Asics Super Blast vs Adidas Adizero Prime X 2 Strung: Two High-Stack Trainers Compared

Introduction

The Asics Super Blast and the Adidas Adizero Prime X 2 Strung sit in a rare category: very expensive, very high-stack shoes that genuinely can do a little bit of everything. Both are modern shoes packed with midsole technology, and both come with prices that are hard to say without wincing: £195 or $200 for the Super Blast, and £250 or $300 for the Prime X 2 Strung.

They are similar enough to be compared directly, but they suit slightly different runners. Here is how they stack up.

Specs and Midsole Tech

The Super Blast is the lighter shoe of the two. It weighs 251g (8.8oz) in UK size 9, with an 8mm drop and stack heights of 45.5mm at the heel and 37.5mm at the forefoot. The midsole is dual density: a big thick layer of Asics FF Turbo foam, the same foam used in the Metaspeed racing shoes, sitting on top of a smaller layer of the more durable FF Blast Plus at the bottom. Foam sidewalls and an internal heel counter add structure, and the wide base helps stability despite the soft, bouncy foam. The upper is a lightweight mesh with a bit more padding around the heel than the Adidas, and the AHAR Plus rubber outsole covers the key impact areas, though coverage is lighter than on the Adidas.

The Prime X 2 Strung is the heavier, more technical build. In UK size 9 it weighs 334g (11oz), with a 6.5mm drop and stack heights of 50mm at the heel and 43.5mm at the forefoot. Adidas built it as a racing shoe: three layers of Lightstrike Pro, the best foam in the lineup and the one used in the Adios Pro 3, sandwiching two carbon plates. The medial side is filled in more than on the original Prime X, and the base is wider, both with stability in mind. The Continental rubber outsole has good coverage, with the whole forefoot covered and two strips at the back, leaving little exposed foam. The Strung upper uses layered yarns in a bootie-style fit with a sock-like tongue that hugs the foot, keeping the top of the shoe lightweight.

Asics Super Blast

The Super Blast has been a long-term favourite with our testers, and the consensus is that it is a fantastic all-rounder. Despite the big stack of midsole foam, the structure of the shoe feels quite firm, so you get a nice pop when you run, and the bounce really comes through when you pick up the pace.

It handles easy runs comfortably and behaves like a plush max-cushion shoe at slower paces, but it also copes impressively well with faster work. Testers have used it for tempo training in a marathon build, done fast track reps in it, and even replaced a carbon-plated racing shoe for a hard road session without regret. There is no plate in the midsole, yet it stays remarkably stable at speed.

Adidas Adizero Prime X 2 Strung

The Prime X 2 Strung is immediately heavy; pick it up without knowing what it is and you would not guess it is a fast running shoe. But it feels much quicker than the weight suggests. Our testers ran half marathon distances in it and came close to personal bests without even trying, which is not what you would expect from a shoe this heavy.

Where it shines is longer tempo runs where you need to hold a consistent pace. It cruises you through, feeling energetic and smooth, with noticeably more bounce than the original Prime X. The stability improvements over the first version make it usable pretty much everywhere, including uneven city pavements, which the wobblier Prime X 1 was not. It performs best from easy pace up to marathon and tempo pace; all-out speed is the one area where the big stack makes turning the legs over harder, though the bounce is certainly there.

Fit and Sizing

The Super Blast fits true to size with a roomy toe box, and its comfort is closer to something like the Gel Nimbus than a typical fast shoe. One tester noted it can run slightly narrow and short at times, but generally described it as a roomy, very comfortable shoe.

The original Prime X had fit problems, and one tester got heel rub that “ripped my heel to pieces.” The Prime X 2 fixes most of that: the new bootie-style upper locks down well around the midfoot, there was no heel rub in testing, and it feels much more dialed in despite a lacing system that looks suspect for such a high, bouncy shoe. Both testers were happy in their normal size. Worth noting: Adidas sizing tends to run smaller than other brands for some runners, but neither tester needed to size up in the Prime X 2.

Run Test: Tempo and Long-Distance Feel

Both shoes behave differently depending on pace. At easy paces, the Prime X 2 is bouncier and more cushioned than the Super Blast, which feels firmer and more structured. When the pace rises, the Super Blast gets noticeably bouncier and the two shoes feel more even, but the Prime X 2 keeps a slight edge thanks to the plates and extra midsole tech, giving more punch for holding good paces over long distances.

The Super Blast’s advantage is weight: it is roughly 83g lighter in the same size, which matters for runners with a high cadence. The Prime X 2’s advantage is sustained energy over distance, and its more aggressive geometry, compared with the Super Blast’s more daily-trainer-like setup.

One lingering concern with the Prime X 2 is whether that weight becomes noticeable in the latter stages of a marathon when legs are tired, in the same way other very bouncy high-stack trainers start to drag past 20 miles. Neither shoe is really a racing shoe; both are too heavy and too high-stacked to match dedicated racers, so think of them as premium trainers.

Which One Should You Buy?

With money out of the equation, the Prime X 2 Strung offers the better experience: it is phenomenally balanced, bouncier at cruising paces, and a genuinely fun shoe to run in. If you want the maximum tech and the best tempo and long-run feel, it is the pick.

But the price gap is substantial: about £50 in the UK and around $100 in the US. Since most buyers will use either shoe as a trainer rather than a racer, the Super Blast is the smarter purchase. It is lighter, more stable, does everything well, and leaves a lot of money in your pocket. If you are purely chasing a superb training shoe, the Super Blast is hard to beat; if you want the most entertaining, tech-heavy ride and the price does not deter you, the Prime X 2 Strung delivers.

Conclusion

These are two of the best high-stack super trainers available, and both are excellent. The Super Blast is the lighter, more stable, more affordable all-rounder that excels from easy runs to fast sessions. The Prime X 2 Strung is heavier and less stable but bouncier at slow paces and better at holding tempo over long distances, with a greatly improved fit over its predecessor. Choose the Super Blast for value and versatility, or the Prime X 2 Strung if you want the fullest expression of modern midsole technology.