As someone who may or may not attended the 5 day pre-exam class back in another life on passing your Registered Rep / Series 7 License, the old salt teaching it let out a gem that forever stuck a cord. However, I have not looked at the evidence since the 1999-2000 bust. His gem was Small Cap Growth highs signal the end of a Bull Market and conversely when they recover, you are coming out of Bear. 2008 was not a typical crash, that was political / legislative / "Moral Hazard" imposed on us by the fartknockers on Capital Hill. However, 1999-2000 does anyone remember "QQQ" on a tear? Your gut told you making 80% a year just wasn't sustainable.
With the markets more efficient via Indexing by ETF and Mutual Funds, I'd have to spend fair amount of time to see if this old salts axiom still holds true, going back to 99'-00' and finding the style box winners for all those years and the dips and upswings in relationship to SCG performance....
The question, as always, is how high is high? And where is your starting reference point? My money is on a LOT more upside.