Track advantage

I'm convinced that running on a tartan track has an advantage but this seems at odds to my belief in minimalist shoes. There was a time when I thought the cushioning on shoes actually returned energy making you run faster, rather than absorbing it to supposedly reduce impact on your knees. I guess the key thing is elasticity and rigidity - how much energy is returned and how quickly. If you look at World Record times on the track for 10,000 meters compared to a 10k road race, there is an improvement of around 1.5% - how much of this is due to the other variables in road running (wind, elevation changes) or the fact that the 10,000 meters track event is much more prestigious, is hard to gauge. What bothers me is having two apparently conflicting ideas in my head at the same time. If the tartan track surface is advantageous, surely I could cut out a foot shaped section of it and stick it to the bottom of my shoe and - voila! - gain an instantaneous 1.5% in speed.

Whatever the case, I went for a 20 minute aerobic run on the running track at work yesterday. The track is a kind of afterthought to the football pitch, being a square 350 meter circuit that is often interrupted by stray footballs or stretching footballers. Nevertheless, I ran an average of 4:02 kilometer splits (just shy of 15kph) with an average heart rate of 149 bpm (my aerobic threshold) and it wasn't even particularly cold - around 27 degrees. Admittedly my heart rate was creeping up by the end but it was very comfortable. Had I been programed to run 20 minutes at 15 kph, I would have spent some of the day fretting about the workout but a 20 minute aerobic run doesn't even register any points in terms of training load.

If anyone can point me to any scientific studies of the benefits of tartan track versus tarmac, I'd be very interested...