Trunk muscle activity during the simultaneous performance of two motor tasks.

摘要: A unique feature of trunk muscles is that they can be activated to meet functional requirements for combined behaviors, including those related posture and breathing. Trunk therefore may have developed mechanisms dealing with simultaneous inputs different task requirements. This study was designed test the hypothesis a linear addition in muscle activities would occur when an isometric pulsed expiration performed simultaneously. Surface electromyograms (EMG) were recorded from four regions (medial lateral back, upper lower abdomen) sitting during performance individual task, pressure (isometric task). The direction static holding varied between flexion extension positions. For subjects produced two consecutive pulses (2/s) target oral pressure. each recording, prediction calculated mathematical EMG tasks. compared actual activity task. Typically showed addition, such relative contribution did not change suggests motor commands reached these neuron pools essentially unmodified. other nonlinear combination patterns. That is, qualitatively both patterns, specific command, evident measured traces but quantitatively all criteria addition. Linear provide simple mechanism combining breathing-related behaviors (expiratory efforts) (holding against gravity). some shared voluntary tasks without changing their either component At same time, are shared, modulated, thus avoiding construction third new plan.