A compression top with an auto-tightening collar that promises to reduce whiplash and concussion is the first product from Canadian sports tech start-up Aexos.

The Halo compression shirt boasts a collar made of a material that stiffens in response to fast, abrupt movement — like collisions that could cause a head injury in contact sports.

This tightening action slows the whiplash motion of the head and neck, which in turn reduces the likelihood of concussion.

Importantly, in the absence of this trigger, the top is soft, flexible and doesn't restrict range of motion.

Aexos (short for Advanced Exoskeletal Systems) started developing the shirt in 2015 and is now preparing to go into full-scale production, with the help of funds raised through a Kickstarter campaign.

"We saw the opportunity to tackle the biggest issue in sports in a way that's never been done before," said Aexos co-founder Rob Corrigan.

"We've spent the last three years developing Halo to create lightweight, high-performance protection for athletes that is unlike anything else available today," added Charles Corrigan, the company's other co-founder and CEO.

"The result is a whole new approach to protecting athletes in a way that wasn't possible a few years ago."

Halo's responsive collar is made possible by the use of active, or smart materials — a class of materials with qualities that change on demand, usually in response to temperature or pressure changes.

Until recently, such materials were rarely seen outside science labs like those at MIT, but sportswear brand Reebok has just launched a sports bra made of a similar textile with Motion Sense Technology. The bra becomes more supportive during high-impact exercise and relaxes during low-impact movement.

In Halo's collar, the material is a closed-cell polymer foam. The collar has no straps or bands, but is instead held in position by the shirt's silicone lining, which sticks to the skin.

Aexos is keen to see Halo used in professional and amateur sports, among adults and children, and by all genders.

The product is endorsed by North American organisation Safe4Sports and is currently being tested by the Canadian Department of National Defence.

Besides the smart collar, Halo offers the support of a more standard compression shirt.

Made of a nylon/spandex blend, it has silicone bands on the torso lining that are said to support the core, improve posture and increase "kinaesthetic awareness" — the body consciousness that allows a person to react fast to protect themselves when hit.

Other sportswear manufactures using technology to improve sporting performance include PUMA, which worked with MIT to envision the self-adapting, performance-enhancing sportswear of the future.