
I recently bought a pair of ST-4s after struggling to find a low-profile yet soft alternative to my venerable Altra Kayentas (the now be taken out of production). . I've tried Topo ST-3 before and had mixed feelings, but after reading reviews and seeing Topo ads for ST-4 I hoped it would work for me. Right out of the box, I was reminded of the Topo shoe's straight-fitting and form-fitting midsection. This, combined with the well-formed heel collar, contributed to a *very* solid fit - literally no side-to-side shifting and no heel-slip, which is unfortunately what I've come to expect from some other brands, even with a very roomy and snug toe box . When I walked indoors these shoes felt like they were literally built around my feet and thanks to the high quality Ortholite insole my feet feel nice and comfortable. Legs. And here's why: 1) Midsole. I originally tried these shoes on indoors at work (temp was set at 75F). I also tested them on some moderate weather (45-60Β°F) runs and liked how responsive and flexible the midsole felt for both walking and running, despite being quite firm already. After a few days, the morning temperature quickly dropped to freezing or below, and I was very surprised at how stiff and unforgiving the midsole became in this weather, especially when running. If I had to choose between running in these shoes in cold weather or just going barefoot/in my minimalist shoes, barefoot would be my choice. 2) Arch Support - My feet are very flexible yet have very strong, muscular arches. (see photo) by running barefoot or in minimalist shoes only in an upright position. They definitely support each other. As a result, even with the Ortholite insole cushioning, they couldn't cope at all with the strongly protruding, very hard arches of these shoes. I'm on my feet all day at work and every day after putting these shoes on I come home feeling like the soles of my feet are bruised. However, I can appreciate what Topo has created in this shoe and I think the fit and functionality will serve many people well for warm weather workouts and walks/runs of an hour or less. It's surprisingly stable for such a light and thin device. Unfortunately, based on someone who normally walks/runs barefoot and with a legitimately "natural" forefoot/midfoot landing, I can say that this shoe didn't allow my feet to function "naturally" at all, except mine toes could spread their legs. It's a "step" in the right direction, but not what I expected based on the ad that the shoe encourages "natural" movement. In any case, I'll look for something else for now while keeping an eye on the ST-5 to see if there are any improvements.