Effects of elastic-band exercise on lower-extremity function among female patients with osteoarthritis of the knee

Objective: To investigate a new style of resistance exercise using elastic bands and explore its therapeutic effect on the lower-extremity function of female patients with osteoarthritis (OA) of the knee. Design: A randomized, controlled clinical trial. Setting: University-affiliated medical center. Participants: Forty-one women with mild-to-moderate knee OA were randomly assigned to one of two groups, an exercise group (n = 24; age: 65.0 +/- 8.4 years), and a control group (n = 17; age: 70.8 +/- 8.4 years). Interventions: The exercise group performed supervised exercise with elastic bands in addition to conventional modality treatments two to three times a week for 8 weeks. The control group received only the conventional modality treatments over the same period. Main outcome measures: The distance of the functional forward-reach, 30 s chair stand repetitions, walking function (time of a 10 m walk, timed up-and-go, and going up-and-down 13-stair tests), and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index scores. Results: Statistically significant improvements in all measures were observed in the exercise group after 8 weeks (p < 0.001). Except for the outcomes on the functional forward-reach (p = 0.108) and going up-and-down 13-stair test (p = 0.278), there were significant differences in the extent of improvement between the two groups. Positive changes in the 30 s chair stand test, 10 m walk test, and timed up-and-go test were 2.5 +/- 1.4 repetitions, 1.4 +/- 1.2 s, and 1.6 +/- 1.1 s in the exercise group, which were significant better than those in the control group (0.6 +/- 0.9 repetitions, 0.5 +/- 1.1 s, and 0.3 +/- 1.1 s, respectively) (p <= 0.001). The lower scores of all three subscales of the WOMAC index were significant after 8 weeks (p <= 0.05), especially for pain (-2.3 +/- 1.3) and physical function (-10.7 +/- 5.9) (both p <= 0.01), and the improvements were all significant better than those of the control group (p <= 0.05). Conclusions: A new style of resistance exercise using elastic bands with four color combinations (yellow-red, red-red, red-green, and green-green) over a period of 8 weeks can significantly improve lower-extremity function among females with mild-to-moderate knee OA.