Dissecting the Physics of Basketball Bank Shots

[jongib369]

BY ERIK MALINOWSKI 03.14.11





Here’s the scenario: You’re a college basketball player and your team is down by one. You’ve got a trip to the NCAA men’s basketball tournament on the line, but the clock shows less than three seconds. After your teammate passes you the ball, you dribble twice, pump-fake the defender, and throw up a jumpshot that could win the game.

Now, do you shoot the ball straight at the rim or aim for the backboard? According to researchers at North Carolina State, you better try to bank it in.

After analyzing computer-generated 3-D simulations of more than 1 million basketball shots, a team led by NC State’s Larry Silverberg determined that, while it does vary, there are large, identifiable areas on the court where a bank shot can be up to 20 percent more successful than attempting a direct swish.

The findings, published in the most recent issue of the Journal of Quantitative Analysis in Sports, make several assumptions about the ball shooter, in order to keep the the results determined by the 3-D sims consistent. One was that the ball be released at a height of either six, seven, or eight feet off the floor — a fairly typical height, if perhaps a little conservative.

Also, a regulation men’s basketball with a 29.5-inch circumference and 22-ounce weight was used in the sim. (Women’s basketball uses a ball that’s an inch smaller and two ounces lighter.) Finally, the ball rotated out of the shooter’s hands with a backspin of 3 Hz (three revolutions per second).





What they uncovered (shown here) was that areas on the wing — between the free-throw area (most of that inner rectangle) and the outermost three-point line — contained pockets (shown in the bottom-most graphic) where a bank shot was much more likely to go in than with a direct shot.


Up top, you can see the area that had the success rate for bank shots. It makes sense that the percentage drops so low on the outer area since you have such little surface area of the backboard to utilize.

Below that, you see the hot spots for converting direct shots.

Finally, at the bottom, you can see the areas (denoted in red) that had the highest increase in success rate with bank shots over direct shots. Indeed, these areas are usually off to the side of the straight-away area, where you’re more likely to get a good angle at the backboard.

The NC State team also discovered that when they plotted the simulated shooter’ aim points, the resulting data created a V that could be used as a training device for teaching players where the most successful bank shots are aimed. The dots that comprise the bottom-most part of the V represent shots taken closer to the free-throw line. Dots higher up on the V were from shots taken farther out on the wing.



But perhaps an even greater finding was that there existed, 3.326 inches behind the backboard, a vertical axis line that could be used to aid shooters in knowing where to aim their bank shots.

It’s actually quite simple: Envision the V (as shown here) on an actual backboard. Then visualize a vertical bar that sits 3.326 inches behind the backboard. Wherever you see the two cross, that’s where you aim for a high-percentage bank shot.



The problem is, teaching players to shoot high-percentage bank shots — because science tells us they have a better chance of going on — runs counter to the basic fundamentals of hoopdom. We see the rim, we want to shoot the ball at the rim. Shooting nothing but bank shots goes against human instinct, but it can be taught.

With enough reps — hopefully not 10,000 hours worth — you could train your eye to launch the ball at some arbitrary point away from the rim. Provided that your release point, ball rotation and body momentum remain constant, aim point can certainly be adjusted, especially if science convinces us our chances of scoring will go up.

http://www.wired.com/2011/03/physics...all-shots/all/

https://www.youtube.com/watch?v=SIaCQEr1oM0

[fpliii]

Cool read, great find!

[ProfessorMurder]

I did a project similar to this while in a trig class, and a stats class back in school.

I would bank a lot of shots when I played. People hated it, and tried to mock me sometimes, but I won almost all the time.

[russwest0]

[jongib369]

I did a project similar to this while in a trig class, and a stats class back in school.

I would bank a lot of shots when I played. People hated it, and tried to mock me sometimes, but I won almost all the time.

Don't you just love it when you play the game correctly and people get mad at you for it?

Earlier today I was shooting around, don't often anymore so like usual I was horrible at first. Takes like 10 minutes of shooting with a few Jimmers thrown in there to get warmed up. (For some odd reason after throwing up "Jimmers" closer shots are a LOT easier for me)....Anyways within the first 10 minutes it wouldn't surprise me if I went 8 for 40...But then I started draining them in little "pockets"....miss 3 make 5, miss 4 make 6, miss 2 make 8, miss 5 make 5 and etc.... Near the end I started practicing my sweeping hook and underhand free throw trying to get the spin and point of contact with the board right....Which made me realize, why am I not practicing my bank shots? (hook was bank shots but you know what I mean)...So I shot all of them from around the red/purple areas shown in the OP which just seemed like the best place to shoot it from and I literally made at least 15-20 in a row....Yes I was wide open and should be making them, but the increase in made shots was so dramatic to what I normally do from that range I'd be a fool to not use it more often

[jongib369]

*bank*

[WallIn]

lol

some epic science right here

[oarabbus]

GREAT post OP

I did a project similar to this while in a trig class, and a stats class back in school.

I would bank a lot of shots when I played. People hated it, and tried to mock me sometimes, but I won almost all the time.

Why the f*ck is this the case? Why are bank shots mocked? Even something friendly "you didn't call the bank"... why? Why? WHY? I just want to know guys. Someone who HATES bank shots please chime in.


edit: I don't bank TOO often but made a game-winning bank runner in pickup few days ago... wasn't trying to bank

[bdreason]

Math / Science telling us what we already know.

[Genaro]

Why the f*ck is this the case? Why are bank shots mocked? Even something friendly "you didn't call the bank"... why? Why? WHY? I just want to know guys. Someone who HATES bank shots please chime in.


edit: I don't bank TOO often but made a game-winning bank runner in pickup few days ago... wasn't trying to bank

Because when you don't call it there's the possibility that you miss by a lot and just got lucky. The bricks that fall are what get people mad.

But when a guy does it everytime (like Timmy) you just know it isn't out of lucky.

[oarabbus]

Because when you don't call it there's the possibility that you miss by a lot and just got lucky. The bricks that fall are what get people mad.

But when a guy does it everytime (like Timmy) you just know it isn't out of lucky.

I tried my hand at a fast break pullup 3 once, tried to swish it like Curry... was clearly way off because it banked in. Is that what you're talking about?

I never understood it, because when someone makes a bank shot I go "damn, this fool can use the glass" not "what a little bitch bankin this shot"

I mean, it's like people almost treat banking shots like it's a bad thing, like you're flopping or you're that guy who calls foul on every play. If it goes in, it goes in, is how I see it.

[Myth]

I'm going to practice imagining that bar behind the backboard. For some reason, I was a very very good bank shooter around the age of 14-15 and as I aged, I remained above average but lost some of the touch for some unexplained reason and I want to get it back.

[jzek]

I would bank a lot of shots when I played. People hated it, and tried to mock me sometimes, but I won almost all the time.

Did you have a quad season?

[oarabbus]

I'm going to practice imagining that bar behind the backboard. For some reason, I was a very very good bank shooter around the age of 14-15 and as I aged, I remained above average but lost some of the touch for some unexplained reason and I want to get it back.

What exactly is the purpose of the bar they're talking about? Seems like you should aim for the "V"

[dreamwarrior]

I shoot banks better, but I don't normally go for banks because it's beta. In pickup games I'm usually the one willing to take any open shot and it's weird because even if I miss 10 in a row people will still keep passing me the ball and nobody gives me shit about chucking because they're all afraid to shoot. If I keep missing I'll go to the bank shot and hit 3 in a row and all of a sudden I'll have my touch back for the rest of the game.