Nike’s Infinity Run 4 represents a major progress in performance through its revolutionary ReactX foam technology. The shoe delivers 13% more energy return than previous models and reduces its carbon footprint by 43% compared to the original React foam. This combination makes it both powerful and environmentally friendly.

The Nike React Infinity Run Flyknit 4 (InfinityRN 4) ranks among the top 25% of daily training running shoes. Marathon runners will appreciate its substantial 39mm heel stack height and plush cushioning that creates a “running on clouds” experience. The shoe weighs 11.1 oz (316g) but offers exceptional comfort and support that benefits both heel strikers and beginners.

This complete review will get into the shoe’s core features, performance metrics, comfort specifications, and value. Our goal is to help runners make informed decisions about their 2025 training needs.

Nike React Infinity Run 4: Key Features and Updates for 2025

The Nike React Infinity Run 4 makes its debut in 2025 with major technological breakthroughs that solidify its place in Nike’s premium running collection. Nike has completely redesigned the 2025 model to welcome innovations that tackle performance, comfort, and environmental sustainability at once.

The rise of ReactX foam technology

Nike’s five-year research and development effort has led to ReactX foam technology in the InfinityRN 4, which is a huge step up from the previous React foam. This new cushioning system strikes the perfect balance between athletic performance and environmental responsibility. Runners get 13% more energy return with ReactX foam compared to the original React foam, which means more spring in every step.

ReactX stands out because of its unique manufacturing approach. The foam uses injection molding instead of traditional compression molding. This simpler process reduces the carbon footprint of midsole production by at least 43%. The reduction comes from using less energy during production without any compromise in performance.

Lab tests prove the foam’s superiority. ReactX foam scores 12.5 HA in durometer tests, making it 20% softer than earlier versions. The foam stays responsive despite being softer, creating what runners describe as:

• Boosted energy return for longer runs
• Much softer impact absorption
• Better bounce without losing stability
• Smaller environmental footprint through smarter production methods

Redesigned Flyknit upper and fit profile

Nike has completely revamped the React Infinity Run Flyknit 4’s upper to fix previous fit issues. The new Flyknit design adds breathable zones where feet heat up most while strengthening areas that need extra durability. This smart upper design creates about 60% less waste than regular shoe-upper manufacturing.

The internal Flyknit fit band works like a rubber band around your midfoot to keep everything locked in place. You’ll find the knit material thick yet flexible, which prevents the transparency issues common in lighter knit uppers. This new design gives you a snug, supportive fit that stays comfortable.

The shoe comes with practical upgrades for versatility. A water-resistant liner keeps your feet dry in wet weather, and there’s more room in the toe box compared to older models. Most reviews suggest going up half a size because of the snug fit, especially if you have wider feet.

Stability enhancements and support system

The Nike React Infinity Run 4 takes a comprehensive approach to support, unlike traditional stability shoes. Rather than using a medial post, the shoe combines several design elements to create stability. The wider midsole base, especially in the forefoot, gives natural stability without limiting foot movement.

The curved outsole helps roll your foot forward, which reduces calf muscle strain and might decrease pronation. This rocker shape not only pushes you forward but helps keep your foot properly arranged throughout your stride. The shoe has a 9.8mm heel-to-toe drop (slightly more than Nike’s stated 9mm), which really helps heel strikers and runners with Achilles or calf issues.

The ReactX midsole’s sidewalls wrap up around your foot to create a cradled feeling instead of just sitting on a flat platform. This design boosts side-to-side stability while keeping all the cushioning and comfort. The heel’s asymmetrical sole flare might resist overpronation or slow down pronation, while the balanced sidewalls and forefoot flare help center your foot as you run.

Performance Analysis: How the Nike InfinityRN 4 Delivers on the Road

The Nike Infinity Run 4 lives up to the company’s promises about their latest tech breakthroughs. Our tests on roads of all types showed why these shoes work so well for daily training and marathon prep.

Cushioning and impact absorption

Nike’s InfinityRN 4 really shines in cushioning. Lab tests prove it’s 20% softer than the previous model. The ReactX foam hits 12.5 HA on durometer tests, putting it right in the plush cushioning sweet spot. Your feet will thank you during those long training miles.

The shoe’s cushioning hits just right – soft enough to soak up impact without feeling too squishy. Its thick midsole soaks up shock and helps your muscles stay fresh during those longer runs.

The measured 9.8mm heel-to-toe drop (a bit more than Nike’s advertised 9mm) works great for heel strikers. This setup helps you:

• Take stress off your Achilles and calves
• Spread impact forces evenly across your foot
• Stay protected during high-mileage training

Energy return and responsiveness

The Nike React Infinity Run Flyknit 4’s energy return tells an interesting story. Nike says their ReactX foam gives 13% more energy return than the old React foam, but real-life testing paints a different picture.

The midsole feels both dense and springy. One tester called it “soft on landing, but responsive on take-off”. All the same, reviewers don’t all agree about its bounce. Some say the ReactX doesn’t give enough spring for faster runs, making these shoes better for easy and recovery runs than speed work.

The curved rocker design helps your feet roll smoothly from heel to toe, creating better forward motion. This shape helps your natural stride and footstrike, so you run more efficiently without extra effort.

Stability during different running conditions

The Nike Infinity RN4 stays remarkably stable despite its tall stack and soft cushioning. We found this stability comes from its super-wide forefoot, measuring 118.4mm – one of the widest running shoes in lab tests.

These shoes keep you stable no matter where you run. The blown rubber outsole grips well on wet surfaces, and the wide base keeps you steady through turns and uneven ground.

The lateral heel caves in more than the slightly rounded medial side, which creates a smooth transition toward the outer edge. Runners who land on their outer foot might find this design helps center their foot as they run, which could prevent underpronation.

These aren’t speed demons – at over 11 oz for a men’s size 9, they’re heavier than tempo trainers. But this trade-off brings amazing stability that marathon trainers will love, especially during those long, tiring sessions.

Comfort and Fit: Sizing Guide for the Nike React Infinity Run Flyknit 4

The right fit makes or breaks a running shoe’s performance. Nike React Infinity Run Flyknit 4 needs special attention to sizing before you buy it. Tests from many reviewers show clear patterns that can affect your runs a lot.

Why you should think about sizing up

Almost every tester agrees – the Nike InfinityRN 4 fits half a size small. Nike knows this and tells buyers to go up half a size on their website. Runners who listened got what they called a “perfectly true to size” fit. This shows the bigger size gives you the fit Nike wanted.

Lab tests back this up. RunRepeat’s detailed study of 432 user votes labels the Nike InfinityRN 4 as “half size small”. Therefore, if you wear a US men’s 10, you should pick a 10.5 in this model.

The Flyknit upper makes the fit tighter because of:

• A low toebox that’s just 22.4mm high compared to the usual 27.2mm in similar shoes
• Soft, stretchy material that wraps your foot “like a sock”
• Regular width but with a “very low forefoot”

Some runners had strong words about the original fit. One said wearing their usual size felt like “applying a tourniquet to my foot” with “cut off my circulation level of tightness”. The thick, warm knit upper means getting the right size matters even more for longer runs.

What to expect while breaking in

These shoes need time to break in, even with the right size. Board-certified podiatrist Bruce Pinker says most running shoes break in after 5-10 miles. The InfinityRN 4 takes a bit longer.

Many testers found the ReactX midsole “very firm and almost dead” on first runs. It started to “slightly soften up after about 20 miles”. The arch support also felt strong at first but became “only minimally noticeable” after running 20 miles.

Experts suggest these steps to break in:

1. Wear them at home for 1-2 hours before slowly adding more time over a week
2. Bend the toe box four to five times to soften the material
3. Start with short runs at half your normal distance and switch between old and new shoes
4. Move up to your regular running schedule as your body adjusts

This careful approach helps prevent sore muscles and injuries. It also lets the ReactX foam and Flyknit upper shape themselves to your feet and running style.

Durability Assessment: Is the Nike Infinity RN4 Built to Last?

The Nike Infinity RN4’s standout feature is its durability. Lab tests back up its impressive longevity. Runners looking to get the most value from their shoes will find solid proof of quality construction in every key component.

Outsole wear patterns after extended use

Lab tests show the InfinityRN 4 has one of the toughest outsoles ever measured. Its 90.4 HC hardness rating is a big deal as it means that the average rating of 79.8 HC for similar running shoes. This exceptional hardness leads to amazing scratch resistance. Dremel tests showed only a 0.3 mm dent compared to the usual 1.0 mm average.

The full-coverage waffle pattern gives great protection against wear. The outsole has extra rubber under the big toe to prevent breakdown during toe-off, since this area takes heavy abuse. Real-life testing shows the InfinityRN 4’s outsole barely shows any wear after heavy use. This suggests it will definitely match the Pegasus 40’s durability.

Upper material longevity

The Flyknit upper scored an impressive 4/5 durability rating in toebox Dremel tests. This score beats almost every other road running shoe we reviewed. The heel padding also proved tough with a solid 3/5 rating.

Beyond the mechanical tests, the Flyknit construction stays strong even when soaked through. This amazing toughness shows Nike’s development of their knit technology. The upper stays supportive and comfortable no matter how long you wear it.

We tested these durability improvements extensively. Many reviewers think the Nike React Infinity Run Flyknit 4 will last well over 500 miles. The water-repellent toe liner helps in wet conditions. Some testers found the upper runs warm and holds onto sweat.

Value retention compared to previous models

The Nike ReactX Infinity Run 4 is much more durable than older versions. Full outsole coverage protects the midsole foam from damage – a weak spot in earlier models. This design upgrade and the tougher ReactX foam point to better long-term value.

Yes, it is unanimous among reviewers – this shoe lasts exceptionally long. One tester put it simply: “grabbing two or three pairs should keep you set for the year”. This shows great value per mile despite the premium price tag.

Cost-Benefit Analysis: Is the Nike ReactX Infinity Run 4 Worth the Investment?

The Nike React Infinity Run 4 makes a great case study to examine both the upfront cost and lasting value of premium running shoes.

Price comparison with competitor models

The Nike ReactX Infinity Run 4 costs $159.99-$160, which puts it squarely in the premium running shoe category. Here’s how the price stacks up:

• $20 less than Nike’s ultra-cushioned Invincible Run 3 ($180)
• Right in line with Asics Gel Nimbus 25 and New Balance Fresh Foam X More v4
• $20 more than Nike’s popular Pegasus 40

The GORE-TEX version costs $179.99, a $20 bump for weather protection. Smart shoppers can find the regular model on sale for $112-$143.97 at different stores, saving up to 30%.

Cost per mile calculation

The InfinityRN 4 really shines when it comes to long-term value. These shoes can handle more than 500 miles before they start showing serious wear. This is a big deal as it means that the cost breaks down nicely:

At full price ($160):

• $0.32 per mile (500-mile lifespan)
• The cost drops even more if the shoes last longer

On sale ($112):

• You might pay as little as $0.22 per mile

The ReactX midsole holds up better against compression than older versions, so these shoes might last even longer than expected.

Who gets the most value from this investment

Different runners will get different value from the Nike Infinity RN4. These runners will get their money’s worth:

Marathon trainers who log heavy miles will see the best return on investment. The stability and cushioning protect their legs during those long training blocks.

Runners who want one shoe for easy and recovery runs will find great value here. Speed demons might not get the same benefit since these shoes are nowhere near light enough (11.1 oz men’s) for fast workouts.

Runners who need extra stability get an excellent deal here since these shoes provide stability features without the usual markup you see on dedicated stability shoes.

Nike’s React Infinity Run 4 represents the most important breakthrough in running shoe technology that balances performance and environmental responsibility. The shoe’s $160 price tag might seem steep, but its 500+ mile lifespan brings the cost down to just $0.32 per mile or less.

ReactX foam technology proves itself with measurable gains – 13% better energy return and a 43% smaller carbon footprint than earlier versions. Runners should grab these shoes half a size larger than usual to let the Flyknit upper work its magic with a comfortable fit.

Daily trainers and marathon enthusiasts will love these shoes the most. The shoe weighs 11.1 oz, yet its stability features, tough construction, and plush cushioning make it perfect for high-mileage training. Nike React Infinity Run 4 delivers a reliable, comfortable, and eco-friendly option that runners need for their 2025 training goals.

Here are some FAQs about Nike Infinity Run 4

What type of stride does the Nike Infinity Run 4 have?

The Nike Infinity Run 4 is designed to support a smooth and stable stride, making it ideal for runners who need extra cushioning and guidance. The shoe features Nike ReactX foam, which enhances energy return and reduces fatigue, as seen in the Nike React Infinity Run 4 and Nike React X Infinity Run 4. This design helps promote a more efficient and comfortable running experience.

What type of mesh does the Nike Infinity have?

The Nike Infinity Run 4 uses a lightweight and breathable Flyknit mesh upper, which provides a snug and adaptive fit. This type of mesh is also featured in the Nike React Infinity Run Flyknit 4, ensuring durability and comfort. The material allows for excellent airflow, keeping your feet cool during long runs.

What does XC mean in Nike shoes?

In Nike shoes, XC stands for “cross-country,” indicating that the shoes are designed for cross-country running. These shoes typically have enhanced traction and durability to handle off-road terrain. While the Nike Infinity Run 4 and Nike React Infinity Run 4 are more suited for road running, XC shoes cater to specific needs of cross-country athletes.

Which Nike shoes are best for running?

The Nike Infinity Run 4 and Nike React Infinity Run 4 are among the best Nike shoes for running, thanks to their responsive cushioning and supportive design. The Nike React X Infinity Run 4 also stands out for its energy-returning ReactX foam, making it a top choice for long-distance runners. These shoes are designed to reduce injury risk and enhance performance.

How can I tell if Nike Running shoes are authentic?

To verify the authenticity of Nike Running shoes like the Nike Infinity Run 4 or Nike React Infinity Run Flyknit 4, check for details such as the quality of materials, stitching, and logos. Authentic Nike shoes will have a unique serial number inside the tongue or sole, which can be verified on Nike’s official website. Purchasing from authorized retailers also ensures authenticity.

What type of shoes should I wear if I have flat feet?

If you have flat feet, stability shoes like the Nike Infinity Run 4 or Nike React Infinity Run 4 are excellent choices. These shoes provide arch support and cushioning to help distribute pressure evenly. The Nike React X Infinity Run 4 also offers a stable platform, making it suitable for runners with flat feet.

What are the Nike shoes that fold called?

Nike shoes that fold are typically referred to as “Nike FlyEase” shoes, designed for easy on-and-off wear. While the Nike Infinity Run 4 and Nike React Infinity Run 4 are not foldable, FlyEase models feature innovative designs for accessibility. These shoes are ideal for individuals who need a more convenient way to wear their footwear.

How much do the Nike Invincible 3 weigh?

The Nike Invincible 3 weighs approximately 10.6 ounces (300 grams) for a men’s size 9, making it a lightweight option for running. While the Nike Infinity Run 4 and Nike React Infinity Run 4 are also lightweight, the Invincible 3 focuses on maximum cushioning. Its weight is balanced to provide comfort without sacrificing performance.

What does ISO mean in Nike?

In Nike, ISO stands for “isolation,” referring to shoes designed to provide a secure and customized fit. While the Nike Infinity Run 4 and Nike React Infinity Run 4 focus on stability and cushioning, ISO models emphasize fit and support. This technology is often used in basketball and training shoes for enhanced performance.