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Opinion & Analysis

The Science of Mud Balls (and predicting their flight)



Recently, I had a few people ask whether we have done any research at Ping on the effects of mud on a golf ball, or “mud balls.” It turns out that one of our engineers had encountered a significant amount of mud on the right side of his ball in a tournament earlier this year. Unsure what the effect on ball flight would be, he aimed for the middle of the green and watched his ball draw into the rough, well left of the green. This spurred a debate as to whether the effect of mud on ball flight could be consistently predicted.

We did some theoretical analysis, which showed that mud on the right side of the ball should almost always cause the resultant ball flight to curve to the left. The main reason is aerodynamics – a golf ball with no dimples on the right would also curve to the left. The question is – with mud, is this effect measurable and repeatable?

To test our hypothesis we set up a G30 4-iron on our Ping Man robot and set the swing characteristics to a faster swing-speed player. The club speed prior to impact was set to 95 mph, leading to center hits carrying a little over 220 yards with a Titleist Pro V1x ball. We then teed up a number of balls with mud caked on different areas. Some had mud covering the entire surface of the ball, while others had mud applied to one area – either the front, back, top, bottom, left or right side of the ball.

We used a lot of mud to try to maximize the effect and get the most measurable results. However, our high-speed video analysis of impact showed that much of the mud fell off the ball immediately, regardless of how much mud we applied.

A short statistics lesson is needed to interpret the results. Ping Man is extremely consistent and so usually no more than three shots are needed in any configuration to establish a reliable set of data. In our bar charts, the average of the three shots is the bar itself, while the “error bars” on either side of the bar show what we call a 95 percent confidence interval. This means we are 95 percent confident that if we took 1,000 or even 1 million shots on Ping Man, the average would fall in this interval.

The more shots you take, and the more repeatable the data, the smaller the error bars are. If you look at 2 bars where the error bars overlap, this means there is no statistically significant difference and a correct statement is that the averages are “broadly the same.” If there is a clear gap between error bars, the statistical conclusion is that there is almost certainly a real difference in the averages.

Does mud on the right of the ball cause it to bend consistently in one direction?


The average offline distance for a clean ball, a ball covered in mud, and balls with mud on the left or right.

The answer is categorically yes. Figure 1 shows that balls with mud on the right ended up around 25 yards left of the target on average – a statistically significant result. Likewise, with mud on the left, the ball ended up around 25 yards right of the target. With mud all over, the balls ended up statistically no different to the clean balls. You can see that the error bars are much wider for all of the mud balls than the clean balls. The mud is making the ball flight less consistent, which is no surprise. However, the take home message is that if you find your ball on the fairway with mud on the right side, aim right of your target and you can be confident that the ball will curve a long way to the left. This was tested by one of our engineers in competition not long after we conducted the test and he was able to aim right with confidence and find the middle of the green.

Does mud on the ball cause it to fly shorter?


Figure 2: Average carry distance for a range of different mud conditions when compared with a clean ball.

Figure 2 shows the carry distance of all the configurations we tested. There was a significant drop in distance for all of the mud balls, but the most dramatic drop by far occurred when mud interfered with the club-ball interaction. With mud on the back or bottom of the ball, the club impacts mud before the ball and — no surprise — mud is not great for energy transfer. Even when mud does not get in the way of the club, ball speed is lower, which is a result of some of the energy in the club head going toward accelerating mud rather than the ball. The message here is: Take an extra club if there is a lot of mud on the ball, maybe even a couple of extra clubs. Our test shows the extreme case because we used a lot of mud, but the effect will exist whenever there is an impediment like mud on the ball.

This kind of little experiment reminds me how fortunate I am to work in an engineering department where if we have a question based on observations during a round, we have all the tools at our disposal to answer that question in a systematic and reliable way. I hope this helps shed a little light on what you can do if you’re unfortunate enough to find mud on your ball during a round.

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Paul is the Vice President of Engineering at Ping, coordinating a department responsible for club design, development, innovation and testing. He moved there in 2005 after completing a PhD studying Solar Flares in the Mathematics Department at St Andrews University, Scotland. He has spent most of his time with Ping in the research department working on the physics of ball flight, the club-ball impact and many other aspects of golf science. Some of his projects at Ping include the nFlight fitting software, iPing, Turbulators and TR face technology. The idea behind these articles is to explain a bit about popular scientific topics in golf in a way that is accessible to most. Hopefully that will be easier than it sounds.



  1. Pingback: 101 Days Until April - The Fried Egg

  2. Graham

    Apr 1, 2016 at 11:25 am

    Intriguing stuff. One question I’d like to ask is “why doesn’t mud detach instantly once a ball is struck?” If I want to get mud off my shoes I bang them together, and I’d imagine the energy imparted to a golf ball on being struck is of a larger order.

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  5. Pingback: The Science of Mud Balls | Honourable Society of Golf Fanatics

  6. Max

    Dec 17, 2015 at 8:37 pm

    This is good info to know but I, personally, avoid this problem by playing winter rules all year.

  7. Pingback: A “Muddy” Lesson | World Junior Golf

  8. Steve Thomas

    Dec 17, 2015 at 2:53 pm

    This is an excellent article. I would like to know what happens to a ball after you have hit a cart path. Most of the time I just buff them out using the strap on my golf cart, kind of like sandpaper, but on some occasions when the ball hits an asphalt cart path, then it’s really scuffed up too bad to use and I just put those balls in my shag bag.

  9. birdeez

    Dec 17, 2015 at 10:02 am

    i’d love to ask those labeling this as shank why they do so….tough to please or just complete jerks. this type of article is what makes wrx unique and the number one site in golf. i’m sure you prefer golf digest articles on how to cure your slice for the umpteenth time.

  10. Pingback: The Science of mud balls and predicting their flight | Welcome to Raflewski Golf!

  11. viking62

    Dec 16, 2015 at 6:28 pm

    so if there is mud on the right side of the ball – your average right handed golfer should hit the ball much straighter. Maybe someone should make a ball that acts like a ball with mud on the right hand side.

    • Da

      Dec 17, 2015 at 2:11 am

      And how would you use that in the fairway or rough? You would only be able to use it off the tee. And how would that affect roll on the green, you thunk?

      What a dumbazz

    • Scooter McGavin

      Dec 17, 2015 at 6:52 am

      They do make those. They’re called Polara golf balls and have dimple patterns that make them fly straight. Non-conforming, though.

  12. Matthew Bacon

    Dec 16, 2015 at 5:59 pm

    I liked the article and echo the sentiments about wondering how scuffs affect the flight

    • Da

      Dec 17, 2015 at 2:12 am

      Just think “range balls” and you’ll get the idea

  13. Jack Nash

    Dec 16, 2015 at 5:53 pm

    What’s a mud ball? When you go and identify your ball you inadvertently brush off the blob when you place it back down. ????

  14. Big t off 2

    Dec 16, 2015 at 5:07 pm

    Think Jordan should learn how to read first before putting his big golf shoe in it you silly boy!
    Great advice for us novice golfers @ this time of year…

  15. 8thehardway

    Dec 16, 2015 at 4:11 pm

    A Hall of Fame article that should be pinned somewhere for permanent exposure.

  16. Shank you very much

    Dec 16, 2015 at 3:09 pm

    After reading this and seeing 3 “shanks” with no comments I have to believe that there are people out there that just shank these articles to be a douche. Don’t understand why someone wouldn’t just clean the mud off the ball before playing a shot? Can’t swing fast enough to notice the difference? Slice so bad that a watermelon sized clump of mud on the ball doesn’t make a difference?

    • jc

      Dec 16, 2015 at 4:16 pm

      duh, because you can’t clean the ball if it is not on the green? read a rules book.

      • JZ

        Dec 16, 2015 at 4:35 pm

        Um, I think that was Shank’s point. 3 people shanked the article with no comment. His 3 reasons were why they could possibly do this – thereby implying one of those 3 didn’t know the rule and just assumed you’d clean the ball. And, you’re assessment isn’t completely accurate as there are times you can clean your ball. Lift, clean and place, anyone? Before you shank on someone, maybe you should take the time to try to understand what they said.

    • Jeff*

      Dec 17, 2015 at 4:31 pm

      Well, the rules of golf. Some folks are cursed by integrity.

  17. Steven

    Dec 16, 2015 at 3:05 pm

    Great article. I really liked seeing the statistics.

  18. Forsbrand

    Dec 16, 2015 at 2:55 pm

    A story from Phil Mickelsons College golf days – Phil is playing a guy called Manny Zerman, Phil calls Manny over asks for relief as his ball has muck on the side of it. Manny says sorry no you’ll have to play it as it is. Phil says ok no problem hits an exaggerated in to out swing and hooks the ball 25 yards through the air and holes it for an eagle. Zermans coach walking with the match calls manny over and tells him next time Phil Mickelson asks for relief you give it to him ok?!

  19. Jordan

    Dec 16, 2015 at 2:29 pm

    I love that you tried to use REAL statistics as empirical evidence but creating a 95% confidence interval off of 3 swings is pretty dumb. Why not just take the generally accepted 30 observations so you can have realistic statistical inference.

    • Paul Wood

      Dec 17, 2015 at 7:53 pm

      Jordan – you make a fair point. 3 swings in general is not very many. To be honest, if I was doing this test for a research paper I’d certainly hit more balls, and I’d also want to repeat with more different swings and on different days, but this was really to satisfy some curiosity at our end. The statistics are real though. The confidence interval takes into account the number of swings and so it’s inherently bigger for 3 swings than 5 or 10 or 30. Part of what makes PING Man valuable is that he is so consistent we can hit 3 shots and see statistical significance in most tests. This particular test played to his strength extremely well. We just set up one swing and all we changed was the ball.

      • Jordan

        Dec 17, 2015 at 7:59 pm

        Very good. Thanks for the reply! Forgot about the precision of “Ping Man”. I’d love to see you guys further pursue this with a bigger sample so we maybe bring that confidence interval into a ultra small range

      • Stretch

        Dec 18, 2015 at 11:57 am

        I would like to see the test add off center hits to see if the ball reacts in a more extreme way.

  20. Max

    Dec 16, 2015 at 2:27 pm

    Awesome. As a lifetime golfer and an engineer, I can say this is one of the best pieces I’ve ever seen on here. Thank you, Paul.

  21. ParHunter

    Dec 16, 2015 at 12:49 pm

    Now that is an article that is relevant for the normal golfer at this time of the year! Thank you.

  22. Double Mocha Man

    Dec 16, 2015 at 12:32 pm

    I always have mud on the back of the ball, thus I smoosh it against the ball at impact and get “knuckleballs”.

  23. Chuck

    Dec 16, 2015 at 12:31 pm

    This is so cool. I always wonder, how much tour players read GolfWRX. I expect that about 500 of the best players in the world will all read this and talk about it on the range. And that every single caddy will have a discussion about it, with their boss or with other caddies.

    • JP

      Dec 17, 2015 at 9:31 pm

      Tour players already know what mud does to their golf balls, and how to play them. There are very few shots tour pros have not encountered or don’t know how to play….

  24. alexdub

    Dec 16, 2015 at 12:04 pm

    This is why I will always play Ping… Innovation and explanation through passion for the game.

  25. Mat

    Dec 16, 2015 at 11:52 am

    THIS is why we come here. Fantastic information! Here’s to lift-clean-replace being in effect…

  26. Ian

    Dec 16, 2015 at 11:35 am

    Needed to know this about a week ago – my course had a lot of rain and I had plenty of mud balls. I was just trying to find fairways so I could lift, clean and cheat.

  27. +2 man

    Dec 16, 2015 at 10:24 am

    Great analysis. I’ve always wondered about the “Ball will fly away from the mud” common advice, given the rotation of the ball in flight.

    Curious about the mud on the bottom causing such a significant distance loss compared to all the others that don’t directly interfere with contact. I wouldn’t have expected that.

    • Emb

      Dec 16, 2015 at 4:49 pm

      Since they’ve shown mud to cause to ball to curve in the opposite direction of where the mud is attached I would guess mud on the bottom reduces backspin so severely that the ball just fell out of the air very quickly and lost a ton of carry distance

  28. Progolfer

    Dec 16, 2015 at 10:09 am

    Fantastic article!

  29. Ben

    Dec 16, 2015 at 9:47 am

    Very interesting! Great to see statistical data on this. This is knowledge I can directly apply on the course. Thanks!

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Opinion & Analysis

Squares2Circles: Course strategy refined by a Ph.D.



What do you get when you combine Division I-level golf talent, a Ph.D. in Mathematics, a passion for understanding how people process analytical information, and a knowledge of the psychology behind it? In short, you get Kevin Moore, but the long version of the story is much more interesting.

Kevin Moore attended the University of Akron on a golf scholarship from 2001-2005. Upon completing his tenure with the team, he found himself burned out on the game and promptly hung up his sticks. For a decade.

After completing his BS and MS degrees at the University of Akron, Kevin then went to Arizona State to pursue his Ph.D. Ultimately what drew him to the desert was the opportunity to research the psychology behind how people process analytical information. In his own words:

“My research in mathematics education is actually in the realm of student cognition (how students think and learn). From that, I’ve gained a deep understanding of developmental psychology in the mathematical world and also a general understanding of psychology as a whole; how our brains work, how we make decisions, and how we respond to results.”

In 2015, Kevin started to miss the game he loved. Now a professor of mathematics education at the University of Georgia, he dusted off his clubs and set a goal to play in USGA events. That’s when it all started to come together.

“I wanted to play some interesting courses for my satellite qualifiers and I wasn’t able to play practice rounds to be able to check them out in advance. So I modified a math program to let me do all the strategic planning ahead of time. I worked my way around the golf course, plotting out exactly how I wanted to hit  shot, and minimizing my expected score for each hole. I bundled that up into a report that I could study to prepare for the rounds.

“I’m not long enough to overpower a golf course, so I needed to find a way to make sure I was putting myself in the best positions possible to minimize my score. There might be a pin position on a certain green where purposely hitting an 8-iron to 25 feet is the best strategy for me. I’ll let the rest of the field take on that pin and make a mistake even if they’re only hitting wedge. I know that playing intelligently aggressive to the right spot is going to allow me to pick up fractions of strokes here and there.”

His plan worked, too. Kevin made it to the USGA Mid-Amateur at Charlotte Country Club in September of 2018 using this preparation method for his events just three years after taking a decade off of golf. In case you missed the implied sentiment, that’s extremely impressive. When Kevin showed his reports to some friends that played on the Tour and the Mackenzie Tour, they were so impressed they asked him to think about generating them for other people. The first group he approached was the coaching staff at the University of Georgia, who promptly enlisted his services to assist their team with course strategy in the spring of 2019. That’s when Squares2Circles really started to get some traction.

At that point, UGA hadn’t had a team win in over two seasons. They also hadn’t had an individual winner in over one season and had missed out on Nationals the previous two seasons. In the spring of 2019, they had three team wins (including winning Regionals to advance to Nationals) and two individual wins (including Davis Thompson’s win at Regionals). Obviously, the credit ultimately belongs to the players on the team, but suffice it to say it appears as though Kevin’s involvement with the team was decidedly useful.

“One of the things we really focused in on was par 3 scoring. They finished 3rd, 2nd, 4th, and 3rd in the field as a team in their spring tournaments. Then at the SEC’s they struggled a bit and finished 6th in the field. At Regionals, they turned it around and finished 1st in the field with a score of +6 across 60 scores (186 total on 60 par 3’s, an average of 3.10).”

Sample Squares2Circles layout for the 18th hole at Muirfield Village. Advanced data redacted.

Kevin is available outside of his work with UGA and has been employed by other D-I teams (including his alma mater of Akron), Mackenzie Tour players, Tour players, and competitive juniors as well. Using his modified math program, he can generate generic course guides based on assumed shot dispersions, but having more specific Trackman data for the individual allows him to take things to a new level. This allows him to show the player exactly what their options are with their exact carry numbers and shot dispersions.

“Everything I do is ultimately based off of strokes gained data. I don’t reinvent the wheel there and I don’t use any real new statistics (at least not yet), but I see my role as interpreting that data. Let’s say a certain player is an average of -2.1 on strokes gained approach over the last 10 rounds. That says something about his game, but it doesn’t say if it’s strategy or execution. And it doesn’t help you come up with a practice plan either. I love to help players go deeper than just the raw data to help them understand why they’re seeing what they’re seeing. That’s where the good stuff is. Not just the data, but the story the data tells and the psychology behind it. How do we get ourselves in the right mindset to play golf and think through a round and commit to what we’re doing?”

“Even if you’re able to play practice rounds, this level of preparation turns those practice rounds into more of an experiment than a game plan session. You go into your practice round already knowing the golf course and already having a plan of attack. This allows you to use that practice round to test that game plan before the competition starts. You may decide to tweak a few things during your practice round based on course conditions or an elevation change here and there, but for the most part it’s like you’ve gained a free practice round. It allows you to be more comfortable and just let it fly a lot earlier.”

Kevin is in the process of building his website, but follow @squares2circles on Twitter for more information and insight.

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The Gear Dive: Mike Yagley and Chad DeHart of Cobra Golf



In this episode of The Gear Dive, Johnny chats with Mike Yagley and Chad DeHart of Cobra Golf Innovation on Cobra Connect, new ways to evaluate good play, and the future of golf improvement.

Check out the full podcast on SoundCloud below, or click here to listen on iTunes or here to listen on Spotify.

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Mondays Off: U.S. Open wrap-up | Steve plays against the new assistant pro



Would Woodland have won the U.S. Open if he had to hit driver on the 18th hole? Knudson doesn’t think so. Steve loved the U.S. Open, but he didn’t really love the commentator crew. Also, Steve tees it up with the new second assistant pro at the club, how did he do?

Check out the full podcast on SoundCloud below, or click here to listen on iTunes or here to listen on Spotify.

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19th Hole