There are many who believe that racing and race-training young horses directly causes racing injuries and catastrophic breakdowns. Two is too young to take the physical strain, so the argument goes, and if not out by December, then washed-up by three. Look at Holy Bull, Thunder Gulch, Go For Wand, Hennessy or Ruffian – successful 2-year-old competitors that suffered career or life-ending injuries at three.

There is, however, scientific evidence that such arguments aren’t entirely valid. In fact, recent University of Sydney research findings concluded that there is no detrimental effect on a horse’s career, or longevity, if it started racing at the age of two. The study, published in the Equine Veterinary Journal, involved more than 115,000 Australian thoroughbred racehorses that were evaluated over a 10-year period.

In the words of the study’s supervising author, Dr. Natasha Hamilton, “… for those thoroughbreds that have started racing at two no ill effect can be detected.”

Not only did the study’s survival analysis show the risk of retirement from racing decreased the younger the horse was when it raced its first race, but it also showed the risk of retirement decreased with the number of starts a two-year-old had, and with the average distance raced.

So, does that mean that science has definitively proven racing 2-year-olds is a good and safe idea?

Not exactly.

While the study did observe that, of the 115,000 thoroughbreds involved, those that started racing at two suffered no ill effects, the scientists involved strongly advised caution when introducing young horses to racing. In essence, racing and training 2-year-old thoroughbreds is not harmful as long as there is an awareness that combining an inappropriate training regime with a genetic predisposition to injuries can result in injuries that prevent the horse from continuing or beginning its racing career.

In other words, it’s fine to put a youngster into training and races only IF your horse has the right genetics, IF
you know what you are doing and IF you proceed with caution.


Two-year-old horses are at a key point in their mental and physical development. Their minds are like sponges, they have the height and length of stride to run, and they have the energy to work. Race-training at this age not only mentally prepares a horse for the atmosphere of the racetrack, frequent transportation as well as changes in stabling location, but it can also optimize the condition of ligaments, tendons, muscles, nervous system, blood chemistry, and capillarization of lung tissue for the demands of racing.

In April or May of their 2-year-old year, most thoroughbreds are at the point in their bone maturation where they can develop the muscular and skeletal modeling required for safe and successful racing. Skeletal modeling basically means growing bones into the correct shape, density and location needed for a particular job or task. Bones can be forcibly modeled, or remodelled, through surgical intervention such as a human nose-job where the cartilage of the nose is broken and reset into a ‘more pleasing shape’. In 2-year-old racehorse training, bones are developmentally modeled – that is bones naturally take on a certain shape without breaking through a process of progressive overload.

Progressive overload is the essence of race-training. It involves a limited period of time when the variables of galloping – such as frequency, duration and intensity – are manipulated in such a way as to stimulate the desired physical changes. For example, classical training involves many miles of long, slow gallops. Most of those gallops stop increasing in length at two miles and the speed usually ranges from 18 to 20 seconds per furlong. Breezes are introduced about once every seven to 10 training days. With modified training, progressive overload is achieved through gallops that are usually one mile to one-mile-and-a-quarter. Speed work is introduced earlier than with traditional training and twice weekly gallops end with speed work that is increases in distance over a period of at least months.

The training idea underlying both of these approaches is that through galloping and breezes, new and dense bone will be formed to counteract the concussive impact of the legs striking the ground at particular angles and at particular speeds. Of equal importance is specificity, that is, the more closely training resembles an actual horse race the better the results will be at race time.

Once horse bones have been developmentally modelled, they typically retain their shape and density until the horse reaches old age. Thus, early race-training exposure benefits both the body and the mind.


Progressive overload and developmental modelling can work well in theory and, in some cases, in practice. The trouble is that not all 2-year-olds are the same.

For instance, individuals can vary widely in their mental maturity. It would be lovely if all 2-year-olds could learn balance, calmness when walking to and from the training track, and a positive reaction to the bit at exactly the same rate, but they don’t. Some youngsters cannot be trusted not to bolt at top speed anytime they leave the barn, while others move like a discombobulated cow under a rider for a week or more before they learn to balance.

Concentration levels can also vary. Some youngsters cannot concentrate for more than two minutes at the end of March, but after four weeks in the paddock to settle down from the stress and excitement of their new life, can learn new lessons in a heartbeat. Some rookies require an older horse as a trailering and training companion, while others are fine going solo. Many 2-year-olds get bored easily with routine training tasks. However, there are some young thoroughbreds that thrive only when kept on a strict routine.

Physiologically, youngsters can also vary widely due to differences in genetics, diet, climate and even learned behaviour. For example, young foals from dams that pace or paw at stall walls and floors are likely to exhibit the same behaviours and can require remedial farrier work prior to beginning training. Those individuals predisposed to osteochondritis may show signs of lameness or pain due to undetected dissecans or lesions while other individuals are extremely slow to develop their endurance and fatigue easily. Two-year-olds accustomed to cold spring months may take two to three weeks to acclimatize to a hot-weather training facility.

Equally important, musculature and muscle maturity is highly individualistic. A lot of muscles don’t necessarily mean a 2-year-old is ready for strenuous training and even if a horse’s muscles seem to be getting bigger and stronger during training it doesn’t mean his tendons and bones are keeping pace.

Big does not necessarily mean better when it comes to training and racing 2-year-olds.


It is extremely easy, and quick, to over-reach with a 2-year-old. By over-reach, I mean the variabilities of training or racing intensifying beyond the maximum stress capacity of the horse. Over-reaching can be mental, wherein the horse becomes over-stimulated and either develops behavioural problems or refuses to cooperate with training or racing. Such horses can become dangerous to handle and ride and may improve with rest or a different trainer. Sometimes, though, mentally burned out horses become unrecoverable and never return to racing.

Often, over-reaching involves physical injury. One of the most common injuries involves the dorsal cortex of the third metacarpal bone. Commonly known as “bucked shins”, dorsal cortical metacarpal injury happens so often with 2-year-olds it is considered a normal adaptive response to training stress. The problem is bucked shins can develop into actual fractures which, if not caught in time, can develop into lameness, swelling or bone breaks one to two years later – that is, during the 3-year-old or 4-year-old season.

Any sudden increase in the intensity (speed or length) of exercise will cause a correspondingly sudden increase in stress on bones, tendons, muscles and even internal organs in a horse at any age – it’s just that 2-year-olds are especially prone to stress injuries that require significant periods of rest to health. For example, 2-year-old thoroughbreds in training are the horse population at highest risk for developing pneumonia which has a recovery time of two or three weeks. Lost training time due frequent disturbances to immune functions from stressful exercise has been scientifically documented (Buschmann et al., 1990) as have recurring digestive ulcers.

By far, though, it’s the legs that take the brunt of the damage. An estimated 60 per cent of all 2-year-olds in training in North America in any given season, will experience an injury to legs bones, joints or tendons severe enough to delay their first racing start by anywhere from one to two months, up to a full racing season. Simply put, it takes longer to bring developing bone back into strong racing form than it does mature bones. Since maximum soundness directly relates to earning potential, musculoskeletal injuries in 2-year-old racehorses can end-up costing more money in the form of lost racing time than musculoskeletal injuries to 3-year-olds.


At the end of the day, it is up to the horse owner to decide if a 2-year-old will start training, but it is in the horse’s best interest to remember that, given all the variables, it is vitally important that training and racing should be conducted with copious amounts of experience, sensitivity, flexibility and caution.

Or, as an old German dressage trainer once told me, with young horses it is better to be a month late than a day too early.