Rebounding, we’re told, is all about effort and toughness – two undeniable traits of the Boston Celtics since the 2007-08 season.

But perceptions aside, Boston is off to a mediocre 6-4 start and they rank 27th in rebounding rate, which is the percentage of missed shots that a team rebounds. The interesting thing is, those two facts might not have anything to do with the other.

“It doesn’t matter if we get outrebounded or not, we just got to play ball,” backup big man Chris Wilcox told HOOPSWORLD. “At the end of the day, if we just go out and play hard, we’ll come out with the victory. We just got to play hard for 48 minutes.”

That’s been the overall philosophy when it comes to the Doc Rivers’ era. His teams haven’t always been great on the boards. They ranked fourth and second in rebounding rate back in 2007-08 and 2008-09 respectively, but have failed to place better than 19^th in that category in the subsequent seasons (notice that the downward trend began before Kendrick Perkins was dealt for Jeff Green in February of 2011).

Oddly enough, Boston’s winning percentages have only declined modestly over that time, from .805 in the 66-win, championship season of 2007-08 to a respectable, if somewhat disappointing, .591 in 2011-12.

And the Celtics haven’t been waiting for the postseason to start rebounding. Last year, they finished 28^th in the league in rebounding rate, only to reach the Eastern Conference Finals while ranking 14^th out of 16 postseason teams in that category.

The disconnect between rebounds and winning continues to this day. Last year’s rebounding rate, 47.3, and winning percentage are congruent with Boston’s performance this year: 46.9 and .600 respectively.

This year the Celtics are 2-2 when they outrebound their opponent, and a surprising 4-2 when they don’t. Of course, you won’t find Rivers saying that rebounding doesn’t matter.

“It should matter and in the long run, it will matter … I felt like we were starting to rebound a little bit better, but you know, last night [Wednesday’s narrow win over the Jazz] we just got smashed to say the least,” Rivers said. “And you’re not going to win it if you don’t rebound better than that.”

Thursday was a rough night for the Celtics on the boards, outrebounded by the Brooklyn Nets particularly in the first half. It marked the second consecutive game Boston gave up 18 offensive rebounds and 15 of those came in the first 24 minutes at Barclays Center.

“It’s like I’ve been saying: You can’t wait,” Paul Pierce said after the loss to Brooklyn. “Obviously to give up 16 offensive rebounds, it’s tough. You know, the last two nights, it’s been very alarming, the offensive rebounding rate we’ve been giving up. That’s all about our effort. It’s all about our grit, you know, how bad we want the ball when it goes up.”

Kevin Garnett, the Celtics’ leading rebounder at 7.7 boards per game, may have had a more revealing answer, saying that the recent trend on the glass is “more than a little bit” concerning.

“When you give up 10, 15 offensive rebounds, that team has a chance at scoring, that doesn’t help us,” Garnett said. “I thought, second half, we made an adjustment and started to actually block out our man, but again, good teams, you can’t spot them [boards]. We’ve got to do a better job of not over helping. We are a help-defensive team, but, like you said, that’s too many [offensive rebounds].”

Yes, the Celtics are big on help defense, which has been known to contribute to these kinds of problems.

When a defense plays strictly man-to-man without much helping or doubling, it’s easy to find the guy you need to box out because chances are, you’re already guarding him. But in the chaos of Boston’s defense – which uncharacteristically ranks 19^th in efficiency this season – it can be hard to prevent offensive players from getting loose balls.

So it’s not necessarily surprising that Rivers’ team is indifferent to rebounding. The priority, rather, is on playing good help defense (the Celtics have finished in the top five in defensive efficiency every year since 2007-08) and everything else is more of a bonus.

“That’s the most important thing, how many stops we’re getting and just covering for each other on the defensive end,” center Jason Collins told HOOPSWORLD. “But yeah, we do have to do a better job of finishing out that possession and coming up with the rebound.”

And Boston is even less interested in rebounding on the offensive end, where players are usually instructed to get back on defense rather than trying for a second-chance opportunity.

The Celtics rank dead last in offensive rebounding rate by a significant margin (they’ve rebounded 17.8 percent of their missed shots), but they’re in good company. The Spurs (23.1 percent), Knicks (22.5 percent), Thunder (22.3 percent), Mavericks (22.2 percent) and the HEAT (21.9 percent) rank 25^th through 29^th in that category respectively, and are obviously some of the best teams in the league.

So no, the Celtics aren’t a good rebounding team, but that might not limit their success. The players and coaches can pay lip service to the topic (Wilcox told HOOPSWORLD: “I think we all just got to improve on the boards”), and they wouldn’t necessarily be wrong.

The larger issue, however, is how the defense is performing. If the Celtics can’t improve in that area, then their up-and-down start could turn into an up-and-down season.