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1.
Sports Biomech ; : 1-14, 2023 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-37332236

RESUMO

This case study examined the association between 50 m freestyle and speed curve parameters of a world-class Paralympic swimmer and analysed the changes in speed curves and their frequency components across her performance levels. From 2018 to 2021, a visually impaired female swimmer (26.59 s in 50 m freestyle, S12 class) underwent 22 tests to obtain instantaneous speed synchronised with video recording. She regularly performed 50 m freestyle in competitions and time trials. The fast Fourier transformation method converted the speed signal into frequency domains and determined the relative contribution of the harmonics with two maxima and minima (H2, arms actions) and six maxima and minima (H6, legs actions). The functional paired t-test compared the speed curves at the beginning (PRE) and end (POST) of the analysed period. The 50 m freestyle time correlated with average speed (r = -0.50, p = 0.02). The contribution of H6 increased in the first year and remained large, whereas the contribution of H2 was lower throughout the whole period. POST was faster than PRE in five moments that coincide with the downward leg kick moments. These changes allowed her to stay longer at the upper part of the curve and improve performance over time.

2.
Res Vet Sci ; 119: 27-36, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29783121

RESUMO

BACKGROUND: To investigate the effect of different fixation strategies of the intramedullary interlocking nail (IIN) on the mechanical behavior of a polymeric implant applied for femoral fracture fixation in calves, and to evaluate the performance of a glass fiber-reinforced polymer applied in a bovine femoral fracture reduction system, five Holstein male animals with a mean weight (±SD) of 62.8 ±â€¯20.4 kg and aged 74 ±â€¯15 were used to generate biomechanical parameters for this study. Twelve models of the fractured bovine femur, simulating a simple oblique fracture, were developed for use during the simulations. The models were divided into three groups, with each group of four models being associated with a different fixation strategy. Models were used to simulate the loading conditions corresponding to a calf in the transition (decubitus position to static position) condition. The maximum stresses found in each set (bone/implant) were compared with the reference stresses of each nail material. RESULTS: Maximum implant stresses were found in the screws and at the interface between the screw and the nail. The performance of implants was influenced by the material and fixation strategy, which can be confirmed by the stress values found in the set. The analysis indicated that the composite nail is able to withstand the loading demands in all fixation strategies. CONCLUSIONS: The finite element analysis (FEA) demonstrated that all polymeric materials analyzed provided sufficient resistance to withstand the loading forces imposed to the femur when an adequate blocking strategy was applied.


Assuntos
Pinos Ortopédicos/veterinária , Bovinos , Fraturas do Fêmur/veterinária , Animais , Fenômenos Biomecânicos , Parafusos Ósseos , Bovinos/lesões , Bovinos/cirurgia , Fraturas do Fêmur/cirurgia , Fixação Intramedular de Fraturas , Masculino
3.
J Appl Biomech ; 30(2): 348-52, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24145625

RESUMO

Lower extremity kinetic data during walking of 12 people with chronic poststroke were reanalyzed, using functional analysis of variance (FANOVA). To perform the FANOVA, the whole curve is represented by a mathematical function, which spans the whole gait cycle and avoids the need to identify isolated points, as required for traditional parametric analyses of variance (ANOVA). The power variables at the ankle, knee, and hip joints, in the sagittal plane, were compared between two conditions: With and without walking sticks at comfortable and fast speeds. For the ankle joint, FANOVA demonstrated increases in plantar flexion power generation during 60-80% of the gait cycle between fast and comfortable speeds with the use of walking sticks. For the knee joint, the use of walking sticks resulted in increases in the knee extension power generation during 10-30% of the gait cycle. During both speeds, the use of walking sticks resulted in increased power generation by the hip extensors and flexors during 10-30% and 40-70% of the gait cycle, respectively. These findings demonstrated the benefits of applying the FANOVA approach to improve the knowledge regarding the effects of walking sticks on gait biomechanics and encourage its use within other clinical contexts.


Assuntos
Transtornos Neurológicos da Marcha/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Análise de Variância , Articulação do Tornozelo/fisiopatologia , Fenômenos Biomecânicos , Bengala , Feminino , Articulação do Quadril/fisiopatologia , Humanos , Articulação do Joelho/fisiopatologia , Masculino , Pessoa de Meia-Idade
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