Be sure and check out the Five Fingers KSO Trek review!
The review covers the KSO Trek's design (sole attributes and thickness), aesthetic, performance, fit, and more. You can read it by going here.
VFF KSO Trek trail run — First impressions
I did about a 30 minute run through a local natural park (a lot of doubling back and just messing around) in the fivefingers KSO Trek last night (Sans socks). Overall conclusion: the KSO Treks performed well thanks to a sturdier, more rugged and grippy Vibram sole, which conquered mud, gravel, and varied trail terrain. They are more water resistant than the KSO and seem to clean pretty easily (and dry over a reasonable timeframe). Further testing will, of course, be required!
Note: Vibram fivefingers "KSO Treks" below are referred to as "Treks;" standard KSOs just "KSOs." This is to avoid confusion as below I make a number of comparisons are made between the two.
Specific tests and observations
Creekbed, gravel, water: I ran back and forth through a creekbed a number of times to get a feel for various gravel sizes and water absorption. Water got in fairly readily at the toes; however, water didn't get in at all through the top. The kangaroo leather seems to do an excellent job keeping water out (KWO?). Overall, less water got in with the Treks than with the KSOs. More on this later.
As for gravel, the slightly stiffer and more aggressive sole seemed to glom together gravel a bit more: rolling gravel beneath your feet didn't "pinch" as much. However, and I'm not a regular runner or a trail runner nor have I done a full barefoot run, it seems to me the trick in conquering gravel is less about the shoe and more about relaxing your feet and not tensing up your ankle, which goes for KSO and Trek alike.
Trail debris: I hopped up large fallen trees and over logs. Grip seemed a bit improved though this is too close to really say. Roots and one-off ground protrusions were a bit more forgiving though still felt.
Ascents and descents: I ran up a couple steep ascents. Here is where I noticed a big difference: the KSO Treks got me up one ascent (50% grade? Maybe more) that I'm pretty sure would have owned the regular KSOs. It was muddy and soft, but the Treks dug in and got me up without me falling flat on my face and sliding down the muddy slope.
As for descents, both low grade, fast descents were confidence inspiring. High-grade descents that I took slower (angling steps downward) also felt stronger than with KSOs.
Mud: In both cases, there was definitely mud uptake from the lugged soles; nothing too bad and it seemed to clear fairly well on its own accord.
Asphalt: I also ran on asphalt (streets) for about a quarter mile at the beginning and end (gotta get to the park!); Treks handled the asphalt fine.
Cleaning and more on water resistance: After, I went ahead and washed them with water in a sink. I ran water from the sink straight into the top of the Treks with my hand inside to feel for permeation. Water was not getting through though the kangaroo suede was turning darker. Next test: I just started filling the Trek up with water to see what would happen. Sure enough, water started blowing up the Trek like a balloon (Reminded me of a bota bag) with points of seepage at the seams and then a sort of bubbling out of water through the synthetic side material (on the left and right of each toe).
This waterproofing made removing the little debris from the inside of the Treks very easy to remove: just fill up the Treks with a little bit of water and then pour it out like rinsing a glass. Big difference here as compared with the KSOs. They seemed pretty easy to clean (though I didn't bother getting too "granular" on getting all dirt out of the tread).
Finally, after the drenching I gave them at around 6pm last night, I hung them to dry in the laundry room. As of 9am this morning, they were dry.
Initial test conclusion: Initial testing of the KSO Treks was positive and I think anyone who wants to use them for trail running or hiking will be pleased.
Long-term use and long-distance use will, of course, require a good deal of further testing and feedback!
Previous posts on the KSO Trek