부산대학교 도서관

Introduction: Stroke is a cerebral vascular disorder affecting the sensory, motor, and mental system resulting in balance problems. One of the key changes is the ability to shift weight together with postural control. Water-based exercise is recognized as a potential approach to improve balance performance (Mehrholz et al., 2011; Barker et al., 2014). Among various water-based programs, Ai Chi is a specific water exercise utilizing a combination of deep breathing and slow, broad movements of the arms, legs, and torso in flowing continual patterns. It highlights the transition of weight to different directions. Limited studies have shown that water-based exercise complemented with Ai Chi resulting in positive effects on muscle strength, postural control, and functional mobility (Noh et al., 2008). However, whether Ai Chi alone can exert beneficial effects is not comprehensively known, nor its superiority to conventional water-based exercise in individuals with chronic stroke. Methods: This was a single-blind controlled, randomized trial with pre- and post- measurements. Participants in the experimental group received 15 min of warm-up, 30 min of Ai Chi, and 15 min of cool-down exercise under the water, 3 times a week for a total of 6 weeks. The difference in intervention between experimental and control group was the participants in the control group received resisted movement training in water instead of Ai Chi intervention. Static and dynamic balance were defined by standing weight distribution and limit of stability (LOS) respectively using the SMART Balance Master (NeuroCom International, Inc., USA). The reaction time (RT), movement velocity (MVL), end point excursion (EPE), maximal excursion (MXE), and directional control (DCL) of the LOS test toward forward, backward, affected, and non-affected directions were analyzed. Functional balance performance was documented with the Berg balance scale. Time and group effects were determined by Wilcoxon rank sum test and Mann-Whitney U test respectively. Statistical significance was set at p less than 0.05. Results and Discussion: Ai Chi group (n = 8, mean age of 56 y and mean post stroke duration of 23.9 m) improved more in LOS test especially in EPE backward direction (23.2%) than the control group (-4.8%) (p = 0.04, effect size: 1.22). The control group (n = 6, mean age of 55.7 y and mean post stroke duration of 13.2 m) seemed to gain dynamic balance control toward the affected side (reaction time decreased by 0.8 s, p = 0.02, effect size: 0.22). The Ai Chi group tended to have larger enhancement than the control group in movement velocity in the LOS test (forward: 1.6% vs 0.5%, backward: 0.5% vs -0.2%, affected: 0.6% vs -0.4%, non-affected: 2.1% vs 0.3%). Conclusion: Overall, water-based exercise is an optimal training for balance deficits in stroke. Ai Chi, with elements of coordination and weight shifting, might potentially achieve superior effects in anteroposterior control, which is important in stroke rehabilitation.