Exercise and Sleep Treatment for Knee Osteoarthritis

Inclusion Criteria: * Self-reported physician diagnosis of knee osteoarthritis * Persistent knee osteoarthritis-related pain of at least moderate intensity (as indicated in the protocol) * Indication of persistent symptoms of insomnia, determined by scoring on the Sleep Condition Indicator questionnaire (as indicated in the protocol) * If receiving medication for pain or sleep disturbances, having had no change in prescription in the previous three months and be willing to make no other changes to medications for pain or sleep during the active study period. * Adequate literacy level to ensure web-based surveys can be completed independently, as assessed using a brief 3-item literacy level screener Exclusion Criteria: * Concurrent diagnosis of a systemic, inflammatory musculoskeletal disorder (e.g., rheumatoid arthritis) * Active malignancy * Neurological conditions (e.g., movement disorders) * Any medical condition which would make graded increase of physical activity unsuitable (determined by a positive answer to the question: "Has a doctor or healthcare professional advised you to avoid physical activity for any reason?"). * Unable to understand English sufficiently to take part in the intervention. * Unable to provide electronic informed consent. * Evidence of significant cognitive impairment (i.e., ≥2 errors on a 6-item cognitive screener). * Presence of severe psychiatric disorder. * Currently participating in an interventional trial or a pain or sleep management program or having done so in the past six months. * Visual or hearing impairment that would prevent use of the intervention. * Serious physical health concerns necessitating surgery or with a prognosis \<6 months * Irregular sleep-wake schedule, e.g., shift work. * Self-report of diagnosis of a specific sleep disorder other than insomnia that is not currently adequately treated, e.g., sleep apnea or narcolepsy. * Currently meeting or exceeding physical activity guidance from the U.S. Department of Health and Human Services (noted in protocol)