High water results in greater hydrostatic pressure exerted on the distal limb which has potential benefits for certain disease conditions such as osteoarthritis (OA) [39]. Increased intra-articular pressure within an OA affected joint is thought to lead to decreased proprioception and impaired muscle function leading to loss of stability of the affected joint. Kamioka et al [44] suggested that afferent excitation of joint mechanoreceptors induced by increased intra-articular pressure (as in OA) may be dampened by the effects of increased hydrostatic pressure provided by aquatic therapy in human patients. OA human patients typically show abnormal postural sway patterns due to decreased joint stability and postural control [45]. King et al [46] conducted a study on the effect of a water treadmill programme on static postural sway in horses with induced carpal OA; finding that the postural stability of horses exercised 5 days a week for 8 weeks on a water treadmill was improved when compared to a control group exercised on a land treadmill.