Physical Therapists Using Clinical Analysis To Discuss The Art And Science Behind Running and The Stuff We Put On Our Feet

Post Page Advertisement [Top]

On Cloudflow 4 Review: A Super-Inspired Overhaul
By David Salas and Matthew Klein

The On Cloudflow line can be viewed as the lightweight training/performance shoe for the company. The shoe has always had a relatively low-profile design and versatile build. The Cloudflow 4 continues upon this tradition with a few updates. This new model has a lot more toe spring in the forefoot to help with maintaining a forward-rolling sensation while maintaining the classic low profile the lineage has had. The Cloudflow 4 pulls some inspiration in part from the Cloudboom Echo 3 with a training focus.

On Cloudflow 4
Price: $159.95 at Running Warehouse
Weight: 8.7oz, 247 g (men's size 9), 7.0 oz, 200g (women's size 8)
Stack Height: 32 mm / 24 mm
Drop: 8mm
Classification: Lightweight Training Shoe, Performance Trainer


Matt: The On Cloudflow 4 is a more traditional stack height, lightweight neutral training shoe. A new upper provides a slightly fit, securing the foot well while staying light. A sharp forefoot rocker with a large amount of toe spring sits up front, which provides a fast roll forward off a slightly firmer Helion/Cloudtec midsole. Inspired by the Cloudboom Echo 3, the Cloudflow 4 is a solid shoe for workouts and potential racing for those who prefer lightweight trainers. 

David: The On Cloudflow 4 is a low riding lightweight training shoe in the neutral category. The shoe pulls some inspiration from the Cloudbloom Echo 3 with more of a training focus. The shoe has a moderate rocker through the heel and midfoot, with a sharp forefoot toe spring to give you a rolling sensation with each step. The shoe also uses a nylon speedboard to help with additional responsiveness when loaded.

: Brooks Launch 10, Adidas Adizero SL


Matt: The On Cloudflow 4 fits me true to size if slightly long in my normal Men's US size 10. The length is not enough to size down but it feels like there is a little extra length at the end. The width is slightly snug throughout the length of the shoe. The light engineered mesh holds the foot well on the platform and is on the performance side. The forefoot fits slightly snug with a light taper with normal-width socks. The volume is average to slightly lower with a performance-like fit. The midfoot is slightly snug with a thin, gusseted tongue. I did not have to lace lock the shoe or overly tighten the laces. However, the thinness of the tongue did cause me to experience some biting on the top from the laces. Thus, be careful how tight you tie the laces. The heel features mild heel collar cushioning with a highly flexible heel counter. The counter did not bother me at all and those with sensitivities should be fine. Outside of the lace bite, wearing this shoe sockless is awesome. The inner liner is seamless and fits comfortable against the skin both while running and wearing causally. Overall, this upper has a performance edge and a solid degree of comfort outside of some lace bite. 

David: The On Cloudflow 4 fits true to size in my Men's 9.5. The length may be on the longer side, though I did not have any issues with slippage or translation. The fit of the upper is done well and the lacing system holds the foot secure. The width in the heel, midfoot, and forefoot are all normal width and are not overly narrow or wide. The mesh material is lightweight and feels performance-esque. It has mild stretch, but maintains its form well. The shoe does draw some inspiration from the Cloudboom Echo line and this upper may have some pull from that as well. There is a flexible heel counter with mild padding that holds the heel cup structure pretty well without being intrusive. The tongue is very thin and is consistent with the performance-esque feeling of the shoe, but does have some mild padding in the meat of the tongue. The volume of the shoe definitely fits more like a training shoe and there is some room for swelling accommodation. Despite some performance inspiration this does fit like a normal training shoe. From a comfort and performance standpoint I am a big fan of the upper. The only thing I'd really note here would be wanting perhaps a tiny bit more padding in the tongue and making the length a tiny bit shorter. Otherwise the upper is really comfortable. 


Matt: The On Cloudflow 4 is a performance trainer/lightweight daily training shoe. The midsole sits at a more traditional stack height, with classical On-styled firmer cushioning. The cushioning is slightly softer than previous as On takes small steps forward in softening their rides. This provides just enough cushioning for moderate mileage and of course higher mileage for those who prefer a slightly firmer ride. The 8mm drop is noticeable in a positive way. This is partially due to the small heel bevel that makes for a slightly clunky rearfoot transition. The midfoot and forefoot take over and roll you forward quickly through the large forefoot rocker. The toe spring (toe extension), is noticeable but does add to the fast transition off the front. The forefoot does has mild flexibility, but is mostly stiff thanks to the speedboard that further adds some snappiness.

The lighter weight and firmness make it easy to pick up the pace in this shoe. I have done a few fartlek workouts (with my students) in this shoe and it responds extremely well. It does not have a ton of bounce but does roll quickly, making it easy to change gears. The firmer cushioning does allow for moderate mileage, so normal daily runs have been fine. The Cloudflow 4 is a little harsh for longer runs, but those who like firmer daily trainers will probably be fine. So pace-wise, daily running, uptempo, tempo and fartlek workouts are all things this shoe can handle.

Durability-wise, I am starting to wear through the small outsole rubber patches after 20 miles. Thus, like most lightweight trainers, I would expect slightly below-average mileage. I will say these are fantastic for casual wear. The roll is extremely comfortable while walking and I have gotten several compliments on these. 

David:  The On Cloudflow 4 is a very fun shoe to run in. The shoe has a low to the ground profile and you certainly feel each step. The shoe has a firm feel to the cushioning, though there is still enough for daily running. Those that like a high amount of cushioning may struggle with this one, as this caters more to the opposite crowd. The shoe has balanced transitions through the heel and midfoot with a very quick rolling sensation in the forefoot thanks to the toe spring. The shoe does have a nylon speedboard throughout the shoe that is relatively flat with a heavy spooning up in the forefoot. This is definitely noticeable and creates that rolling feeling each step in the forefoot. The shoe has decent rigidity to it but under load there is mild flexibility. The weight of the shoe combined with the toe spring make for a pretty nimble experience. You consistently feel like you are rolling forward without dragging too much shoe around. There are some mild sidewalls, though this shoe is definitely a very neutral experience.

This reminds me of the likes of a shoe like the original Cloudboom, but with having more cushion and a more training friendly upper. Those wanting close ground feel and a rockered experience in the same shoe may have some appeal with the Cloudflow 4. From a usage standpoint, this would definitely lean on the training side of things for me, but there is enough responsiveness to justify some tempo runs as well. This shoe offers good versatility across daily running, slight uptempo, and even casual wear. This would not be a bad "everything shoe" investment if your shoe purchases extend beyond the usage of running as well. 


Matt: The On Cloudflow 4 is a neutral shoe. There are no traditional methods of stability integrated into the shoe. There are small sidewalls in the anterior heel on the medial and lateral sides but these are not that noticeable. The sole is slightly narrower overall, which adds to the neutral feeling but does make the shoe more nimble. Outside of the sidewalls, these are solidly neutral. 

David:  The On Cloudflow 4 is very neutral shoe. The shoe does not have any major sole flaring, sidewalls, or reinforcement in the platform. The low-to-the-ground nature and speedboard do help with some stabilization, but the overall experience is very neutral. There are some small sidewalls in the medial and lateral heel, but they do not seem to do too much. Upper security is pretty good, though I can't say I feel the platform is "stable."

Thoughts as a DPT: Toe Spring in a flat shoe? 
By David Salas, PT, DPT, CSCS

In today's world it seems that every shoe has to have a rocker, a stiff platform, and a lot of cushioning. For shoes that do not fit that category it seems that they need to be on the flatter end, lower profile, and flexible. There are not many shoes that meet in the middle. The On Cloudflow 4 does. One of the things that make the On Cloudflow 4 an interesting shoe is the usage of the rocker component on a lower stack height shoe. It gets most of its rocker profile through the forefoot by the usage of a toe spring.

A toe spring essentially is a rounding of the platform in an upward direction, placing the toes in a small moment of extension. This is normally done with firmer foam or through the usage of a plate/board. In the case of the Cloudflow 4 it is done with a nylon-based Speedboard. 

One thing that we talk about a lot at Doctors of Running is muscular demands with certain types of footwear. With the higher stacked rockered shoes we can normally infer that the loads from running move away from the ankle and towards the knee and the hip. Because of the larger amounts of foam, some inference may also be made that the intrinsic muscles of the foot and ankle stabilizers may be highly active as well if sufficient strength is not present in the musculature surrounding the hip and the knee. This would largely be in part due to stabilizing mechanisms. 

The On Cloudflow 4 does not fit our normal bill as a rockered shoe. The shoe is much lower to the ground and uses most of its rocker up front. What is interesting about this is that you may get a more balanced muscular usage profile. The lower stack and flatter geometry will still use some of the calf musculature as the driver, but the toe spring up front will unload the lever arm at the great toe and shift muscular load higher up. This is anecdotally and theoretically speaking, though I do feel this on myself running in these. Pertaining to walking, (Sichting, Holowka, Hansen, & Lieberman 2020), found that an upward curvature of toe springs may decrease the negative work of the MTP joints during push off due to a decrease in the range of motion they have to move through without a change in arch stiffness. Though this is walking, this could be a nice window into some of the usage for rocker designs. If the lower stack design can decrease some of the intrinsic foot demand we might get a unique balance of work load between the musculature of the ankle, knees, and hips. More research and testing needs to be done, but it is an interesting thing to look into. 


Sichting, F., Holowka, N. B., Hansen, O. B., & Lieberman, D. E. (2020). Effect of the upward curvature of toe springs on walking biomechanics in humans. Scientific Reports 10. Article number: 14643 (2020). 


Matt: While I have enjoyed my miles casually in the On Cloudflow 4, it is not something I will keep reaching for. Partially due to the fact that I don't want to get these dirty, but also due to the fact that these are a little too firm for me for mileage. I typically like firmer rides but the extra toe spring and firmer ride is just a little much. ON is getting better with their midsoles but I want to continue to encourage them to live up to their "clouds" tagline and continue to soften their rides. This will improve the comfort with running (walking is fine) over longer miles. I would also like to see the tongue protect the top of the foot a little more from the laces. A little bit more padding will fix this and will still maintain the lighter weight. 

David: I really enjoyed my experience in the On Cloudflow 4. My recommendations mainly lie with the upper. Despite the comfort I do think the length could be shortened a tad and the tongue a little more padded. I do find I get a small amount of biting. It isn't a deal breaker, but for comfort reasons the tongue could use a little more padding. 


Matt: The On Cloudflow 4 is a lightweight/performance training/workout/potential non-super racing shoe for those who want a firmer, lower to the ground ride with a highly rockered forefoot. The light upper provides a slight performance fit, although some adjustments may need to be made to the tongue to avoid lace bite. The firmer ride and large forefoot rocker lends itself to moderate mileage and quick pace changes, continuing the Cloudflow's legacy as a shoe with uptempo/speed capabilities. While this will serve as a great workout companion to the On Cloudboom Echo 3, it also is an excellent causal shoe based on the comfort with walking and its looks. Thus, those who want a versatile shoe for moderate miles with some uptempo efforts and some casual wear/walking may want to look at the On Cloudflow 4. 

David: The On Cloudflow 4 is a lightweight running shoe for someone that wants a low to the ground experience alongside a rocker profile. The shoe is definitely on the firmer side of cushioning. The weight provides a pretty nimble package. The shoe has a lot of toe spring in the forefoot and so you definitely notice a rolling sensation forward. There is also decent comfort with casual wear as well and so this could even serve as an option for someone looking to have an "everything" shoe that extends beyond running into everyday wear as well.


Fit: B+ (Comfortable lighter mesh with slightly snug fit. Mild lace bite from thin tongue. )
A- (Slightly firmer ride that lends to pace changes from moderate distance easy runs to faster intervals)
Stability: B/B- [Neutral] (Highly neutral ride. Mild stiffness from speed board helps a tiny bit but not much)
DPT/Footwear Science: B- (Versatile shoe but slightly too firmer for distances. Excessive toe spring may not be necessary)
Personal: B (Great for casual wear and impromptu uptempo efforts but a little firm and not quite stable enough for me during daily miles). 
Overall: B/B+ 

Fit: B+/A- (Length a tad long, tongue could use a little more padding, mild biting)
Performance: A 
(Simple, nimble, fun forefoot rocker. Lightweight package that gives an enjoyable rocker experience to the lower profile category.)
Stability: B (Very neutral shoe throughout, not much sole flaring, sidewalls, etc. Speedboard and firm nature help.)
DPT/Footwear Science: A- (Very good usage of toe spring in otherwise a relatively flat shoe)
Personal: A (One of my favorite shoes right now that I keep reaching for. Great for easy mileage and strides, some tempo potential.)
Overall: A- (A solid daily training shoe for those wanting a low stack, firm, rockered ride.)


On Cloudflow 4
Price: $159.95 at Running Warehouse

Shop Men | Shop Women

*Using the link to purchase helps support Doctors of Running. Thanks so much!

Check out Gear We Love
Ultraspire Fitted Race Belt: The best way to carry your phone and goods on the run. No bounce and various sizes for waist. (Also recommend the Naked belt)
Saysky Running Gear: We were really taken aback by this Scandinavian company's ultra-thin, durable performance clothing
Skratch Recovery, Coffee Flavor: Mental and physical boost post run. Coffee flavor is excellent and goes great straight into a fresh brewed cup
goodr Sunglases: Run in style with goodr's super fun sunglasses.
Feetures Socks: Massively grippy socks that will make you feel more one with the shoe
Amphipod Hydraform Handheld Water Bottle: Perfect for long runs when you need hydration in the summer
Trigger Point Foam Roller: Help get those knots out post-run and feel better for tomorrow
Ciele Hat: Our team's favorite running hat of choice!
Fractel Hats: Our team's wider fitting running hat of choice!


ASICS Gel-Cumulus 25 - A big update to this daily trainer makes it the softness, most cushioned yet
Adidas Adizero SL - A remodernized daily trainer for the Adidas line
AltraFWD Experience - Altra's first non-zero drop trainer
Brooks Launch 10 - Huge value training for everyday runners
Brooks Revel 6 - At $100, a simple, but effective neutral trainer that fits well
Hoka Clifton 9 [Stable Neutral Trainer] - A change to the midsole shapes the change to this classic maximal trainer
Mizuno Wave Rider 27 - Retooled to feel a little lighter underfoot and with a greatly improved fit
New Balanace FuelCell Propel v4 - Version 4 adds a forefoot plate to this budget trainer
New Balance Fresh Foam X 880 v13 - A new update to this versatile "wogger" shoe
Nike Pegasus 40 - A light upper update makes this the most comfortable Pegasus to slip on yet
Nike Vomero 17 - More ZoomX midsole helps make this trainer excel
On Cloudsurfer - The softest On yet ushers in a new redesign for the future of On
On Cloudswift 3 - A versatile run/everyday activity trainer with classic On elements
Puma ForeverRun Nitro - A new "stability" entry in the lineup that provides a cushioned ride
Reebok Floatride Energy 5 - Major changes to the popular training series, including a torsion system
Salomon Aero Blaze - A new lightweight trainer from Salomon
Salomon Aero Volt - An old-school flat that's light and versatile
Saucony Echelon 9 [Stable Neutral Trainer] - A wide-fitting, high cushion shoe that also fits orthotics perfectly well
Saucony Kinvara 14 - Higher stacked than ever, and lighter as well
Saucony Ride 16 - A light update that refines the daily trainer to its very best yet
Skechers GO RUN Ride 11 - New HYPERBURST ICE makes for an incredibly soft new entry
Topo Phantom 3 [Stable Neutral] - A daily training shoe with a fantastic upper and simple, functional ride
Tracksmith Eliot Runner - All-new trainer from the apparel brand, featuring a peba midsole

Find all Shoe Reviews at Doctors of Running here.

Thanks for reading!


Facebook: Doctors of Running
Youtube Channel: Doctors of Running
Instagram: @doctorsofrunning
LinkedIn: Doctors of Running
Strava: Doctors of Running
Podcast: Virtual Roundtable
Pinterest: Doctors of Running


Check out the Doctors of Running Podcast to find more reviews, interviews, and running features from the team.

Visit our Podcast Page
Find us on Apple
Find us on Spotify

Editor's Note: As always, the views presented on this website belong to myself or the selected few who contribute to these posts. This website should not and does not serve as a replacement for seeking medical care. If you are currently injured or concerned about an injury, please see your local running physical therapist. If you are in the Los Angeles, Santa Barbara, Danbury and Stevens Point areas, we am currently taking clients for running evaluations.

***Disclaimer: These shoes were provided free of charge in exchange for a review.  We thank the people at On Running for sending us pairs.  This in no way affected the honesty of this review. We systematically put each type of shoe through certain runs prior to review. For trainers and performance trainers, we take them on daily runs, workouts, recovery runs and a long run prior to review (often accumulating anywhere from 20-50 miles in the process). For racing flats we ensure that we have completed intervals, a tempo or steady state run as well as a warm-up and cool down in each pair prior to review. This systematic process is to ensure that we have experience with each shoe in a large variety of conditions to provide expansive and thorough reviews for the public and for companies. Our views are based on our extensive history in the footwear industry and years testing and developing footwear. If you are a footwear rep looking for footwear reviews or consultations on development, we are currently looking to partner with companies to assist, discuss and promote footwear models. Partnership will not affect the honesty of our reviews.

Please feel free to reach out, comment and ask questions!
Contact us at

Nike Vomero 17

Bottom Ad [Post Page]

// ]]>