Studying the Effect of Cross-education on the Quadriceps Atherogenic Muscle Inhibition in Women With Unilateral Knee Osteoarthritis

Patients with knee osteoarthritis (KO) commonly show quadriceps muscle weakness. One of the important reasons for this weakness is arthrogenic muscle inhibition (AMI), a process in which neural inhibition causes the failure of quadriceps activation. The present study aims to evaluate the effect of cross-education on the AMI and the maximum extensor force of quadriceps in women with unilateral KO.

this study, 21 women with unilateral KO (grade 2) participated. The AMI and the maximum extensor force of the quadriceps in the affected knee were measured before, immediately after, and 15 minutes after cross-education. The cross-education included isometric training of the contralateral quadriceps in 5 sets of 8 repetitions in one session. For measuring the AMI and maximum extensor force of the quadriceps, a burst of electrical stimulation was superimposed on the maximal voluntary contractions in 6 seconds.

Immediately after one session of cross-education, the AMI of the affected knee significantly decreased and the maximum extensor force of quadriceps significantly increased compared to the pre-test phase (P=0.001). Fifteen minutes after cross-education, AMI significantly increased compared to the post-test phase (P=0.018), but was still lower than that in the pre-test phase (P=0.001)

One session of cross-education can reduce AMI and increase maximum extensor force of quadriceps in women with KO, and this effect remains for at least 15 minutes.