Data from large randomized, controlled trials
(RCTs) and systematic reviews of the literature indicate
that exercise provides small to modest benefits
(effect sizes ranging from 0.2 to 0.4) for pain relief,
improved function, and reduced disability.
However, details on the frequency, intensity, duration,
and type of exercise (aerobic, flexibility, dynamic
or static strengthening, balance activities) are
not always specified. Helmark and colleagues reported
that in a group of women with knee OA, exercise
increased both intraarticular and perisynovial
concentrations of interleukin-10, an antiinflammatory
cytokine that protects chondrocytes (cartilage
cells) and may be responsible for the benefits for OA
seen with exercise.