Objective To quantitatively assess measures of static balance and limits of stability (LOS) in an aquatic environment compared to on land.
Methods Fifteen healthy, young adults (23 _ 2 years) performed 90 s static balance trials on land and aquatic immersion at two different depths (greater trochanter, xiphoid process).Measures of 95% ellipse area and center of pressure (CoP) mean velocity were computed from the force data. Additionally, participants completed a visual analog scale (VAS) of perceived stability for each environmental condition. Following the static balance trials, participants performed anterior-posterior and medial-lateral LOS assessments.
Results Significant differences in 95% ellipse area and CoP mean velocity were observed for the aquatic environments compared to on land (p < 0.05). VAS data revealed significant differences in perceived balance in an aquatic environment compared to on land (p < 0.05). LOS assessments revealed a significant difference in maximum CoP excursions in an aquatic environment compared to land (p < 0.05).
Conclusion When participants performed a quiet double-leg stance task, measures of balance and perceived stability were inferior when the task was performed in water than on land. Additionally, participants achieved greater CoP maximum excursions in the water compared to on land. Although future research is needed to assess factors influencing balance in the water, the added instability in the water is clinically relevant. Results ofthis study further highlight the importance of considering the inclusion of aquatic training as part of a comprehensive training / rehabilitation program.
Keywords: Static Balance, Postural Sway, Center of Pressure, Aquatic, Water