. O presente estudo foi dividido em dois capítulos em que foram avaliadas as seguintes variáveis: Capítulo I: 1) perfil bioquímico dos pacientes; 2) nível de atividade física; 3) força dos extensores de joelho, flexores plantares e de preensão manual; 4) espessura muscular dos flexores e extensores do cotovelo, dos extensores de joelho, dos flexores plantares e flexores dorsais do tornozelo; 5) qualidade muscular (força/espessura muscular) do braço, dos extensores de joelho e dos flexores plantares. Os resultados do presente capítulo demonstram que os pacientes com DRC que realizam HD quando comparados ao grupo controle apresentam: 1) menor nível de atividade física; 2) maior tempo despendido sentado durante a semana e o final de semana; 3) nenhuma diferença na força de preensão manual (FPM); 4) menor capacidade de força máxima dos extensores de joelho e flexores plantares; 5) menor espessura muscular dos flexores e extensores de cotovelo, dos extensores de joelho e dos flexores plantares e dorsais; 6) menor qualidade muscular dos membros superiores, extensores de joelho e flexores plantares; Capítulo II: Neste capítulo, o perfil neuromecânico e funcional foi observado a partir das variáveis: 1) taxa de produção de força dos extensores de joelho e flexores plantares; 2) tempo de reação total dos extensores de joelho e do gastrocnêmio medial; 3) atividade elétrica muscular dos extensores de joelho e do gastrocnêmio medial; 4) eficiência neuromuscular dos extensores de joelho e do gastrocnêmio medial; 5) arquitetura muscular do vasto lateral, gastrocnêmio medial, sóleo e tibial anterior. Os resultados do capítulo II demonstram que os pacientes com DRC que realizam HD quando comparados ao grupo controle apresentam: 1) menor taxa de produção de força e eficiência neuromuscular dos extensores de joelho e flexores plantares; 2) maior tempo de reação total dos extensores de joelho e flexores plantares; 3) nenhuma diferença na magnitude da ativação dos músculos extensores de joelho e do gastrocnêmio medial durante a CVMi; 4) menores comprimentos de fascículos relativo (comprimento de fascículo/comprimento da tibia) do gastrocnêmio medial e do sóleo; 5) menor comprimento de fascículo absoluto para o sóleo; 6) menor espessura muscular do vasto lateral, sóleo e tibial anterior; 7) nenhuma diferença no ângulo de penação das musculaturas dos membros inferiores; 8) comprimento de fascículo relativo do gastrocnêmio medial pode influenciar o desempenho do TC6’ em pacientes com doença renal. Tais resultados podem auxiliar médicos, fisioterapeutas e professores de educação física na prescrição do treinamento voltado para cada uma das propriedades (morfológicas e neuromecânicas), uma vez que nosso estudo parece ser um dos primeiros a avaliar de forma sistemática e associada essa plasticidade morfológica e neuromuscular em doentes renais crônicos. / Chronic Kidney Disease (CKD) is characterized by progressive degeneration and irreversible components of the kidney’s structures system. In patients with end-stage renal disease (ESRD) is indicated renal replacement by hemodialysis (HD). This treatment is accompanied by comorbidities such as malnutrition and muscle weakness, which have strong association with decreased functional independence. Thus, this study presents the following objectives: (1) Characterize the muscle morphology in patients with CKD in HD tratment, compared to healthy subjects; (2) To evaluate neuromechanical characteristic of the lower limbs muscle of patients with CKD in HD tratment, compared to healthy subjects (3) To investigate the influence of lower limbs neuromechanics and morphological characteristics of patients with CKD in performance of the six-minute walk (6MWT). They participated in the survey 17 CKD patients and 17 healthy subjects paired for age and anthropometric characteristics. This study was divided into two chapters in which the following variables were evaluated: Chapter I: 1) biochemical profile of patients; 2) level of physical activity; 3) force of knee extensors, plantar flexors and handgrip; 4) muscle thickness of the flexors and extensors elbow, quadriceps, the plantar flexors and ankle dorsal flexosr; 5) quality muscle (force / muscle thickness) of the arm, the knee extensors and plantar flexors. The results of this chapter show that patients with CKD in HD tratment when compared to healthy subjects present: 1) lower level of physical activity; 2) increased time spent sitting during the week and the weekend; 3) no difference in the handgrip; 4) lower capacity of maximum force of the knee extensor and plantar flexors; 5) less muscle thickness of the flexors and extensors elbow, the knee extensors and plantar flexors and dorsal flexors; 6) lower quality muscle of the upper limbs, knee extensor and plantar flexors; Chapter II: In this chapter, the neuromechanics and functional profile was observed from the variables: 1) rate development force production of knee extensors and plantar flexors; 2) reaction time of the knee extensors and the medial gastrocnemius; 3) muscular electrical activity of the knee extensors and the medial gastrocnemius; 4) neuromuscular efficiency of knee extensors and the medial gastrocnemius; 5) muscle architecture of vastus lateralis, medial gastrocnemius, soleus and tibialis. The Chapter II results demonstrate that patients with CKD in HD tratment when compared to healthy subjects present: 1) less rate development force production and neuromuscular efficiency of the knee extensor and plantar flexors; 2) more reaction time of the knee extensor and plantar flexors; 3) no difference in the magnitude of the extensor muscles of the knee and the medial gastrocnemius activation of during CVMI; 4) lower relative fascicles lengths (fascicle length / tibia length) of the medial gastrocnemius and the soleus; 5) shorter length of absolute fascicle for the soleus; 6) less muscle thickness of the vastus lateralis, soleus and tibialis; 7) no difference in penation angle of the lower limbs muscle; 8) relative medial gastrocnemius fascicle length can influence of the 6MWT in performance patients with CKD. These results may help doctors, physical therapists and physical education teachers in the prescription of training focused on each of the properties (morphological and neuromechanics), since our study appears to be among the first to evaluate systematically and associated form that morphologic and neuromuscular plasticity in CKD.

A Doença Renal Crônica (DRC) é caracterizada pela degeneração progressiva e irreversível das estruturas componentes do sistema renal. Em estágio avançado da DRC é indicado o tratamento substitutivo renal, também conhecido como Hemodiálise (HD). Este tratamento é acompanhado por comorbidades como desnutrição e fraqueza muscular, que apresentam forte associação com a diminuição da independência funcional. Neste sentido, este trabalho apresenta como objetivos: (1) Caracterizar a morfologia muscular de pacientes com doença renal crônica (DRC) que realizam HD, comparada a um grupo controle; (2) Avaliar a característica neuromecânica muscular dos membros inferiores de pacientes com doença renal crônica (DRC) que realizam HD, comparada ao grupo controle (3) Investigar a influência das características morfológicas e neuromecânicas dos membros inferiores dos pacientes com DRC no desempenho do teste de caminhada de seis minutos (TC6’). Participaram da pesquisa 17 pacientes com DRC e 17 sujeitos controle, pareados por idade e características antropométricas. O presente estudo foi dividido em dois capítulos em que foram avaliadas as seguintes variáveis: Capítulo I: 1) perfil bioquímico dos pacientes; 2) nível de atividade física; 3) força dos extensores de joelho, flexores plantares e de preensão manual; 4) espessura muscular dos flexores e extensores do cotovelo, dos extensores de joelho, dos flexores plantares e flexores dorsais do tornozelo; 5) qualidade muscular (força/espessura muscular) do braço, dos extensores de joelho e dos flexores plantares. Os resultados do presente capítulo demonstram que os pacientes com DRC que realizam HD quando comparados ao grupo controle apresentam: 1) menor nível de atividade física; 2) maior tempo despendido sentado durante a semana e o final de semana; 3) nenhuma diferença na força de preensão manual (FPM); 4) menor capacidade de força máxima dos extensores de joelho e flexores plantares; 5) menor espessura muscular dos flexores e extensores de cotovelo, dos extensores de joelho e dos flexores plantares e dorsais; 6) menor qualidade muscular dos membros superiores, extensores de joelho e flexores plantares; Capítulo II: Neste capítulo, o perfil neuromecânico e funcional foi observado a partir das variáveis: 1) taxa de produção de força dos extensores de joelho e flexores plantares; 2) tempo de reação total dos extensores de joelho e do gastrocnêmio medial; 3) atividade elétrica muscular dos extensores de joelho e do gastrocnêmio medial; 4) eficiência neuromuscular dos extensores de joelho e do gastrocnêmio medial; 5) arquitetura muscular do vasto lateral, gastrocnêmio medial, sóleo e tibial anterior. Os resultados do capítulo II demonstram que os pacientes com DRC que realizam HD quando comparados ao grupo controle apresentam: 1) menor taxa de produção de força e eficiência neuromuscular dos extensores de joelho e flexores plantares; 2) maior tempo de reação total dos extensores de joelho e flexores plantares; 3) nenhuma diferença na magnitude da ativação dos músculos extensores de joelho e do gastrocnêmio medial durante a CVMi; 4) menores comprimentos de fascículos relativo (comprimento de fascículo/comprimento da tibia) do gastrocnêmio medial e do sóleo; 5) menor comprimento de fascículo absoluto para o sóleo; 6) menor espessura muscular do vasto lateral, sóleo e tibial anterior; 7) nenhuma diferença no ângulo de penação das musculaturas dos membros inferiores; 8) comprimento de fascículo relativo do gastrocnêmio medial pode influenciar o desempenho do TC6’ em pacientes com doença renal. Tais resultados podem auxiliar médicos, fisioterapeutas e professores de educação física na prescrição do treinamento voltado para cada uma das propriedades (morfológicas e neuromecânicas), uma vez que nosso estudo parece ser um dos primeiros a avaliar de forma sistemática e associada essa plasticidade morfológica e neuromuscular em doentes renais crônicos. / Chronic Kidney Disease (CKD) is characterized by progressive degeneration and irreversible components of the kidney’s structures system. In patients with end-stage renal disease (ESRD) is indicated renal replacement by hemodialysis (HD). This treatment is accompanied by comorbidities such as malnutrition and muscle weakness, which have strong association with decreased functional independence. Thus, this study presents the following objectives: (1) Characterize the muscle morphology in patients with CKD in HD tratment, compared to healthy subjects; (2) To evaluate neuromechanical characteristic of the lower limbs muscle of patients with CKD in HD tratment, compared to healthy subjects (3) To investigate the influence of lower limbs neuromechanics and morphological characteristics of patients with CKD in performance of the six-minute walk (6MWT). They participated in the survey 17 CKD patients and 17 healthy subjects paired for age and anthropometric characteristics. This study was divided into two chapters in which the following variables were evaluated: Chapter I: 1) biochemical profile of patients; 2) level of physical activity; 3) force of knee extensors, plantar flexors and handgrip; 4) muscle thickness of the flexors and extensors elbow, quadriceps, the plantar flexors and ankle dorsal flexosr; 5) quality muscle (force / muscle thickness) of the arm, the knee extensors and plantar flexors. The results of this chapter show that patients with CKD in HD tratment when compared to healthy subjects present: 1) lower level of physical activity; 2) increased time spent sitting during the week and the weekend; 3) no difference in the handgrip; 4) lower capacity of maximum force of the knee extensor and plantar flexors; 5) less muscle thickness of the flexors and extensors elbow, the knee extensors and plantar flexors and dorsal flexors; 6) lower quality muscle of the upper limbs, knee extensor and plantar flexors; Chapter II: In this chapter, the neuromechanics and functional profile was observed from the variables: 1) rate development force production of knee extensors and plantar flexors; 2) reaction time of the knee extensors and the medial gastrocnemius; 3) muscular electrical activity of the knee extensors and the medial gastrocnemius; 4) neuromuscular efficiency of knee extensors and the medial gastrocnemius; 5) muscle architecture of vastus lateralis, medial gastrocnemius, soleus and tibialis. The Chapter II results demonstrate that patients with CKD in HD tratment when compared to healthy subjects present: 1) less rate development force production and neuromuscular efficiency of the knee extensor and plantar flexors; 2) more reaction time of the knee extensor and plantar flexors; 3) no difference in the magnitude of the extensor muscles of the knee and the medial gastrocnemius activation of during CVMI; 4) lower relative fascicles lengths (fascicle length / tibia length) of the medial gastrocnemius and the soleus; 5) shorter length of absolute fascicle for the soleus; 6) less muscle thickness of the vastus lateralis, soleus and tibialis; 7) no difference in penation angle of the lower limbs muscle; 8) relative medial gastrocnemius fascicle length can influence of the 6MWT in performance patients with CKD. These results may help doctors, physical therapists and physical education teachers in the prescription of training focused on each of the properties (morphological and neuromechanics), since our study appears to be among the first to evaluate systematically and associated form that morphologic and neuromuscular plasticity in CKD.

A Doença Renal Crônica (DRC) é caracterizada pela degeneração progressiva e irreversível das estruturas componentes do sistema renal. Em estágio avançado da DRC é indicado o tratamento substitutivo renal, também conhecido como Hemodiálise (HD). Este tratamento é acompanhado por comorbidades como desnutrição e fraqueza muscular, que apresentam forte associação com a diminuição da independência funcional. Neste sentido, este trabalho apresenta como objetivos: (1) Caracterizar a morfologia muscular de pacientes com doença renal crônica (DRC) que realizam HD, comparada a um grupo controle; (2) Avaliar a característica neuromecânica muscular dos membros inferiores de pacientes com doença renal crônica (DRC) que realizam HD, comparada ao grupo controle (3) Investigar a influência das características morfológicas e neuromecânicas dos membros inferiores dos pacientes com DRC no desempenho do teste de caminhada de seis minutos (TC6’). Participaram da pesquisa 17 pacientes com DRC e 17 sujeitos controle, pareados por idade e características antropométricas. O presente estudo foi dividido em dois capítulos em que foram avaliadas as seguintes variáveis: Capítulo I: 1) perfil bioquímico dos pacientes; 2) nível de atividade física; 3) força dos extensores de joelho, flexores plantares e de preensão manual; 4) espessura muscular dos flexores e extensores do cotovelo, dos extensores de joelho, dos flexores plantares e flexores dorsais do tornozelo; 5) qualidade muscular (força/espessura muscular) do braço, dos extensores de joelho e dos flexores plantares. Os resultados do presente capítulo demonstram que os pacientes com DRC que realizam HD quando comparados ao grupo controle apresentam: 1) menor nível de atividade física; 2) maior tempo despendido sentado durante a semana e o final de semana; 3) nenhuma diferença na força de preensão manual (FPM); 4) menor capacidade de força máxima dos extensores de joelho e flexores plantares; 5) menor espessura muscular dos flexores e extensores de cotovelo, dos extensores de joelho e dos flexores plantares e dorsais; 6) menor qualidade muscular dos membros superiores, extensores de joelho e flexores plantares; Capítulo II: Neste capítulo, o perfil neuromecânico e funcional foi observado a partir das variáveis: 1) taxa de produção de força dos extensores de joelho e flexores plantares; 2) tempo de reação total dos extensores de joelho e do gastrocnêmio medial; 3) atividade elétrica muscular dos extensores de joelho e do gastrocnêmio medial; 4) eficiência neuromuscular dos extensores de joelho e do gastrocnêmio medial; 5) arquitetura muscular do vasto lateral, gastrocnêmio medial, sóleo e tibial anterior. Os resultados do capítulo II demonstram que os pacientes com DRC que realizam HD quando comparados ao grupo controle apresentam: 1) menor taxa de produção de força e eficiência neuromuscular dos extensores de joelho e flexores plantares; 2) maior tempo de reação total dos extensores de joelho e flexores plantares; 3) nenhuma diferença na magnitude da ativação dos músculos extensores de joelho e do gastrocnêmio medial durante a CVMi; 4) menores comprimentos de fascículos relativo (comprimento de fascículo/comprimento da tibia) do gastrocnêmio medial e do sóleo; 5) menor comprimento de fascículo absoluto para o sóleo; 6) menor espessura muscular do vasto lateral, sóleo e tibial anterior; 7) nenhuma diferença no ângulo de penação das musculaturas dos membros inferiores; 8) comprimento de fascículo relativo do gastrocnêmio medial pode influenciar o desempenho do TC6’ em pacientes com doença renal. Tais resultados podem auxiliar médicos, fisioterapeutas e professores de educação física na prescrição do treinamento voltado para cada uma das propriedades (morfológicas e neuromecânicas), uma vez que nosso estudo parece ser um dos primeiros a avaliar de forma sistemática e associada essa plasticidade morfológica e neuromuscular em doentes renais crônicos. / Chronic Kidney Disease (CKD) is characterized by progressive degeneration and irreversible components of the kidney’s structures system. In patients with end-stage renal disease (ESRD) is indicated renal replacement by hemodialysis (HD). This treatment is accompanied by comorbidities such as malnutrition and muscle weakness, which have strong association with decreased functional independence. Thus, this study presents the following objectives: (1) Characterize the muscle morphology in patients with CKD in HD tratment, compared to healthy subjects; (2) To evaluate neuromechanical characteristic of the lower limbs muscle of patients with CKD in HD tratment, compared to healthy subjects (3) To investigate the influence of lower limbs neuromechanics and morphological characteristics of patients with CKD in performance of the six-minute walk (6MWT). They participated in the survey 17 CKD patients and 17 healthy subjects paired for age and anthropometric characteristics. This study was divided into two chapters in which the following variables were evaluated: Chapter I: 1) biochemical profile of patients; 2) level of physical activity; 3) force of knee extensors, plantar flexors and handgrip; 4) muscle thickness of the flexors and extensors elbow, quadriceps, the plantar flexors and ankle dorsal flexosr; 5) quality muscle (force / muscle thickness) of the arm, the knee extensors and plantar flexors. The results of this chapter show that patients with CKD in HD tratment when compared to healthy subjects present: 1) lower level of physical activity; 2) increased time spent sitting during the week and the weekend; 3) no difference in the handgrip; 4) lower capacity of maximum force of the knee extensor and plantar flexors; 5) less muscle thickness of the flexors and extensors elbow, the knee extensors and plantar flexors and dorsal flexors; 6) lower quality muscle of the upper limbs, knee extensor and plantar flexors; Chapter II: In this chapter, the neuromechanics and functional profile was observed from the variables: 1) rate development force production of knee extensors and plantar flexors; 2) reaction time of the knee extensors and the medial gastrocnemius; 3) muscular electrical activity of the knee extensors and the medial gastrocnemius; 4) neuromuscular efficiency of knee extensors and the medial gastrocnemius; 5) muscle architecture of vastus lateralis, medial gastrocnemius, soleus and tibialis. The Chapter II results demonstrate that patients with CKD in HD tratment when compared to healthy subjects present: 1) less rate development force production and neuromuscular efficiency of the knee extensor and plantar flexors; 2) more reaction time of the knee extensor and plantar flexors; 3) no difference in the magnitude of the extensor muscles of the knee and the medial gastrocnemius activation of during CVMI; 4) lower relative fascicles lengths (fascicle length / tibia length) of the medial gastrocnemius and the soleus; 5) shorter length of absolute fascicle for the soleus; 6) less muscle thickness of the vastus lateralis, soleus and tibialis; 7) no difference in penation angle of the lower limbs muscle; 8) relative medial gastrocnemius fascicle length can influence of the 6MWT in performance patients with CKD. These results may help doctors, physical therapists and physical education teachers in the prescription of training focused on each of the properties (morphological and neuromechanics), since our study appears to be among the first to evaluate systematically and associated form that morphologic and neuromuscular plasticity in CKD.

Tendon transfer surgery is used to improve the hand function of patients with nerve injuries, spinal cord lesions, cerebral palsy (CP), stroke, or muscle injuries. The tendon of a muscle, usually with function opposite that of the lost muscle function, is transferred to the tendon of the deficient muscle. The aim is to balance the wrist and fingers to achieve better hand function. The position, function, and length at which the donor muscle is sutured is essential for the outcome for the procedure. In these studies the significance of the transferred muscle’s morphology, length and apillarization was investigated using both animal and human models. Immunohistochemical, biochemical, and laser diffraction techniques were used to examine muscle structure. In animal studies (rabbit), the effects of immobilization and of tendon transfers at different muscle lengths were analyzed. Immobilization of highly stretched muscles resulted in fibrosis and aberrant regeneration. A greater pull on the tendon while suturing a tendon transfer resulted in larger sarcomere lengths as measured in vivo. On examination of the number of sarcomeres per muscle fiber and the sarcomere lengths after 3 weeks of immobilization and healing time, we found a cut-off point up to which the sarcomerogenesis was optimal. Transfer at too long sarcomere lengths inhibited adaptation of the muscle to its new length, probably resulting in diminished function. In human studies we defined the sarcomere lengths of a normal human flexor carpi ulnaris muscle through the range of motion, and then again after a routinely performed tendon transfer to the finger extensor. A calculated model illustrated that after a transfer the largest force was predicted to occur with the wrist in extension. Morphological studies of spastic biceps brachii muscle showed, compared with control muscle, smaller fiber areas and higher variability in fiber size. Similar changes were also found in the more spastic wrist flexors comparing with wrist extensors in children with CP. In flexors, more type 2B fibers were found. These observations could all be due to the decreased use in the spastic limb, but might also represent a specific effect of the spasticity. In children and adults with spasticity very small fibers containing developmental myosin were present in all specimens, while none were found in controls. These fibers probably represent newly formed fibers originating from activated satellite cells. Impaired supraspinal control of active motion as well as of spinal reflexes, both typical of upper motor syndrome, could result in minor eccentric injuries of the muscle, causing activation of satellite cells. Spastic biceps muscles had fewer capillaries per cross-sectional area compared to age-matched controls, and also a smaller number of capillaries around each fiber. Nevertheless, the number of capillaries related to the specific fiber area was normal, and hence the spastic fibers are sufficiently supplied with capillaries. This study shows that the length of the muscle during tendon transfer is crucial for optimization of force output. Laser diffraction can be used for accurate measurement of sarcomere length during tendon transfer surgery. Wrist flexor muscles have more morphological alterations typical of spasticity compared to extensors.

No description available.