We determined whether physical function and its response to exercise training are associated with polymorphisms in cytokine genes (interleukin-6 [IL-6] -174 G/C; tumor necrosis factor alpha [TNFalpha] -308 G/A and -238 G/A; and TNFalpha receptors [TNFR]1+36 A/G, TNFR2 +676 T/G, and TNFR2 +1663 A/G), in 214 older (> or =60 years), overweight (body mass index > or =28 kg/m(2)) individuals with knee osteoarthritis.