Summary: Reasons for performing study: Water treadmill exercise is often incorporated into rehabilitation programmes for horses yet little is known about the biomechanical and physiological responses to water walking. Objectives: To establish whether stride frequency (SF) reached steady state as a result of 6 introductory water treadmill sessions and then to investigate the effect of increasing water height on SF, stride length (SL) and heart rate (HR). Methods: Nine horses with no previous experience of water treadmills completed 6 sessions of walking for between 15 and 30 min. Each horse was fitted with a leg mounted accelerometer to measure SF. The effect of session on SF was tested using univariate ANOVA. Eight horses completed 3 further sessions at each of the following water heights; proximal interphalangeal joint (PIP), carpus and ulna. SF, SL and HR at each water height were compared to a control (hoof height) using univariate ANOVA. Results: When SF during introductory sessions 4–6 were compared, there was no significant effect of session on SF (P>0.05). In the second part of the experiment, SF was 0.57 ± 0.03 strides/s at control, 0.54 ± 0.03 strides/s at the PIP joint, 0.51 ± 0.02 strides/s at the carpus and 0.52 ± 0.03 strides/s at the ulna. Stride frequency at carpal and ulna height was significantly lower than at control (P<0.05). Stride length was 1.53 ± 0.09 m for control, 1.63 ± 0.10 m at the PIP joint, 1.71 ± 0.08 m at the carpus and 1.68 ± 0.10 m at the ulna. Stride length at carpal and ulna height was significantly greater than control (P0.05). Conclusion: Horses reached steady state gait within the first 6 sessions of water treadmill exercise. Walking in water at the level of the carpus or ulna resulted in a lower SF compared to walking in water at hoof height.

Water treadmill exercise has become popular in recent years for the training and rehabilitation of equine athletes. In 2019, an equine hydrotherapy working group was formed to establish what was commonly considered to be best practice in the use of the modality. This article describes the process by which general guidelines for the application of water treadmill exercise in training and rehabilitation programmes were produced by the working group. The guidelines describe the consensus reached to date on (1) the potential benefits of water treadmill exercise, (2) general good practice in water treadmill exercise, (3) introduction of horses to the exercise, (4) factors influencing selection of belt speed, water depth and duration of exercise, and (5) monitoring movement on the water treadmill. The long-term goal is to reach a consensus on the optimal use of the modality within a training or rehabilitation programme. Collaboration between clinicians, researchers and experienced users is needed to develop research programmes and further guidelines regarding the most appropriate application of the modality for specific veterinary conditions.

Outcome measures (OMs) are a requirement of professional practice standards in human and canine physiotherapy practice for measurement of health status. Measures such as pain and functional capacity of specific regions are used to track treatment impact and can be used to develop optimal management strategies. To achieve comparable patient care in equine physiotherapy, OMs must be incorporated into practice; however, no reliable and valid OMs exist for equine rehabilitation. This study utilised the experience and opinion of a panel of experts working in the equine rehabilitation sphere to gain consensus on the core areas (domains) to be included in a model, to lead to an OM scale for horses undergoing rehabilitation. The Delphi method and content validity ratio testing was used to determine agreement with domains reaching the critical value required for inclusion. The expert panel agreed on ten domains to be included in the OM scale: lameness, pain at rest, pain during exercise, behaviour during exercise, muscular symmetry, performance/functional capacity, behaviour at rest, palpation, balance and proprioception. An OM with these domains would provide a holistic objective assessment tool which could be used by equine rehabilitation professionals in clinical practice.