Effects of aquatic exercise and land-based exercise on postural sway in elderly with knee osteoarthritis

Objectives: The objective of this study is to compare effects of aquatic exercise and land-based exercise on postural sway and physical performance in elderly with knee osteoarthritis. Methods: The assessor-blinded randomized controlled trail was done. Elderly women with mild to moderate osteoarthritis, age 60-75 yrs were recruited. Postural sway viewed by COPx or anterior– posterior (A–P) amplitude, COPy or medio– lateral (M–L) amplitude, Total Area or XY area in during double and single leg stance while eyes opened and closed measured by the Force platform (Bertec # FP 4060-08), functional outcome tested by Modified WOMAC and Knee injury and Osteoarthritis Outcome Score (KOOS), pain scale tested by Visual Analog Scale (VAS), leg muscle strength tested by chair stand, and leg muscle flexibility tested by sit and reach test were measured before training as baseline and 6 weeks after training. The patients were randomized into two groups. Aquatic group exercised in therapeutic pool of King Chulalongkorn Memorial Hospital and Land-based group exercised at home, 45-60 minutes per day, 3 times a week, for 6 weeks. Results: The reduction of postural sway in aquatic group was significantly more than land-based group at p <0.05. ANCOVA showed that WOMAC, KOOS scores and sit and reach test after 6 weeks training were significantly improved after exercise in both group but were not significantly different between groups at p > 0.05, except that chair stand was significantly increased and VAS was significantly decreased in the aquatic group more than the land-based exercise group at p <0.05. Conclusion: Aquatic exercise for 6 weeks was better than land-based exercise for 6 weeks in term of sway reduction, pain reduction and strength increment but not the functional outcome and muscle flexibility.