ABSTRACT : FACULTY OF MEDICINE, HEALTH AND BIOLOGICAL SCIENCES REHABILITATION RESEARCH UNIT Doctor of Philosophy QUANTITATIVE MUSCULAR PERFORMANCE AND TRAINING IN PATIENTS WITH OSTEOARTHRITIS OF THE KNEE by Ahmed Rustam Mohamed Osteoarthritis (OA) of the knee is a disabling condition characterized by pain, stiffness, and muscle weakness leading to reduction in normal functional activities. A variety of exercise programmes are used in order to reduce clinical symptoms in patients with OA of the knee, but there is little evidence to determine the most effective exercise programme in the conservative treatment of this condition. This dissertation is divided into four major parts. The first part reviews the literature relating to OA of the knee, the strength of quadriceps and hamstring muscles, functional activities, and the effects of training programmes. It then describes previous experimental studies. The second part outlines methods used in assessment and their reliability and validity. The third part describes the differences in torque and myoelectrical activity between healthy subjects and patients with OA of the knee. This part also details a pilot study which determines the feasibility and acceptability of Squat Closed Kinetic Chain Training (Squat Closed KCT) in these patients. The fourth part describes a prospective trial. In the prospective trial, the effects of Squat Closed KCT compared with traditional Open Kinetic Chain Training (Open KCT) and progress in a control group. Outcomes include maximum isometric knee extension and flexion torques and agonist and antagonist myoelectrical activity. The study also investigates intensity of pain and functional activity using a Self-reported Pain and Functional Knee Assessment (SPFKA). The assessments were undertaken before treatment (initial baseline), at three and six weeks during training, and at fifty weeks from baseline. Maximum isometric knee extension and flexion torques and agonist myoelectrical activity significantly increased in both exercise groups compared with the control group at three and six weeks during the training. There was a relative reduction in the antagonist coactivation index during maximum isometric knee extension. The increases in torques and agonist myoelectrical activity were accompanied by improvements in functional activities and reduction in knee pain. These gains had declined at fifty weeks. There was a trend for Squat Closed KCT to produce greater torque and myoelectrical activity than Open KCT, but this trend was not statistically significant. The differences in pain and walking disability scores were significantly less in Squat Closed KCT compared with Open KCT at fifty weeks, but the number of patients was too small and subjects were too highly selected to draw a firm conclusion about the longer term results. The results of this study suggest that Squat Closed KCT, using a modified tilting table (MTT) and painful squat angle, is safe and is probably more appropriate than traditional Open KCT in providing clinical benefits, and improving functional activities.