 Methods: Nineteen patients with knee OA were enrolled and randomized into two groups: group I was treated with CKC NMES, and group II was treated with CKC NMES placebo. Both groups underwent 20 sessions of mini-squat exercises at 30 degrees of knee flexion that were associated with and interspersed with NMES for 5 minutes at a frequency of 40 hertz Hz, 10 minutes at 70 Hz and an addition 10 minutes at 150 Hz, for a total of 25 minutes. The data were analyzed using SPSS Statistical Package for the Social Sciences version 17.0. Data were expressed as a frequency, mean and standard deviation and were statistically analyzed using a one-way analysis of variance ANOVA for repeated measurements followed by Bonferronis post-hoc test. The investigators also used an unpaired Students t-test and Kruskal-Wallis and Wilcoxon tests with a level of significance of P 0.05. 