Abstract:Objective This study aimed to evaluate the reliability of the standard isometric contraction (SIC) and maximum voluntary isometric contraction (MVIC) tests, and electromyography during jogging normalized by SIC and MVIC among patients with knee osteoarthritis, respectively. Methods The electromyography data in gluteus maximus, semitendinosus, rectus femoris, vastus lateralis, tibialis anterior, gastrocnemius lateral, and soleus of their affected legs during jogging, SIC tests and MVIC tests were collected using a wireless electromyography system (Noraxon, Boston, USA). Intra-class correlation coefficients with 95% confidence intervals were calculated to assess the between-day reliability. Results Compared with the MVIC tests, the SIC tests had higher ICCs in all target muscles, and none were statistically higher. Compared with MVIC, ICCs during jogging were higher in all target muscles and higher statistically in rectus femoris when normalized by SIC. Conclusion For patients with knee osteoarthritis, SIC is a more reliable electromyography normalization method than MVIC, and has good clinical promotion potential.