Rebounders - Born or Made?

One of the big topics of the offseason always seems to be about how Post Player is really working hard in the weight room. It goes something like this:

**Post Player Bulking Up

**In his freshman campaign, Post Player learned the hard way how physical the Big Ten can be.

"[Upperclassman post player] really took it to us last year. I just wasn't big enough to hold position, and he made us pay," Player remarked about Team's 67-59 loss last season to [other Big Ten team].

But Player hopes to change all that this season. After coming in at [Weight #1], Player now tips the scales at [Weight #1, plus 20 pounds]. The extra mass is the payoff from many nights and weekends spent in the weight room.

"[Team strength and conditioning coach] has really been working me hard, and I'm stronger now than I've ever been."

[Team strength and conditioning coach] agrees. "Post Player has really put in the time, and that's going to pay big dividends over the season. This is a physical conference we play in, and unless you have the necessary bulk to hold your ground, you're not going to play to your potential."

But it hasn't been all work for Player. [Team strength and conditioning coach] has had Player on a [eye-popping amount of calories] per day diet this summer.

"Yeah, it's been a lot of food. I eat until I can't eat another bite, and then I eat some more," said Player, whose daily diet consists of plenty of milkshakes, pizza, ice cream, fried chicken, Chicago-style pizzas, lard, BK Quadruple Stacks, cotton candy, and steak-fat.

[Team strength and conditioning coach] wants Player to improve his conditioning as well, so that he holds the weight during the season. Last year, Player lost 10 pounds over the course of the season.

"The Big Ten can become a grind, so it's real important that Player adds muscle that he can hold throughout the season."

These kinds of stories are literally everywhere. And I mean everywhere. Really, everywhere.

Now surely, added bulk helps in a lot of ways. It can help establish and hold position, finish through contact, and can even help with endurance. But when I think of post players bulking up, I normally associate those efforts with a desire to improve rebounding. Which made me wonder - does bulking up really help? Is improved rebounding merely a function of adding on the pounds?

So, I put together some numbers -- looking back to 1996-97, I looked for four-year players who were between 6'9" and 7'1", and played significant minutes. I tracked DReb% for each of those four seasons, occasionally having to cut out a season here or there for lack of PT. There were about 40 Big 10 post players meeting this criteria. Here are the average DReb% for each of those seasons:

Freshman: 14.9
Sophomore: 15.2
Junior: 17.0
Senior: 17.5

It appears that the jump is, on average, made from the Junior to Senior seasons. That seems easy and logical enough. But unfortunately, the world is not really so simple, and neither is basketball. Here's how the numbers look graphically:

What we expect is for the light blue line to stay above the yellow line, which is above the pink line, which is above the dark blue line, for most of the data points. But that doesn't happen here. This graph is all over the place. The one thing I will note, however, is that big gaps appear rare, or at least fleeting. A gap indicates significant improvement (if it's the proper years - otherwise, it's a significant decline). James Augustine is a nice story here - he went from 16.6, to 18.7, to 19.2, and finally to 23.8. But there are a lot of weird cases, like Aaron Jennings, who went from 19.1, to 15.2, to 18, and then to 14.9. And then there's Spencer Tollackson, who flatlined his entire career between 10.7 and 12.5.

Are rebounders born or made? Well, the highest correlation was between the Freshman seasons and the Junior seasons, but that was only a moderate correlation. None of the other coefficients were enticing enough to see a link, although the freshman season had a moderate correlation to all of the other seasons. Curiously, the correlation didn't seem to get any better as players aged. The sophomore season was actually a lousy predictor to the junior and senior years, and the junior year was an OK predictor of the senior season.

I'm just dipping my toes into this (what about 3 year players? Guys between 6-7 and 6-8?), but I'd have to say that, for the most part, rebounders are born. But certainly, a hard and fast rule is not something you'll find here.