Rebounding isn’t sexy. Just look at the imagery we associate with it: “Cleaning the glass.” “Crashing the boards.” “Snatching the rebound.” Missed shots are filth, and rebounding is the subsequent janitorial duty for a defense.

Even amongst the basketball intelligentsia, rebounding is falling out of favor. ESPN.com’s Zach Lowe wrote a seminal piece titled, “Why are teams bored with boards?”, citing several coaches on their preference for players to hustle back on defense rather than going for offensive rebounds. Teams have rebounded only 24% of their misses so far this year, declining for the fourth year in a row and over a percentage point below last year’s rate. “If you study the numbers,” Charlotte Hornets head coach Steve Clifford tells Lowe, “you find that offensive rebounding just isn’t important in winning big.”

So what is driving everyone away from the offensive glass? Many point to transition defense. When an offense player goes after his own team’s miss and fails, the defensive rebounding team is rewarded with a potential transition opportunity. Getting out in transition is one of the most efficient plays for an offense, resulting in 110 points per 100 possessions across the whole league, nearly 5 points higher than the total league average. So it makes sense that coaches are interested in getting back on defense and minimizing these opportunities for opponents.

The Value of Improved Defensive Rebounding

Even while teams are devaluing offensive rebounds, defensive rebounds are still extremely important. For one, securing a defensive rebound deprives the opposing team of another possession. And not all possessions are created equal: possessions immediately following an offensive rebound are the second-most efficient type of possession, only behind those coming off of steals. So snatching a contested defensive rebound takes away a super-charged possession for the opponent.

Defensive rebounding’s value is quantifiable and considerable. Between the best (Spurs) and worst (Bucks) defensive rebounding teams, the Spurs allow 4.1 fewer offensive rebounds per 100 possessions. And at 103 points per 100 possessions off of offensive rebounds, that difference becomes 4.3 points per 100 possessions.

In other words, the difference between the best and worst defensive rebounding teams accounts for the same difference as that between Toronto’s 5th-best offense and Milwaukee’s 21st.

Tim Duncan: Basketball Player, Human Being, and Rebounder Extraordinare

No basketball player in history has combined skill, longevity, modesty, leadership, and loyalty as Tim Duncan has. Since the Clinton administration, he has put together jaw-dropping accolades, earning him the top spot on ESPN’s All-Time Best Power Forwards. He and head coach Gregg Popovich have been the bedrock of the San Antonio Spurs organization for nearly two decades, winning five championships and making the playoffs every single year. By all accounts, he sets the tone for the entire organization with his steady leadership and dogged work ethic. But perhaps most impressively, for a guy who is elder to four NBA head coaches, he leads the league in Defensive Real Plus Minus. Holy freaking cow.

Even as The Big Fundamental chugs along through one of his final years, he somehow goes relatively unnoticed. He doesn’t demand max salaries. He doesn’t publish sappy poems. He doesn’t hijack possessions from young developing players. He doesn’t sucker punch teammates. He doesn’t command special treatment in opposing stadiums. Tim Duncan is a world-class professional who, as cliché as it may be, puts the team before himself, and he should be commended as such.

While enough can’t be said for his rock solid post game and heady team defense, Duncan’s rebounding, particularly his defensive rebounding, is amongst the all-time greats. Since the NBA started distinguishing offensive and defensive rebounds in 1973-74, he is third in all-time defensive boards and seventh in defensive rebound percentage. He has the most defensive rebounds in the playoffs by a long shot, both a testament to his rebounding prowess as well as his longevity and consistency. He is the Spurs all-time leader in rebounds, defensive and offensive, beating out his big man predecessor, David Robinson. Fourteen of his nineteen seasons, the Spurs have been in the Top 4 for defensive rebounding percentage, and Duncan has led the team in boards for every season thus far.

This season, he has anchored the Spurs back line to rebounding greatness. Their defensive rebounding percentage is on pace to be the best for any team ever at 80.0%, and that number is even higher when he is on the floor. Amongst players that have chased at least a third of defensive rebounds, Duncan is fourth in Win %. This indicates that he is really good at battling for and winning contested rebounds, which are the most valuable kind because they deprive the other team of a possession and set your team up for a potential transition opportunity. While Duncan’s per-minute production has in fact slipped this season, his presence is still immensely important and valuable to a Spurs team that has a very real chance to bring him a Jordan-esque sixth ring.

How Duncan Rebounds

Defensive rebounding is difficult, even for big fellas. There is a fine balance between guarding your man, playing help defense, boxing out, and leaking out in offensive transition that requires accurate instantaneous decisions. Turn around too soon, and you are just leaving your man open. Overly commit on defense, and your opponent will be rising for the putback slam as you are descending from your block attempt. It takes a special combination of strength, agility, skill, and basketball IQ to know when and where to play defense and to snatch boards.

From watching hours of Duncan’s defensive rebounds, I’ve identified a few key techniques that he uses in order to help him and his teammates secure the most difficult and most valuable rebounds:

Always aware of his man while playing help defense

Duncan’s phenomenal rebounding is as much about what happens before the shot goes up as it is about what happens after the shot is released. Just like any great help defender, he knows precisely how to walk the fine line between helping and staying home on his man. Part of that his calculation includes the risk of leaving your weak-side wing defenders to try to box out a big man, a dangerous proposition. Check out how Duncan patiently stays home on Joakim Noah in this possession:

For most of the possession, Duncan is watching the ball to see if he needs to help. But all the while, he uses his arm to probe for Noah. Twice Duncan thinks that a shot may be coming and starts to box Noah out, a necessary head start in order to beat one of the league’s best offensive rebounders. At the very end, Noah cleverly moves beyond Duncan’s reach and circles back towards the hoop along the baseline, getting parallel with Duncan and giving himself a pretty good shot at a board. However, Duncan uses his left arm to keep Noah ground-bound while corraling the ball with his right.

Textbook box outs

Similarly, The Big Fundamental keeps DeAndre Jordan on his back side for this whole possession, never giving DJ a real chance at a rebound:

If I ever have to teach kids how to box out, I will show them videos of Tim Duncan, starting with this one.

Retrieving his own blocks

Duncan will soon pass 3000 blocks for his career and will be only the fifth player ever to do so. As exhilarating as an emphatic swat into the stands may be, it is largely unproductive because it gives the ball right back to the opponent. Duncan is savvy enough to know how to leap and block shots just enough to prevent them from going in, come back down, and immediately spring back up to grab the loose ball. The athleticism and agility necessary for this play is underrated but considerable, and Duncan is still really freaking good at it:

Here’s another play against the Timberwolves, where Duncan isn’t at all fooled by Karl-Anthony Towns’s movement to the weak-side elbow, instead coming down to deny Andrew Wiggins:

This is literally the stuff of legends.

Tip to teammate / self

Old Man Riverwalk knows that he can’t always get both of his mitts on the ball. When he can’t, he will tip the ball to a teammate or sometimes even to himself, typically to avoid getting the ball swiped away, as well as in cases where he doesn’t have as good position as his opponent.

Yes, you just witnessed 39-year-old Tim Duncan outleap two men who won’t even be able to legally go out for a beer together for another 10 months. Specifically pay attention to how he gets back up so quickly for his second and third jumps after his initial contest. If a player did this this at the draft combine, experts would commend him for having a “high motor.” And 39-year-old Duncan is still motoring along on a nightly basis. How does he do it?

Here’s a great example of when he couldn’t grab the board on the first or second tries, but smartly tips it into a position where he can pull it down himself:

It is so easy to miss these little things that he does night in and night out, but each game can hinge on just a few possessions. Winning these contested rebounds is essential to winning the possession battle and ultimately the game itself.

Will he ever retire?

While Duncan’s minutes are down, his per-minute rebounding stats are nearly on pace with his career averages, and his other stats are down in large part due to his own decreased burden on offense, coinciding with LaMarcus Aldridge’s arrival. He’s not the kind of player that needs a certain number of touches or minutes or shots or anything. As long as he believes that he can help his team win, he will continue to play, in whatever capacity that may be. Ultimately, he clearly has the clout in the Spurs organization such that retirement will be his decision, not theirs.

On-court statistics aside, the Spurs should want to keep Old Man Riverwalk in a uniform for as long as possible, even as his productivity declines. High character veterans (Jameer Nelson, Elton Brand, Prof. Andre Miller, PhD, etc.) can be worth their weight in gold for teams looking to develop young players, which the Spurs have been surprisingly good at considering that they’ve been known for their three veterans stars for so long (Tony Parker and Manu Ginobili being the other two). I mean, young players just aren’t going to do things like this on their own:

Spotted on a local HS track, running conditioning drills in triple-digit South Texas heat: Tim Duncan, James Anderson, Danny Green. #spurs — Jeff McDonald (@JMcDonald_SAEN) August 10, 2011

Tim Duncan is one of the greatest players of all time, not because his peak was all that much higher than a lot of players, but because he has sustained his greatness for so incredibly long. He does the unglamorous things that are more about value and less about flair. So when the filth of missed shots soil his basket, he puts on his hard hat, grabs his lunch pail, and fulfills his janitorial duties.

Update 2/3/2016, 6:51 PM PST: Tim Duncan is older than four, not three, NBA head coaches. J.B. Bickerstaff of the Houston Rockets has been added to the list.