The quadriceps of the participants with RA were weaker than those of the healthy participants and were unable to be fully activated during an MVC. Voluntary activation was directly related to quadriceps strength. The AFPT of individuals with RA was slower and knee JPS was less accurate than healthy participants. Prior to rehabilitation, there were no differences between the control RA group and the rehabilitation group. Following rehabilitation, the quadriceps muscles of the rehabilitation group were stronger and better activated than the control group. The acuity of knee JPS did not change, although the function and level of disability improved in the rehabilitation group. All measures of disease activity decreased after exercise, but reduction in morning stiffness was statistically significant. There was no increase in plasma concentrations of pro-inflammatory cytokines at the end of a single exercise session or at the end of the entire rehabilitation. A six -month follow-up assessment showed that the improvement achieved during rehabilitation had been maintained with incremental improvements in AFPT.