Combined Application of Electrical Stimulation and Volitional Contractions for Muscle Strengthening and Knee Pain Inhibition (Seated Study)

The purpose of this study is to assess the efficacy of a 12-week low-load neuromuscular electrical stimulation with volitional contraction (NMES-VC) training program to improve quadriceps strength and activation, while not adversely affecting knee-related pain, activities of daily living or quality of life in women with knee pain. The primary outcome will be change in maximal isokinetic knee extensor torque. The investigators will test the following hypotheses. In comparison with low-load (40%) resistance training without electrical stimulation, a 12-week NMES-VC training program will: Hypothesis 1: Increase maximal isokinetic knee extensor torque Secondary questions and response variables Hypothesis 2: Not adversely affect knee pain or quality of life, assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire Additional hypotheses in women with risk factors for incident symptomatic or progressive KOA: 1. Determine the extent to which NMES-VC-enhanced low-intensity resistance training increases quadriceps muscle rate of force development 2. Determine the extent to which NMES-VC enhanced low-intensity exercise is tolerated (using numeric rating scale survey \"level of pain you experienced during the hybrid training or 40% isokinetic exercise\") 3. Determine the extent to which NMES-VC-enhanced low-intensity resistance training increases physical function (20m walk, chair stand)