Super Old Spikes vs. Super Spikes

Recently when moving houses, I found my old high school track spikes (Nike Zoom Kennedy) in a box in the attic. I was surprised that I still had them and that they hadn't completely disintegrated. This particular pair is over 20 years old. I ran all my high school PRs in them back in 2004. The Nike Zoom Kennedy was the go to racing spike for 3k-10k back in the early 2000s, inspired by US distance great (and sub 13 5-k man way back in 1996) Bob Kennedy. Despite my pair being old as hell, I knew I had to test them against modern-day super spikes just for fun.

Testing Methods

For this case study comparison I looked at my 20-year old Nike Zoom Kennedy spikes against the modern-day super spike, the Nike Dragonfly. I tested the spikes over 5-minute trials at 6:00/mile pace on a Woodway treadmill. Yes, you can you run on a rubber-slatted treadmill like the Woodway in spikes...see. I measured oxygen consumption (VO2) throughout the trials and determined the percent difference between the Kennedy and the Dragonfly. Check out this link to see what running economy is, how it is measured, and how it impacts performance.

Results

My running economy was 2.7% better in the Dragonfly than the Kennedy.

Performance Translation

How does a percentage improvement in running economy translate to a percentage improvement in performance times? Well, it's not a perfect 1:1 ratio, particularly at faster speeds. Kipp et al. published a cool modeling paper to help translate just that. The full-text of the paper is free, and if you access it via your computer instead of mobile, you can download the supplementary MS Excel file that allows you to enter your height, weight, running economy benefit, race time and distance in order to get a performance improvement prediction for various distances.

Using the Kipp et al. calculator for my body size in high school and the paces I was racing on the track, the 2.7% running economy benefit of the Dragonfly spike should translated to ~2.1 performance time improvement. So with that...here are my new high school PRs!

Shoe Specs Comparison

Final Thoughts/Limitations

This was a fun, novelty test that I had to do after finding my old spikes. They performed admirably giving up a less than 3% economy advantage to the Dragonfly. I was actually surprised they didn't fall apart for the trial. I'm not so sure they would hold up for a 3k or 5k at my old race paces however. One limitation to economy testing is it must be done at sub-threshold intensities so we can obtain a steady state oxygen consumption value for comparisons. That said, the economy benefits observed in a lab at sub-threshold intensities do translate to performance time improvements for shorter race distances run at faster than threshold intensities as shown by Hoogkamer et al. Beyond the issues with running pace and the spikes being super old, there are several limitations in my performance extrapolation that I am well aware of. I am old and slow now and my legs are less springy than they once were. I also wear a 1 size larger shoe than my old spikes, which made for a pretty tight fit for this testing. Anyhow, it was fun to do, and I may just have to go around quoting my adjusted PRs to the new super spike generation of kids now!