ATLHawksfan21 wrote:Is there any concrete evidence that proves that players rapidly deteriorate at 30?
Comparing 40 and 30 is quite the stretch
"Concrete" might be a bit generous here, but there have been studies on this. There have been several that show basically the same thing, but the one I recall off the top of my head was one from boxscoregeeks. All these studies show that a player's career trajectory in terms of whatever stat is being measured (boxscoregeeks has their own formula that attempts to measure Wins Produced) is in the shape of a bell curve which peaks around 27-28. The interesting part about that study is that it also shows that the "average" player would still produce positive value until about 32 before he starts to become a liability. There was another study (and sorry, but I can't recall where I saw this or even if I looked at the original study and have just seen it referenced in other places) that basically says that the bell curve is "flatter" at the end of the career for players without a lengthy injury history. IOW, players who throughout their career always seem to have something wrong with them and miss games because of it seem to drop off a cliff faster than those who remain relatively healthy in their younger years.
As I said, I wouldn't consider anything as "concrete" here - there are a lot of ifs, ands, ors, and buts. How does one explain Kyle Korver who made his 1st AS game about a month before his 34th birthday? Also, there have been many players who, at the sunset of their career, have had a bounce back season and recapture the magic they had at 28 (albeit typically in smaller minutes). Further, none of this information is particularly new; teams have had this information for several years. Hence, if the research was geared more for the last 5-10 years and isolated everyone on a team by team basis, I'd imagine that we'd see trends in which certain teams get more out of players well into their 30's than others - PHX is a team that jumps immediately to mind here. Lots of factors here and lots of things that will skew numbers; if we get caught in the minutiae of individual cases then we'll find a lot of exceptions. But I do think that the overriding rule - that the "average" NBA player will go from being still useful to a liability somewhere in their early to mid 30s - does stand.
