PUMA's design department have always played around with the grey areas of design and innovation. They have created some of the most striking silhouettes in the running world over the past couple of years. Have they outdone themselves here?
PUMA Fast-RB Introduction:
A Designer’s Playground
Andy: Some companies like to play in grey areas of design. Mizuno have finessed World Athletics’ stack height rules with clever engineering. Nike are the reason for many of the rules. Puma have played with possibilities in the past with the Fast-R and the Fast-FWD. Many companies have shoes which breach the rules that elites have to stick to. adidas set the tone with the Prime X. Hoka picked up the gauntlet with the Skyward X. You can find plenty of online photos of Conner Mantz wearing Nike’s Alter-G shoes. These are proudly emblazoned with ‘Not World Athletics Approved’ on the rear of the midsole next to the 47.5mm stack height measurement.
With the Fast-RB PUMA have decided to use the rulebook as a suggestion of how to push the envelope to the extreme. The RB standing for rule breaker, the technological assistance packed into the shoe probably makes Seb Coe roll his eyes. You certainly won’t see this on the feet of any of the elites taking podiums in major road races around the world. However, if you are reading this review, you are unlikely to be a sponsored elite. You are here to make a choice on which shoe to spend your hard earned money on.
Rather than questions of legality, you will probably be more concerned with comfort, fun and value. Let’s delve into the Fast-RB and see how it delivers on those all important criteria.
Specs:
Stack Height: 58mm in the heel to 46mm in the toe
Drop: 12mm
MSRP: £300 | $350
Available: 28th August in a limited run from specialist retailers and online
PUMA Fast-RB Upper:
For The Right Foot
Andy: The first thing you will notice about the upper is that it is laceless. This is the second super shoe in quick succession which come without laces. On stole the march with the release of the Cloudboom Strike LS. Whilst I don’t believe that PUMA have a captive robot weaving furiously in their Herzogenaurach it follows a similar principle. I have not had the opportunity to run in the Cloudboom Strike LS.
In fact, the only laceless running shoes (BOA system excluded) I have used previously are Nike’s Epic Phantom React Flyknit. My experience of these was that the first run was super comfy and every run after that was awful as the Flyknit stretched and lockdown was non-existent. After the flashbacks has dissipated, I slid into the Fast-RB. Surprisingly, getting my foot inside was not as tricky as I expected. However, this also made me worry about how secure the fit would be.
Once inside, I found the Fast-RB to continue PUMA’s heritage of being slightly longer than most shoes. My pair came half a size down from my normal and was still a little long. That said, to secure the foot, it is very snug in places. At the widest point of my foot, the Fast-RB really bites in to hold things in place. Sadly, this bite doesn’t extend to the heel. I found the fit here to be very sloppy and could feel constant heel lift on every run. Not something which is confidence boosting in a shoe built for speed.
Despite the idiosyncrasies of the fit, it has been a relatively breathable upper. I have run longer sessions in it with high temperatures and my feet have not overheated or become drowned in sweat. Overall, the upper is built for a very specific foot shape which I do not seem to have. My longest run in the Fast-RB so far has been 17km. I was very happy to take it off afterwards and let my feet decompress from the crunching in the forefoot. Whilst it hasn’t caused me to blister or bleed, it certainly isn’t the most comfortable shoe I have worn recently.
The Fast-RB Can Be Uncomfortably Snug
Ivan: The first glance at the PUMA Fast-RB was almost overwhelming – like an extreme concept shoe, leaving you uncertain of what to expect in terms of fit and ride. The design is visually striking, but it’s difficult to anticipate how it will perform. Naturally, I immediately weighed the shoe, and at nearly 340g (12oz) in my relatively small size us8.5/eu 41, it’s clear this isn’t an uptempo shoe, despite the inclusion of superfoams and plates. First thought was that heavier runners might better exploit the weight-to-cushioning trade-off, but even so, it initially seemed borderline too heavy for any kind of uptempo efforts.
Setting the weight aside, the upper appears well-built, sturdy and streamlined. The absence of laces is particularly noticeable and raises concerns from a runner’s perspective, especially for those with narrow feet who might struggle with the lack of adjustability. Like Andy, I share the worry about this design choice. Although I’m wearing my usual size, the shoe runs slightly long, as is often the case with PUMA. However, the length wasn’t an issue for me; the overall fit, on the other hand, was problematic.
The front part of the shoe is tight, both in volume and width, causing discomfort on the tops of my toes and also on my pinky toes where the PUMA logo is positioned, leading to small blisters. This discomfort is exacerbated by the rugged material of the upper. While a snug fit might be expected in a laceless shoe, it shouldn’t come at the expense of comfort.
The more significant issue, however, lies in the heel area. Like Andy, I experienced heel slippage, and the tight toe box leaves no room for thicker socks as a solution. The laceless design eliminates any possibility of adjustment, which is frustrating. While I appreciate PUMA’s attempt to “break rules” of conventional design, this lack of adjustability is a serious drawback, particularly when there’s no way to customise the fit to personal preferences.
Midsole:
Everything, Everywhere, All At Once!
Andy: This is an occasion when I was so blinded by the design and technology in a shoe that I completely forgot to consider its physics. The Fast-RB midsole is basically a springboard from the swimming pool. As a forefoot striker, I looked at the amount of additions to the forefoot and forgot the practicality.
PUMA have packed three carbon fibre plates into the midsole. The first comes half the length of the shoe. Starting at the forefoot and with a 5mm (or so) pad of NITRO Elite foam between it and the road. Atop this are a pair of NITRO Elite foam pods which are scissored between another half length plate. This creates a platform for the third, full-length, carbon fibre plate to bounce off. The top layer of the midsole is only attached to the bottom layer at the very forefoot of the shoe.
Sadly, my footstrike means that I land at the confluence of the three carbon fibre plates. Ultimately, this means that while wearing the most mechanically assistive shoe on the market, I get zero mechanical assistance. It turns the landing into quite a firm and harsh landing especially when pushing the pace and really getting up onto my toes. Additionally, the width of the base of the forefoot makes it a very stable landing. All the plates and that width really give something to push off. However, despite PUMA’s claims, it is not a fast shoe for me.
When I have been playing with the shoe, I have used heel striking. This totally changes the nature of the shoe. When hitting with the massive, and it genuinely is massive, NITRO Elite heel, the shoe does feel like a diving board. The heel sinks, then the carbon fibre plate pushes the foot forward and it really comes alive. The bounce and propulsion is there. If you are a heel striker, go ahead and give this a try. It genuinely feels like nothing else I have ever worn.
Perhaps, if I were to take up race walking, this would be the perfect ride. But, until then, it is not going to be my race day shoe. The Fast-RB is also penalised by its weight. At 340+ grams in my EU 40.5, it is almost the equivalent of wearing two ASICS Metsapeed Sky Paris on each foot. I think that would be a preferable option for me.
Meditative Mechanical Marvel
Ivan: I have to admit, the midsole design of the Nitro-RB is one of the most intriguing I’ve ever encountered. From the moment I first saw it, I was eager to figure out how it would perform and who it would be best suited for. As a midfoot striker with a relatively flat gait, the combination of foam and plate, accentuated by an extreme rocker, seemed like a dream come true. It’s actually quite entertaining to manually initiate the rocker by tipping the shoe on the ground. It just keeps rolling, and I’ve never experienced anything quite like it. There’s even something soothing, almost meditative, about it – seriously!
However, when I actually took it out for a run, I was surprised to find that it performed best (by far) when heel-striking, a point Andy also noted. The heel-to-toe transition is nothing short of amazing. I’ve never experienced such a smooth roll through the gait cycle, with a satisfying bounce that, while not as extreme as the shoe’s design might suggest, still delivers a unique feel. It’s also comfortable for midfoot landings, though it feels more dampening than the dynamic, fun ride you get when heel-striking. On longer runs, I noticed the foam compressing, leading to a peculiar squeaking noise – probably from the foam interacting with the top plate.
As for the weight, I can’t see this working as a race-day shoe for me, regardless of the distance. That said, for someone with a pronounced heel strike and enough force to fully leverage the springy nature of the materials and geometry, it might actually work quite well. The shoe’s stability, aided by its width, raised wall of foam around the heel cup and the stiffness from the triple carbon plate setup, is also a significant advantage.
Despite the fit issues, I personally enjoyed running in the PUMA Fast-RB when cruising along without focusing too much on pace. Interestingly, I found myself heel-striking more often than usual, likely because it felt the most comfortable. The ride felt nice and most importantly, incredibly protective. And perhaps that’s where its greatest value lies – not as a race-day shoe, but as a fun, max-cushioned option that could actually work for uptempo runs for some, and as a reliable shoe for logging casual miles for the many.
While the price might not justify these use cases for the majority, I can definitely see those opting for the PUMA Fast-RB – not just to turn heads, but also to enjoy the fun, explosive, and yet protective benefits it offers.
PUMA Fast-RB Outsole:
Good Grip
Andy: The bulk of the forefoot is covered in a solid layer of PUMAGRIP. We have discussed this enough times now to know that it is excellent. In the Fast-RB that is also true. The heel has two small, black pads to land on. These are not marked as PUMAGRIP, however, when I have been playing as a heel striker, they have not given me fear of slippage.
Aside from road dirt, the outsole still looks like new after my initial runs in the Fast-RB. I have no doubt that it will be a very durable shoe.
Ivan: There’s really not much more to add here. The PUMAGRIP coverage on the PUMA Fast-RB is extensive, as always, and it seems both durable and grippy. The heel section, in particular, has an extra-thick layer that should hold up really well over time. Although I haven’t had the chance to test it in wet conditions yet, based on past experiences with PUMAGRIP, I can’t imagine traction being an issue.
PUMA Fast-RB Conclusion:
The Fast-RB Is A Monster Shoe
Andy: The Fast-RB is PUMA’s wildest shoe yet. If you have the correct foot strike and shape of foot, I am sure that this will be an amazing experience. However, I do not have that foot or the correct strike. Unfortunately, I am left with a very heavy shoe which gives me a firm landing. It won’t be a shoe in which I break any records. It is, however, quite a fun shoe for easier runs when I am landing further back on my foot and the weight is not as much of an issue.
Finally, the sheer size of the Fast-RB is not to be underestimated. When the Alphafly was released it was a behemoth of a shoe. Sitting the Fast-RB next to it makes the Alphafly seem like a very cutesy, svelte and demure little shoe. The Fast-RB is a beast but maybe not in the way that I expected. For a second version, can we please have some laces?
Cutting-Edge Buzz Maker
Ivan: Evaluating a shoe like the PUMA Fast-RB isn’t easy. Designed as a “Rule Breaker,” it represents PUMA’s effort to showcase the company’s innovation. From what I understand, it will be released in limited quantities, and its price will likely put it out of reach for many runners. That said, I believe PUMA will still achieve its goals with this release. The Fast-RB is likely to attract running shoe enthusiasts eager to try the latest and most cutting-edge options on the market. More importantly, it has the potential to generate significant buzz in the media.
From a more serious review perspective, I do think there’s a specific segment of runners who will appreciate and benefit from this unique midsole setup. Particularly, powerful heel strikers looking for a max-cushioned shoe with an excellent transition for any distance may find it appealing – provided they don’t mind the extra weight and unconventional upper.
Ivan
48 years old
180cm (5’9″) – 63kg (138lbs)
Midfoot striker – Cadence runner
Mild pronator
