RESUMO
In response to sudden perturbations of stance stability, muscles of both legs are activated for balance recovery. In conditions that one of the legs has a reduced capacity to respond, the opposite leg is predicted to compensate by responding more powerfully to restore stable upright stance. In this investigation, we aimed to evaluate between-leg compensatory control in automatic postural responses to sudden perturbations in a situation in which plantar flexor muscles of a single leg were fatigued. Young participants were evaluated in response to a series of perturbations inducing forward body sway, with a focus on activation of plantar flexor muscles: lateral and medial gastrocnemii and soleus. Muscular responses were analyzed through activation magnitude and latency of muscular activation onset. For evaluation of balance and postural stability, we also analyzed the center of pressure and upper trunk displacement and weight-bearing asymmetry between the legs. Responses were assessed in three conditions: pre-fatigue, under single-leg fatigue, and following the recovery of muscular function. Results showed (a) compensation of the non-fatigued leg through the increased magnitude of muscular activation in the first perturbation under fatigue; (b) adaptation in the non-fatigued leg over repetitive perturbations, with a progressive decrement of muscular activation over trials; and (c) maintenance of increased muscular activation of the non-fatigued leg following fatigue dissipation. These findings suggest that the central nervous system is able to modulate the descending motor drive individually for each leg's muscles apparently based on their potential contribution for the achievement of the behavioral aim of recovering stable body balance following stance perturbations.
Assuntos
Perna (Membro) , Equilíbrio Postural , Eletromiografia , Fadiga , Humanos , Músculo Esquelético , PosturaRESUMO
O conceito de catarse de integração é a invenção original de J. L. Moreno para as ciências psicológicas e sociais. Refere-se ao acontecimento ab-reativo, de ordem afetivo-emocional, produzido e expresso durante um trabalho, operativo ou terapêutico, da dinâmica grupal. Trata-se de contribuição criada a partir das ações dramáticas. Em Moreno, é fundamental que se entenda esse fenômeno como resultante do movimento dialético: catarse mental ancorada na ação dramática e ação dramática ancorada na catarse mental. Para enriquecer os nossos conhecimentos sobre o assunto em pauta, torna-se necessária uma divagação de compreensão histórica da teoria subjacente ao tema. Pois é disso que este artigo trata.(AU)
Catharsis of integration is an original concept developed by J.L. Moreno for the psychological and social sciences. Based in and emerging from the dramatic action, it refers to an affective-emotional ab-reactive response that is produced and expressed during an operative or therapeutic piece of work with group dynamics. In Moreno's view it is fundamental that we understand this as a dialectic phenomenon: mental catharsis anchored in the dramatic action and dramatic action anchored in mental catharsis. In order to further our understanding of this issue, it is necessary to make a digression around the historical connotations of the underlying theory. It is this that this paper aims to do.(AU)