Under Armour FLOW midsole: Are running shoes without rubber outsoles reliable?

April 2, 2025 By Wellness Footwear Editors Off

In running shoe design, rubber outsoles have always been considered indispensable – they provide wear resistance, anti-skid properties, and protect the midsole material from being worn out too quickly. But Under Armour boldly launched a running shoe FLOW Velociti without a rubber outsole, which directly contacts the ground with the midsole material. Is this design really feasible? Let’s analyze it from the perspective of actual use.

1. What is FLOW midsole?

FLOW is a new midsole material developed by Under Armour and Dow Chemical. Its features include:

Lightweight: about 25% lighter than traditional EVA foam

High rebound: energy return rate reaches 83% (close to the level of top racing shoes)

Self-wear resistance: the specially treated surface can directly contact the ground

This technology was originally developed for basketball shoes (Curry FLOW 8) and was later applied to running shoes.

2. Actual experience of the outsole-free design

We tested the FLOW Velociti running shoes for about 200 kilometers and found that:

Advantages:

Weight reduction: size 43 is only 240 grams

Direct foot feel: no rubber layer barrier, clearer feedback

Good grip on slippery roads: special pattern design can also maintain stability on rainy days

Disadvantages:

Average wear resistance: obvious wear can be seen after 300 kilometers

Not suitable for complex terrain: gravel roads easily scratch the midsole

Cleaning is more troublesome: the midsole directly contacts the ground and is easy to get dirty

3. Which runners are suitable?

Road running enthusiasts: people who mainly train on asphalt roads/tracks

Runners who pursue lightweight: about 30-50 grams lighter than traditional running shoes

People who like unique foot feel: direct ground feedback is very special

Not suitable for:

People who often run off-road or on complex roads

Heavy weight runners (over 85kg)

Users who pursue ultra-high durability

4. Maintenance suggestions

Avoid using on gravel roads

Clean the midsole with a damp cloth regularly

Consider professional sole repair when wear is severe

A bold attempt

FLOW technology does bring a unique running experience, but there are also some limitations. It is best used as a second pair of training shoes for speed training or short-distance road running. If you like to try new technologies, it is worth trying; if you value durability more, traditional running shoes are still a safer choice.

Tips: Some offline stores now offer trial wear, it is recommended to try it before deciding whether to buy.

Editorial boundary note: This article is independent sports, wellness, footwear, or nutrition commentary. It is informational only and is not medical, mental-health, nutrition, therapy, legal, financial, safety, coaching, brand, retailer, or professional advice.

Health and safety note: Exercise, sleep, mental wellness, yoga, meditation, recovery, pain, overpronation, plantar-fasciitis-adjacent topics, nutrition, keto, healthy fats, and performance topics are discussed in general terms. They are not diagnosis, treatment, therapy, medical care, dietetics, crisis support, injury rehabilitation, individualized training, or a substitute for qualified healthcare professionals.

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CategoryFitness Recovery Footwear Tech