The shoes are great. Since I got them, I’ve been faster over familiar routes every time I’ve worn them. Despite the miserable conditions, my half marathon time was almost 14 minutes faster than the previous time. Even with possible explanations of why the previous time was so bad, the results are hard to explain except by looking at the shoes. One daughter says they are magic. Another calls them cheaters.
My times over a 5 mile route around my home are interesting to observe. I have a schedule that is easy to follow on the run when fatigue makes calculation difficult. Five miles is 8k. My schedule is 2k in 15 minutes (yes, I know that is slow–no need to point that out). My 5 mile (8k) route has some long hills whichever way I go around it, so my times have always been behind schedule, even when my times on a flat route are on or ahead of schedule. I’d been running 2:30 to 3:15 behind schedule. New shoes, new times. 1:15 behind. On time. 1:15 ahead. 2:30 ahead. I just kept getting faster–more so than my lackadaisical approach to performance improvement would suggest was reasonable.
Magic seemed like an explanation, but I don’t believe in magic, so I decided to examine the shoes. It took quite a while, but I finally found out what was happening. First there was the discovery of a bunch of little holes in the sole and the outsides of the cushion material. The ones in the outsides were directed down and back like the ones in the sole. I tried probing the holes, but didn’t get anywhere. Then, with some help from a friend, an x-ray showed air chambers in the cushioning material connected by little tubes to the holes in the sole. Why? What is going on here?
Lots of pondering to no avail. Then it hit me. Foot strike compresses the air in the chambers. Little jets of air come out the holes. They literally blow your foot off the ground and forward (because of the angle of the tubes). The result is to lengthen your stride and effectively lighten the shoe. Faster turnover rate plus longer stride, even by just a little, means you cover the ground in less time.
When I first wore the shoes, I thought the foot plant felt somewhat unstable. I now realize that the feeling came from not properly managing the air jets. Since then, I have unconsciously adjusted my foot plant, and the feeling is now stable. Further conscious adjustments will let me take advantage of the air jets and bring my times down much more. Another 14 minutes next time? Back on track for 2 hours.