Postural sway characteristics in women with lower extremity arthritis before and after an aquatic exercise intervention

Objective: To examine the reliability of postural sway assessment in women with lower extremity arthritis and to ascertain the effects of an aquatic exercise intervention program on these measures. Design: The reliability of postural sway measures was analyzed by within-subjects (Subject times Trial) analysis of variance (ANOVA). The effects of aquatic exercise were analyzed by repeated measures ANOVA using a planned comparison approach with an independent 2 x 2 (Group times Test) design. Setting: Testing in a motor control research laboratory; aquatic exercise in a warm water pool at an area YMCA. Participants: Volunteer sample, 24 women with lower extremity arthritis (rheumatoid [RA] n = 11, osteo [OA] n = 13) randomly assigned into an aquatic exercise group (n = 14) or control group (n = 10). Intervention: Postural sway measures under a two-legged stance test on two separate test days: day 1, pretest; day 2, posttest, administered after a 6-week aquatic exercise program. Results: Reliability correlation coefficients for postural sway measures ranged from .64 to .94 for both subject groups. Aquatic exercise subjects significantly reduced lateral sway and total sway area scores (by 18% to 30%) under both visual conditions after the 6-week intervention. Postural sway scores were significantly higher under the no-vision condition than under the vision condition in each group for both test sessions. Both OA and RA groups had normal sagittal/lateral ratio scores. Conclusion: Women with lower extremity arthritis can be reliably assessed on postural sway measures on a stable two-legged stance test. Although they had normal sagittal/lateral sway ratio scores (ie, scores typical for nonarthritic peers), vision played an important role in their postural stability for this balance task. Aquatic exercise reduced postural sway in women with lower extremity arthritis, as demonstrated by a two-legged stance test, and this exercise program appears to be a viable treatment for increasing postural stability in this population.