Sugestões para professores de orientação e mobilidade a partir de um estudo da marcha de alunos com deficiência visual

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Revisão sistemática do efeito do envelhecimento no andar livre e adaptativo

Aging seems to impair the walking. However, it is not clear the effects of aging on walking. The aim of this study was to determine changes in kinematic, kinetic and electromyographic parameters of the free and adaptive gait, in preferred velocity, caused by aging. The initial search strategy was performed to identify all articles that examined the free and adaptive gait. The electronic databases analyzed were: MEDLINE, PubMed, EMBASE, CINAHL, Sports Discus, DARE, PsychInfo, ERIC, AusportMed, AMI, Cochrane and PEDro. Twenty-three articles were reviewed in full. Elderly are slower, with shorter step length and longer double support duration than young adults during free and adaptive gait. Even, they showed higher muscular demands, with redistribution of joint power and torque and decreased force in the propulsion and absorption phases. It was concluded that elderly present altered kinematic, kinetic and electromyographic parameters of free and adaptive gait compared to young adults.

Visual cues and gait improvement in Parkinson's disease: which piece of information is really important?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Positive effects of auditory cue in locomotor pattern of people with Parkinson's disease (off and on medication)

Gait disorders are identified in people with Parkinson’s disease. The aim of this study was to investigate the effect of auditory cues and medication on kinematic, kinetic and EMG parameters, during different gait phases of people with PD and healthy elderly. Thirty subjects distributed in two groups (Group 1, PD patients off and on medication; Group 2, healthy elderly) participated in this study and were instructed to walk in two experimental conditions: non-cued and cued. Therefore, kinematic, kinetic and electromyography analyses were utilized to investigate the locomotor pattern. Changes in locomotor pattern (greater muscular activity) with auditory cue were observed for PD patients. Regarding the medication, locomotor parameter improvement was observed after levodopa intake in association with the auditory cue. These results confirm the hypothesis about the external cues therapy that could be used as a complement to drug therapy to achieve improvement in the locomotor pattern of PD patients.

Gait analysis in giant anteater (myrmecophaga tridactyla) with the use of a pressure-sensitive walkway

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Excess body weight and gait influence energy cost of walking in older adults

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gait analysis in dogs with pelvic fractures treated conservatively using a pressure-sensing walkway

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Recovery of gait after quadriceps muscle fatigue

The aim of this study was to investigate the effect of recovery time after quadriceps muscle fatigue on gait in young adults. Forty young adults (20-40 years old) performed three 8-m gait trials at preferred velocity before and after muscle fatigue, and after 5, 10 and 20min of passive rest. In addition, at each time point, two maximal isometric voluntary contractions were preformed. Muscle fatigue was induced by repeated sit-to-stand transfers until task failure. Spatio-temporal, kinetic and muscle activity parameters, measured in the central stride of each trial, were analyzed. Data were compared between before and after the muscle fatigue protocol and after the recovery periods by one-way repeated measures ANOVA. The voluntary force was decreased after the fatigue protocol (p<0.001) and after 5, 10 and 20min of recovery compared to before the fatigue protocol. Step width (p<0.001) and RMS of biceps femoris (p<0.05) were increased immediately after the fatigue protocol and remained increased after the recovery periods. In addition, stride duration was decreased immediately after the fatigue protocol compared to before and to after 10 and 20min of rest (p<0.001). The anterior-posterior propulsive impulse was also decreased after the fatigue protocol (p<0.001) and remained low after 5, 10 and 20min of rest. We conclude that 20min is not enough to see full recovery of gait after exhaustive quadriceps muscle fatigue.

Complexidade do ambiente e assimetria no andar de idosos com doença de Parkinson

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A articulação do quadril em uma perspectiva preditora da velocidade de marcha em idosas e como foco de intervenção de duas modalidades terapêuticas: Método Pilates e Haste Vibratória

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Detection of gait perturbations based on proprioceptive information. Application to Limit Cycle Walkers

Walking on irregular surfaces and in the presence of unexpected events is a challenging problem for bipedal machines. Up to date, their ability to cope with gait disturbances is far less successful than humans': Neither trajectory controlled robots, nor dynamic walking machines (Limit CycleWalkers) are able to handle them satisfactorily. On the contrary, humans reject gait perturbations naturally and efficiently relying on their sensory organs that, if needed, elicit a recovery action. A similar approach may be envisioned for bipedal robots and exoskeletons: An algorithm continuously observes the state of the walker and, if an unexpected event happens, triggers an adequate reaction. This paper presents a monitoring algorithm that provides immediate detection of any type of perturbation based solely on a phase representation of the normal walking of the robot. The proposed method was evaluated in a Limit Cycle Walker prototype that suffered push and trip perturbations at different moments of the gait cycle, providing 100% successful detections for the current experimental apparatus and adequately tuned parameters, with no false positives when the robot is walking unperturbed.

Kinematic distances of pre-main-sequence stars in the Lupus star-forming region

To reliably determine the main physical parameters (masses and ages) of young stars, we must know their distances. While the average distance to nearby star-forming regions (<300 pc) is often known, the distances to individual stars are usually unknown. Individual distances to members of young moving groups can be derived from their radial velocities and proper motions using the convergent-point strategy. We investigate the kinematic properties of the Lupus moving group with the primary objective of deriving individual distances to all group members.

Procedura di progettazione di protesi a basso costo per l'arto inferiore

L'attività di ricerca descritta in questa tesi fornisce linee guida per la progettazione di arti protesici inferiori, con particolare riferimento alla progettazione di protesi a basso costo. La necessità di efficienti protesi a basso costo risulta infatti sentita nei Paesi in via di sviluppo ma anche dalle fasce meno abbienti dei paesi occidentali. Al fine di comprendere le strategie adottate dall'apparato locomotorio per muoversi con le protesi sono analizzati il cammino fisiologico, le protesi presenti sul mercato ed infine le modalità con cui le loro prestazioni sono valutate. Con il presente lavoro, dopo aver osservato la presenza di una scarsa strutturazione della metodologia di progettazione che riguarda specialmente il settore del basso costo, si propone una metodologia il più possibile oggettiva e ripetibile tesa ad individuare quali sono gli aspetti essenziali di una protesi per garantire al paziente una buona qualità di vita. Solo questi aspetti dovranno essere selezionati al fine di ottenere la massima semplificazione della protesi e ridurre il più possibile i costi. Per la simulazione delle attività di locomozione, in particolare del cammino, è stato elaborato un apposito modello spaziale del cammino. Il modello proposto ha 7 membri rigidi (corrispondenti a piedi, tibie, femori e bacino) e 24 gradi di libertà. Le articolazioni e l'appoggio dei piedi al suolo sono modellati con giunti sferici. La pianta del piede consente tre possibili punti di appoggio. I criteri di realizzazione delle simulazioni possono comprendere aspetti energetici, cinematici e dinamici considerati come obiettivo dall'apparato locomotorio. In questa tesi vengono trattati in particolare gli aspetti cinematici ed è mostrata un'applicazione della procedura nella quale vengono dapprima identificati i riferimenti fisiologici del cammino e quindi simulato il cammino in presenza di una menomazione al ginocchio (eliminazione della flessione in fase di appoggio). Viene quindi lasciato a sviluppi futuri il completamento della procedura e la sua implementazione in un codice di calcolo.

Kinematic description of the rupture from strong motion data: strategies for a robust inversion

We present a non linear technique to invert strong motion records with the aim of obtaining the final slip and rupture velocity distributions on the fault plane. In this thesis, the ground motion simulation is obtained evaluating the representation integral in the frequency. The Green’s tractions are computed using the discrete wave-number integration technique that provides the full wave-field in a 1D layered propagation medium. The representation integral is computed through a finite elements technique, based on a Delaunay’s triangulation on the fault plane. The rupture velocity is defined on a coarser regular grid and rupture times are computed by integration of the eikonal equation. For the inversion, the slip distribution is parameterized by 2D overlapping Gaussian functions, which can easily relate the spectrum of the possible solutions with the minimum resolvable wavelength, related to source-station distribution and data processing. The inverse problem is solved by a two-step procedure aimed at separating the computation of the rupture velocity from the evaluation of the slip distribution, the latter being a linear problem, when the rupture velocity is fixed. The non-linear step is solved by optimization of an L2 misfit function between synthetic and real seismograms, and solution is searched by the use of the Neighbourhood Algorithm. The conjugate gradient method is used to solve the linear step instead. The developed methodology has been applied to the M7.2, Iwate Nairiku Miyagi, Japan, earthquake. The estimated magnitude seismic moment is 2.6326 dyne∙cm that corresponds to a moment magnitude MW 6.9 while the mean the rupture velocity is 2.0 km/s. A large slip patch extends from the hypocenter to the southern shallow part of the fault plane. A second relatively large slip patch is found in the northern shallow part. Finally, we gave a quantitative estimation of errors associates with the parameters.

Inferences on earthquake kinematic properties from data inversion: two different approaches

During my PhD, starting from the original formulations proposed by Bertrand et al., 2000 and Emolo & Zollo 2005, I developed inversion methods and applied then at different earthquakes. In particular large efforts have been devoted to the study of the model resolution and to the estimation of the model parameter errors. To study the source kinematic characteristics of the Christchurch earthquake we performed a joint inversion of strong-motion, GPS and InSAR data using a non-linear inversion method. Considering the complexity highlighted by superficial deformation data, we adopted a fault model consisting of two partially overlapping segments, with dimensions 15x11 and 7x7 km2, having different faulting styles. This two-fault model allows to better reconstruct the complex shape of the superficial deformation data. The total seismic moment resulting from the joint inversion is 3.0x1025 dyne.cm (Mw = 6.2) with an average rupture velocity of 2.0 km/s. Errors associated with the kinematic model have been estimated of around 20-30 %. The 2009 Aquila sequence was characterized by an intense aftershocks sequence that lasted several months. In this study we applied an inversion method that assumes as data the apparent Source Time Functions (aSTFs), to a Mw 4.0 aftershock of the Aquila sequence. The estimation of aSTFs was obtained using the deconvolution method proposed by Vallée et al., 2004. The inversion results show a heterogeneous slip distribution, characterized by two main slip patches located NW of the hypocenter, and a variable rupture velocity distribution (mean value of 2.5 km/s), showing a rupture front acceleration in between the two high slip zones. Errors of about 20% characterize the final estimated parameters.