Nike has announced its new Nike Free running shoe range for 2016, ditching the Free 3, 4 and 5 models for a more universal approach that should appeal to a wider audience of runners.

While the range now looks to offer separate features for different runners and athletes, core to the new flagship trainer in the line is a new sole that, according to Nike, makes huge advancements over previous shoes that the company has released over the last 12 years.

While the sole still works around being as flexible as possible, it now takes a similar approach to how sports compression gear works.

Nike, being Nike, call this technology "progressive geometric auxetic". Put simply, it is the ability for the sole to stretch in all directions rather than just one.

The midsole is now designed to enable an athlete’s natural motion and develop strength, whether they are running or training.

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The reason, says Nike, is because studies have revealed that the foot expands and contracts upon impact with - and lift off from - the ground. Trying to either take advantage of this or combat it (we aren’t sure), the now splaying, auxetic midsole mimics how the body and foot react to force.

Nike adds that the tech "absorbs shock while accounting for the dual-plane expansion in foot size (approximately one size in length and two sizes in width) that occurs throughout an athlete's foot strike". It claims that the resulting flexibility puts the foot, rather than the shoe, in control.

We got a chance to try the tech in practice, during a 7.5km test run with Nike around Victoria in London.

The Nike Free RN Flyknit shoes certainly feel very natural. They give a good balance of cushioning and feeling the ground you are running on, without being overly “spongy”.

It is not a soft run by any means, and we wouldn’t feel comfortable running more than 10km in them for fear of our calves and an overall lack of ankle support, but there was plenty of spring to cope with bursts of acceleration. A balancing exercise on one leg proved fairly difficult. 

Sitting in the middle of the range, the RN Flyknit is probably most akin to the Nike Free 4.0 from 2015. It features a lightweight Flyknit upper, this time in blue, that delivers a sock-like fit with a classic silhouette that moulds to the foot.

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The midsole features the same expansive auxetic technology, but with IU foam for additional underfoot comfort compared to the Nike Free RN Motion Flyknit that ops for a 3D ribbing sole from the forefoot to heel.

Those not taken with the Nike Flyknit approach can go for a more traditional upper made with mesh.

There is also a low-profile training shoe featuring a 5/8-height Flyknit upper designed to promote a feeling of support, while Flywire locks down the foot during lateral cuts and an integrated heel counter ensures stability during hard cuts. It’s called the Nike Free Train Force Flyknit.

The new trainers are now available, with the RN Motion coming in May.