When the great racemare Winx powered through 33 consecutive wins, 25 of them Australian Group 1s between 2015 and her retirement in April 2019, horse racing experts and scientists raced to seek the source of her talent.

Some of those studies involved performance analytics including Winx’s racing stride and cadence (the stride frequency) and other bio mechanical traits to her physique, said to be key to her remarkable success.

Physicist Dr Graeme Putt, from the University of Auckland, determined that Winx (Street Cry (Ire)) had been able to put in 2.7 strides per second, compared to the average of 2.3 for other horses. This cadence would translate to speeding 170 lengths per minute, about 30 lengths better than her competition.

At the same time, Dr. Putt noted that the mare’s stride length came in at around seven metres, well short of other greats he has studied such as Phar Lap and Secretariat, each charted at 8.2 metres. Rather than crushing her rivals with a long stride, it was her stride cadence that made her great.

Equine exercise physiologist Dr David Evans added that Winx also had other key qualities.

“It boils down to her anatomy and physiology, in other words the structure of her heart, her blood system and her muscles,” Dr Evans said.

Watch the great Winx in action here:

Yes, horses that move with more strength and efficiency have more success at the race track.

Collection of stride, cardio and bio mechanic data (such as length of bones) for Thoroughbreds has been around since the late 1980s and as technology has developed, so too have products offered by numerous companies that sell this information to breeders and prospective buyers.

Body and bone measurements on Thoroughbreds can begin in their weanling year but is used more for yearlings and 2-year-olds. Stride measurements and cardio scores are popular products during 2-year-old training sales.

Take it in Stride

The length of a horse’s racing stride and cadence are linked to ability, speed and stamina. A long stride is certainly a desired quality but cadence is an equally important part of the equation. Stride measures can be affected by different track surfaces such as dirt, synthetic and turf, how a race is run and configuration of a track.

There is a relationship between cadence and stamina; the more strides per minute a horse has suggests quickness but perhaps distance limitations whereas a steady rhythm of fewer strides per minute suggests long distance runners.

Suzanne Smallwood is president of Equix which has provided performance analytics for Thoroughbreds since the 1980s. Equix offers stride data, cardio heart scores, bio mechanical analysis and mating data. One of its most popular products is its ProStride™ high-speed digital stride analysis offered for 2-year-old in training sales.

“The data we collect and sell has added another dimension to the process of buying and breeding horses,” said Smallwood, who began as an analyst soon after Equix was formed. “We apply our technology to measuring yearlings and studying 2-year-olds, their stride and the way they move.”


Equix’s niche is ProStride, a package of data that includes average stride length, gallop-out times, quartile rank plus motion analysis offered at juvenile sales in the US. A potential buyer, bloodstock agent of trainer can purchase the data for individual horses ($25), or horses of a session or entire sale ($750-$3,000).

“We do our own filming at each gallop show with a high tech camera that shoots at 180 frames per second and we analyze the stride on site during the show. We film from the sixteenth pole to the wire and look at the stride cycles and stride length. We clock the gallop out time, also. The videos are uploaded quickly and are available to people a few hours after the gallop show.”

Other data considered as part of the stride length includes hind leg placement, foot strike timing, launch and landings and body position. These detailed, slow motion videos and measures can tell a big story about the young horse on display.

“Horses could be doing something very special out there and it may not be evident to the naked eye,” said Smallwood. “We have a massive database. I run the analytics and look at graphic representation of these relationships: will this horse be versatile? Does he have power in his hind end and leverage to be tactical in a race? Or maybe he is a one run kind of horse.” Smallwood also offers a free link to the slow motion videos from the gallop shows for people to view.

At DataTrack International, on offshoot of the original Equix team, BreezeFigs have become its most popular product. A BreezeFig is a speed-figure that combines the time of the work (speed), stride length, angulation, segmental distances in the body and a unique “thrust” factor for each horse that breezes at a 2-year-old in training sale. A true bio mechanical study of a horse in motion it works just like most other speed figures—the higher the number, the faster and more successful the horse should be— regardless of breeze time and stride length alone. BreezeFigs are published in Daily Racing Form when one of these sale juveniles starts his racing career.

“BreezeFigs would be our most popular item,” said Frank Mitchell, director of bio mechanics for DataTrack. “And they are also the least pricey,” said Mitchell. “In addition to the figs offered at DRF, at the sales we can give clients the stride length, the average stride length of the day, those horses slowing down or speeding up over the work, and a couple other insights into the work’s speed and efficiency.”

Mitchell also measures horses of all ages, does cardio scans and discusses results of scores with owners and buyers as part of his DataTrack work.

The interest in data has grown surprisingly over the years,” said Mitchell. “I’d say it’s largely a result of people being more aware of the use of data as a sounding board of other opinions, but there’s also the greater importance of data and technology in people’s lives; so they look for it in racing and breeding also.”

Heart and Mechanics

Cardio reports are done predominantly for yearlings and older and is based on an ultrasound of the left ventricle of a horse’s heart taken when he is standing quietly. Studies have shown that maximum oxygen delivery in racehorses is positively correlated to left ventricular mass.

“This is the output valve,” said Smallwood. “We store several consistent beats of the heart and take measurements when the chamber is in the expanded state and then when the chamber contracts. From this we calculate Stroke Volume, or how much blood is being pumped per beat. We also measure the thickness of the heart wall muscling and observe and note the pace, timing, and function of the chamber. The data derived is computed with a set of body measurements, and an EF (ejection fraction) score given for each horse is based on the horse’s size, sex, exact age, and level of fitness.”

Smallwood explained that horses with average EF scores have suitable oxygen delivery for racing at most distances (based upon their own bio mechanical potential). However, horses who have above-average heart capacity gain oxygen delivery potential when racing at distances over a mile, particularly colts.

Indeed a big heart, such as Secretariat’s reported 20-plus pounder, can mean efficient and strong power but the size of the horse must be considered.

“The heart has to fit the horse’s body,” said Smallwood. “We check the heart capacity, how much blood they are able to get around their body to stave off the lactic acid. How much blood they are able to pump.”

A bio mechanics analysis uses proven data models and about 37 measurements from a horse to predict its growth patterns, racing potential and overall efficiency.

“Measurements are done around the girth area, back lengths, body length, bones in the hind quarters, the front leg bones, length of stomach to ground and height, all that pertain to their centre of gravity. And from yearling age we will project the growth up to 72 months. The program studies the relationship of all these bone and muscle groups at all the ages and it assigns bio mechanical efficiency scores.”

Prospective buyers can examine the bio mechanical and cardio scores through the Racing Analysis package that Equix offers for $675 (US). This amount is discounted once the horse sells. Smallwood noted that 2019 Horse of the Year, Bricks and Mortar, had “very high bio mechanical scores”.

Consignors of yearlings will also use measurement data before they sell the horse at auction. This information can also give clues to the breeder about how the match-up worked between sire and dam.
“Our Opti-Match matings program is also very big for us. We measure mares and stallions to find sires that fit with the mare’s structure.”

Smallwood also analyzes data herself and is hired by prospective buyers to scout out prospects. One of Equix’s first clients was Eugene Melnyk, who purchased dozens of major stakes winners through the company including champion and top sire Speightstown.

Currently she has been purchasing horses for Angelo and James Freda’s Ilium Stables who started a small stable two years ago and will race several at Woodbine in 2020.

One of the first horses Smallwood purchased for the Fredas, who are from New York but live in Connecticut, was Jezebel’s Kitten (Kitten’s Joy) who won the 2019 Exacta Systems Juvenile Fillies Stakes at Kentucky Downs, a $494,420 race on turf.

“My son James and I are interested in all the analytical aspects of racehorses, we like numbers,” said Angelo Freda. “We started using Suzanne since we got into racing. We didn’t know too much when we started and were looking for something different we could analyze and an agent to help us purchase horses.”

Little about buying or raising a racehorse is a sure-thing but these measures can narrow down the pool of prospects. Said Smallwood, “I had one of my long-time clients say to me, I don’t expect to be buy a champion every time but I would like you to stop me from buying a bad one.”

Performance analytics puts a scientific slant to the art of picking out the next star racehorse, offering buyers a wealth of information on what the physical make-up of a racehorse may suggest about a runner.