During muscle contraction, electrical signals are generated by the muscle cells. The analysis of those signals is called electromyography (EMG). The EMG signal is mainly determined by physiological factors including so called central factors (central nervous system origin) and peripheral factors (muscle tissue origin). In addition, during the acquisition of EMG signals, technical factors are introduced (measurement equipment origin). The aim of this dissertation was to develop and evaluate methods to estimate physiological properties of the muscles using multichannel surface EMG (MCsEMG) signals. In order to obtain accurate physiological estimates, a method for automatic signal quality estimation was developed. The method’s performance was evaluated using visually classified signals, and the results demonstrated high classification accuracy. A method for estimation of the muscle fibre conduction velocity (MFCV) and the muscle fibre orientation (MFO) was developed. The method was evaluated with synthetic signals and demonstrated high estimation precision at low contraction levels. In order to discriminate between the estimates of MFCV and MFO belonging to single or populations of motor units (MUs), density regions of so called spatial distributions were examined. This method was applied in a study of the trapezius muscle and demonstrated spatial separation of MFCV (as well as MFO) even at high contraction levels. In addition, a method for quantification of MU synchronisation was developed. The performance on synthetic sEMG signals showed high sensitivity on MU synchronisation and robustness to changes in MFCV. The method was applied in a study of the biceps brachii muscle and the relation to force tremor during fatigue. The results showed that MU synchronisation accounted for about 40 % of the force tremor. In conclusion, new sEMG methods were developed to study muscle function and motor control in terms of muscle architecture, muscle fibre characteristics, and processes within the central nervous system.

Contexte : Le cancer de l'endomètre est le plus fréquent des cancers gynécologiques. Il a été suggéré que les traitements oncologiques entraînent des dysfonctions des muscles du plancher pelvien. Ces dysfonctions pourraient contribuer au développement de conditions débilitantes comme la douleur lors des relations sexuelles (dyspareunie) qui atteint plus de la moitié des survivantes. Or, à l'heure actuelle, aucune étude n'a investigué la fonction des muscles du plancher pelvien en lien avec la dyspareunie chez des survivantes d'un cancer de l'endomètre. Objectifs : L'objectif principal vise à explorer les différences quant à la fonction des muscles du plancher pelvien entre des survivantes d'un cancer de l'endomètre atteintes de dyspareunie et des femmes sans douleur ayant subi l'hystérectomie totale pour des raisons bénignes. L'objectif secondaire est d'explorer les différences entre les deux groupes quant aux variables urogynécologiques, sexuelles, psychologiques et sociales. Méthodologie : Dans cette étude comparative exploratoire bicentrique, des survivantes d'un cancer de l'endomètre atteintes de dyspareunie (n=7) et des femmes asymptomatiques (n=7) ont assisté à une séance d'évaluation menée par une physiothérapeute. Les deux groupes ont été équilibrés selon l'âge, l'indice de masse corporelle et le nombre d'accouchements par voie vaginale. La fonction des muscles du plancher pelvien, y compris le tonus, la force maximale, la vitesse de contraction, la coordination et l'endurance, a été évaluée à l'aide du spéculum dynamométrique. Des questionnaires validés ont permis d'évaluer les variables secondaires. Des tests de Mann-Whitney ont été employés pour comparer les deux groupes quant à la fonction des muscles du plancher pelvien et les variables urogynécologiques, sexuelles, psychologiques et sociales (!=0,050). Résultats : Concernant la fonction des muscles du plancher pelvien, les survivantes atteintes de dyspareunie ont démontré un tonus à une ouverture vaginale minimale supérieur (p=0,018) et une endurance inférieure (p=0,048) aux femmes asymptomatiques. Les survivantes ont également présenté plus d'incontinence fécale (p=0,005) et une fonction sexuelle inférieure (p=0,004) comparativement aux femmes asymptomatiques. Aucune différence n'a été détectée pour les variables psychologiques et sociales. Conclusion : Les résultats de cette étude exploratoire suggèrent des dysfonctions des muscles du plancher pelvien, notamment un tonus supérieur et une endurance inférieure, chez les survivantes d'un cancer de l'endomètre atteintes de dyspareunie. D'autres études sont nécessaires afin de confirmer ces résultats. Ces constats préliminaires pourraient servir d'assises pour mieux comprendre les dysfonctions des muscles du plancher pelvien impliquées dans la dyspareunie chez cette population. / Abstract : Context: Endometrial cancer is the most common cancer in gynecological cancers. Oncological treatments are suggested to cause pelvic floor muscle dysfunction that could contribute to the development of debilitating conditions such as pain during sexual intercourse (dyspareunia), which affects more than half of survivors. However, to date, no study investigated pelvic floor muscle function in relation to dyspareunia in endometrial cancer survivors. Objectives: The main objective is to explore differences in pelvic floor muscle function between endometrial cancer survivors with dyspareunia and women without pain who underwent a total hysterectomy for benign conditions. The secondary objective is to explore differences between the two groups on urogynecological, sexual, psychological and social variables. Methodology: In this exploratory, bicentric comparative study, endometrial cancer survivors with dyspareunia (n=7) and asymptomatic women (n=7) attended one evaluation session conducted by a physiotherapist. The two groups were balanced in terms of age, body mass index and number of vaginal deliveries. The pelvic floor muscle function, including tone, maximal strength, contraction speed, coordination and endurance, was assessed with the dynamometric speculum. Validated questionnaires were used to evaluate secondary variables. Mann-Whitney tests were used to compare the two groups on muscular, urogynecological, sexual, psychological and social variables (!=0.050). Results: Concerning pelvic floor muscle function, survivors with dyspareunia demonstrated higher tone at a minimal vaginal aperture (p=0.018) and lower endurance (p=0.048) compared to asymptomatic women. Survivors also presented more fecal incontinence (p=0.005) and lower sexual function (p=0.004) compared to asymptomatic women. No differences were detected for psychological and social variables. Conclusion: The results of this exploratory study suggest impaired pelvic floor muscle function, notably higher tone and lower endurance, in endometrial cancer survivors with dyspareunia. Further studies are needed to confirm these findings. This preliminary evidence can be used as empirical data to better understand pelvic floor muscle impairments implicated in dyspareunia in this population.

The effect of serum 25-hydroxycholekalciferol levels on musculoskeletal system in children with inflammatory bowel disease Background: Low bone mineral density and osteoporosis represent severe secondary complications that can be a result of childhood chronic disease. According to Frost's mechanostat theory impaired muscle functions may contribute to the changes observed on the skeleton. Aims: The aim of this study was to: 1) evaluate parameters of bone mineral density, bone geometry and dynamic muscle functions in children and adolescent with chronic disease - inflammatory bowel disease (IBD) and type 1 diabetes (T1D); 2) evaluate a possible effect of vitamin D deficiency and vitamin D supplementation or duration of the disease on the musculoskeletal unit; 3) determine clinical or laboratory predictors of muscle and bone parameters. Methods: The study was divided into two substudies according to the diagnosis. Seventy patients with IBD (median age 13.8 years) were included in one study, fifty-five of which completed all of the planned procedures. During the study, IBD patients were supplemented with 2000 IU/d of vitamin D. In the second study 95 patients with T1D were included (median age 16.4 years). BMD and bone geometry of non-dominant tibia was evaluated using peripheral quantitative computed...

Sarcopenia is a disease of muscle wasting primarily seen in older adults. Although this term was first coined over three decades ago, there is a lack of consensus on a definition, screening criteria, and treatment protocol for sarcopenia. The primary purpose of this study is to determine whether registered dietitian nutritionists (RDNs) in the United States (U.S.) screen for sarcopenia. Study participants were recruited through a randomized email list and included RDNs throughout the U.S. Respondents completed a survey questioning knowledge of sarcopenia, screening tools and company protocols in place, and the need and desire for sarcopenia education. Data revealed a lack of pre-existing protocols in place, a dissonance of validated and unvalidated screening tools used in practice, and substantial need for sarcopenia education.

Doxorubicin (DOX) is an effective chemotherapeutic treatment with lasting deleterious side effects in heart and skeletal muscle. As an increased percentage of patients live many years past their cancer treatments, addressing the long-term side effects of chemotherapy treatment becomes critical. In an attempt to prevent heart and skeletal muscle damage caused by DOX, two co-treatments, exercise (EX) or metformin (MET) were studied for their effectiveness in maintaining muscle function, mitochondrial respiration and iron regulation. DOX is known to bind with iron, contributing to oxidative damage resulting in cardiac and skeletal muscle toxicity. However, the degree to which the toxic side effects are due to iron dysregulation is poorly understood. To address this gap in understanding, the changes in proteins involved with iron regulation following DOX treatment with or without EX or MET was examined in liver, heart, and skeletal muscle. To study the effects of EX or MET on DOX muscle toxicity and the effect of DOX on iron regulation, C2C12 myotube cell culture and a mouse model were used. Results from this research suggest that the some of the toxic effects of DOX treatment can be reduced with EX or MET treatments. EX is effective at preventing an impairment in muscle relaxation, promoting positive iron regulation changes in the liver and blunting DOX-induced changes in iron regulation in muscle. MET partially prevents loss of mitochondrial respiration and promotes positive changes in iron regulation in the liver. Additionally, study of DOX on iron regulation in liver, heart, and skeletal muscle suggests that DOX promotes iron dysregulation. However, the cellular response is protective against excessive iron dysregulation and increased oxidative stress. This cellular response is at least partially dependent on NF-κB activation.

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive, progressive muscle-wasting disease characterized by mutations in the dystrophin gene. Duchenne muscular dystrophy is the most common and most severe form of inherited muscle diseases, with an incidence of 1 in 3,500 male births1,2. Mutations in the dystrophin gene result in non-functional dystrophin or the complete absence of the protein dystrophin, resulting in necrosis and fibrosis in the muscle, loss of ambulation, cardiomyopathies, inadequate or failure of respiratory function, and decreased lifespan. Although there has been little research for effective nutritional strategies, dietary intervention may be effective as an adjuvant treatment. In this study, wild type (WT) and mdx animals were provided either a control or elevated branched chain amino acid (BCAA) diet nocturnally for 25 weeks to determine if the elevated BCAAs would attenuate muscle torque loss. Twenty-five weeks of chronic, elevated BCAA supplementation had no impact on muscle function measures. Interestingly, mdx and WT animals had the same torque responses in the low stimulation frequencies (1 Hz – 30 Hz) compared to higher stimulation frequencies. Tetanus was reached at a much lower stimulation frequency in mdx animals compared to WT animals (100 Hz vs +150 Hz). The mdx mouse consistently had more cage activity in the light cycle X- and Y-planes. Interestingly, animals on the BCAA diet increased X-, Y-, and Z-plane activity in the dark cycles at four weeks while animals on the control diet more Z-plane activity at 25 weeks, although not significant. All three BCAAs were elevated in the plasma at 25 weeks, although only Leu was significantly elevated. The BCAAs had no effect on. The diaphragm and skeletal muscle masses were larger in mdx animals, and WT animals had a significantly larger epididymal fat pad. The active state of BCKDC determined by phosphorylation of the E1α enzyme was greater in WT animals in white skeletal muscle, but not red skeletal muscle. Protein synthesis effectors of the mTORC1 signaling pathway and autophagy markers were similar among groups. Wild type animals had increased mTORC1 effectors and animals on the BCAA diet had decreased autophagy markers, although not significant. Although BCAAs did not affect muscle function, fibrosis, or protein synthesis effectors, this study illustrates the functionality of mdx muscles over time. It would be interesting to see how the different muscle fiber types are affected by DMD, noting the differences between the diaphragm, heart, red muscle, and white muscle fibrosis markers. Although there was no increase in mTORC1 effectors with an elevated BCAA diet, it would be interesting to determine muscle protein synthesis, myofibrillar protein synthesis, and total protein turnover in the mdx mouse with an elevated BCAA diet, although the dietary intervention started when mice arrived at 4 weeks of age, earlier intervention may be beneficial early in the disease process. / Doctor of Philosophy / Duchenne Muscular Dystrophy (DMD) is an X-linked recessive, progressive muscle-wasting disease characterized by mutations in the dystrophin gene. Duchenne muscular dystrophy is the most common and most severe form of inherited muscle diseases, with an incidence of 1 in 3,500 male births1,2. Mutations in the dystrophin gene result in non-functional dystrophin or the complete absence of the protein dystrophin, resulting in necrosis and fibrosis in the muscle, loss of movement and walking ability, cardiomyopathies, inadequate or failure of respiratory function, and decreased lifespan. Although there has been little research for effective nutritional strategies, dietary intervention may be effective as an adjuvant treatment and palliative care. The branched chain amino acids (BCAAs) are known to directly stimulate muscle protein synthesis by direct activation of the mechanistic target of rapamycin complex 1 (mTORC1). This study aimed to illustrate the differences between diseased and healthy mice and determine if BCAAs can reduce muscle torque loss. Twenty-five weeks of chronic, elevated BCAA supplementation had no impact on muscle function measures. Interestingly, mdx and WT animals had the same torque responses in the low stimulation frequencies (1 Hz – 30 Hz) compared to higher stimulation frequencies. Tetanus was reached at a much lower stimulation frequency in mdx animals compared to WT animals (100 Hz vs +150 Hz). The mdx mouse consistently had more cage activity in the light cycle X- and Y-planes. Interestingly, animals on the BCAA diet increased X-, Y-, and Z-plane activity in the dark cycles at four weeks while animals on the control diet more Z-plane activity at 25 weeks, although not significant. All three BCAAs were elevated in the plasma at 25 weeks, although only Leu was significantly elevated. The BCAAs had no effect on. The diaphragm and skeletal muscle masses were larger in mdx animals, and WT animals had a significantly larger epididymal fat pad. The active state of BCKDC determined by phosphorylation of the E1α enzyme was greater in WT animals in white skeletal muscle, but not red skeletal muscle. Protein synthesis effectors of the mTORC1 signaling pathway and autophagy markers were similar among groups. Wild type animals had increased mTORC1 effectors and animals on the BCAA diet had decreased autophagy markers, although not significant. Although BCAAs did not affect muscle function, fibrosis, or protein synthesis effectors, this study illustrates the functionality of mdx muscles over time. It would be interesting to see how the different muscle fiber types are affected by DMD, noting the differences between the diaphragm, heart, red muscle, and white muscle fibrosis markers. Although there was no increase in mTORC1 effectors with an elevated BCAA diet, it would be interesting to determine muscle protein synthesis, myofibrillar protein synthesis, and total protein turnover in the mdx mouse with an elevated BCAA diet, although the dietary intervention started when mice arrived at 4 weeks of age, earlier intervention may be beneficial early in the disease process.

Cardiovascular disease secondary to atherosclerosis is the most common cause of human morbidity and mortality. An early and fundamental event in the development of atherosclerosis is abnormal vascular endothelial and smooth muscle function. This can be measured by flow mediated dilatation and glyceryl trinitrate mediated dilatation in children at risk of atherosclerosis. Folic acid improves endothelial function (flow mediated dilatation) in adults with coronary artery disease. No studies have previously investigated the effects of folic acid on vascular function in at risk children with diabetes or obesity. In a cross sectional study an evaluation of vascular endothelial and smooth muscle function and their determinants was performed in 159 children with type 1 diabetes, 58 children with obesity, and 53 healthy children. Children with type 1 diabetes and children with mild to moderate obesity had comparable and severe vascular dysfunction but different determinants. Vascular function in healthy and obese children related to both body mass index and weight (adjusted for age and sex), and blood glucose. Children with obesity had lower folate levels and higher homocysteine levels than children with type 1 diabetes, an abnormal lipid profile and raised inflammatory markers. A randomised double blind placebo controlled cross over trial of 8 weeks of folic acid supplementation was performed in 38 children with type 1 diabetes. In these children, folic acid improved endothelial function with a sustained increase in folate levels but independent of homocysteine levels. Folic acid did not improve smooth muscle function. A randomised double blind placebo controlled parallel trial of 8 weeks folic acid supplementation was performed including 53 obese children. Folic acid did not improve vascular function in obese children in spite of sustained increase in folate levels, and a decrease in homocysteine levels. It was concluded that children with type 1 diabetes and obesity have comparable and severe endothelial and smooth muscle function. Determinants of vascular function in children, including weight and glucose, represent a continuum effect. Folic acid supplementation improved endothelial function in children with type 1 diabetes but not in children with obesity, whose metabolic changes causing endothelial dysfunction differ from children with diabetes. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1317003 / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2008

The prevalence of low back pain (LBP) is higher in pregnant women compared to women of the same age in a general population. Pregnancy-related LBP persists 6 years after pregnancy in 16% of women. Consequently, pregnancy represents a specific risk for LBP and persistent LBP. Pregnancy-related LBP is usually studied as a single entity, however, only one subgroup of LBP, i.e. pelvic girdle pain (PGP), seems to be associated with pregnancy. Accordingly, possible differences in subgroups of patients with LBP are unknown. The aims of this thesis were the following: 1) to describe the prevalence of clinically classified subgroups of women with LBP in a cohort (no LBP, lumbar pain, PGP, and combined pain (PGP and lumbar pain)) during pregnancy and postpartum, and 2) to determine if there was a disparity in the course, health-related quality of life (HRQL), pain intensity, disability, depressive symptoms, or muscle function in subgroups of the cohort, and 3) to identify predictors for having persistent pregnancy-related PGP postpartum. Consecutively-enrolled pregnant women were classified into LBP subgroups by mechanical assessment of the lumbar spine, pelvic pain provocation tests, standard history, and pain drawings. All women answered questionnaires (background data, EQ-5D). Women with LBP completed the Oswestry Disability Index and pain measures. The Edinburgh Postnatal Depression Scale was used to evaluate depressive symptoms at 3 months postpartum (cut-off ≥10). Trunk muscle endurance, hip muscle strength, and gait speed were investigated. Multiple logistic regression was used to identify predictors from self-reports and clinical examination. At the 12-18 gestational week evaluation, 118/308 (38%) women had no LBP, 33 (11%) had lumbar pain, 101 (33%) had PGP, and 56 (18%) had combined pain. Three months postpartum, 183/272 (67%) women had no LBP, 29 (11%) had lumbar pain, 46 (17%) had PGP, and 14 (5%) had combined pain. Pregnant women with combined pain were most affected in terms of HRQL, pain intensity, and disability. Depressive symptoms were three times more prevalent in women with LBP (27/87, 31%) than in women without LBP (17/180, 9%). Women with PGP and/or combined pain had lower values for trunk muscle endurance, hip extensor strength and gait speed compared to women without LBP. Postpartum, 16-20% of the women had persistent combined pain or PGP, whereas 1/29 had lumbar pain. Predictors for persistent PGP or combined pain were work dissatisfaction, older age, combined pain in early pregnancy, and low endurance of the back flexors. In conclusion, women with combined pain were identified to be a target group since they had the lowest recovery rate and since the classification of combined pain was found to be a predictor for persistent PGP or combined pain postpartum. The hypothesis of an association between muscle dysfunction and PGP was strengthened. Based on the finding of high comorbidity of postpartum depressive symptoms and LBP, it seems important to screen for and consider treatment strategies for both symptoms.

Cardiovascular disease secondary to atherosclerosis is the most common cause of human morbidity and mortality. An early and fundamental event in the development of atherosclerosis is abnormal vascular endothelial and smooth muscle function. This can be measured by flow mediated dilatation and glyceryl trinitrate mediated dilatation in children at risk of atherosclerosis. Folic acid improves endothelial function (flow mediated dilatation) in adults with coronary artery disease. No studies have previously investigated the effects of folic acid on vascular function in at risk children with diabetes or obesity. In a cross sectional study an evaluation of vascular endothelial and smooth muscle function and their determinants was performed in 159 children with type 1 diabetes, 58 children with obesity, and 53 healthy children. Children with type 1 diabetes and children with mild to moderate obesity had comparable and severe vascular dysfunction but different determinants. Vascular function in healthy and obese children related to both body mass index and weight (adjusted for age and sex), and blood glucose. Children with obesity had lower folate levels and higher homocysteine levels than children with type 1 diabetes, an abnormal lipid profile and raised inflammatory markers. A randomised double blind placebo controlled cross over trial of 8 weeks of folic acid supplementation was performed in 38 children with type 1 diabetes. In these children, folic acid improved endothelial function with a sustained increase in folate levels but independent of homocysteine levels. Folic acid did not improve smooth muscle function. A randomised double blind placebo controlled parallel trial of 8 weeks folic acid supplementation was performed including 53 obese children. Folic acid did not improve vascular function in obese children in spite of sustained increase in folate levels, and a decrease in homocysteine levels. It was concluded that children with type 1 diabetes and obesity have comparable and severe endothelial and smooth muscle function. Determinants of vascular function in children, including weight and glucose, represent a continuum effect. Folic acid supplementation improved endothelial function in children with type 1 diabetes but not in children with obesity, whose metabolic changes causing endothelial dysfunction differ from children with diabetes. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1317003 / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2008

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