Water Treadmill Training Programs Show Positive Effects On Fitness Measures In Horses

Conditioning equine athletes on water treadmills significantly improves peak oxygen consumption (1) investigates the cardiovascular performance benefits of training equine athletes on a water treadmill (WT) compared to a conventional dry treadmill (DT). Before this study, the effects of conditioning using a WT had not been investigated as they are primarily used to rehabilitate musculoskeletal injuries to equine athletes. This study aimed to answer the question of if water treadmill conditioning using a high-water level improved fitness. The authors hypothesized that they would see a greater improvement in fitness with the horses conditioned with the WT than in the DT control group. Previous studies conducted using WT with water height at the stifle compared with water height at the mid-cannon bone failed to elucidate muscular or cardiovascular changes. It is known that when training on a WT, the water creates a high degree of resistance, increasing the workload without increasing treadmill speed (1).

Three different programs were tested during the study. A WT training program with a high-water height, where the water level was equal to the height of the stifle, a lower water height, where the water level was equal to the height of the carpus, and a traditional dry treadmill. After an 18-day conditioning program on the WT and postconditioning tests, data was compared to the control group that did the same preconditioning and postconditioning test and the same conditioning program on a DT. The horses conditioned on the WT showed greater VO2 peak and endurance improvement. These conclusions support that training on a WT with high water levels has a greater impact on equine cardiovascular performance than traditional training programs (1).

Nine Thoroughbred horses, all out-of-season competitive polo ponies, were randomly assigned to the control and treatment groups. The three horses assigned to the control group were worked on a DT, and the six horses assigned to the treatment group were worked the same way but on a WT. Diets were individually made for each horse using a combination of hay and concentrate to keep the horses at constant body weight. Horse health records were examined to ensure no recent lameness, health issues, or poor performance. Before the study was started, visual psychical and lameness examinations and cardiac auscultation were performed by board-certified veterinarians of internal medicine, sports medicine, and rehabilitation.

Table 1. Conditioning protocol of Thoroughbreds on a water treadmill











Water height










Duration (minutes)










Protocol for all WT horses for the first eight days of training. Water height was determined using anatomical locations on horses individually. Duration is given in minutes and excludes warm-up (filling) and cool-down (emptying time). Days 9–18 occurred with water at stifle height for the entire duration of 20 minutes. A speed of 1.45 m/s was set for the entire conditioning period. WT, water treadmill.

All horses in the study were stabled and trained at a private rehabilitation and conditioning facility in Alberta, Canada. During the preconditioning sessions, the horses trained on the treadmill without using water to ensure that they could safely work on the treadmill. Both groups in the study were trained for a total of 18 days for the same twenty-minute period at the same treadmill speed of 1.45 m/s. The first nine days of training for the WT group consisted of increasing water height and duration, as seen in Table 1. Days 9 through 18 consisted of an exclusive twenty-minute training session with warm-up and cool-down. The warm-up and cool-down were conducted as the WT was filled and when it was emptied. The total maximal workout duration for the study, including warm-up, training, and cool-down, was forty minutes. The DT group followed the same increasing duration schedule over the first eight days as the WT group, then worked for twenty minutes for days 9 through 18.

Before and after the training on the treadmills, all the horses in the study underwent incremental exercise tests on a racetrack. The track was groomed on the morning of the tests, and conditions ranged from ‘good’ to ‘fast’ based on North American track standards. One week before the beginning of the training on the treadmills, the pretraining racetrack tests were conducted. Two days after the 18-day treadmill training program, the post-training racetrack tests were conducted. The stages of the racetrack testing were as follows; 300m at ~4 m/s, two 300m steps at ~6 and 8 m/s, and a final 800m gallop at maximal effort. All the racetrack testing was performed by the same high-quality jockey that could achieve maximal performance from all the horses. The speed of the horses at each interval in the racetrack test was determined using GPS and then communicated with the jockey via mobile phone. Using a new portable ergospirometry, VO2 readings were collected once on day nine of conditioning and during both racetrack tests.

After all the training and testing were completed, the data was analyzed to see the effect of WT conditioning. The VO2 peak of all the horses during the preconditioning test was 103.1 ml/(kg.min). After the training period, the WT group had a greater VO2 peak increase, an average of 16.1%. The DT group’s VO2 peak shows no significant change between preconditioning and postconditioning tests. Table 2 compares WT and DT preconditioning and postconditioning physiological responses. The average speed of the horses in the 800m maximal intensity racetrack tests was analyzed to compare the endurance of the horses. The WT horses average speed increased by 17.4%, from 8.7 m/s to 10.5 m/s. The total average time of the 800m stage decreased from 92 seconds to 76 seconds for the horses trained on WT. The average speed and time for those horses trained on the DT did not change.

Table 2. Preconditioning and Postconditioning Responses of Thoroughbreds After an 18-day WT or DT Training Program


WT preconditioning

WT postconditioning

DT preconditioning

DT postconditioning

V̇O2peak (ml/(kg.min))

96.3 (87.5–113.1)

121.0 (101.7–141.7)*

103.1 (92.8–106.7)

84.2 (76.8–86.3)

RF (breaths/minute)

134.4 (132.0–141.0)

143.4 (129.8–149.2)

128.8 (125.5–136.2)

140.8 (135.4–146.0)

VT (litre)

12.1 (11.9–13.3)

12.2 (12.0–13.6)

12.8 (11.2–13.7)

12.8 (11.6–13.7)

E (l/min)

1659.5 (1529.3–1852.0)

1763.0 (1730.5–1851.0)

1567.0 (1466.5–1725.0)

1797.5 (1691.3–1845.3)

HRmax (bpm)

218 (211–225)

212 (205–217)

212 (210–215)

209 (207–211)

5 minutes lactate (mmol/l)

19.0 (17.3–20.8)

19.6 (18.0–20.4)

13.3 (11.5–16.0)

16.3 (13.8–16.7)

60 minutes lactate (mmol/l)

11.8 (11.2–12.9)

12.4 (11.6–12.7)

7.5 (7.0–9.0)

9.1 (8.2–9.5)

80 minutes lactate (mmol/l)

8.5 (7.9–9.1)

9.4 (8.7–10.3)

4.6 (4.2–5.0)

6.1 (5.8–6.6)

Physiological responses during a maximal test of nine Thoroughbreds before and after 18 days of conditioning (WT training with water at the height of the stifle, 1.45 m/s; DT training without water, 1.45 m/s); 5, 60 and 80 minutes lactate=postexercise lactate. All values are presented as median (IQR).
* Values that are significantly different from WT preconditioning. † Values that are significantly different from WT postconditioning. DT, dry treadmill; HRmax, maximum heart rate; RF, respiratory frequency; V̇E, minute ventilation; V̇O2peak, peak oxygen consumption; VT, tidal volume; WT, water treadmill

This study aimed to determine whether or not high-water level WT conditioning improved fitness. The resulting information determined that WT training was considered less than maximal exercise under these conditions. While WT exercise is relatively low intensity, the authors significantly increased the VO2 peak and endurance by using a high-water height. This result led the authors to believe that even though WT programs may not be the most beneficial exercise to increase fitness, they positively affect conditioning VO2 peak and endurance in Thoroughbred horses.

This study's methods and testing procedures appear to be run with the utmost professionalism and follow the scientific method. The study's authors collected multiple types of data, differentiated between the control and experimental groups, repeats were done using the same circumstances and keeping the variables the same throughout all testing, and the data was collected, recorded, and interpreted accurately.

The conclusions made based on data collected and previously known knowledge of the subject show solid research efforts from all authors and demonstrate a need for similar research to fully explore how this type of conditioning can help increase fitness in horses. The author have stated within their findings that minimal research and testing has been conducted using WT training, which makes the data collected from studies like this one even more important and interesting because of the lack of available data to answer questions regarding the correlation or connection between WT training and equine fitness.

Connections made from the results of this study are very beneficial to many different individuals or companies within the equine world, especially those operating competitively. Individuals who own racehorses or operate within the industry would benefit from this and similar studies by gaining insight into how horses can be conditioned and trained more efficiently and to a higher standard of fitness and the possibility of discovering and modifying specific genetic traits affecting fitness. This kind of conditioning could also benefit any therapeutic rehabilitation services and research, including hydrotherapies and muscle or ligament rehabilitation, by helping to understand further how building and rebuilding different responses to trauma or loss of motor function could impact horses recovering from injuries. Discovering the effects of WT training programs, how varying the intensity of these programs affects different types of horses, and what results they yield will help increase the understanding of the equine body and how it reacts to a new type of conditioning program, which would help owners be able to offer better care and comfort to their animals, as well as to increase their potential safely and effectively.


  1. Greco-Otto, P., Bond, S., Sides, R., Bayly, W., & Leguillette, R. (2020). Conditioning equine athletes on water treadmills significantly improves peak oxygen consumption. The Veterinary Record, 186(8), 250.

By Emily Morse, Mitchell Shimmin, and Peggy Auwerda
The report is a project for ANS313 Exercise Physiology of Animals.