Made available in DSpace on 2016-03-22T17:27:40Z (GMT). No. of bitstreams: 1 michele.pdf: 618985 bytes, checksum: 5aea5d3d30e1efe7646a8613ea316b46 (MD5) Previous issue date: 2006-12-19 / Background & objectives: To determine reference values for healthy adults subjects and to study the influence of determinants factors for handgrip strength. Methods: Three hundred subjects were studied, aged 18 to 90 years old. The handgrip strength (HS) was assessed by a hand dynamometer, as well as the adductor pollicis muscle (APM) thickness and other anthropometric variables. The results were analyzed by age group and gender. A multiple linear regression was performed to identify the significant determinant variables of handgrip strength. Results HS depends on gender significantly and decreases after 60 years old (p<0.001). Different reference values are presented to be used for each gender and age categories, for dominant and non-dominant hand. APM had a high correlation with HS (R2=0.71 e 0.70 for DHS and NDHS, respectively. After the adjustment for other variables as sex, age and body mass index, APM was still significantly associated to HS. Conclusion Reference values are necessary for using HS as a muscular function assessment tool and it should be stratified for gender and age group. The combined use of HS and APM may be useful as a nutritional assessment method / Justificativa e propósito - Determinar valores de referência para indivíduos adultos e saudáveis e estudar a influência de fatores determinantes para a força do aperto de mão (FAM). Métodos Foram estudados 300 voluntários, com idades de 18 a 90 anos, sendo avaliados a FAM com um dinamômetro de mão, a espessura do músculo adutor do polegar (MAP) e outras variáveis antropométricas. Os resultados foram analisados após estratificação por faixa etária e gênero. Foi realizada regressão linear múltipla para identificação das variáveis significativamente determinantes da FAM. Resultados A FAM depende significativamente do gênero e decresce após os 60 anos (p<0,001). Os diferentes valores de referência são apresentados para uso para cada gênero e categoria etária. O MAP teve alta correlação com a FAM (R2 = 0,71 e 0,70 para FAMD e FAMND, respectivamente). Após o ajuste para outras variáveis como gênero, idade e IMC, o MAP ainda é significativamente associado a FAM. Conclusão Os valores de referência são necessários para o uso da FAM na avaliação da função muscular e devem ser estratificados por gênero e idade. O uso associado da FAM e MAP pode ser útil como método de avaliação nutricional

The aim of my thesis was to collect, compare and evaluate body size, body composition, vital lung capacity, dynamometry and a level of motor performance of men aged from 18 to 25 years of two target groups - men who are professional swimmers or floorball players, and males of a common population. Using standard somatometric methods, a group of 39 swimmers, a group of 39 floorball players, and a group of 39 non-sportsmen of a common population were examined. The examined body parametres were body length, body weight, bustline, arm line, contracted-arm line, forearm line, thigh line, calf line; width of epiphysis of humerus and femur, wrist, ankle, biacromial and bicristal breadth, breadth of the transverse and sagittal section of chest; skin folds. The ascertained data were compared with the results of previous researches. The thesis also includes the results of motor tests, dynamometry and vital lung capacity.

Background: Knee osteoarthritis is a degenerative disease characterized by damaged joint tissues (e.g., cartilage) that leads to joint pain, and reduced mobility and quality of life. Various factors are involved in disease progression, including biomechanical, patient-reported outcome and mobility measures. This thesis provides important longitudinal data on the role of these factors in disease progression, and the trajectory of biomechanical factors in persons with knee osteoarthritis. Objectives: (1) Determine the extent to which changes over 2.5 years in knee cartilage thickness and volume in persons with knee osteoarthritis were predicted by the knee adduction and flexion moment peaks, and knee adduction moment impulse and loading frequency. (2) Determine the extent to which changes over 2 years in walking and stair-climbing mobility in women with knee osteoarthritis were predicted by quadriceps strength and power, pain and self-efficacy. (3) Estimate the relative and absolute test-retest reliabilities of biomechanical risk factors for knee osteoarthritis progression. Methods: Data were collected at 3-month intervals during a longitudinal (3-year), observational study of persons with clinical knee osteoarthritis (n=64). Magnetic resonance imaging of the study knee was acquired at the first and last assessments, and used to determine cartilage thickness and volume. Accelerometry and dynamometry data were acquired every 3 months, and used to determine knee loading frequency and knee muscle strength and power, respectively. Walking and stair-climbing mobility, as well as pain and self-efficacy data, were also collected every 3 months. Gait analyses were performed every 6 months, and used to calculate lower-extremity kinematics and kinetics. Results: (1) The knee adduction moment peak and impulse each interacted with body mass index to predict loss of medial tibial cartilage volume over 2.5 years. These interactions suggested that larger joint loads in those with a higher body mass index were associated with greater loss of cartilage volume. (2) In women, lower baseline self-efficacy predicted decreased walking and stair ascent performances over 2 years. Higher baseline pain intensity/frequency also predicted decreased walking performance. Quadriceps strength and power each interacted with self-efficacy to predict worsening stair ascent times. These interactions suggested that the impact of lesser quadriceps strength and power on worsening stair ascent performance was more important among women with lower self-efficacy. (3) Relative reliabilities were high for the knee adduction moment peak and impulse, quadriceps strength and power, and body mass index (i.e., intraclass correlation coefficients >0.80). Absolute reliabilities were high for quadriceps strength and body mass index (standard errors of measurement <15% of the mean). Data supported the use of interventions effective in reducing the knee adduction moment and body mass index, and increasing quadriceps strength, in persons with knee osteoarthritis. Conclusion: Findings from this thesis suggest that biomechanical factors play a modest independent role in the progression of knee osteoarthritis. However, in the presence of other circumstances (e.g., obesity, low self-efficacy, high pain intensity/frequency), biomechanical factors can vastly worsen the disease. Strategies aiming to curb structural progression and improve clinical outcomes in knee osteoarthritis should target biomechanical and clinical outcomes simultaneously. / Thesis / Doctor of Philosophy (PhD) / Knee osteoarthritis is a multifactorial disease whose progression involves worsening joint structure, symptoms, and mobility. Various factors are linked to the progression of this disease, including biomechanical, patient-reported outcome and mobility measures. This thesis provides important information on how these factors, separately and collectively, are involved in worsening disease over time, as well as benchmarks that are useful to clinicians and researchers in interpreting results from interventional or longitudinal research. First, we examined how different elements of knee loading were associated with changes in knee cartilage quantity over time in persons with knee osteoarthritis. Second, we examined how different elements of knee muscle capacity and patient-reported outcomes were related to changes in mobility over time in persons with knee osteoarthritis. Third, we examined the stability over time of various biomechanical risk factors for the progression of knee osteoarthritis. Novel results from this thesis showed that: (1) larger knee loads predicted cartilage loss over 2.5 years in obese individuals with knee osteoarthritis but not in persons of normal weight or overweight; (2) among women with knee osteoarthritis with lower self-efficacy (or confidence), lesser knee muscle capacity (strength, power) was an important predictor of declining stair-climbing performance over 2 years; and (3) clinical interventions that can positively alter knee biomechanics include weight loss, knee muscle strengthening, as well as specific knee surgery and alterations during walking to reduce knee loads. Interventions for knee osteoarthritis should target biomechanical and clinical outcomes simultaneously.

Gleichgewichtsstörungen und Stürze gehören zu den wichtigsten Symptomen der Parkinson Krankheit (PD). Bei jungen PD-Patienten werden diese Probleme durch Nebenwirkungen der Medikation zusätzlich verstärkt. Aufgrund des noch sehr limitierten Verständnisses der zugrunde liegenden Mechanismen, die zum erhöhten Sturzrisiko bei jungen PD-Patienten beitragen, mangelt es derzeit an alternativen und effektiven bewegungsbasierten Therapien, um diese Sturzgefahr zu verringern. Diese Arbeit zielt darauf ab, solche Mechanismen zu identifizieren und eine effektive Methode zur Früherkennung des Sturzrisikos bei jungen PD-Patienten zu entwickeln. Es wurde der Beitrag der zentralen und peripheren neuromuskulären sowie sensomotorischen Fähigkeiten, dynamischen Stabilitätskontrolle und Anpassungsfähigkeit der Fortbewegung auf die Sturzrate junger PD-Patienten mittels eines Vergleichs zwischen gesunden Probanden und jungen PD-Patienten mit und ohne Sturzerfahrung (Fallers vs. Non-Fallers) untersucht. Der Vergleich zeigte, dass die PD-Fallers zentral begründete Defizite in der Muskelkraft ihrer Beinstrecker aufwiesen sowie eine verringerte Abfangleistung nach simulierten Vorwärtsstürzen. Die Parameter „Muskelkraft“ und „Annäherung an die vordere Stabilitätsgrenze“ identifizieren gemeinsam 90% der Fälle junger PD-Faller. PD-Patienten zeigten auch eine uneingeschränkte prädiktive Anpassungsfähigkeit auf Gangstörungen, aber ein weniger stabiles Gangmuster und weniger effektive reaktive Antworten auf wiederholte Gangstörungen im Vergleich zu Kontrollpersonen. Diese Arbeit stellt relevante Informationen dar, die für die Entwicklung von alternativen nicht-medikamentösen Therapien zur Reduzierung des Sturzrisikos bei jungen PD-Patienten nützlich sind. Darüber hinaus wurde eine akkurate Methode zur Früherkennung von jungen PD-Patienten mit einem erhöhen Sturzrisiko erarbeitet. Diese Patienten könnten von Training der Beinstrecker und der dynamischen Stabilität profitieren. / Postural instability and falls are some of the main symptoms associated with the Parkinson`s disease (PD). In early-onset patients (diagnosed before the age of 51) these problems are worsened by medication-related side-effects. There is a lack of effective exercise-based training interventions to reduce the risk of falling due to our limited understanding of the underlying mechanisms contributing to falls in early-onset PD. The present thesis aims to identify those mechanisms responsible for falls and to develop a sensitive method of assessment for the early discrimination of patients at risk of falling in early-onset PD. We investigated the contribution of central and peripheral neuromuscular and sensory-motor capacities, dynamic stability control and locomotor adaptability to the increased risk of falling in young PD patients by means of comparing healthy controls and early-onset PD fallers and non-fallers. The comparison revealed that PD fallers have central originated deficits in leg extensors` muscle strength - evidenced by increased antagonistic moments and activation deficit of the agonists - and a reduced increase of the base of support in response to simulated forward falls, both resulting in decreased recovery performance. The factors “muscle strength” and “approach to the anterior limit of stability” together could correctly classify 90% of the PD fallers. In addition, while young PD patients showed unaltered predictive adaptability to gait perturbations, they exhibited less stable gait patterns and less effective reactive responses to repeated gait perturbations compared to controls. This thesis provides relevant information for the development of alternative non-medication based therapies aiming to reduce falls in early-onset PD and an accurate assessment tool for the early identification of young patients at a high risk of falling. These patients may benefit from leg-extensors'' strengthening and dynamic stability training.