Fitness improvement of show jumping horses with deep water treadmill training

Athletes, including equine athletes need high intensity training in order to achieve high performance. However, continuous high intensity training often results in injuries to the locomotive system. The buoyancy of water reduces the force born on joints; therefore, training in water has been used for rehabilitation purposes both in humans and horses. The few studies dealing with water treadmill training of horses suggest that the fitness of horses can be improved using this training method, but none tested the subsequent performance of horses after water training. Therefore, the aim of this study was to test the effect of water training of varying intensity on the fitness-related parameters of show jumpers during training and after competition. Four similarly trained show jumper sport horse (aged between 7-11 years) competing at the same level (110 cm) were selected. Horses were subjected to 44-min deep water treadmill training with three intensities (9, 11, 13 km/h maximum speed) three times a week in addition to their normal training. At the conclusion of the week, horses participated in a two-day indoor show jumping event. Blood samples (4 ml) were taken from the jugular vein during the third water training and before and after the completion of the show jumping course on each day. From the blood plasma, lactate dehydrogenase (LDH), creatine kinase (CK) and aspartate aminotransferase (AST) activities, as well as lactate, glucose and triglyceride levels were determined. Data analysis was carried out with SAS (SAS Inst. Inc., Cary, USA) using the GLM procedure and Duncan's new multiple range test. Pearson correlation coefficients were calculated between the same blood parameters from different sampling times. No interactions were detected between training intensity and sampling time during water training. Plasma lactate and glucose levels were decreased during the water training, while values increased afterwards. In contrast, heart rate, triglyceride and cortisol levels were elevated as a result of water training. Increasing the maximum speed of the water treadmill had no influence on the average heart rate of horses subjected to the training. Plasma lactate levels decreased with the increased maximum speed of the water trainer. Activities of AST, CK, LDH, and levels of cholesterol, cortisol and bilirubin decreased when the maximum speed of the treadmill was set to 11 km/h compared to the 9 km/h training. Water training resulted in lower heart rate measured right after completing the show jumping course when horses were subjected to medium intensity water training. The AST, CK and LDH activities measured before and after water training had only weak to moderate positive correlations with values measured after competition. In conclusion, our results indicate that deep-water training alters the biochemical processes and can improve the aerobic energy supply of show jumpers. Water training is a strenuous exercise, which initially leads to increased muscle damage. However, this initial phase is followed by subsequent adaptation.