In the last few years, some notable indoor records have been broken or seriously challenged. Lindgren's 8:40 from 1964 finally went down at the Armory, Rupp is set to attack sub 3:50 in the next few weeks and has already run well indoors at Boston U. An active thread is discussing Putteman's indoor 8:13 2 mile in 1973, which seems amazing for the time.
It all got me thinking about the differences in "speed" between different generations of indoor tracks. Outdoor tracks haven't really changed since the 1970s, as Ventolin always reminds everyone via the IAAF max energy return rule. Prior to that, cinder tracks conferred an always debatable handicap that varied on the track quality, the level of upkeep it had, and if it had rained recently. Synthetic tracks eliminated all of those variables and enabled statisticians to compare records with the only variable being altitude and how favorable the heat/humidity/wind were for races.
Indoor tracks went through a similar revolution at roughly the same time. We can break up indoor tracks into different generations, based on how much more "speed" they gave:
1st gen: 11-lap to the mile banked board tracks. These gave some energy return via the elevated surface and the bounce from the planks, but they had dead spots where the supports were. Lindgren's record was set on one of these.
2nd gen: ll-lap to the mile synthetic tracks: These came along by the '70s (I'm sure many have seen the pics of Pre racing on synthetic at the 1973 Sunkist meet) and allowed for better traction and more energy return than boards. Coghlan's 3:49 mile record was set on one of these, as (I assume) was Puttemans.
3rd gen: 200m banked or oversized flat synthetic tracks. As far as I can tell every modern record has been set on a 200m banked synthetic track.
My question/discussion is: how fast are each of these relative to each other and to a perfect outdoor venue, such as Oslo or Rieti?
Directly comparing records doesn't tell the whole story, since it can be pretty safely assumed that the record holders did not attempt to run their best indoors, as it would have meant sacrificing money and prestige on the outdoor circuit. Thus the relative merit of Hicham's 3:43 outdoors and 3:48 indoors is debatable. Cheserek's 8:39 on a banked armory track is not directly comparable to Lindgren's old record either; too many extraneous variables.
How much slower do you think indoor tracks are than outdoor tracks, assuming the best possible scenarios for each? By how much do you think these different "generations" differed?
For me, I believe that modern indoor tracks, especially permamently banked 200m tracks are about as fast as outdoor tracks, depending on the athlete. Hydraulic tracks are a bit slower, since they don't give back the bounce that those tracks build up on frames do. UW's track is incredible as well, nearly as fast as an outdoor track.
I think old indoor tracks were measurably slower than modern ones, I'm just not sure by how much.