Altra Experience Flow 2 Review
By Nathan Brown
Altra Experience Flow 2Price: $139.95 at Running Warehouse
Weight: 8.15oz, 231g (men's size 9), 7.3oz, 207g (women's size 8)
Stack Height: 32 mm heel / 28 mm forefoot
Drop: 4 mm
Shoe Purpose: Daily Trainer
Pros: Good fit, softer (but not too soft) foam, light enough for some versatility
Cons: Nothing inherent in design, cons will be preference dependent (flexibility, stack, etc)
RUNNING SHOE SUMMARY
The Experience Flow 2 from Altra is their neutral daily trainer in their 4mm line options. Compared to the previous versions, it gets a foam upgrade to a significantly softer platform, which also changes this shoe to be much more flexible in the forefoot. These changes add both a modernized underfoot feel, but actually make it feel much more of a grounded experience. Both changes are welcome, creating a solid daily trainer accessible to anyone who likes neutral trainers.
SIMILAR SHOES: Topo Phantom 4
PAST MODEL: Altra Experience Flow
FIT
(To learn how a shoe should fit, check out our full podcast on fit by Matt Klein.)
Nathan: The Altra Experience Flow 2 features Altra's Standard FootShape Fit, meaning that it has an anatomically shaped design but overall is a standard width, and fits me true to size. The upper is a relatively simple engineered mesh, but has some mild flexibility to it, allowing accommodation around the metatarsals/balls of the feet, though I wish there was just a bit more. This is good, because the last for Altra in the last few years had been a bit snug for me in this region, but this shoe accommodated well enough and had no tight areas. Given the anatomically designed toe box, there is good room for toe splay. The heel and tongue have moderate padding which protect the top of the foot well and lead to a very secure fit with no slippage in the rear or midfoot. There are minimal overlays, which allos this upper to overall disappear on foot given its simplicity. In the summer, it has felt good overall, but is slightly thicker.
Pros: durable and secure and good for 95% of Wisconsin days.
Cons: slightly warm on the hottest 5% of days. Overall this is great upper for a trainer, as it offers comfort, security, and durability.
Typical Size: Men's US Size 9
Shoes that have fit Nathan well: Topo Phantom 3, Saucony Endorphin Speed 4, ASICS Novablast 4
Shoes that have fit snug: HOKA Mach 6, Puma Deviate 3, New Balance Rebel v3
Shoes that have fit large: Saucony Triumph 22, Brooks Launch 9 (length)
Doctors of Running Checklist
Is This a Good Shoe for Walking: Yes
Is This a Good Shoe for Standing: Yes
Is the Forefoot Flexible: Yes
How Flexible is the Shoe: Quite
Is This a Good Heel Bevel: Somewhat
Recommended for Haglunds: Yes
Is This Shoe Orthotic Friendly: Somewhat
Durability Expectation: Better than average
PERFORMANCE
Nathan: The Flow 2 has been a delight to run in. I've taken it on every type of run I'm currently doing in my training. This has included a long run (11 miles, 90 minutes), tempo repeats, and a smattering of mid-distance easy runs. There isn't one run that I'd take back from what I've brought it through. For the long run, the cushioning was sufficient, it was light enough for the tempo repeats, and the flexible design made it great for daily and easy runs. The most remarkable feature of this shoe compared to other Altra offerings is the midsole (EGO P35, a compression-molded POE blend). It's the first midsole from Altra that I would actually consider soft. Despite Altra offering higher-cushioned zero-drop shoes, they've always used firmer foams (for good reasons that we will talk about later). This softer foam isn't overly compliant, but gives just a touch of pop and compliance, which is why I think it worked so well for the long runs, tempos, and easy miles.
The other biggest change from the original version is how flexible the forefoot is. With the softer foam, there is more bending available in the forefoot, which makes this ride feel very "natural," allowing you to use your foot throughout the run. It's been a welcome change from a lot of the higher-stacked, stiffer shoes I've been training in. Given the flexibility, this shoe doesn't really operate on a rocker platform. The heel bevel is sufficient for the shoe given the relative lack of heel flare. In all, this is a simple yet successful iteration of a daily trainer with a good combination of ground feel and cushion.
STABILITY
(Learn more about stability in our full guide)
Nathan: The Experience Flow 2 is a neutral shoe. Despite my talking about how soft the foam is, I'm really referencing that in relation to other Altra shoes. It's on the firmer end of soft, keeping the shoe neutral and not unstable. Additionally, although the forefoot is flexible, allowing the toes to bend, there isn't excessive torsional flexibility to the shoe, maintaining structure underfoot. Finally, there are some sidewalls (albeit small) that cradle the foot, but not in an obtrusive way. Despite some of these features that add structure, the lower drop, mild softer foam, and flexibility in the forefoot require you to do the stabilizing on your own, making it neutral. If you have a history of medial ankle pain or plantar foot pain that responds well to stable neutral or structured shoes, this doesn't provide enough for you.
Thoughts as a DPT: Dynamic Drop
By Nathan Brown
It was just a year ago that Altra moved away from producing only zero-drop shoes and providing a line of 4mm drop shoes. In my opinion, this has allowed Altra to innovate their line a bit more while still staying true to their roots and philosophy. Innovations are found in the foam compounds they can use in the 4mm drop models, which comes down to how "drop", though measured statically, is more accurately something that should be considered when loaded.
First, let's make a distinction. There is a difference between minimalist shoes and zero-drop shoes. Minimalist shoes have little to no cushioning underfoot (stack) and typically have high longitudinal and torsional flexibility. A 2015 modified Delphi study by Esculier et al resulted in this consensus definition of minimalist footwear: "Footwear providing minimal interference with the natural movement of the foot due to its high flexibility, low heel to toe drop, weight and stack height, and the absence of motion control and stability devices." In essence, the goal of a minimalist shoe is to avoid impacting the foot as much as possible.
Notice that low drop is only one of the factors making a shoe minimalist, though many conflate minimalist and zero-drop, thinking they are the same thing. The reality is that most Altra shoes are not minimalist, as they have higher stack heights and guidance mechanisms.
Now, onto why innovations can happen in these new 4mm drop models. Since Altra shoes have higher stacks, the foot and body will load the shoe, changing the shape of the midsole underfoot during the running cycle. Since most runners are rearfoot strikers (Bovalino & Kinsgley, 2021), this means that the heel is going to be loaded first. If a foam is softer, the heel compresses, changing the static drop measurement by functionally decreasing the heel stack height for a time. What this means for zero-drop shoes is that dynamically, if the foam is soft, the drop will go from zero to below zero (negative drop). Given the reality that lower drop shoes load the calf, foot, and ankle more already (Richert et al., 2019), a negative drop may add unnecessary load, while also being less pleasant to run in.
Having a starting point of 4mm drop is what makes the Flow 2 work. Loading the heel does not result in a negative drop shoe, but instead keeps the heel at a starting point a little higher so that when it is loaded, it transitions smoothly throughout the rest of the gait cycle. I'm looking forward to seeing what else Altra does with foams. now that they have some room to play with, and they did a great job with the Flow 2.
Bovalino, S. P., & Kingsley, M. I. (2021). Foot strike patterns during overground distance running: a systematic review and meta-analysis. Sports Medicine-Open, 7(1), 82.
Richert, F. C., Stein, T., Ringhof, S., & Stetter, B. J. (2019). The effect of the heel-to-toe drop of standard running shoes on lower limb biomechanics. Footwear Science, 11(3), 161-170.
RECOMMENDATIONS
Nathan: This was a great update and an offering on the market that isn't easily found (moderate stack, flexible). There are two small considerations for improvement. Despite the fit being overall fine, I'd love to see either slightly more flex in the upper or opening the transition between the midfoot and forefoot. Additionally, widening the midfoot contact with the ground may add just a bit more structure, making it stable neutral -- however, I don't think this is necessary as it would remove part of what I like about this shoe in being a bit nimble. Maybe there is a way to make a slightly different model with a bit more stable neutral features.
WHO IS THIS SHOE FOR?
Nathan: This shoe is for someone wanting to try Altra but hasn't wanted a zero drop shoe, or they haven't gotten along with their firmer foams. This shoe is a high value at $140 (please don't raise the price) and provides versatility. If you want a flexible forefoot, moderate cusioning, and some good ground feel, this is a great model to add to your lineup.
GRADES
Nathan
Fit: A- (Mildly stiff upper)
Performance: A (Natural feel while still feeling modern)
Stability: B (Neutral)
Value: A (Versatile and durable for the price)
Personal: A (Love getting daily miles on this thing)
Overall Design: A
SHOP | SUPPORT DORAltra Experience Flow 2Price: $139.95 at Running Warehouse
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FURTHER READING
Hoka's super shoe update.
On's premium stacked trainer.
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