The Nike Alphafly 4 is lightweight despite its tall midsole and substantial cushioning. It sheds about 14 g per shoe compared with the Nike Alphafly 3 in our men's size 9, a noticeable weight reduction. This makes it less cumbersome when you pick up the pace and helps reduce the effort needed to sustain fast running.

The midsole pairs Nike's new, lighter ZoomX LT with a layer of standard ZoomX, both PEBA-based foams. The latter is the familiar foam used in the brand's performance running shoes.

The sawtooth laces have limited stretch, giving you a consistent feel as you tighten them.

Pros

• Excellent energy return at both heel and forefoot.

Cons

The forefoot foam has excellent energy return, springing back efficiently as you push off. This can help you sustain fast paces with less effort, making it a strength for racing. It returns a similar amount of energy to other mainstream racing shoes such as the adidas Adizero Adios Pro 5. 

The heel foam provides excellent energy return, giving back a high proportion of the energy put into it during compression. That efficient rebound can help make sustained fast running feel less demanding for heel strikers. The heel is very energetic, but not quite as much as alternatives like the Li-Ning Feidian 6 Elite.

Pros

Cons

• Tall, soft platform offers limited stability.

The heel remains soft across light and strong landings, giving it a plush, yielding feel. That softness is appealing if you enjoy sinking into the foam, but it also contributes to the shoe's limited stability.

The forefoot is very soft and much softer than the Nike Alphafly 3, whether you land lightly or apply more force. This creates a plush feel beneath the front of your foot, but provides less support and a less direct push-off than a firmer midsole.

The carbon-fiber plate adds bending stiffness and helps stabilize the soft foam. Two Air Zoom pods beneath the forefoot are marketed by Nike as improving energy return and adding propulsion, but our tests don't isolate their contribution, so their actual effect isn't confirmed. There's no separate tongue; rather, the upper is continuous.

Pros

• Excellent cushioning, especially under the forefoot.

Cons

The Nike Alphafly 4 provides great heel cushioning, absorbing substantial impact energy across the tested forces. This gives heel strikers strong protection, including under the heavier impacts associated with greater body weight and/or faster running.

Forefoot cushioning is outstanding, absorbing plenty of impact energy across the tested forces. It remains protective under stronger impacts, including those from heavier and/or faster runners.

Forefoot cushioning remains excellent in our simulated 50 km long-run test, with only a small decline across the reported checkpoints. If you're using it for a marathon, which is what it's designed for, that sustained cushioning should keep it feeling protective even through the final miles.

Pros

• Low water absorption and fast drying.

Cons

The upper provides good breathability, allowing air to pass through during warm-weather running.

Drying performance is outstanding, with the shoe taking less than a day to dry in our test. That makes it practical to lace up again the next day after a wet run.

The shoe absorbs very little water, helping it stay lightweight if rain hits during your race or you repeatedly splash it while drinking or cooling off at aid stations.

Pros

• Very good bounce underfoot.

Cons

The heel lets you sink noticeably into the foam before it rebounds, with deeper compression than the Nike Vaporfly 4. You feel more of that sinking and rebounding motion underfoot, while the Vaporfly feels more direct.

Forefoot compression depth is decent, allowing noticeable sinking beneath the front of the foot as you load it before push-off.

Pros

• Stiff forefoot springs back effectively during push-off.

Cons

• Soft forefoot lacks a firm base for fast push-offs.

The forefoot has great bending energy return, springing back effectively as it straightens during push-off. This adds a snappy sensation as you move into the next stride.

The forefoot strongly resists bending, giving push-off a stiff, structured feel. However, it's less rigid than the Nike Alphafly 3, so it takes less force to bend.

The forefoot rocker geometry is decent, with an upward curve that helps guide you toward toe-off. However, it's less pronounced than the adidas Adizero Adios Pro 5's, which starts farther back and lifts the toes higher for a more noticeable rolling sensation.

Pros

• Decent assistance rolling forward toward toe-off.

Cons

• Rocker provides only modest resistance to flattening.

The rocker offers adequate resistance to flattening but loses some of its curved shape when you apply a lot of pressure. Heavier and/or faster runners may therefore experience less of its rolling effect.

This shoe has a tall stack under both the heel and forefoot, leaving plenty of material between your feet and the road. The high platform won't suit runners who prefer a low-to-the-ground feel.

The heel rocker geometry is sub-par, as the rear curve is quite shallow. It offers limited assistance in rolling forward from heel contact, making it less useful for runners seeking a strongly guided heel-to-toe transition.

Pros

• Width around the ball closely matches the expected fit.

Cons

• Short, tapered fit with limited room through the arch and above the toes.

The fit is short, and the tapered front leaves limited space for your toes. Your usual size should be fine for shorter races if you prefer a snug fit, but consider going half a size up for a marathon to allow for foot swelling.

The arch runs quite narrow, as is typical of racing shoes, so it may feel restrictive if you need more room through the midfoot.

The forefoot offers only adequate vertical room, with a low ceiling over the toes. Runners who need more height in this area may find it snug.

The Nike Alphafly 4 is the better choice for marathon racing than the Nike Alphafly 3. It's lighter, softer, and more protective, with stronger energy return to help you maintain your pace as the race goes on. However, the Alphafly 3 is firmer, more stable, and feels more immediate when you push off, making it a better fit for shorter races or runners who dislike a soft ride. For those reasons, a discounted Alphafly 3 remains a good buy.

The Nike Alphafly 4 is a better choice for longer races than the Nike Vaporfly 4, which is better suited to shorter distances. The Alphafly offers substantially more protection and a softer, deeper bounce, helping keep your feet comfortable late in a marathon. The trade-off is extra weight and a less immediate response when you push off. The Vaporfly feels lighter, firmer, and quicker underfoot, making it the stronger option for fast 5K and 10K races.

The ASICS METASPEED SKY TOKYO is the better overall racing shoe than the Nike Alphafly 4. It's noticeably lighter, returns more energy, and feels quicker when you push off, making it a strong choice across shorter and longer races. The Nike has a softer feel and more protection under the forefoot, particularly late in a marathon. At similar prices, choose the ASICS if you prioritize low weight and a quicker response; choose the Nike only if you prefer extra protection over long distances.

The adidas Adizero Adios Pro 5 is the better overall racing choice than the Nike Alphafly 4. It's lighter, making it a strong option across shorter and longer races. Both return plenty of energy, but the Nike offers a softer feel and more protection under the front of your foot. That gives it an advantage if comfort late in a marathon is your priority.