Postural Preparation to Making a Step: Is There a ¿Motor Program¿ for Postural Preparation?

• Autores: Adriana M. Degani, Alessander Danna Dos Santos, Mark L. Latash
• Localización: Journal of applied biomechanics, ISSN-e 1543-2688, ISSN 1065-8483, Vol. 23, Nº. 4, 2007, págs. 261-274
• Idioma: inglés
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• Resumen

  • We tested the hypothesis that a sequence of mechanical events occurs preceding a step that scales in time and magnitude as a whole in a task-specific manner, and is a reflection of a ¿motor program.¿ Young subjects made a step under three speed instructions and four tasks: stepping straight ahead, down a stair, up a stair, and over an obstacle. Larger center-of-pressure (COP) and force adjustments in the anterior-posterior direction and smaller COP and force adjustments in the mediolateral direction were seen during stepping forward and down a stair, as compared with the tasks of stepping up a stair and over an obstacle. These differences were accentuated during stepping under the simple reaction time instruction. These results speak against the hypothesis of a single motor program that would underlie postural preparation to stepping. They are more compatible with the reference configuration hypothesis of whole-body actions.