In the paper a way of people identification, based on ground reaction forces during gait, is presented. The authors established that each individual has an unique gait pattern that can be described by quantitative parameters, calculated using measurements coming from the force plates. Fifteen volunteers took part in this study. Each person walked barefoot at least 100 times through 10-m-long walkway with the force plates built in. Determinants were calculated based on vertical and anterior-posterior components of the ground reaction force. The obtained parameters were used as an input matrix of the artificial neural network designed for identification of each person. Effectiveness of the recognition was assessed as root mean square error between expected and obtained output values. It was proved, that human identification based on presented determinants of the gait and artificial neural network is possible at a high level.
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In recent decades, the technological progress has contributed to the development of appliances that significantly improve human life. The biomedical field has benefited more than others from this innovation process. In particular, robotics advances have led to the development of prostheses that allow who suffered the amputation of a lower limb to walk almost like a healthy person. Although sophisticated, the current solutions are not yet able to completely reestablish the function of their biological counterpart. According to authors' opinion this deficiency is principally due to the lack of suitable development and verification methods rather than of appropriate technology resources. Therefore, an innovative bench for testing lower limb prostheses considering working conditions more realistic than those defined by the legislation in force is presented in this paper. The mechanical setup is composed of a 6-axis industrial robot and a custom 2-axis active force plate. The first one is used to replicate the movements of the limb residual segment in space. The second one to load the prosthetic foot both in longitudinal and vertical direction, that is, in the sagittal plane. Both the design choices and the operation procedure are illustrated. Then, a numerical model of the bench is developed in order to assess the merits and the limits of the proposed solution.
The aim of the study was to determine whether it is possible to assess static balance on an unstable surface using center of pressure velocities obtained with a force platform when standing on a wobble board. Methods: The center of pressure velocities were recorded with a force platform within three days (four trials per day) in thirty young adults in three conditions: standing on a rigid surface, compliant surface, and on a wobble board. Reliability of mean velocities of the center of pressure was examined using intraclass correlation coefficients. Relationships between the three conditions were assessed with Pearson correlation coefficients. Results: Intra-session reliability was excellent for standing on a rigid surface and on a compliant surface and good for standing on a wobble board. Inter-session reliability was good for all parameters in all conditions, except for poor reliability in the anterior-posterior direction in standing on a wobble board. All correlations between the same parameter in different conditions were statistically significant (P < 0.05), except for velocity of the center of pressure in the anterior-posterior direction between stance on a rigid surface and stance on a wobble board. Conclusions: Centre of pressure velocity parameters obtained with a force plate when standing on a wobble board can provide valuable information about postural stability in unstable conditions.
Umiejętność wszechstronnej i obiektywnej oceny układu równowagi jest niezbędna do oceny postępów terapii i umiejętności równoważnych w sporcie. Niestety, wciąż bardzo niewiele osób zajmujących się fizjoterapią, leczeniem czy treningiem sportowym posiada wiedzę wystarczającą do przeprowadzenia badań równowagi i ich prawidłowej interpretacji. Celem pracy jest przedstawienie podstawowych pojęć, koncepcji i metod niezbędnych do prowadzenia tego typu badań. Szczególną uwagę zwrócono na terminologię, ogólną interpretację sygnałów mierzonych za pomocą platformy sił podczas swobodnego stania oraz na przebieg procedur doświadczalnych.
EN
The ability to assess the postural performance and stability in a comprehensive and objective way is a prerequisite for the evaluation of progress in therapy or to judge about the significance of postural control in sports. However, neither therapists, clinicians, nor athletic trainers have sufficient skills to perform such assessment. The purpose of this paper is to present the basic notions and methods needed to perform such studies. Attention is focused on terminology, the general interpretation of time-series recorded during quiet stance on force plates and on the experimental procedures.
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