Nike and Adidas both have some clever trainer technology which they say can make all the difference to the way you run: Adidas has the Boost range or trainers, Nike has the Free.
Both Nike and Adidas's offerings are loaded with tech buzzwords and potentially gimmicky bits of stitching. But do they work? We have spent about a month running in each, putting down plenty of miles and working closely with fitness experts to learn exactly how our running has changed, if at all.
The shoes on test are the Adidas Energy Boost and the Nike Free 5.0. These are flagship products for Nike and Adidas when it comes to comfort and ease of use, intend to make running as smooth and easy as possible. The core concepts around each are slightly different.
We spoke to Tobie Hatfield, designer of the Nike Free 5.0, who said that the concept behind them was to free up your feet. Hatfield explained that we already had some brilliant "natural technology" in the form of our feet and that the Free was all about designing around that.
"We just needed to design to the natural motion of the foot. Back in 2001 athletes liked to barefoot train, so we thought, let's understand the foot first and then build for that," he said.
The result is a shoe which is as dynamic and flexible as Nike can make. It incorporates Flywire technology, which essentially turns the whole upper part of the trainer into a suspension bridge for your foot. You also get a thin sole divided into sections, which is where the flex comes from in the shoe.
The Boost is a very different trainer compared to the Nike in terms of design. Rather than going for flexibility, the support and comfort all comes from the sole.
It features a set of capsules bonded together to make up the base of the shoe. It provides "the highest energy return in the running industry while combining usually conflicting performance benefits", says Marcus Wucherer, category manager running, at Adidas.
"With standard EVA material which is used in most running shoes, runners have to choose between soft and responsive cushioning. Boost changes this as it combines these performance needs into one incredible running experience."
Plenty of buzzwords to get the tech fan excited in both sets of shoes. The cynic in us however didn't quite believe either would do much for our running apart from just adding comfort. We ended up being very wrong, but for reasons we hadn't expected.
The first thing we needed to do with the shoes was test them out at a running track. We brought personal trainer Turner Moyse along. A running expert, he would be able to provide tips on our technique as well as offer feedback as to what exactly the shoes were doing.
The first thing we learnt about the Free 5.0 was the potential they had to improve our running. Most people inherently run on their heel, with the back of their foot taking the majority of the impact at the start of each stride. Over time this can cause you all sorts of issues with your joints, so the trick is to try and change the way that you run.
Before we took the Free 5.0 for a spin, Turner had us running barefoot in an attempt to trick our brains into running on the toe and front part of our foot.
"You need to run barefoot to learn how to use the Free properly. It is all about toe then heel with the Nikes, but the opposite with Adidas." Turner explained.
A few laps of the track and we started to see exactly what he meant. Once you start to run on the front of your foot, the flex in the toe box of the Free 5.0 means you can get much more power in your stride, without your toes constantly being under pressure from the stiffness at the front of the shoe. It works brilliantly and made a noticeable difference to the muscle and joint pain you might feel after an intense few hours at the track.
We also noticed that the flexibility in the front of the shoe helped us get off the line quicker when doing sprint starts. This is an important fact to consider, especially for those planning to use the Free to do short sprint training or in sports that require increased flexibility in your feet.
Any length of time spent in the Energy Boost around the track and it becomes immediately apparent just how well suited they are to long-distance running. They don't even come close to the Nike in terms of flexibility, but totally demolish it in the amount of support offered.
Using Usain Bolt as an example, Turner explained to us that his skill is in his foot speed. Bolt is a big guy who can run with the foot speed of a short person, all the while keeping the stride of someone taller. Mirror this and your running should get quicker. Practice comes from doing sprint starts and then gradually rising up, which the Nikes were ideally suited to.
The Adidas's benefit only became clear about 200 metres into a run. They really do add a boost to your stride, making you feel markedly faster than before. It's a much more impressive effect than you might imagine and initially meant we found the Adidas more impressive.
This changed once the run had finished. The amount of spring they put in your step meant we found they were putting increased strain on our calf muscles. After a 9km run and a warm down, our legs were in a fair amount of pain the next day. But we were quicker around the track by about 10-15 seconds.
Given the Adidas had performed so admirably around a running track, we wanted to find out how well they coped off the beaten path, where flexibility may offer more of an advantage.
As such, we did an identical set of laps at around 5km each on our usual off-road run, splitting them with a day between to let our muscles rest up.
As we suspected the Nikes performed better here. The added flex meant that running across uneven terrain was a bit easier. Each time your foot hits a rock, say, the shoe can bend around the shape of it, rather than hitting it dead on.
The load placed on our ankles and the ball of our feet was drastically reduced by the amount of give in the Nike. Because our foot could bend naturally to the contours of the run, we felt more stable when running and less prone to twisting ankles.
The Flywire found in the lacing system of the Nike is also there to help bring more support to your feet. While we never directly felt it in action, we did feel the whole shoe was wrapped tightly around our foot, never coming loose even after the bumpiest of runs.
Without a completely flat surface, a lot of the extra spring that the Boost provided was gone. The shoe appears much stiffer, like a traditional trainer, when you are running off road. In fact, the lack of flex meant we much preferred the Nikes in the case, which is surprising as you would think the cushioning that Boost offers would help.
Instead it was almost like driving a sports car off road, with the spring in the shoe meaning they skitter around and never settle over bumps. Our feet felt more prone to impact and the longer run was less comfortable.
Does all this trainer technology really work? In the case of the Adidas Boost trainers, they offer unparalleled levels of comfort and speed when running long distances. It really is amazing what sort of a difference they can make the first time you put them on and start running on a flat surface.
The flexibility of the Nike is also very impressive, although we can't help but feel that comes for the most part from the sole and little else. Having used a set of Nike Free Run +3 Shields over the winter, the sole is what really matters with the shoe. If you can learn to run on them correctly, they could also bring about a drop in the strain placed on joints and muscles when training, resulting in a shortened recovery time.
So yes, the trainer technology does work but in very different ways. Nike is all about flexibility and the Free 5.0 are perfectly suited to anyone who plays a sport that needs freedom of feet. Compared to the rest of the Nike Free range, they are also easily the best.
Adidas is on to something really special with Boost. Let's not forget these are the first version of the new trainer technology that the company has released. On the track, we loved them, but our muscles didn't quite as much afterwards. What we really want is a set of Boosts with the flexibility of the Nike Frees, then you will have a pair of trainers where the technology can utterly change the way you exercise.