Excitatory drive to the alpha-motoneuron pool during a fatiguing submaximal contraction in man.

Contraction in Humans Coactivation During a Submaximal Fatiguing Cortical and Spinal Modulation of Antagonist

Cortical and spinal modulation of antagonist coactivation during a submaximal fatiguing contraction in humans.

This study investigates the control mechanisms at the cortical and spinal levels of antagonist coactivation during a submaximal fatiguing contraction of the elbow flexors at 50% of maximal voluntary contraction (MVC). We recorded motor-evoked potentials in the biceps brachii and triceps brachii muscles in response to magnetic stimulation of the motor cortex (MEP) and corticospinal tract (cervic...

Spinal reflexes and coactivation of ankle muscles during a submaximal fatiguing contraction.

This study examined the involvement of spinal mechanisms in the control of coactivation during a sustained contraction of the ankle dorsiflexors at 50% of maximal voluntary contraction. Changes in the surface electromyogram (EMG) of the tibialis anterior and of two antagonist muscles, the soleus and lateral gastrocnemius, were investigated during and after the fatigue task. Concurrently, the co...

Activation varies among the knee extensor muscles during a submaximal fatiguing contraction in the seated and supine postures.

Ten young men sustained an isometric contraction of the knee extensor muscles at 20% of the maximum voluntary contraction (MVC) torque on three separate occasions in a seated posture. Subjects performed an isometric knee extension contraction on a fourth occasion in a supine posture. The time to task failure for the seated posture was similar across sessions (291 +/- 84 s; P > 0.05), and the MV...

Shear elastic modulus can be used to estimate an index of individual muscle force during a submaximal isometric fatiguing contraction.

The present study was designed to determine whether fatigue alters the ability to estimate an index of individual muscle force from shear elastic modulus measurements (experiment I), and to test the ability of this technique to highlight changes in load sharing within a redundant muscle group during an isometric fatiguing task (experiment II). Twelve subjects participated in experiment I, which...