Last updated on 15.07.2020
The sport of polo is one of the oldest ball sports dating back to 600 BC originally from Tibet, the equine discipline was picked up by British soldiers and brought back to England. The first match was played in the UK in 1871. The aim of polo is to score more goals than the opposing team. The pitch polo is played on is 300 yards long (274m) long and 200m (182m) wide on a grass surface. The game is played over four, five or six periods of 7 minutes each which are called by the Indian name “Chukka”.
The teams are made up of four players with two mounted umpires. In polo, there is no specified height for the horses however most are between 15 and 15.3 hands. Their schooling is devoted to stopping and turning quickly and being able to accelerate and ride-off another pony, much of this work is high paced but quick in duration, meaning they use fast bursts of energy followed by rest. The ponies usually only play two chukkas in an afternoon with a rest of at least one chukka in between.
Fitness testing methods
One of the most simple
One of the most simple and longest used fitness test in polo ponies is to work than in sets, a set is a performed on a measured outdistance, usually in a field or an arena. The rider will take the horse out at a set gait, on a set distance then recording the time taken for the horse to then achieve a resting heart rate after the exercise. This can be done for both aerobic and anaerobic forms of exercise. See below for an example set. A table showing an example set, EquiMed, LLC, 2012
Heart rate measurements
The first HR monitors were validated for use in equine exercise assessments in the 1980s. However since then, there have been many steps forward in new heart rate monitors specifically for horses, Most studies exercising horses use HR monitors like the Polar systems Vantage XL, S610, S810i and RS800CX (Parker et al, 2010). A study by Kingston et al (2006), showed that a GPS/heart rate monitor system provides a reliable measure of daily workload in horses during training. The technology also gives a detailed picture of horses’ training sessions and can be used in order to maximise the training techniques used.
However, there are no studies in which any of the commercial HR monitors have been tested during exercise against a simultaneously recorded electrocardiogram (ECG) for use in horses (Hodgson and McGowan, 2014). There have however been movements of wireless ECG in human science a study by Anchana, (2019) Where a prototype ECG wireless device was used in humans with abnormal heartbeats, The results from the study showed that the Real-time ECG signal monitoring system detected 17 abnormal ECG signal, the accuracy is 85%. With further testing in the field of human science this type of technology could, therefore, be used in the equine industry to help improve the reliability of heart rate monitoring as a form of fitness testing.
Lactate concentration measurements
During maximal exercise, glucose is broken down through glycolysis to produce energy. When the oxygen supply to the cell is insufficient due to the horse not getting enough oxygen-rich blood around the body during a stage of exercise, pyruvate and hydrogen ions combine to form lactic acid. This Lactic acid (LA) can be a good energy source however if the intensity of exercise requires maximal effort for a long period (20–120 seconds), it will have reached its anaerobic threshold meaning blood lactate concentration increases (Assenza.A et al., 2014). Blood and/or plasma LA concentrations have been used in humans and horses to measure the intensity of exercise (Hodgson, McGowan, 2014). The concentration of lactate in the blood and/or plasma is a result of the production of LA in the muscle, the diffusion of LA from muscles to the blood and the uptake of LA into several tissues. Lactate concentration can be measured in whole blood, total blood (where the erythrocytes are lysed), or in plasma.
However, this method of testing if the horse is fit by the amount of lactate in the blood has a lot of inaccuracies, as if whole blood samples are used they are not deproteinized immediately meaning lactate can be absorbed still meaning the values may not represent accurate blood LA levels (Rainger et al, 1995). It is important to take into account variations in tubes used for storage (different additives as an anticoagulant), storage time, temperature of blood samples, and sampling time in relation to exercise. Consequently, caution is needed when comparing and interpreting LA concentrations and derived fitness indices due to possible differences in sampling locations and analytical methods as found in the study by Leonhard et al.”,(2010).
Measuring and calculating the velocity of each exercise is done by the use of a global positioning system (GPS) technology that can be used simultaneously with an HR monitor. However, while using a commercial velocity system, the values of GPS distance and Heart rate are usually displayed with a delay of a few seconds that could be confusing. Therefore to make the most of the measurement equipment it is best to use a SET routine (Munsters et al, 2013b). If therefore GPS technology is not available or the horse is ridden in an indoor arena. Simple speed and distance measurements can facilitate measurement of speed at a given HR (e.g. V140) in ridden or lunged conditions (Harris et al, 2007), or using a marked track.
According to Harris et al., (2007) both techniques provide reliable results when used consistently, and the choice between them is a matter of personal preference and/or pragmatic dealing with logistical or other constraints. Campbell, (2011) recording that Several indices of fitness can be calculated from HR, LA and velocity measurements. The Mean HR and velocity of each exercise can be calculated by averaging HR and velocity from the last minute of each step. Plus the relationships between LA and velocity, and LA and HR can be determined by plotting velocity and HR against LA. These values are thought to be a reliable variable for the evaluation of fitness during incremental exercise. Based on studies in humans, it has been shown that blood/plasma LA starts to increase rapidly after reaching a concentration of 4 mmol/L, with VLA4 termed the lactate threshold. Similarly, in horses, lactate threshold is expressed as VLA4 and this can therefore frequently used for comparative purposes (Serrano et al., 2001).
Recent developments related to equine fitness testing
Blood lactate new developments
Within the equine industry, there is a need for more convenient, faster, and more reliable methods of measuring blood lactate concentrations. A new handheld Lactate Plus lactate meter (LPlus) which was originally developed and tested for use in humans was used in a study by Ashlee.A et al., (2014) which could provide dependable results when used in horses undergoing an exercise conditioning program and therefore see if a horse’s fitness would improve following individualized conditioning based on each horse’s velocity where lactate was equal to 4 mmol/L (VLA4) was reached. The study showed that although the LPlus tended to significantly underestimate LA by 0.39 mmol/L (P < .001), the LPlus did prove to be a dependable device for use in horses based on good correlation with the biochemical analysis (r = 0.978). All horses showed an increase in VLA4 from SET-1 to SET-2, consistent with improved fitness following a three week exercise training protocol. Ashlee.A et al.”,2014 finally stated that The LPlus can reliably be used in horses to determine [LA] ranging from 0–8 mmol/L. This study however only used 5 adult horses without specifying the type or discipline the horse was in therefore it could be hard to say that this has the same result and works for every horse without testing it on a bigger sample size.
In a study by Stefan et al., (2007) in human fitness testing used muscle biopsy in order to stain for myosin ATPase and calculate percentages of fast-twitch (FT) and slow-twitch (ST) muscle fibres as well as mean individual FT and ST fibre areas were determined. Their test included six female volunteers who participated in a training program in which to improve cardiovascular endurance. A muscle biopsy from the lateral aspect of the gastrocnemius muscle was also included. The training produced significant changes in the exercising subjects for the l2-minute run (p=0.006) and VO2max(p=0.003).
No changes were found in the tests of muscular power or individual fiber areas. The data indicated that the endurance training program was of sufficient intensity to effect an increase in cardiovascular fitness but the improvements in endurance were not accompanied by any significant changes in muscular leg power or individual muscle fiber size. However, a test like this could be used in the equine industry in order to see a difference i muscle fiber types or in order to measure the fiber type in a certain muscle group to then compare again after a training program to see any difference.
Maximum oxygen uptake (VO2 max ) expresses the maximum rate use of oxygen during exercise, and it defines the aerobic capacity of the horse. The VO2 max is the maximum amount of oxygen that the horse has the capacity to transport through the lungs, pump by the heart and use in muscles for the production of energy. It sets the upper limits for a high work potential, especially in events lasting longer than approximately 50-60 seconds. R Sides et al., 2014 states that the ability to accurately assess equine oxygen consumption (VO2) under field conditions had been limited by the need for unrestricted gas exchange methods, However, Two new variations of the original mask and an associated electronics were designed to enable the horse to have measurements taken while being ridden. Against the traditional VO2 mask, the VO2 measurements were reproducible for each of the new field masks. And concluded that the masks were capable of measuring VO2 during field exercise and were accurate by multiple users. A high VO2 max does not guarantee excellent performance, but, in general, Standardbred horses with a higher VO2 max have superior performance.
Unfortunately, there have been no studies of the associations between VO2 max and racing performance in Thoroughbreds, event or endurance horses. Performance of horses with a high VO2 max but low anaerobic capacity will probably be limited by poor sprinting ability. (Evans”,2000) This form of fitness testing is however very expensive and done under the control of a professional who is experienced with the equipment making it a lot less accessible to the equine industry as a whole.
In any equine discipline, it is essential to have the knowledge of the competitive demands of that practical activity as this is important for designing appropriate training programmes. This will ensure that the animal will reach a sufficient level of fitness in order to reduce the risk of overexertion and injury or illness”, and therefore helping to achieve the best possible performance in relation to an individual’s genetic potential.
There are many ways in which this can be carried out and it is completely dependant on the individual trainer as to what they find easiest to use as well as being cost-effective. However, Whilst the physiological demands of many equestrian sports have been described, there is little research into the cardiovascular demands of polo alone and therefore the fitness test methods from other disciplines can be pulled across to be used instead, however, research into the high anaerobic exercise polo ponies would be interesting it could be seen in other similar disciplines like racing where horses are working at a fast pace for a short period.