Article

Co-contraction of the agonist and antagonist muscles acting across the same joint has been related to many activities which require motor coordination and joint stability, and has also been linked to neuromuscular pathologies as a possible cause of abnormal and inefficient movement. To date, co-contraction has been qualitatively observed but not quantified. The purpose of this study was to define and quantify a co-contraction index for the dorsi- and plantarflexors of the ankle joint during normal gait. Ten subjects (five males and five females) were assessed using biotelemetry of surface EMG of the tibialis anterior, extensor digitorum longus, soleus and gastrocnemius muscles. Initially, a calibration co-contraction was established for the ankle joint in static position. EMG plus footswitch signals were then recorded for two trials of ten steps each. The tibialis anterior was assessed as representative of the phasic activity of the pre-tibial group and the soleus was determined to represent the plantarflexors. The EMG data were processed and the co-contraction index was calculated for the total stride, and for three phases : heel-contact to heel-off, heel-off to toe-off and swing. The ten subjects were retested one week later. The results for the normals showed that the co-contraction index was 61%, and also was a reliable measure from trial to trial and between test sessions.

Langue : ANGLAIS

Identifiant basis : 1985002454