Proceedings of The Physiological Society

University College London December 2005 (2006) Proc Physiol Soc 1, C14

Oral Communications

Is muscle afferent contribution to the soleus muscle activity decreased during human spastic walking?

Mazzaro, Nazarena; Nielsen, Jens Feldbaek; Grey, Michael James; Sinkjaer, Thomas;

1. Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark. 2. Hammel Neurorehabilitation Center, Hammel, Denmark.

The aim of this study was to investigate the contribution of proprioceptive feedback to the activation of the soleus muscle during the stance phase of walking in spastic patients. Twelve hemiparetic spastic patients (cerebral stroke) and 12 age-matched able-bodied controls participated in the study. Antispastic medication was interrupted 24 hr before the test and the spasticity level was evaluated with the Ashworth score. All subjects walked on a treadmill at a comfortable speed (~ 1 km/h) with the left leg attached to a robotic actuator that can dorsiflex and plantarflex the ankle. Fast plantar flexion perturbations (6 deg, 500 deg/s) were applied in the mid-stance phase to investigate the contribution of feedback from ankle plantar flexors to the soleus EMG. To investigate the afferent-mediated modulation of the soleus EMG, the ankle dorsiflexion during the stance phase was slightly enhanced or reduced mimicking variations in the ankle kinematics during normal walking. Four levels of ankle dorsiflexion enhancements and reductions (

Where applicable, experiments conform with Society ethical requirements