Dave Tutelman

Well said. My experience was similar but more so than that. Until my youngest was in high school, I immersed myself in the family. That was much to the detriment of my other activities, including golf, and worth every minute of it. I was part of my children's lives for their formative years. If that meant I was their soccer coach, monitored their piano practice, was there if they needed homework help, then so much the better. Even if that meant I didn't even play golf once a year. I got back into golf seriously when they got to high school. Think about it. Think about your situation. Teaching is a full-time job. If you're a teacher, you know that parenting is very important -- and also time-consuming. If you have time for regular golf, then either your work or your family is being short-changed.

One day in September of 1996 (wow! almost 30 years ago), I was in Newark OH. I spent the morning on a tour of Dynacraft and the afternoon on a tour of GolfWorks. I was there for a 3-day golf event, but the Friday got rained out. The host of the event "had connections", so he set us up to do this instead. Ralph Maltby was out of town, so a marketing guy led the GolfWorks tour; but Jeff Summitt showed us around Dynacraft and spent an hour answering questions afterwards. (Tom Wishon left Dynacraft a couple of years earlier, so we didn't get to talk to him.) I documented the visit (mostly the Dynacraft visit, where we had Jeff as the host) in an article that's on my web site. Come to think of it, that weekend was the annual convention of the Association of Clubfitting Professionals (now long defunct); Jeff had to leave about lunchtime to catch a plane to the convention. I bet that's why Ralph was missing when we got to GolfWorks. My impression of the Maltby stuff was that it was kind of ugly at the time, but effective. Their cosmetics are much better today. I believe the Maltby Playability Index was definitely on the right track, and they were after good numbers on that scale. That meant they were selling stuff for the average golfer. Tour players probably didn't need it, and most low handicappers of the time turned their noses up at it. Back in the '90s, I built a driver with a Maltby wooden head and a rather flexy graphite shaft. It worked pretty well, and was my gamer for most of a year.

I love the feel. Not squishy, but it's not hard and never seems to get hard nor cracked. I have also found that the tack not only lasts a long time, it is restored to "almost new" with a good washing (water and strong detergent or de-greaser). A litle history here. A friend who is a reseller of a lot of golf components first told me about Star almost 20 years ago. Since I tried them back then: They have been the only grip I use on my own clubs. I have never had to replace one due to wear nor age. My current irons have had the same grips for over 400 rounds and their feel and tack are still very good. (Yeah, I know that speaks to Star's and Pure's business model. So be it!.) I blow grips on and off without tape. (2" of tape over the butt to get it started makes it easier, but far from necessary.) In fact, I just lengthened a driver, which involved removing the grip (with an air compressor), putting in a shaft extension, and blowing the old grip back on. No problems, and the old grip is still fine. The formulation (common to Pure and Star but no other grip I know) retains its elasticity as long as my experience with them.

It does indeed. If that is important to you, then I fully understand why you are going to miss Pure. I'm an engineer. Yes, I appreciate aesthetics, but my primary concern is function. In that regard, Star and Pure are quite similar. Star does offer a pretty good color choice, but (a) nothing as eye-catching as that neon yellow, (b) only solid colors (I think dispersed into the rubber) -- nothing like the black logo on the light-colored grip. But check it out; you might like it.

Pure was originally a spinoff from Star Grips. The folks who left Star for Pure were unhappy about Star's inattention to cosmetics and marketing -- but NOT the formulation of the grips. Star is still in business and still my favorite. Try them. If you liked the feel, handling, and longevity of Pure, you should like Star.

I have known Tom, mostly over the internet through articles, emails, and forums, for 30 years. I have read four of his books. I have a few things I'd like to say that I haven't seen yet in this discussion. (1) More than anybody else in the world, Tom was the one who has made custom clulbfitting mainstream. He was the indefatigable evangelist for custom fitting. He wrote books about it at several levels, from readers assumed to be naive consumers to experienced clubfitters. He "took the show on the road" frequently. He backed up his ideas about club design with the investment necessary to build clubs to those design principles. Most of the people I know who have Wishon clubs fitted by Wishon-approved clubfitters really like them. (But they are not generally especially noisy about them.) Without Tom's constant efforts in this vein, the adoption of custom fitting by most of the OEMs would never have happened. (Let me except Ping from that statement; they had elements of custom fitting in their design and sales process almost 40 years ago.) (2) Those who know me know I'm pretty serious about the technical -- engineering and physics -- aspects of golf clubs. Tom may not have been an engineer, but I have only had one and a half such topics where I disagreed with him. Our main disagreement had to do with vertical gear effect. Time and research in the more than a decade since that disagreement have shown him to be wrong. Unfortunately, his later driver designs were based on his assumptions about gear effect, resulting in too much loft low on the face. The half-disagreement was about how to profile shafts. Not that we need to profile shafts. Not even what we should glean from those profiles. Rather the types of measurements we should be making. As the technically sophisticated parts of the shaft making and shaft fitting community adopted EI profiles obtained by deflection measurements, Tom insisted that frequency measurements interpreted according to his database were the future of custom clubfitting. Why do I count this a half-disagreement? Because there was a substantial cost involved in switching all his followers from frequency to deflection; I'm not sure the indie custom clubfitters would have held together as a force for custom fitting if they were forced to spend for the change. And it is probably preferable for the clubfitting community to be doing something useful if highly imperfect, rather than just accept the shaft manufacturers' pronouncement about their shafts. Those didn't work until the clubfitting community, led by Tom, educated enough consumers that the manufacturers had to improve. There were other issues where I initially disagreed with Tom, but studied them more closely and concluded he was right. And there was one issue (MOI matching) where I was leading him by several years. Just my two cents... DaveT

I certainly hope they are getting it. From my participation in one online forum, I know some are. I also know some aren't. They glaze over at math and physics, and biomechanics is math and physics. I hope a majority are getting it, but I wish I could say "believe" rather than just "hope".

Thanks for throwing my own writing back at me. Always a good start to a debate. You did well. Yes, I did write that. It was 10 years ago. 7 years ago, I learned what the up-and-in force (Brian Manzella dubbed it "going normal") does for clubhead speed. Once I learned that, it was much more clear that the significance was in the high curvature before impact. I really ought to edit that when I get a chance; thanks for pointing it out. As for the counterintuitive explanations of what goes on very early in the downswing... Yeah, it is highly counterintuitive. But the equations hold up, and they are really very simple physics at these slow speeds. Rather than belabor what Sasho has already explained in images, videos, and papers, let me suggest a few reasons it might not jibe with anybody's intuition. (I have to agree, it offends my intuition as well, until I think really hard about it.) Here are a few factors that contribute to the confusion. We have forces that we need to exert just to stabilize, or even just to hold onto, the club. We don't think of them as large, but they are often larger than the forces we are consciously exerting to move the club in the way we want to. Gravity is one of those forces, especially at low speed. At higher speeds, we are exerting many tens of pounds just to keep the club from flying off into space. That is probably more than the forces we consciously use to accelerate the club. Actually, they are accelerating the club -- not faster, but along a curved path. But we don't think about that; we just do it. But those forces are still part of any analysis of motion, and often dominate that analysis. Some of the forces may happen without our conscious help. Here's one I don't see discussed in any of the biomechanics papers, but... When I start the downswing, the hand couple accelerating the club's angular motion is substantial. In fact, it is substantial the whole time the shaft-forearm angle is the same as it was at transition. But I don't think this is exerted by the muscles controlling the wrist at all. We are, I believe, looking at hard tissue interaction. At transition, that angle is likely determined by the range of motion of radial deviation. If the hand couple to rotate the club did not happen, then that angle would collapse. It would collapse in such a direction as to defy radial deviation range of motion -- to fracture one of the bones involved. (I have run computer simulations; you'd be amazed how much it collapses without the mechanical "stop" of radial deviation limits.) So all that hand couple torque is not supplied by hand effort at all. It is dependent on the bones of the wrist joint not allowing anything different to happen. I know I didn't explain your specific question. But I hope I've given you some insight into why a satisfying explanation can be difficult.

A couple of different issues here. Let me deal with the Rory hip reversal in this response and the early downswing behavior separately. That's a couple of good observations, WildThing. Phil uses nothing but the best in motion capture, so I trust his pronouncements about kinematics. I also looked at a bunch of Rory McIlroy swings to check on some of his points, and he is certainly right that the hip reversal occurs clearly after impact. Even in the swings where the hips don't reverse, their minimum forward angular velocity is about the same place that the hip reversal was on other swings. So you're absolutely right to call me out on that. When it happens, it happens after impact. Why would students/instructors care about it, if it happens after impact? Don't know. But it's a fact that I saw a number of YouTube videos at that time discussing how to imitate Rory's hip reversal. And whether reaction torque is all of it or shares the cause with leg drive, trying to accomplish your own hip reversal does not sound like a good idea. But historically, golf instruction has been, "Look at what the greats do, and do it like them." I have received enough of those lessons myself, which made no sense to me even then. Now let's look at his explanation of why the reversal, in response to John Dunigan. Phil starts by saying there are two effects that are happening. The first is exactly what I said. But then he says that alone is probably not enough to reverse the hips, so let's look at what else could be doing it. (Bear in mind, he's not saying reaction torque isn't happening, but rather that he doubts it's the only thing happening to reverse the hips.) He points out that Rory's rear leg is still extending even after impact, so it is producing a force on the right hip. I took a good look at this. We are talking about after impact, often as late as full horizontal extension toward the target. We know that Rory has fast hips, and they are open substantially at impact, then continue to open (except for the reversal -- but that doesn't count because we're looking for what causes the reversal). The force from extension that Phil talks about should be pushing the right hip forward. If the hips are already open, that force would not cause a reversal; in fact, it would reinforce the opening of the hips. So I have to respectfully disagree with Phil and John about this. If Phil has cranked this motion capture into an inverse dynamics program, and can show that the leg's force on the hip joint creates a hip-reversing torque, I'll be glad to concede the point. But while we're all just using eyeballs to see what is going on, I'll take a stand. It certainly looks to me like that force is causing the hips to open more, not cause hip reversal. Looks like reversal is all reaction to the upper body.

I agree, but you're a bit of an optimist here. I don't think many instructors understand the biomechanics being discussed here. A bunch do, but I'll bet that's not even half of professional golf instructors. And if you don't know the physics and biomechanics, you're at a disadvantage when it comes to recommending what part of a pro's swing to copy, and how to copy it. Case in point! A few years ago, the golf instruction world noticed that Rory McIlroy's hips reversed direction briefly at some point in his downswing. Rory was undeniably the best driver at that time. So lots of instructors tried to understand how to make that move and teach it to their students. (Sometimes this was driven by instructors. More often the students saw some TV analyst's video commentary on Rory's swing and said to the instructor, "I want to get better. Teach me this." But the instructor did try, so it's on them too.) If you know physics, it is not hard to figure out that the reversal of hip motion is not something you do; it happens as a side effect of something else in the swing. That something else is Rory's delaying a strong torso release until most of the energy of his hip release has been expended. The hip reversal is an "equal and opposite reaction" to the torso release. I was appalled at the amount of time it took for the instruction community to absorb this fact, so obvious if you know something about biomechanics.

Absolutely correct! No argument here.

OMG, could we possibly be making this any more complicated? If you're competing at the professional level, either golf or long drive, then this level of detail is probably warranted. If not, we can deal with a much simpler narrative. Let's look at just two issues: Sasho's paper on how amateurs create speed, and curvature of the hand path. (The latter was the thing that started this thread, but we don't seem to be focusing on how nor why in the right way.) How do amateurs create clubhead speed Sasho MacKenzie wrote a paper that examined four possible ways to generate clubhead speed. (Here is a link to a slide talk on the subject.) The average force pulling the club along the hand path. The average couple torqueing the club. The length of the hand path. (colloquially "bigger turn") The angular change of the club during the downswing. (colloquially "more wrist cock") By far the strongest correlation to clubhead speed is the first factor. So for top clubhead speed, look for things that will push or pull the hands along the hand path as strongly as possible over the whole downswing. Those don't have to be hand-focused; something like a powerful torso turn toward the target will cause a hand-path force to be exerted. But do judge any proposal by whether it does this! Anything else has much less effect on clubhead speed. Justify it if you want by effect on clubhead position and path at impact, but it ain't a clubhead speed thing. Hand path curvature Let's assume you are more skilled, more advanced, have more control of your swing. You have already gotten as much clubhead speed out of it as you can through force along the hand path, but you are capable of doing what it takes to control the shape of the hand path. (We'll talk in a bit about "what it takes".) As long ago as 2009, Steven Nesbit and Ryan McGinnis correlated the shape of the hand path against clubhead speed and skill of four golfers. (It was just four, and they were very different in strength and skill.) The golfer with the most skill and the most clubhead speed also had a high curvature of the hand path shortly before impact. I'll go further and say there is probably causation there, not just correlation. (But I could be wrong, and even the correlation isn't strongly supported on a statistical basis; too few golfers involved.) I say this because an increased curvature just before impact can be caused by pulling up and in late in the downswing. Up-and-in force is well-known to increase the moment of force that angularly accelerates the club. Two factors: it requires increased centripetal force, and it increases the moment arm (force acting more in front of the club's CoM). There are plenty of ways to make this up-and-in pull happen, and almost all the pros do something in that direction. Plenty of them jump off the ground at impact. The "power squat" early in the downswing and subsequent straightening later is a less extreme version of the jump. Some (Jordan Spieth, Jamie Sadlowski) bend the left arm; looks like a chicken-wing, but rather different kinetics involved. Tiger famously wrote about "snapping the left knee" when he wanted a few yards of extra distance; history tells us this may be effective but not safe. Notice that I said nothing about flattening the early part of the hand path, which is what much of this thread has focused on. It is all about increasing the curvature near impact, not decreasing the curvature after transition. The latter may be a side effect of some strategies, but isn't where the speed comes from.

OK, so there's a tendency for golfers looking at swings to focus on minutiae, to not see the forest for the trees. Here is Sasho MacKenzie's most recent research, which is just about as simple as it can be in terms of what a golfer has to do to maximize clubhead speed. (https://www.golfsciencejournal.org/article/12640-how-amateur-golfers-deliver-energy-to-the-driver) BTW, when I said "simple", I didn't mean you don't have to know physics or math. It is a very simple explanation in terms of the physics needed. The message from the study is that the most effective way to get clubhead speed is to maximize the work done along the hand path. In physical terms, work means force in the direction of motion. So it is the component of the force (not torque couple) the hands apply to the club in the direction of the hand path, integrated over the hand path from transition through impact. If you are familiar with physics and math, this is a very simple statement of what you have to do. If not, let me suggest a similar goal that will probably be the same in practice. (If Sasho is on this forum, I'll be glad to defer to him as to whether this is accurate.) During the downswing, move the hands along the hand path as fast as possible. Not the release of the clubhead nor any slap at the ball; torque applied to the grip during the downswing is pretty ineffective in producing clubhead speed. If you are doing this and want even more clubhead speed, you might try a longer hand path (bigger turn). That works better than trying for more wrist cock, according to Dr Sasho. I have said nothing about what the hips, the feet, the glutes, the trail pinkie need to do to make this happen. That is technique, which may be different for different golfers, or starting from a different swing. But the goal is clear: accelerate the hands to the maximum possible speed all through the downswing.

What tony said, and use an old toothbrush to scrub it, in case it's caked in the grooves.

As others have said, that design seems to have more than one manufacturer. I own a Wilson Black Jack putter with the same shape, probably the same insert, but different markings. A single sight line on the body, but not the three above the face. Brand and model ID on the sole. You can see what it looks like because there is currently one like it for sale on eBay at https://www.ebay.com/itm/133754903842?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=133754903842&targetid=1328894427317&device=c&mktype=pla&googleloc=9003692&poi=&campaignid=11211718007&mkgroupid=122765038032&rlsatarget=pla-1328894427317&abcId=9300435&merchantid=6296724&gclid=Cj0KCQjwl_SHBhCQARIsAFIFRVXaSAaZ7lIDamkASaPEQqXf5FDyAD2tOhsJe55mBGeO4hIdphvwzqMaAuCFEALw_wcB

I'm just agreeing with everybody else here. There is a wealth of data from manufacturers of clubs and balls supporting the notion that more than half of what we perceive as the feel of impact is really the sound of impact. The companies knew this from actual research, good experiments that verified this every time, starting before the 1990s (which was when I became aware of it. Here's a little supporting (but unscientific) anecdote. The best golfer in my group needs a hearing aid. We were playing a few years ago, and he was playing his usual solid game until late in the front nine. Then his game completely fell apart, and stayed bad until the end. I asked him afterwards what had happened. Seems the batteries were running low in his hearing aid. It was behaving disturbingly, so he turned it off. Then, "All of a sudden, I had no feel at all. I couldn't play because I was getting no feel feedback."

Two things made the arm-lock putter popular recently, but the concept has been around for quite a while. The USGA/R&A banned anchoring, but bracing against a forearm was still legal. Matt Kuchar adopted it. As early as 2002, I built myself an arm-lock putter. It didn't go nearly as high on the arm as a modern ones, but it shared a lot of characteristics with them. At the time, it didn't stay in my bag. But I made the switch for good about 7 years ago. I built myself a few variants of the modern arm-lock, and still use the one I found best at the time Here is what I would expect you to find, at least based on my experience. Good news: your line is likely to be better than before. More good news: if you have any tendency to the yips, this is likely to ward them off. I developed the yips in my early 70s. Tried a lot of things, with varying degrees of success. The arm-lock was the most successful. Not-so-good news: You will have to recalibrate your distance, especially if you were a "feel" putter. You may find it hard to dial in your distance feel. Stick with it; you will probably get there. It just may take some time. Hope this helps.

There is both evidence (actual measured experiments) and analysis saying that higher on the face will give more distance -- until you get so high that you are losing COR from the face flex. Because of vertical gear effect, higher on the face subtracts some from the backspin, so lower backspin. Because of face roll (vertical curvature of the clubface of a driver), higher on the clubface gives higher launch. I have done quite a bit of work quantifying this. You can see the short form of both the experiments (not mine, but published) and my mathematical model which agrees with the experiments at <https://tutelman.com/golf/ballflight/gearEffect2.php#validation>. On later pages of my article, I cover how face roll figures in. Turns out the optimum face roll makes the distance fall off less than a flat face would, as impact gets farther from the sweet spot. BTW, the sweet spot is not the center of the face; it is higher than that to get higher launch and lower spin. I agree with blackngold_blood that this assumes a driver fit roughly to the golfer's clubhead speed and angle of attack. If mismatched, reduced spin could lose distance for you. I have a case study on that at <https://tutelman.com/golf/clubs/centerOfGravity3.php>.

Grew up in the Bronx. I know only these courses, and only from the last half of the 1950s and early '60s. From that point of view... Yes, Split Rock is probably the cream of the crop. (Ferry Point was only a park, an open space for a city kid to run around on grass; the golf course wasn't even a gleam in anybody's eye yet.) I played Pelham more than Split Rock. It's an OK course, but no better than OK. (Gotta admit, I'm spoiled now. I live in a county where the County Parks Dept has 8 courses, and I'd rate 4 of them outstanding.) I played Mosholu a lot -- which I don't see on the list. Does it still exist? I could get there after school on the Jerome Ave subway, and my high school locker was big enough for a bag of clubs. I'd take the subway up there and get on the list. It was first come, first served; no tee times. I'd do homework for the 60-90 minutes before my name was called. Typically finished around dark, and took the subway home. At the time, Mosholu was a fairly short 18-hole course. Last time I looked, it was 9 holes and they hosted the NY First Tee Program. I had one opportunity to play Clearview, in the early '60s. I agree completely with your assessment. Thanks for the trip down memory lane.

My bag is somewhat similar. I have been losing distance since I turned 65 (I turn 80 in about a month). More recently, my strength and motor coordination are slowly becoming compromised. I have been fitting and building clubs since the 1980s, so it is likely you won't recognize the non-OEM names of my components. Driver - 12° Disukaba, Project X Hybrids - 16, 19, 22 degree Dynacraft HyperSteel, SK Fiber TT-100 Irons - 5-9 and PW, GW Pinhawk Single Length, Hireko house brand shaft SW - 54° PinPoint, house brand shaft LW - 60° Titleist Vokey SpinMill, bought at yard sale and modified to fit me Putter - ProSwing Hyper 3-ball, steel 3-bend arm-lock shaft With several of these (Driver & hybrids especially), I went back to these older components because I hit them better and/or more consistently. I also own what I consider the best 3-wood ever (Hireko Acer XS Titanium, which is very innovative, with a SK Fiber TT-80 shaft). My good shots with this 3w go slightly farther than the 16° hybrid, but my average distance is less because I am so much more consistent with the hybrid.

The best 3-wood I've ever used for both distance and ease of getting up in the air is the Acer XS Titanium 3-wood. There are several things about this head design that make it so. I think Hireko stopped making them around 2015. If you can still find one, consider it. If it's the wrong shaft flex, it's not hard to re-shaft. That said, I no longer have it in my bag. Instead, I have a 16° hybrid. My good shots go almost as far as that 3-wood, and a noticeably larger percentage of my shots are good. Easier to get up in the air, too. So consider a low-loft hybrid instead of a 3-wood.

That has been my experience as well. I went with single-lengths to try out the concept when I was doing a study in 2016. They are still in my bag. WaffleHouseTour's observations are the same as mine. BTW, one reason (but not the only one) I like the one length wedges is that my tired, old back likes them. (Tired? L5-S1 requiring PhysTherapy. Old? I'll be 80 next month.) I don't have to bend over nearly as much to hit them.

Thanks for the heads-up. Interesting device. I have never used one, but from the videos I'm pretty sure I know what it is. I have been involved in the development of several training aids, so I think I know what's going on. What it is: There is a 6DOF inertial sensor in the "watch" on your wrist, along with some sort of electrode or, more likely, vibrator (piezoelectric transducer would be my guess). There is a two-way wireless link (probably Bluetooth, but maybe WiFi or some other wireless technology) to an app in your smart phone. The app does the math of inertial navigation to tell where the device is -- both position and attitude -- throughout the swing. The app has a GUI to set up the mode and to report results. (Note: "attitude" is navigation-speak for "the direction where it is pointing".) What it can do: Everything in the videos (swing plane, length of backswing, transition, tempo) all seem well within the reach of the technology. It is less ambitious than some other products (e.g.- SkyPro or SwingByte) in that regard. It can measure and report anything that depends on the position and attitude of the forearm just above the wrist joint. That includes pronation/supination, but not flexion/extension nor radial/ulnar deviation. That brings us to... What it can't do: I just cited flexion/extension and radial/ulnar as things it can't do. That would take something like Hackmotion to tease out those wrist motions. It also doesn't know where the club itself is pointing. So it would not be able to diagnose casting, track lag or clubhead speed and direction, detect ungrip/regrip at the top, or anything else that the club does outboard of the forearm. It would be nice if someone technical from DeWiz could tell us their story instead of my having to play Sherlock Holmes. But please, someone technical, prepared to talk technical! Not a glorified sales pitch, which is what the videos are.

I have some agreement and some disagreement. Agreement: "What he said." What Middler said is spot-on! Agreement: "The difference in feel, if any, is a product of the design of the club head, not whether it is forged or cast." Mostly agree. It's hard -- and expensive -- to forge a deep-cavity clubhead, so you don't see many forged clubs with thin clubfaces. There have been experiments proving that feel comes with the design, not the forming process. Where I disagree is that the softer and perhaps denser metallurgy of a forged head probably makes a different sound from a typical cast head. It has been repeatedly determined with controlled experiments that about half of what we sense as "feel" is really sound. Disagreement: "The higher the swing speed, the more relative increase in ball speed with a thin faced iron." The higher the swing speed, the higher the absolute ball speed increase -- that is, the difference in yards. But the relative ball speed increase -- the difference in percent -- is just about the same. In fact, I have seen at least one analysis that shows the low-speed golfer to have ever so slightly more percent increase from a thin face.

Be careful how you go about this. A negative AoA with a driver often (usually?) results in a low launch angle. Launch angle and spin are closely related in what they do to distance. Yeah, I know the folklore that says: "Lower spin and higher launch for more distance." Well, a key word there is AND! If you have a low launch and you reduce spin without increasing the launch, you will LOSE distance, not gain. You have to do both to increase distance -- really, even just preserve distance. Think of it this way. Launch angle give the ball a higher flight initially. This will keep it in the air longer. Spin keeps the ball in the air longer, because of aerodynamic lift. There is an ideal balance between launch angle and spin. For a given ball speed and launch angle, there is an ideal spin. For a given ball speed and spin, there is an ideal launch angle. Why is speed involved? Because lift varies as the square of speed, so it has to be part of the equation. What that says is that, if you have a low launch angle, the first thing you need to do is raise the launch angle, not reduce the spin. If you can get a higher launch angle, then too much spin will cause ballooning and reduce distance. But if you have too low a launch angle, you need the spin to keep the ball in the air. If you're interested in a more rigorous treatment of this, I have written an article which resides on my web site.