We recruited 132 subjects with bilateral knee osteoarthritis (Altman Grade II) to compare the effects of different stretching techniques on the outcomes of isokinetic muscle strengthening exercises. Patients were randomly divided into four groups (I–IV). The patients in Group I received isokinetic muscular strengthening exercises, Group II received bilateral knee static stretching and isokinetic exercises, Group III received proprioceptive neuromuscular facilitation (PNF) stretching and isokinetic exercises, and Group IV acted as control