Bryan2B said:
"The numbers you cite for high school runners in your post was also accompanied by an analysis of those numbers, which stated (in part): "If we take the U.S. birth rate graph and create an overlay graph by adding 18 years to the birth years, and then plot the number of sub-4:10 milers (using a three-year moving average to smooth year to year fluctuation), there is a near identical match between the birth rate line and the number of elite runners."
So if it's really just a numbers and birth-rate game, how does that support the contention that we need to get back to training like the runners in the 70s and 80s? Apparently, the training isn't what makes the difference."
Bryan2B, your zeal to make a point is causing you to fabricate facts. I know they didn't teach you that in Pasadena. Those comparisons are not extrapolated birth rates, they are the average yearly numbers of ACTUAL high school aged (15-17) boys during each decade (70s 80s 90s). The participation rates are the average of the ACTUAL number of total participation by high school boys during the same decades. The only weak link in the data is that the NFHS study (the only comprehensive one that I could find) did not break out the participation numbers for each sport for each year in the study. One could make the assumption that since basketball and track have the highest participation numbers that they'd have a high correlation with the overall participation rates. The whole point is to debunk the common notion that it's the declining birth rate (and by extension the available pool) that caused the decline in performance during the 80s and 90s.
So what you have is
1) total average yearly number of high school aged (15-17) children during the 70s
2) total average yearly number of high school kids participating in sports(70s)
3) total of sub 4:10 milers in the 70s
4) total sub 9:00 2-miles in the 70s
Put the same data up for the 80s and likewise the same from the 90s. Make percentage comparisons. The performance drop-offs are statistically significant and confirm what we all know to be true anecdotally. Surely you can see if the enrollment/participation rates were 12.4-12.9 percent less than the 70s and the number of 4:10/9:00 were 21.1 and 39.3 percent fewer, respectively, then there must be something other than numbers to explain the decline? Moreover, if the enrollment/participation rates are only 7.2-9.7 percent less in the 90s than the 70s yet the numbers of 4:10/9:00 are a whopping 62.1 and 82.1 percent fewer!!!! Declining participation has no close correlation to the decline in performance. So what's the answer? Could it possibly be what we've been telling you all along? Hmmmm. In the 70s it wasn't unusual at all for the kid down the block to be putting in 80-100 a week in high school. Yet, I've talked to college XC coaches in the 90s who've said when they suggested that their kids might try to bump up the work-load over the 50mpw they were doing and kids responded like they were from Mars or something.
All of those kids from the seventies - including the hundreds and thousands in the second tier (4:10-4:25/9:00-9:30) and third tier(4:25-4:40/9:30-10:00) - formed a huge pool of runners from which to draw from and making it possible for the depth that you saw in the 80s.