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1.
ARP Rheumatol ; 2(2): 111-119, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37421190

RESUMO

INTRODUCTION: Despite years of experience with biological disease modifying anti-rheumatic drugs (bDMARD) in rheumatoid arthritis (RA), little is known about differences in infectious risk among bDMARDs. The aim of this study was to assess the incidence and type of infections in RA patients on bDMARDs and to determine possible predictors. METHODS: A retrospective multicenter cohort study that included patients registered in the Rheumatic Diseases Portuguese Registry (Reuma.pt) with RA, and exposed to at least one bDMARD until April 2021. RA patients under bDMARD and with at least one episode of severe infection (SI), defined as infection that requires hospitalization, use of parenteral antibiotics or that resulted in death, were compared to patients with no report of SI. Demographic and clinical data at baseline and at the time of each SI were collected to establish comparisons between different groups of bDMARDs. Comparisons between different bDMARDs were assessed and logistic regression was performed to identify predictors of SI. RESULTS: We included 3394 patients, 2833 (83.5%) female, with a mean age at RA diagnosis of 45.5±13.7 years. SI was diagnosed in 142 of the 3394 patients evaluated (4.2%), totaling 151 episodes of SI. At baseline, patients with SI had a significantly higher proportion of prior orthopedic surgery, asthma, interstitial lung disease, chronic kidney disease and corticosteroid use, higher mean age and longer median disease duration at first bDMARD. Nine patients died (6.0%). Ninety-two SI (60.9%) occurred with the first bDMARD, the majority leading to discontinuation of the bDMARD within 6 months (n=75, 49.7%), while 65 (43.0%) restarted the same bDMARD and 11 (7.3%) switched to another bDMARD (6 of them to a different mechanism of action). In the multivariate analysis, we found that chronic kidney disease, asthma, infliximab, corticosteroid use, interstitial lung disease, previous orthopedic surgery, higher Health Assessment Questionnaire and DAS284V-ESR are independent predictors of SI. CONCLUSION: This study described the incidence and types of SI among Portuguese RA patients on biologics, identifying several predictors of SI, both globally and with different bDMARDs. Physicians should be aware of the real-word infectious risk in RA patients on bDMARDs when making treatment decisions.


Assuntos
Antirreumáticos , Artrite Reumatoide , Asma , Produtos Biológicos , Humanos , Feminino , Adulto , Pessoa de Meia-Idade , Masculino , Estudos de Coortes , Portugal/epidemiologia , Artrite Reumatoide/tratamento farmacológico , Antirreumáticos/efeitos adversos , Produtos Biológicos/efeitos adversos , Asma/induzido quimicamente , Corticosteroides/uso terapêutico
2.
Disabil Rehabil ; : 1-8, 2023 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-37403374

RESUMO

PURPOSE: To evaluate the balance in patients with total knee arthroplasty (TKA) and knee osteoarthrosis (KOA), measured by postural stability computerized evaluation (PSCE), and to evaluate the effect of post-TKA patients' characteristics in their performance on PSCE. MATERIALS AND METHODS: An observational cross-sectional study was conducted in two sets of patients: (A) patients with KOA and primary TKA surgery scheduled and (B) patients who underwent primary TKA >9 months. Sociodemographic, radiographic, clinical and PSCE parameters (using the Biodex Balance System) were assessed. RESULTS: Post-TKA patients placed more load on the replaced knee than the contralateral osteoarthritic knee (p = 0.027). They had less imbalance on the balance tests performed with the eyes open, on stable (p = 0.032), and unstable platforms (p = 0.022). These patients also showed better postural stability in monopodalic stance, both standing on the TKA (p = 0.010) and contralateral knee (p = 0.017). Age, weight, pain on the operated knee, extension deficit on the operated knee, and Berg Balance Scale scores on post-TKA patients were significantly associated with their performance on PSCE tests. CONCLUSIONS: PSCE can be useful to quantify the balance of post-TKA and KOA patients.


Total knee arthroplasty is the definitive treatment for knee osteoarthrosis and it has several benefits, but its effect on balance is still unknown.Postural stability computerized evaluation is used to evaluate balance on vestibular diseases and it has been recently studied on musculoskeletal conditions.Postural stability computerized evaluation may be useful to evaluate patients' balance before and after total knee arthroplasty.

3.
Clin Rheumatol ; 42(8): 2125-2134, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37154983

RESUMO

INTRODUCTION/OBJECTIVES: The study aims to define the clinical and subclinical calcinosis prevalence, the sensitivity of radiographed site and clinical method for its diagnosis, and the phenotype of Portuguese systemic sclerosis (SSc) patients with calcinosis. METHOD: A cross-sectional multicenter study was conducted with SSc patients fulfilling Leroy/Medsger 2001 or ACR/EULAR 2013 classification criteria, registered in the Reuma.pt. Calcinosis was assessed through clinical examination and radiographs of hands, elbows, knees, and feet. Independent parametric or non-parametric tests, multivariate logistic regression, and sensitivity calculation of radiographed site and clinical method for calcinosis detection were performed. RESULTS: We included 226 patients. Clinical calcinosis was described in 63 (28.1%) and radiological calcinosis in 91 (40.3%) patients, of which 37 (40.7%) were subclinical. The most sensitive location to detect calcinosis was the hand (74.7%). Sensitivity of the clinical method was 58.2%. Calcinosis patients were more often female (p = 0.008) and older (p < 0.001) and had more frequently longer disease duration (p < 0.001), limited SSc (p = 0.017), telangiectasia (p = 0.039), digital ulcers (p = 0.001), esophageal (p < 0.001) and intestinal (p = 0.003) involvements, osteoporosis (p = 0.028), and late capillaroscopic pattern (p < 0.001). In multivariate analysis, digital ulcers (OR 2.63, 95% CI 1.02-6.78, p = 0.045) predicted overall calcinosis, esophageal involvement (OR 3.52, 95% CI 1.28-9.67, p = 0.015) and osteoporosis (OR 4.1, 95% CI 1.2-14.2, p = 0.027) predicted hand calcinosis, and late capillaroscopic pattern (OR 7.6, 95% CI 1.7-34.9, p = 0.009) predicted knee calcinosis. Anti-nuclear antibody positivity was associated with less knee calcinosis (OR 0.021, 95% CI 0.001-0477, p = 0.015). CONCLUSIONS: Subclinical calcinosis high prevalence suggests that calcinosis is underdiagnosed and radiographic screening might be relevant. Multifactorial pathogenesis may explain calcinosis predictors' variability. Key Points • Prevalence of subclinical calcinosis in SSc patients is substantial. • Hand radiographs are more sensitive to detect calcinosis than other locations or clinical method. • Digital ulcers were associated with overall calcinosis, esophageal involvement and osteoporosis were associated with hand calcinosis, and late sclerodermic pattern in nailfold capillaroscopy was associated with knee calcinosis. • Anti-nuclear antibody positivity may be a protective factor for knee calcinosis.


Assuntos
Calcinose , Osteoporose , Escleroderma Sistêmico , Feminino , Humanos , Estudos Transversais , Portugal , Calcinose/complicações , Calcinose/diagnóstico por imagem , Osteoporose/complicações
4.
Eur Spine J ; 31(7): 1599-1610, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35562617

RESUMO

PURPOSE: To provide a systematic review with meta-analysis providing evidence of the current diagnostic test accuracy (DTA) of pedicle screw electrical stimulation. METHODS: A systematic database search on PubMed, Scopus and Web of Science was performed according to the PRISMA-DTA guidelines, and eligibility criteria applied to reduce the results to: (1) only journal articles reporting electrical stimulation of the pedicle screw head, (2) screw position confirmation by imaging techniques, and (3) enough information allowing the calculation of a 2 × 2 contingency table. Sample characteristics, image confirmation method, electrical current threshold and stimulation results were retrieved and analyzed using according to appropriate DTA analysis methods, and allowing the calculation of specificity, sensitivity for pedicle screws insertion at the lumbar and thoracic levels. RESULTS: Lumbar screw stimulation presents a higher sensitivity (0.586 [0.336, 0.798] and specificity (0.984 [0.958, 0.994]) than thoracic screws (sensitivity: 0.270 [0.096; 0.562]; specificity: 0.958 [0.931, 0.975]). The same is observed in terms of the diagnostic odds ratio for lumbar (88.32 [32.136, 242.962]) and thoracic (8.460 [2.139, 33.469]) levels. When performing a sub-group analysis, it is possible to divide the lumbar stimulation threshold as 8 and 10-12 mA, and the thoracic threshold as 6 and 9-12 mA. A threshold of 8 mA at the lumbar level provides higher sensitivity and specificity. Increasing the threshold results in higher specificity but not sensitivity. In fact, at the range of 10-12 mA, the diagnostic validity is too low to confer this technique any robust diagnostic validity. Similarly, at the thoracic level, lower threshold currents are associated with increased sensitivity, but their diagnostic validity is very low. CONCLUSION: Electrical stimulation of the pedicle screw can be used as an adequate diagnostic capability at the lumbar level with a threshold of 8 mA. However, thoracic stimulation is currently not reliable, with very low sensitivity and diagnostic validity at 6 mA or higher.


Assuntos
Parafusos Pediculares , Fusão Vertebral , Testes Diagnósticos de Rotina , Estimulação Elétrica/métodos , Eletromiografia/métodos , Humanos , Vértebras Lombares/cirurgia , Monitorização Intraoperatória/métodos , Fusão Vertebral/métodos , Vértebras Torácicas/cirurgia
5.
Int J Sports Med ; 43(9): 818-824, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35419778

RESUMO

Patients who undergo bariatric surgery (BS) have an increased risk of falls. Our aim was to determine if a multicomponent exercise intervention after BS improves balance. Eighty-four patients with obesity enrolled for BS were recruited and 1 month after BS randomly allocated to a control (CG; standard medical care) or exercise group (EG; exercise plus standard medical care) consisting of a supervised multicomponent training program (3d/week; 75 min/session; 5 months). Anthropometry, lower limb muscle strength (isokinetic dynamometer), vitamin D (ELISA) and balance in bipedal stance (force platform) were assessed pre-BS, 1 month and 6 months post-BS. One month post-BS, significant balance improvements were observed, namely in antero-posterior center of gravity (CoG) displacement and velocity, and medio-lateral and total CoG velocity. Between 1- and 6-months post-BS, improvements in balance were observed only in the EG, with a significant treatment effect on CoG displacement area and antero-posterior CoG displacement. No significant differences were observed between EG and CG over time in any of the anthropometric, muscle strength, and vitamin D variables assayed. In conclusion, a multicomponent exercise intervention program improves some balance parameters in patients with severe obesity following BS and therefore should be part of post-BS follow-up care as a potential strategy to reduce falls and associated injuries.


Assuntos
Cirurgia Bariátrica , Exercício Físico , Acidentes por Quedas/prevenção & controle , Exercício Físico/fisiologia , Terapia por Exercício , Humanos , Força Muscular/fisiologia , Equilíbrio Postural/fisiologia , Vitamina D
6.
Bone ; 153: 116153, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34416407

RESUMO

INTRODUCTION: Mechanical unloading associated with weight loss might be one of the main causes for bariatric surgery (BS) induced bone loss. However, no study has tested this hypothesis through objectively measured accelerometry-derived gravitational loading. We aimed to assess how gravitational loading changes following BS and how this correlates with bone mass losses. METHODS: Twenty-one patients submitted to gastric bypass were assessed before, 1, 6 and 12 months after BS for areal bone mineral density (BMD), calciotropic hormones, sclerostin, body composition and daily physical activity. Gravitational loading was determined as the sum of ground reaction forces assessed by accelerometer which considered the interaction between weight and daily ambulation. RESULTS: Mechanical stimuli promoted through the significant increase in steps number counterbalanced the gravitational loading decreases derived from the significant weight loss after BS. Gravitational loading volume decreased between pre-BS and 1 month post-BS (-2215 kN·d-1; p = .023), but remained stable between 6 and 12 months post-BS, despite decreases on hip (-7.0%; p < .001), femoral neck (-8.8%; p < .001) and lumbar spine (-5.2%; p < .001) BMD. Serum sclerostin increased from pre-BS to 1 month post-BS (+0.118 ng·mL-1; p = .021), returning to pre-BS levels 6 months after surgery. Neither vitamin D nor parathyroid hormone were affected by BS. Weight variation was a predictor of BMD decreases at total hip (R2 = 0.06; p = .026) and femoral neck (R2 = 0.12; p = .022), whereas daily gravitational loading volume was not. Fat and lean mass changes were also predictors of BMD decrease at total hip (R2 = 0.05; p = .031) and femoral neck (R2 = 0.14; p = .010), respectively. CONCLUSION: Our findings suggest that gravitational loading only decreased during the first month after surgery remaining stable thereafter, and these changes do not seem to explain BS-induced bone loss. The association between weight and bone loss seems to result from other physiological aspects, fat and lean mass loss, rather than from gravitational loading decrease.


Assuntos
Cirurgia Bariátrica , Derivação Gástrica , Densidade Óssea , Colo do Fêmur , Humanos , Redução de Peso
7.
World Neurosurg ; 154: 3-12, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34280542

RESUMO

Intraoperative neuromonitoring (IONM) techniques are usually implemented during spine surgery to avoid nefarious abuse of the nervous system, which can cause postoperative problems. A lack of bibliometric analysis on the topic of IONM in spine surgery has been identified. Therefore, the aims of this study are to provide information about the main contributors to this field and their publication dynamics, as well as conceptual and cooperative networks. Results have shown that a steady publication increase has been occurring since 1991, with high levels of citations in the first decade, but irregular publication rates have been recorded more recently. Research production by country seems to be in line with what is observed in other surgical fields, but research funding for IONM in spine surgery seems to be lower, even with the clear interest of private funding agencies. The conceptual networks have shown the importance of motor-evoked potential, electromyography, and the effect of anesthesia, particularly in scoliosis surgery.


Assuntos
Bibliometria , Monitorização Neurofisiológica Intraoperatória , Coluna Vertebral/cirurgia , Humanos , Procedimentos Neurocirúrgicos/métodos
8.
Porto Biomed J ; 6(1): e122, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33884318

RESUMO

Ankle sprains are common and often develop into chronic ankle instability. Ankle laxity is usually assessed by manual testing followed by magnetic resonance imaging to confirm the diagnosis. Manual testing however provides a subjective measure and is limited to the assessor sensibility. Current available technologies incorporate arthrometers to objectively measuring ankle laxity, but are not capable to assess the structural integrity of the capsuloligamentous structures. To overcome these limitations, we developed a novel medical device to assist in the diagnosis of ankle ligament injuries-the Porto Ankle Testing Device. With this device, it is possible to combine and correlate the assessment of the capsuloligamentous' structural integrity with the joint functional competence (ie, joint multiplanar laxity). The main purpose of this work is to present the fundamental aspects and step-by-step development of the Porto Ankle Testing Device. We discuss the design specifications and technical requirements with the purpose to design and develop this medical device, described the features of the different components and explained the mechanical systems that are incorporated emulate manual testing and to measure the multiplanar ankle laxity. The preliminary findings are presented with the purpose to display the assessment protocol, the method of laxity measurement and the obtained results. We propose a unique and reliable medical device to safety and effectively assess ankle ligament injuries and contribute to enhance diagnosis, refine treatment indications and allow objective measurement of ligament laxity before and/or after stabilization surgery.

9.
J Bone Miner Res ; 36(3): 489-499, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33295063

RESUMO

Exercise has been suggested as a therapeutic approach to attenuate bone loss induced by bariatric surgery (BS), but its effectiveness remains unclear. Our aim was to determine if an exercise-training program could induce benefits on bone mass after BS. Eighty-four patients, submitted to gastric bypass or sleeve gastrectomy, were randomized to either exercise (EG) or control group (CG). One month post-BS, EG underwent a 11-month supervised multicomponent exercise program, while CG received only standard medical care. Patients were assessed before BS and at 1, 6, and 12 months post-BS for body composition, areal bone mineral density (BMD), bone turnover markers, calciotropic hormones, sclerostin, bone material strength index, muscle strength, and daily physical activity. A primary analysis was conducted according to intention-to-treat principles and the primary outcome was the between-group difference on lumbar spine BMD at 12 months post-BS. A secondary analysis was also performed to analyze if the exercise effect depended on training attendance. Twelve months post-BS, primary analysis results revealed that EG had a higher BMD at lumbar spine (+0.024 g∙cm-2 [95% confidence interval (CI) 0.004, 0.044]; p = .015) compared with CG. Among total hip, femoral neck, and 1/3 radius secondary outcomes, only 1/3 radius BMD improved in EG compared with CG (+0.013 g∙cm-2 [95% CI 0.003, 0.023]; p = .020). No significant exercise effects were observed on bone biochemical markers or bone material strength index. EG also had a higher lean mass (+1.5 kg [95% CI 0.1, 2.9]; p = .037) and higher number of high impacts (+51.4 [95% CI 6.6, 96.1]; p = .026) compared with CG. In addition, secondary analysis results suggest that exercise-induced benefits may be obtained on femoral neck BMD but only on those participants with ≥50% exercise attendance compared with CG (+5.3% [95% CI 2.0, 8.6]; p = .006). Our findings suggest that an exercise program is an effective strategy to ameliorate bone health in post-BS patients. © 2020 American Society for Bone and Mineral Research (ASBMR).


Assuntos
Densidade Óssea , Derivação Gástrica , Exercício Físico , Terapia por Exercício , Colo do Fêmur , Humanos
10.
Rev. bras. educ. fís. esp ; 30(2): 271-277, graf
Artigo em Português | LILACS | ID: lil-787969

RESUMO

Resumo Uma variedade de disfunções congênitas pediátricas demonstra que deformidades do pé interferem na capacidade de locomoção. No entanto, há em muitas vezes incertezas sobre os seus reais efeitos mecânicos. O pé torto congênito é um exemplo de uma disfunção pouco conhecida no que diz respeito as suas influências na locomoção de crianças. Desta forma, uma melhor compreensão da marcha destas crianças pode auxiliar no melhor no direcionamento de futuras ações na tentativa de minimizar ou corrigir tais possíveis desequilíbrios. O objetivo da pesquisa foi analisar parâmetros cinéticos e cinemáticos da marcha de crianças com pé torto congênito unilateral e bilateral submetidas a tratamento cirúrgico. Artigo Científico Original Observacional. O protocolo consistiu da investigação da marcha em velocidade auto-selecionada, com identificação de parâmetros em forças de reação do solo vertical e antero-posterior, além de parâmetros angulares do tornozelo e do joelho. Testes estatísticos não-paramétricos foram utilizados na análise dos resultados. As crianças com pé torto mostraram maiores desequilíbrios nos parâmetros investigados, com ênfase para as diferenças entre o grupo de pé torto unilateral e controle. Nesta comparação, no início da fase de apoio, foram encontradas maior primeiro pico da força vertical e alterações angulares do joelho e tornozelo; no médio apoio, foram observados aumento da flexão do joelho e dorsiflexão do tornozelo, além de menor magnitude da força vertical; na fase de propulsão foram encontrados menores valores na força antero-posterior e no segundo pico da força vertical, além de menor flexão plantar. Crianças com pé torto unilateral apresentam maiores desequilíbrios em parâmetros biomecânicos da marcha em comparação com crianças acometidas bilateralmente. As alterações encontradas nos parâmetros da marcha no presente estudo podem contribuir nas compreensões dos desequilíbrios e fornecer informações para entender os movimentos dos membros inferiores durante a marcha em crianças pé torto.(AU)


Abstract A variety of congenital pediatric disorders have demonstrated that foot deformities interfere in locomotion ability. However, there are uncertainties about the mechanical effects of this deformity. Quantitative gait analysis allows the measurement and assessment of walking biomechanics, which facilitates the recommendation of treatment alternatives. The purpose of this investigation was to analyze gait parameters in unilateral and bilateral clubfoot children after operative therapy. Observational Original Scientific Article. The protocol consisted of self-selected speed gait investigation with parameter identification in vertical and antero-posterior ground reaction forces and ankle and knee angles. Non-parametric statistics tests were used in analysis of the results. Children with clubfoot showed larger imbalances in parameters with an emphasis towards the greatest differences occurring between unilateral clubfoot group and controls. For initial stance phase, we found higher first vertical force peak and knee and ankle angular alterations. For midstance, we observed more knee flexion and ankle dorsiflexion, and less vertical force. For propulsion phase, there were smaller values in antero-posterior force, second vertical force peak and plantarflexion. Unilateral clubfoot presents more imbalances in gait biomechanical parameters compared with bilateral clubfoot children. The alterations in gait parameters in this study help to understand the imbalances and provide information to understand the lower extremity movements during gait in clubfoot children.(AU)


Assuntos
Humanos , Criança , Fenômenos Biomecânicos , Marcha , Pé Torto
11.
Rev. bras. med. esporte ; 19(3): 186-190, maio-jun. 2013. ilus, graf, tab
Artigo em Português | LILACS | ID: lil-683310

RESUMO

INTRODUÇÃO: Tradicionalmente, os estudos da cinética do consumo de oxigênio são conduzidos a intensidades de exercício baixas, bem distintas daquelas em que o desempenho desportivo acontece. OBJETIVO: Considerando que a magnitude da cinética deste parâmetro fisiológico depende da intensidade a que o esforço é realizado, pretendeu-se com este trabalho comparar a cinética do consumo de oxigênio em 200 m crowl nadados a duas intensidades distintas: moderada e extrema. MÉTODOS: Dez nadadores do sexo masculino, de nível internacional, realizaram dois testes separados: (i) protocolo progressivo e intervalado de7 x200 m, com 30 segundos de intervalo e incrementos de 0,05 m.s-1 para determinação do patamar correspondente ao limiar anaeróbio; e (ii) 200 m à máxima velocidade. Em ambos, realizou-se uma recolha contínua de gases expirados respiração-a-respiração. RESULTADOS: Diferenças significativas foram obtidas na amplitude e constante temporal determinadas nos 200 m nadados à intensidade extrema e moderada, respectivamente: 38,53 ± 5,30 versus 26,32 ± 9,73 ml. kg-1.min-1 e 13,21 ± 5,86 versus 18,89 ± 6,53 s (p ≤ 0,05). Não foram encontradas diferenças no atraso temporal (9,47 ± 6,42 versus 12,36 ± 6,62 s (p ≤ 0,05), à intensidade extrema e moderada, respectivamente. O atraso temporal correlacionou-se negativamente com a constante temporal à intensidade moderada (r = -0,74, p ≤ 0,05). CONCLUSÕES: Ambas as intensidades estudadas foram bem descritas por aproximações mono-exponenciais, tendo-se verificado diferenças significativas entre as mesmas no que concerne à amplitude e constante temporal.


INTRODUCTION: Traditionally, studies regarding oxygen consumption kinetics are conducted at lower intensities, very different from those in which the sports performance occurs. OBJECTIVE: Knowing that the magnitude of this physiological parameter depends on the intensity in which the effort occurs, it was intended with this study compare the oxygen consumption kinetics in the 200 m front crawl at two different intensities: moderate and extreme. METHODS: Ten international male level swimmers two separate tests by 24h: (i) progressive and intermittent protocol of 7 x 200 m, with 30 seconds intervals and with increments of 0.05m.s-1, to determine the anaerobic threshold correspondent step; and, (ii) 200 m at maximal velocity: in both expiratory gases were continuously collected breath-by-breath. RESULTS: Significant differences were obtained between amplitude and time constant determine in the 200 m at extreme and moderate intensities, respectively (38,53 ± 5,30 ml. kg-1.min-1 versus 26,32 ± 9,73 ml. kg-1.min-1 e 13,21 ± 5,86 s versus 18,89 ± 6,53 s (p ≤ 0,05). No differences were found in time delay (9,47 ± 6,42 s versus 12,36 ± 6,62 s, at extreme and moderate intensity, respectively (p ≤ 0.05). A negative correlation between time delay and time constant at the moderate intensity was reported (r = - 0,74, p ≤ 0,05). CONCLUSIONS: Both intensities were well described by double-exponential fittings, and there were significant differences between them in terms of amplitude and time constant.

12.
Braz. arch. biol. technol ; 55(6): 851-856, Nov.-Dec. 2012. ilus, tab
Artigo em Inglês | LILACS | ID: lil-660332

RESUMO

The purpose of this study was to analyse the effect of wearing a swimsuit on swimmer's passive drag. A computational fluid dynamics analysis was carried out to determine the hydrodynamic drag of a female swimmer's model (i) wearing a standard swimsuit; (ii) wearing a last generation swimsuit and; (iii) with no swimsuit, wearing light underwear. The three-dimensional surface geometry of a female swimmer's model with different swimsuit/underwear was acquired through standard commercial laser scanner. Passive drag force and drag coefficient were computed with the swimmer in a prone position. Higher hydrodynamic drag values were determined when the swimmer was with no swimsuit in comparison with the situation when the swimmer was wearing a swimsuit. The last generation swimsuit presented lower hydrodynamic drag values, although very similar to standard swimsuit. In conclusion, wearing a swimsuit could positively influence the swimmer's hydrodynamics, especially reducing the pressure drag component.

13.
Braz. arch. biol. technol ; 53(2): 437-442, Mar.-Apr. 2010. ilus
Artigo em Inglês | LILACS | ID: lil-546576

RESUMO

The purpose of this study was to develop a three-dimensional digital model of a human hand and forearm to apply Computational Fluid Dynamics to propulsion analysis in swimming. Computer tomography scans of the hand and forearm of an Olympic swimmer were applied. The data were converted, using image processing techniques, into relevant coordinate input, which could be used in Computational Fluid Dynamics software. From that analysis, it was possible to verify an almost perfect agreement between the true human segment and the digital model. This technique could be used as a means to overcome the difficulties in developing a true three-dimensional model of a specific segment of the human body. Additionally, it could be used to improve the use of Computational Fluid Dynamics generally in sports and specifically in swimming studies, decreasing the gap between the experimental and the computational data.


O objetivo do presente estudo foi desenvolver um modelo digital tridimensional de uma mão e um antebraço humano para aplicar a Dinâmica Computacional de Fluidos ao estudo da propulsão em natação. Foram aplicados procedimentos computorizados de tomografia axial na mão e antebraço de um nadador Olímpico. Através de técnicas de processamento de imagem, os dados foram convertidos em coordenadas tridimensionais, que podem ser utilizadas em programas de simulação computacional. Através dos resultados encontrados, foi possível verificar uma semelhança quase perfeita entre o segmento humano e o modelo digital. Esta técnica pode ser utilizada como uma forma de ultrapassar as dificuldades em desenvolver um modelo digital tridimensional de um segmento específico do corpo humano. Complementarmente, pode ser bastante útil na melhoria da utilização da Dinâmica Computacional de Fluidos no Desporto, de uma forma geral, e, mais especificamente, nos estudos em natação, diminuindo a diferença entre a investigação experimental e a investigação computacional.

14.
Artigo em Português | LILACS | ID: lil-476427

RESUMO

O objetivo deste trabalho é apresentar uma revisão bibliográfica das principais características cineantropométricas do nadador e a forma como estas influenciam a sua prestação na modalidade. As principais conclusões obtidas foram as seguintes: (i) os nadadores são mais altos e pesadosdo que a população em geral; (ii) os nadadores apresentam um elevado índice envergadura/altura, explicitando valores elevados do diâmetro biacromial e do comprimento dos MS; (iii) verificaseuma elevada razão entre os diâmetros biacromial e bicristal, traduzindo um fator decisivo na modalidade: a promoção de um coeficiente de arrasto inferior; (iv) foram observados elevados valores de comprimento e superfície dos membros dos nadadores (afetando positivamente a sua capacidade propulsiva); (v) os nadadores de elite apresentam um somatótipo médio ecto-mesomorfo eas nadadoras são centrais ou mesomorfas equilibradas; (vi) como grupo, os nadadores apresentamum maior percentual de massa gorda do que outros desportistas, fator este que poderá beneficiá-los relativamente à sua flutuabilidade.


The aim of this work is to present a bibliographic revew, based in the specialised literature, of the kineantropometric characteristics of swimmers and their importance for swimming performances. The main conclusions were: (i) swimmers are taller and heaviest than the general population; (ii) swimmers present an high index of arms span/height (explained by a high biacromial diameter and length of the upper arm); (iii) high values of the ratio biacromial/bicristal diameter were verified, allowing a smaller drag coefficient; (iv) it was observed high values of length and surface of the arms and legs of the swimmers (witch influence positively their propulsive capacity); (v) elite male swimmers presents a ectomorph-endomorth somatotype and elite female swimmers are central or equilibrated mesomorphs (vi) swimmers presented a higher percentage of body mass than other athletes, witch may benefit positively their floatability.


Assuntos
Humanos , Antropometria , Natação
15.
Rev. paul. educ. fís ; 14(2): 107-117, jul.-dez. 2000. tab, graf
Artigo em Português | LILACS | ID: lil-327695

RESUMO

A atividade desportiva em geral reveste formas de extrema complexidade, quer no que concerne à estrutura da realizaçäo desportiva, quer e, porventura, sobretudo no que respeita à estrutura da preparaçäo desportiva. A complexidade das realidades que säo objeto de abordagem científica constitui um dos principais eixos em torno dos quais se define a necessária profundidade e complexidade do discurso da ciência. Vale isto por dizer que näo existem abordagens complexas, nem porventura úteis, sempre que a complexidade da abordagem näo corresponder à complexidade do fenômeno em causa; ou, pelo menos, e melhor dizendo, sempre que a complexidade da abordagem näo respeitar a complexidade do objeto, constrangendo a percepçäo da sua dimensäo e das suas relaçöes. Neste trabalho, o autor procura sistematizar um discurso complexo que seja adequado para a promoçäo do reconhecimento e para a fundamentaçäo mais consequente da complexidade da nataçäo, desde o treino à excelência competitiva...


Assuntos
Humanos , Esportes , Biofísica , Fenômenos Biomecânicos , Natação
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