Patient case (clinical description): A 47-year-old woman comes to the office complaining of pain in the calf and knee when she bends down. The pain limits her activity. Her medical history is significant for osteoarthritis, for which she uses nonsteroidal anti-inflammatory drugs (NSAIDs) for the past two years. She is living with her husband and has 3 children. She doesn't smoke but drinks alcohol occasionally. Her vital signs are normal. On physical examination, there is a small effusion in the right knee. The effusion grew a little larger and she developed a tender swelling in the popliteal fossa and calf. Both the pain and swelling worsened as she bent and straightened her knee.

Patient's own account: I'm a 47-year-old woman, married with 3 kids. I don't smoke and I drink occasionally. I went to the doctor because of pain in my calf and knee when I was bending down. This has been limiting my daily activities. I have been diagnosed with osteoarthritis for which I have taken anti-inflammatory drugs for the past 2 years. The doctor saw a small fluid buildup in my right knee. This buildup became a bit bigger and I have a swollen calf. The pain is worse when I bend and straighten my knee.

Clinical trial: Strengthening Exercise and Quadriceps Force During Walking

Eligibility criteria:
Inclusion Criteria:

        A medical doctor will perform the screening of potential participants. Subjects must meet
        the following inclusion criteria to be eligible for study entry:

          -  Knee OA diagnosed according to the American College of Rheumatology criteria (26),
             with clinical symptoms and radiographically verified tibio-femoral osteoarthritis in
             one or both knees.

          -  Aged between 40 and 65 yrs.

          -  Untrained (i.e. less than 2 hours of exercise per week)

          -  Subject must not be using assistive walking device

          -  Willing and able to complete study visits and procedures

          -  Willing to hold activity and exercise level generally consistent during the study
             except that encompassed in the study.

          -  In general good health, in the opinion of the investigator, based on medical history
             and physical examination and, if necessary, laboratory values. Laboratory tests are
             prescribed by the medical doctor at the screening visit.

          -  A body mass index (BMI) of 19<BMI≤32kg/m2

          -  Speaks, reads and writes Danish and/or English language

        Exclusion Criteria:

        Subjects who meet any of the following exclusion criteria will be ineligible for study
        entry:

          -  Subjects depending on walking device

          -  Pregnant or breastfeeding

          -  Radiographic evidence of Patello-femoral knee OA only (and no tibio-femoral OA).

          -  History of symptoms of autoimmune disorders (e.g., inflammatory bowel disease,
             multiple sclerosis, lupus, rheumatoid arthritis)

          -  Planned surgical procedure during the duration of the study

          -  History or diagnosis of musculoskeletal injuries or pathologies, including but not
             limited to:

               -  Anterior cruciate ligament injuries

               -  Meniscal injuries related to trauma (degenerative changes allowed)

               -  Patellofemoral Pain Syndrome

               -  Low back pain

          -  History, diagnosis, or signs and symptoms of clinically significant cardiovascular
             disease, including but not limited to:

               -  Ischemic heart disease

               -  Arthrosclerosis

               -  Peripheral artery disease

          -  History, diagnosis, or signs and symptoms of diabetes

          -  History, diagnosis, or signs and symptoms of neurological disorders including but not
             limited to

               -  Stroke

               -  Parkinson's disease

               -  Multiple sclerosis
No condition on gender to be admitted to the trial.
No healthy subjects accepted to join the trial.
Subject must be at least 18 Years old.
Subject must be at most 70 Years

Eligibility (NLI label): Entailment