Every minute Winx is in full motion she takes 170 strides. That's 30 more than the average racehorse, with each one about seven metres in length.

It's an unusual formula for a champion sprinter, especially when compared to the sport's greats like Black Caviar and Phar Lap, each with a stride length close to 8.5m.

"Many think the horse with a bigger stride will always win," said Dr Graeme Putt, a University of Auckland academic who has studied the science of racehorse success.

But Winx is turning conventional wisdom on its head.

As the champion mare eyes a 19th consecutive win at Royal Randwick this weekend, she has already eclipsed Phar Lap's record of 14 on the trot and is closing in on Black Caviar's all-time mark of 25.

And the secret to her success is all in a freakish stride rate, which can increase in the dying stages of a race as other horses taper off.

As her fatigued rivals push to maintain 12 footfalls every five seconds, Winx can up the pace to 14.

"This means she can settle or accelerate at any time during a race. I think this makes her unique."

Dr Putt has published research on both Phar Lap and Black Caviar, examining the mechanics of their winning strides with scientific precision.

Black Caviar the Usain Bolt of the racing world

Photo: Black Caviar's huge stride helped her cover ground in classic sprint mode. (AAP: David Crosling)

Black Caviar was known for her acceleration and instantaneous speed, making her "both massive and the fleetest of sprinters in the equine world," according to Dr Putt.

At the peak of her career before retiring in April 2013, Black Caviar's size gave her a stride a full metre-and-a-half longer than Winx.

Similar mechanics drive the success of Olympic gold medallist Usain Bolt in the 100m and 200m sprints, according to Dr Putt.

"Bolt took 41 strides to win the 2008 Olympic Beijing gold in the 100m dash — the others took 43 to 44 strides," he said.

"He had the larger stride length by about 5 per cent, but that alone did not cause him to win.

"He won because he was able to maintain the same — or maybe only 2-3 per cent less — stride frequency as the losers."

Winx's last win took her career earnings over the $13 million barrier, closing in on Makybe Diva's all-time prizemoney record of $14.52 million.

Photo: Winx has a shorter stride, but she still distanced her Cox Plate rivals in 2016. (AAP: Joe Castro)

Equine exercise physiologist Dr David Evans said a champion horse like Winx has several other key qualities which set her apart from her rivals.

"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.

"She has to be built with the right muscle structure, she has to have the right amount of muscle relative to her body weight and she has to have the right type of muscle fibres.

"So not all muscle fibres are the same and she has to have the right mix of muscle fibres to enable her to sprint."

But those looking to spot a champion racehorse in the making may find it is very difficult to pick these qualities by sight in a foal.

"Back in the '80s there was enthusiasm for taking a biopsy and testing a small amount of muscle, but that didn't go anywhere because you're taking a couple of grams of muscle from a 500-kilogram horse.

"So you can't predict their sprinting ability from a tiny sample of muscle like that.

"Basically the best way to see what they can do is take them to a racetrack and test them over 400 and 600 metres and see what they can do."

Winx's ability to turn on speed at will was perhaps never more evident than at her last run in the Warwick Stakes, where she missed the start by five lengths but managed to pull off a dramatic comeback to clinch victory.

Winx caught the lead horse in the shadow of the post to win by barely a nostril in her final stride.

The performance has already drawn comparisons with Phar Lap's legendary comeback in the 1931 Futurity Stakes at Caulfield.

"Both Phar Lap and Winx were left flat-footed at the start and trailed off by about five lengths," Dr Putt recalls.

"Phar Lap's was probably more sensational because he raced hard to catch up and passed some of the tailenders only to get pocketed by other riders.

"His jockey Jim Pike had to drop him back to get out of the pocket so he could come around wide and close on the leaders.

"Phar Lap actually got to the front by about a half-length before the finish line but then had to hold off the others as he fatigued."

But even having studied the sport's greatest racehorses, Dr Putt had to concede:

"In some ways Winx's win would have been more breathtaking for observers at the course because it was only in the last stride that she won," he said.