Written by Matthew Low I was first introduced to the On Running company when I witnessed my triathlon idol British athlete Tim Don breaking the Ironman world record by four minutes in May 2017 at the South American Ironman Championship in Florianopolis, Brazil. Needless to say, it wasn’t surprising to discover that the team behind On’s success is led by ex-Duathlon World-Champion and six-time Ironman winner Olivier Bernhard. The Zürich-based shoe brand was founded in 2010 to create a shoe that would deliver the perfect Goldilocks running sensation with every step: a soft landing, followed by a firm toe-off. Those familiar with innovation in running shoes will recall that Newton Running was founded with a similar goal in mind. The difference being On Running seemed to get the recipe correct almost immediately, winning an ISPO Brandnew Award — which recognises innovation among athletic startups — with their 1 month-old prototype. The secret to On Running’s success lies in their unique structure, attention-to-detail, and luxury materials used. The most iconic part of any On Running shoe is CloudTec, which is the company’s patented cushioning construction. Essentially, CloudTec consists of hollow tubes of rubber or foam making up the entire outsole of the shoe, which are designed to absorb any vertical and/or horizontal forces experienced during each stride, as well as provide a sturdy platform for the toe-off. Another unique and patented aspect of On shoes is the use of “speedboards”, which consist of specialised layers of strong material beneath the CloudTec structures to support and channel the motion of the foot for the most efficient technique — similar to the carbon plate in the Nike Vaporfly 4%. I recently picked up my first pair of On Running shoes, the On Cloudflow, and put them to the test to write this On Cloudflow review. Curious about the Cloudflows? Read on to learn about my experience in these innovative trainers.An Introduction to On Running
The unboxing experience is quite the special experience indeed. Open the box and you are greeted with an inner artwork of a black and white cloudscape which was extremely satisfying given that it matched the colourway of the Cloudflows. The shoes have no horrible stickers or tags on them, and they come with their own plastic shoe stays to keep them from losing shape. There was also a “owners card” with an ID number specific to the shoes so they can be registered online. Truth be told, I’m not really sure what the purpose of this is, but it did instil an additional sense of pride and ownership of the new shoes. The upper construction of the On Cloudflow is made primarily of a modern mesh that is both breathable and soft to the touch. The materials used are high quality and built to ensure the most natural movement of the foot as possible. That being said, the upper is sturdy enough to not feel flimsy or unstructured. The tongue is perforated allowing for some well needed airflow into the foot chamber keeping the shoe from becoming too hot. Inside the foot chamber, the Cloudflow features a built-in sock and extremely well-engineered in-sole. The sole features a soft rubber-like material, both of which create a secure yet comfortable environment, preventing any likelihood of hotspots and skin-irritation. Lastly, the entire upper and in-sole is treated with an anti-microbial coating, keeping the shoes fresh and resistant to odor-causing bacteria. This, coupled with the built-in sock means that forgetting your socks is not the end of the world in this shoe.
On Cloudflow first impressions
The Unboxing experience is very special
The Upper – Shoe companies can learn a thing or two from this
On Running has spent a lot of time perfecting what it calls their Zero-Gravity EVA foam and their Speedboard – a rigid plate (non-carbon) that promotes lateral stability and reduces stride momentum loss -- essentially reducing the strain and fatigue felt by the muscles of the underfoot. The Zero-Gravity foam is lightweight and durable yes, but requires a little more oomph in the responsiveness department. Having something as responsive to the midsoles of competing shoe brands would mean sharing the load with the Speedboard and cloud ‘pods’ in the outsole. Presently, there seems to be a lack of response to the explosive toe-off needed to support the natural foot-motion as the shoe goes through the gait cycle.The Midsole – Lightweight yes, Responsive not so much
This is the secret sauce, or “where the magic happens”. The outsole of the On Cloudflow features 18 semi-circular pods called ‘clouds’ which complete the remainder of the cushioning system. Not only are they quite radical looking, but their functionality is surprising. They attenuate the impact the shoe experiences during the landing, and help grip, twist, and push off the ground in a responsive and energized way. These ‘clouds’ are made of On Running’s ‘CloudTec’ rubber material which is durable enough to protect the more vulnerable EVA foam from the abrasive nature of asphalt for around 600kms. An extremely effective honeycomb pattern is imprinted on the ‘CloudTec’ rubber to improve the shoe’s grip on most surfaces. Overall, these shoes run true to size and quite comfortable in the sizing. Some external reviews may advise that the sizing runs bigger than the average user’s size, however, I did not find this to be the case.The Outsole – 18 Clouds what’s not to like?
Are the On Cloudflows true to size?
The On Cloudflows are extremely soft and comfortable with sufficient space to keep the worries at bay. After tying the laces tightly, using the extra eyelets to ensure sufficient ankle support, there was zero heel slippage and the in-sock is the warm hug your foot deserves. With the immediate concern that gravel and stones might get stuck in-between the ‘cloud’ pods I ensured that they were put to their paces in the most harsh conditions possible i.e. rain, mud, loose gravel, sand, dust, and thick vegetation. Surprisingly, over the 420kms in which I tested these shoes, I had to stop to press a rock out of the outsole only 3 times. No more frequent then I might have to pry a pebble from any other outsole. The compression and decompression of the widely spaced pods allowed for them to shake debris really easily… most of the time. On wet and slippery conditions, the CloudTec rubber outsole did an incredible job to sustain traction and grip even on various steep gradients. The toe box sits low which means that you could quickly develop some discomfort over longer training runs. Be aware that if your toes naturally flex throughout your running gait, then you could very soon develop either a blister, or a hole in the fabric covering the toe box. Ideally, the On Cloudflow is best suited as a performance trainer-slash-race day flat. It comes to life when air rushes through the well-ventilated rubbery tongue. Additionally, the Zero-gravity EVA foam, Speedboard, and ‘Cloud’ pods are pushed to their max in unison. Resulting in a responsiveness similar to that of a track shoe, but with the comfort of a slipper.Are the On Cloudflows any good?
Yes, the in-sock mechanism coupled with the insole provide ample support for even the most oddly shaped feet. Whether you are flat-footed, have high arches, or anything in between the carefully designed in-sock of the On Cloudflow has you covered (and supported).On Cloudflow running shoes for flat feet
Plantar fasciitis is a fairly common running injury, with symptoms of pain around the heel or the arch of the foot. It is caused by straining the small fibres that connect your heel to your toes, or plantar fascia. So are On Cloudflow running shoes good for plantar fasciitis? Given the attention to detail of the inner of the Cloudflow, one would believe that this would a great shoe to help repair the inflamed tissue asymptomatic of plantar fasciitis. However, the shoe does not perform well when a heelstrike is required, due in part to the midsole being less responsive at slow pace. Therefore, the shoe leaves the plantar fascia vulnerable to the same stresses that likely caused the inflammation to begin with. With this in mind, the Cloudflow is not ideal for the sensitive heels that plantar fasciitis afflicts. Are the Cloudflows waterproof? Sadly, no. Although the upper is made of fairly durable and high quality materials, the ventilation of the forefoot and the tongue means an almost immediate moist foot in the lightest of drizzles. Thankfully, On have a waterproof shoe to see you through the wet weather. Check out the On Running Cloud Waterproof. 
On Cloudflow running shoes for plantar fasciitis?
Are On Running Cloudflows waterproof?
The On Cloudflow is a running shoe that’s created for those who want to have faster running outputs. Those with a natural foot-roll are the ones who are going to enjoy what this package has to offer. The Cloudflow has a 6 mm heel drop and feels low to the ground, especially when subjected to tempo runs. Overall, the On Cloudflows are great tempo shoes that could be used for middle distance races, as well as, the occasional paced parkrun. Although the midsole could be more responsive at lower speeds, they always feel fast, comfortable and well-ventilated irrespective of the surface they are subjected to. The laces definitely require a double-knot, and the toe box can feel shallow depending on your gait, but these qualities shouldn’t scare anyone away from this shoe if you are looking into them for the purpose for which they were designed: a run at pace. These lightweight shoes really bring the A-game with cushion and ventilation too. So if you want a good tempo, speed, or racer shoe with great traction, look no further than the Cloudflows. If you are not sure which On Running shoes are best for you, check out our On Running review where we test the top 5 On Running shoes: On Cloud, Cloud X, Cloudflow, Cloud Beam and the Cloudswift. Up Next On Running Review: the World's Lightest Trainers >> Here's What you Need to Know about Electrolytes >>On Cloudflow Verdict
