In the words of Nike, they are on a mission to keep runners running. Injuries are unfortunately part and parcel of the sport. To progress in running, we need to apply stress to muscles, tendons and ligaments so that they adapt and get stronger. It’s very easy to do too much or apply too much load too frequently and that’s when problems can occur. Injuries will usually be multifactorial and it is unlikely that there will be one cause of a problem. However, the right running shoes can play a significant role in reducing the likelihood of an injury occurring. One of Nike’s key objectives is to create running shoes which reduce the chances of getting injured. The Nike ZoomX Invincible Run Flyknit is a product of the Nike Sport Research Lab and part of the “Project: Run Fearless” which has a clear goal: to keep runners running.
Validated by Science
Let’s look at the science behind the Nike ZoomX Invincible Run. It’s best to start with an external study that was previously done on the Nike React Infinity Run. The study, conducted in 2019 with 226 men and women during a 12-week running programme, found that runners wearing a Nike React Infinity Run missed 52% fewer consecutive running sessions (3 or more) due to running-related pain than those running in a Nike Air Zoom Structure 22.
An additional study was conducted in 2020 with the Nike ZoomX Invincible Run to assess its effectiveness. This involved 314 runners doing variable training over a 12-week period. Each runner completed a total of 44 runs and a total of 104,248km were completed by the group. The results showed that the Nike ZoomX Invincible Run showed no statistically significant difference in the incidence of running-related pain compared with the Nike React Infinity Run in the original study. The “Nike Run Fearless System” appears to be producing footwear which is independently proven to reduce the chances of injury.
Runners should again take note that other factors will be at play when an injury occurs and a shoe alone cannot completely eliminate the chances of one happening. Nike is simply proving that advancements in technology, materials and knowledge of biomechanics can help aid running footwear design and improve the likelihood of a runner achieving their goals with less obstacles in the way. The design and materials used in the Nike ZoomX Invincible Run is a product of the commitment they have to help runners keep going. Everything about this creation is designed to help you run further and longer with more ease than ever before.
The ultimate shoe for long distance training
ZoomX foam is Nike’s lightest midsole foam. Originally used in aerospace innovation, it’s also softer and more responsive than any other Nike foam. Normally softness is compromised when a foam delivers amazing energy return. However, this is not the case with ZoomX. Despite delivering an incredible 85% energy return, ZoomX foam feels supremely comfortable underfoot and ultra plush. First used in shoes to help achieve the goal of breaking the 2-hour marathon barrier, ZoomX foam has traditionally been used in Nike models that were designed purely for fast-paced running. ZoomX first appeared in the Nike Zoom Vaporfly 4% in 2016. Since then it’s been used to make the midsole of other Nike models which are the epitome of speed: Vaporfly Next%, Alphafly, Zoom Pegasus Turbo and Tempo Next%. So, why stop there? ZoomX foam has benefits beyond just aiding fast-paced runs.
ZoomX foam is used in the Invincible Run as it delivers an ultra-soft underfoot feel to make the miles feel less impactful. Softer foams can help reduce the stress that goes through joints and muscles as a result of less flexion in the leg. ZoomX also delivers unparalleled levels of underfoot comfort. Nike increased the stack height and midsole thickness of the Invincible Run in comparison to other models so there’s more foam underfoot for even more cushioning. The men’s midsole height is 36.6mm to 27.6mm and the women’s midsole height is 34.2mm to 25.8mm. The exceptional levels of energy return create a propulsive feel to make the miles feel easier too.
The midsole geometry has been optimised to make long runs feel easier. Nike have created the midsole with a rocker-like construction. This basically means the midsole is curved from heel to toe. Designed to provide support for the three phases of a runner’s stride, the geometry of the midsole helps aid propulsion and reduce the amount of work that muscles and joints have to do. A rocker shape can help increase forward momentum and make running feel easier. This is of particular benefit over longer distances or recovery runs when legs are fatigued and form suffers as result. In addition to the rocker, Nike exaggerated the width of the forefoot to create a more stable platform and offer more support for long runs.
Nike created the upper using an evolved Flyknit design. Flyknit is a digitally engineered knitting process that results in uppers which are lightweight and essentially seamless. The upper in the ZoomX Invincible Run is strong and durable but specific zones maximise breathability in the areas which heat up most. Stability, comfort and lightness are all delivered by the Flyknit upper. A heel clip that wraps around the lower ankle area delivers more support.
Reviews from wear testing
Myself and my colleague Amy received a pair of ZoomX Invincible Runs from Run4It to wear test for the purpose of this review and knowledge sharing across the team. Having put the ZoomX Invincible Run through its paces, Amy and I share our opinions on the shoe below. We will conduct a secondary review at 500 miles of running to provide further insight into the performance of the ZoomX Invincible Run.
Finlay’s Shoe Review
I rotate between a variety of Nike models for my training and racing. I race Ironman triathlon and the Alphafly is the perfect shoe for me in the marathon leg. For half Ironmans, I opt for the lighter Vaporfly, which is also faster to slip on in transition. Over the last year or so, I have been doing most of my training in the Zoom Fly 3. I was really excited to try the ZoomX Invincible Run so I could add another option to my footwear rotation. I’m a firm believer in using different tools for different tasks.
Performance at various paces
As soon as I put the Invincible Runs on I knew they were going to be good. The initial step-in feel is just superb. I took them straight out for an easy hour run, precisely what they’re for. The trademark feel of the ZoomX foam was just as expected, like nothing else out there. It feels so protective and yet energetic at the same time. The foam even makes a distinct noise, synonymous with ZoomX models, which delivers an almost therapeutic effect as I know my feet have something special on. As I got into my stride and relaxed into my pace, I barely noticed my feet. It felt like I had pillows under my feet that were also loaded with springs! The protection and energy return was faultless. It was a perfect run; my legs felt easy and relaxed the whole way.
I didn’t particularly notice the rocker geometry but I took that as a good thing. It was clearly doing its job as I felt no stress through my lower leg and that’s normally where I feel some tightness if somethings not right. I normally get on well with shoes that have a rocker as it reduces the load going through the calf muscles as it reduces ankle flexion. Nike have clearly designed the midsole geometry very well as the rocker produces the desired result in a smooth and seamless way.
I was keen to try out the ZoomX Invincible Run at some faster paces too, as the foam offers such high levels of energy return. My easy-paced runs are at around 4.30-4.45min/km, the pace of my first test run. I go down to about 3.45-4.00min/km for my steadier-paced runs and I was curious to see if the Invincible Run would perform at that pace. The shoes coped well with the pace and they did feel smooth and bouncy. However, they lack a bit of the ‘snappiness’ I typically like at this effort. For me, I noticed the distinct absence of a carbon fibre-plate. The Zoom Fly 3 features React foam, a firmer and lesser energy returning material than ZoomX, but critically it has a carbon fibre-plate. The plate in the Zoom Fly 3 creates a different style of propulsion from the softer midsole of the ZoomX Invincible Run. I definitely prefer the more responsive feel of the Zoom Fly 3 at faster paces and find it easier to run at tempo efforts.
In contrast, I much prefer the feel of the ZoomX Invincible Run midsole for the lower to steadier effort runs and this is ultimately what it’s been designed for. The style of propulsion is different from anything else I’ve tried and I’ve never experienced a running shoe quite like it. I’ve seen some reviews being critical of the weight of the ZoomX Invincible Run but there’s just no place for this. The shoe has been optimised to take the stress off legs and there’s a misconception that lighter shoes feel easier to run in. The ZoomX Invincible Run is a little heavier because it has so much cushioning and this is precisely what makes long runs feel easier. Nike have expertly tuned the midsole to create incredible softness, energy return and protection for the task at hand.
Fit and feel
When it comes to the fit, it’s hard to find any fault. While a shoe will never fit every runner, I can’t see many people having issues with the fit of the Invincible Run. The heel collar grips my ankle perfectly and provides a great level of support without any restriction at the same time. The forefoot is an accommodating fit without being overly wide. It would easily fit a variety of foot shapes. The wide forefoot base creates great stability underfoot too. Despite the shoe being ultra soft, the upper, geometry and shape of the midsole all work in perfect harmony to deliver a smooth and stable underfoot feel.
At £159.95, the ZoomX Invincible Run is at the higher end of the price spectrum. You will not be disappointed with what you get though. I have never run in anything like this before and no shoe has ever delivered the level of energy return and cushioning at slower to steadier like these do. It truly is a special shoe and at the forefront of footwear innovation. There is no doubt in my mind that this will significantly help my training as my lower intensity and long runs are going to be a whole lot easier. Make the hard training hard and the easy training easy is my mantra. I averaged 4.22min/km pace for a steady 21km run which included about 35mins at just under 3.50min/km average. I had absolutely no muscle tightness or fatigue whatsoever after this, so the ZoomX Invincible Run clearly has incredible capacity to ease the load on your legs. I have been searching for a long time for a shoe like these and I’m looking forward to a lot of stress free runs.
My initial impression of the new ZoomX Invincible Run was that of bubble wrap. It sounds strange, and it certainly amused my colleagues, but when I delved a little deeper into why my brain had immediately jumped to bubble wrap it became clear: it has everything to do with impact absorption.
I run with my heart – which means I go as far and as fast as my body wants at the time. This usually finds itself in the range of between 5-15km at around 5.30 min/km, give or take, so my trainers need to be content with pounding the pavements for a while.
I took the shoes for an easy 8km and from my first stride, I knew the ZoomX foam in the heel was going to be a real showstopper. Both my knees have nerve damage, so impact absorption is a huge must for me in a daily trainer. I strike heavily on my heels, so what amazed me was I could hardly feel the impact. Just like bubble wrap encases and protects its contents from heavy and sudden pressure, I felt the ZoomX foam absorbing the shock and propelling me back up again so I could repeat the motion over and over. What this created for me was an interesting feeling of weightlessness where there is usually excess impulse.
Speaking of weight, there’s no denying the ZoomX Invincible feels hefty when first tried on, and the wider base gives the illusion that the shoe will feel heavy to run in, however this just isn’t the case. The misconception that a supportive shoe is going to feel weighty to run in is squashed by the ZoomX Invincible. I felt both stable (as someone who always runs in stability shoes) and agile on my feet.
Living in a city centre means my runs involve a lot of quick swerves, sudden stops, and jumping on and off curbs. The waffle outsole was designed to give traction when runners need it most, and I found the traction – combined with the foam – provided me with effortless, less impactful stops, and fast springy starts.
I don’t have a huge shoe rotation, but I’ve been using the Nike Air Zoom Tempo NEXT% as my 5K runner for a faster, lighter feel. The Tempo NEXT% also uses ZoomX foam, along with React foam and a Zoom Air Unit, and does outperform the ZoomX Invincible at a faster pace due to its ultra-responsiveness and weight difference. However, the two shoes create a great training partnership – the Invincible for longer steady runs, and Tempo for fast, short runs. The continuity of the ZoomX foam means I always have the highest quality impact protection. There aren’t many runners out there who the ZoomX Invincible wouldn’t work for. My thoughts in three words: soft, protective, fun.
Who is this shoe for?
It’s evident from both mine and Amy’s reviews that the ZoomX Invincible Run delivers the ultimate level of cushioning and feels pretty special. We both found it to be soft, yet offer unmatched levels of energy return. It was a unanimous consensus that the ZoomX Invincible Run is best suited to easier to steadier effort sessions and longer runs as it makes running feel less stressful. Amy and I clearly train in a different way from one another with varying goals. However, we both have the common goal of not getting injured during training and importantly, having an enjoyable run.
The ZoomX Invincible Run is the perfect neutral shoe to make long runs feel easier. Nike has created the perfect tool to take the stress out of tired legs. ZoomX cushioning is combined with the optimum geometry to create a sense of weightlessness during runs. While it could be used for some faster-paced runs, it’s best saved for lower intensity sessions. Runners will also enjoy a versatile upper that works for a range of foot shapes and guarantees support for the miles.
It’s only now and again that something special comes along in the running world. The ZoomX Invincible Run has the power to help a lot of runners and reduce the chances of getting injured. If you want to make your long runs feel easier, this is the shoe for you.
Other Nike Options
If you are looking for a Nike model that’s better suited to faster paced sessions, the Zoom Fly 3 is a great option. Despite using React foam, which isn’t as energy returning as ZoomX, it features a full-length carbon fibre-plate that feels highly propulsive at top-end speeds. This is my top Nike pick for high heart rate runs.
The Air Zoom Pegasus 37 features React foam and a Zoom Air Unit in the forefoot. This delivers a protective yet responsive underfoot feel. Referred to as the “workhorse” by Nike, this neutral responsive model is suitable for a wide range of paces and suits runners who like a slightly firmer underfoot feel. It will be firmer and more rigid than the ZoomX Invincible Run.
If you’re looking for a bit more support, check out the React Infinity Run Flyknit 2. The midsole is also made with a rocker liker geometry and high midsole height to help reduce the stress on legs. Unlike the ZoomX Invincible Run, it features a more structured support frame that wraps around the heel and down the lateral edges. This may be a better option for runners who pronate to greater ranges.