Nike restricts self-lacing trainers to app users Published duration 17 March 2016

image copyright Nike image caption The Nike HyperAdapt's laces can tighten themselves - but require the wearer to adjust the fit

Nike has unveiled its much-anticipated range of self-lacing shoes.

It said the HyperAdapt trainers would be released to the public before the end of the year.

A pair of Nike-branded shoes with self-tightening laces featured in the 1989 film Back to the Future II, but it was not until 2013 that the firm started trying to make real-world versions.

In an unexpected move, the US firm has said that sales would be restricted to users of its apps

image copyright Nike image caption The laces are tightened by small electrical motors built into the shoes

While some might see the self-lacing function as being more gimmicky than useful, the tie-in to the Nike+ software will help the company promote other goods to those curious about HyperAdapt.

Nike+ apps are currently focused on tracking data about users' activities and offering them training programmes. But from June, the platform will introduce personalised shopping recommendations and an online store.

"Nike has lost a fair bit of traction recently to sportswear upstarts including Under Armour, which bought the MyFitnessPal app, and Asics, which has acquired Runkeeper," said Marc McLaren, online editor of Stuff, a tech-focused magazine.

"This will help keep people engaged, and we can already see from the reaction our readers are having to the announcement that they are very excited by it."

image copyright Nike image caption The Nike+ software will introduce shopping functions

Mini motors

Although Marty McFly's trainers appeared to tie themselves up in the Back to the Future movie, the effect was in fact created using a prop that was bolted to the ground, below which a stagehand pulled on the laces.

Nike has achieved the effect for real by using small electric motors to adjust the laces.

These are activated when the user's heel touches a sensor.

image copyright Universal Pictures image caption The shoes featured in Back to the Future II did not really lace themselves up

Two buttons on the side allow the wearer to tighten or loosen the fit. A glowing component built into the sole acts as a wireless charging point, while LEDs on the back indicate how much charge remains.

Attendees at the company's Innovation Summit in New York were able to try on functioning prototypes.

The firm said the final product should need to be recharged about once a fortnight.

In time, Nike added, it intends to develop the idea further.

image copyright Nike image caption The shoes contain a unit in their base that allows them to be charged wirelessly

"Wouldn't it be great if a shoe, in the future, could sense when you needed to have it tighter or looser?" asked the trainers' designer Tinker Hatfield.

"Could it take you even tighter than you'd normally go if it senses you really need extra snugness in a quick manoeuvre? That's where we're headed."

The firm is not alone in developing self-tightening footwear.

At the CES tech show in January, French start-up Digitsole unveiled a pair of self-tightening "smartshoes" that also featured an app-controlled heater - but they have yet to go on sale.

image copyright Digitsole image caption Digitsole says its smartshoes will tighten their fit, count calories and warm their users' feet

Nike, however, has a stronger brand.

"I think it's a canny move to get people to sign up to the Nike+ service, but if they do prove popular I'm sure the firm will open them up to a wider audience eventually," added Mr McLaren.

"But maybe that will be another year down the line."