ASICS S4+ Yogiri running shoe

ASICS S4+ Yogiri upper

The upper of the ASICS S4+ Yogiri running shoe sits right between performance-focused and comfort-first uppers. It’s made from a thin yet soft mesh that offers average (but perfectly okay) breathability. The tongue is very similar to ASICS’ race-ready shoes (Metaspeed): a thin, faux-suede-like material that isn’t gusseted. It’s worth taking a moment to adjust it properly when you put the shoe on. The laces are also Metaspeed-like—textured/serrated—so they’re less likely to come undone and they hold the foot more securely. The heel collar is minimally padded and very stiff, as you’d expect from stability-oriented running shoes. The upper has a narrow build, but it’s not as narrow as a pure racing shoe upper. Sizing is true-to-size overall, but it’s close—I personally felt it ran a touch smaller than other shoes with comparable sizing. The insole is removable, but it’s held in place by a tacky material that grips the shoe.

ASICS S4+ Yogiri midsole

The midsole of the ASICS S4+ Yogiri running shoe consists of 3 layers. The top layer is a lightweight, lively, bouncy foam called FlyteFoam Turbo Plus (FF Turbo+). ASICS uses the same foam in its top-tier racing shoes. The bottom layer is a firmer, denser foam called FlyteFoam; it’s less about pop and more about stability. Between the two foams there’s a curved carbon plate. One important thing: the ratio of the two foams changes along the shoe. In the heel, the softer, more energetic FF Turbo+ makes up about ~25% of the total midsole, while in the forefoot it makes up around 75%. You can really feel this difference: if you land on the heel, it doesn’t feel as dynamic, but if you load the forefoot, it’s much bouncier and more energetic. The midsole doesn’t deliver Metaspeed-level propulsion, but it’s still more dynamic and faster than average. The rocker is mild in the heel but quite pronounced in the forefoot, which makes transitions quick and smooth. ASICS achieves stability with multiple elements. For one, the heel platform isn’t as narrow as it is on pure racing shoes. The heel is also asymmetric, with visibly more support on the medial side. The carbon plate makes the midsole very stiff, and the firmer FlyteFoam creates a solid, planted landing. Torsional rigidity is high—it’s hard to twist—which is great for stability, but if your feet aren’t used to it, it’s worth easing into it gradually. The midsole is built for sustained fast running over long distances, designed for sub-4-hour marathon efforts (sub-4). In other words: if you run marathons between 3 and 4 hours and you need more stability, you’re better off choosing this shoe rather than the Magic Speed line. I think it’s a bit more dynamic and faster than the Magic Speed 4, and also slightly stiffer.

ASICS S4+ Yogiri outsole

The outsole of the ASICS S4+ Yogiri running shoe is right up there with the best of the best for grip. I already knew ASICSGRIP rubber has excellent traction, but in the S4+ Yogiri it reaches another level. You can confidently say there’s currently no better-gripping outsole among road running shoes. ASICS uses this compound across all of its racing shoes, but on the S4+ Yogiri it’s the thickest and covers the largest area. Traction is outstanding on both dry and wet surfaces. The S4+ Yogiri outsole is thicker than average—especially compared to racing shoes—so while wear resistance is a bit weaker, overall durability can still be considered good.