Grip Force/Strength and Swing Speed

[clevited]

I have always wondered how a person's phyiscal grip strength might relate to his or her swing speed in so far as how fast they can swing as well as how well they can control the golf club at a given speed. In another thread, I attempted to quantify the amount of force a person would need to apply to a golf club grip in order to keep it from sliding/moving at all in their hands. That discussion was a bit of a tangent from the main discussion so I thought I would post in a new thread. Below are some of the calculations I made, assumptions made, as well as a list of some of the items not considered that would or could certainly play a role. If you find this interesting, have some anecdotal information to share, or have done some testing on this sort of thing, please share.
The calculations below are based on my own 44 inch long driver. Balance point was used for CG (@32 inches from butt end of club), 332 g total club weight. Assumptions are that club pivots at very butt end of grip, centripetal force at peak speed causes the majority of the force on the club, the swing is fundamentally sound (meaning no extreme path issues or excessive face rotation etc), both hands apply equal force. Velocity in the table is of the clubhead at center of face.
Some of the variables or items not considered but could certainly be important: Do both hands apply equal force or does one tend to apply more than the other and if so, what might that balance of force be? One hand has glove on one had does not. How hand size and grip size apply. The torque felt in the hands from club face rotation, the force of impact with the ball and impact location, the vibrations from impact. How much the taper of the grip prevents slipping, there are many different textures on grips and materials they are made from what would the best possible friction value be?
Calculated grip strength needed per hand for a very slippery grip (wet grip, sweaty grip, oily needs to be cleaned grip)
[img]https://s3.amazonaws.com/golfwrxforums/uploads/FCRE6Z10L6UN/image.png[/img]
Grip strength needed for what I estimate might be a range of actual friction values for a used golf grip and leather glove, this is just an educated guess based on my own tests (friction values of .5 to .7)
[img]https://s3.amazonaws.com/golfwrxforums/uploads/LIZ8RUWPVZQI/image.png[/img]
[img]https://s3.amazonaws.com/golfwrxforums/uploads/IHOG3R8TSEFI/image.png[/img]
Grip strength needed given the friction value I calculated with a brand new, plain rubber grip and brand new leather glove.
[img]https://s3.amazonaws.com/golfwrxforums/uploads/A7HOUOLVDQBL/image.png[/img]
Some other notes: Brand new plain rubber grip in my bare hand showed friction value of about .7 while brand new glove and the same grip produced .8. A used, MCC grip I recently played 36 holes with (so not freshly cleaned) showed a friction value of .55 with a used but still in good condition leather glove. Both represented typical wear a golfer might have in my opinion.

Below are some quote's from a coupler other WRXer's regarding this subject. that I thought were interesting.5 Techniques to Improve Grip Strengthhttps://www.mytpi.com/articles/fitness/5_techniques_to_improve_grip_strengthThe hands are you only contact point to the club so it seems obvious that they are a key area in the golfers body. However, grip strength is often ignored completely by golfers, or if…"Basically, it seems like it's not possible for you to have too much grip strength. The stronger your grip gets, the easier it will feel to hold onto the club. The actual amount of force needed to hold onto the club remains the same, but that might mean you now just need to grip it with a "3" out of 10 instead of a "6". This means that the tension in your swing should decrease as well. It of course benefits you even more hitting the ball from deep rough buried bunker shots."-@SirFuego "I might regret opening this potential can of worms, but wouldn't taper on the grip also make it easier to hold onto the club, thus requiring less grip strength? Does the fingers wrapping around the grip create some sort of "Chinese finger trap" effect (I'm sure there is a more formal term for this and I'm not even sure it's the right "concept", but that's as close as I can think of) where (effectively) the coefficient of friction is also increasing as the speed increases?Also, I've seen videos of guys like Vijay Singh and Fred Couples whose right hand is basically off the grip at impact. Not to mention that most golfers only wear one glove. So the lead hand likely needs to work "harder" to hold onto the club than the trail hand, so I don't know that it makes sense to distribute the force equally across both hands from a simulation point of view. I'm not a mechanical engineer, but my day job is writing software simulations of real-world things, so I understand the need for certain simplifications (especially as a first cut), but I always need to question whether or not a model is too simple. "All models are wrong, but only some are useful."
-@SirFuego "This was a comment made on another website that is forbidden to be mentioned here (google "SuperSpeed grip strength" and the article on a SuperSpeed case study should show up). If you dig into the comments section, there is a comment by a user named "SUPERSPEED GOLF" (of which is probably safe to assume is legit):It is very important when you gain speed quickly like you did in your case to also make sure that your body can support and stabilize this new speed. In your case, we would test your grip strength. Research shows that most tour players have significantly stronger grip force than most amateur players. This doesn’t mean that they grip harder, just that their potential for grip strength is greater. For example a tour player may average somewhere in the 55-60 PSI range when tested for max with a golf grip sized dynamometer. Most amateurs will test for a max around 30 PSI. We find tour players usually grip with about 50% of their max (this changes throughout different parts of the swing), so their effective grip strength is about 25-30 PSI. Most amateurs cannot maintain this as it is near their max potential.It might give you something more to work with to see how realistic those forces are."-@SirFuego "I don't know what a reasonable number is for the coefficient(s) of friction. Could it be higher than 1 for a good grip/hand or grip/glove combo? Also, with the skin being pushed into the pattern on - say - a Lamkin Crossline grip, there might be more to it than just friction."-@Fade "I took a couple lessons when Golftec was new. They had that device that you strapped on with a large umbilical connecting to the computer and a ballistic camera. Early days. The one thing that they emphasized was hand strength limiting club head speed. Can't remember the numbers but I did get one of those hand exercise gizmos and used it in the car. Anyone remember what their rule of thumb was? I think I remember it conforming to the numbers in the .5 friction table above.It would seem that the really tacky grips might have a better friction coefficient and require less grip strength."-@cxx

[Arthur_Vandelay]

You mention: "Also, I've seen videos of guys like Vijay Singh and Fred Couples whose right hand is basically off the grip at impact."

However, I think grip force is most important in the transition to the down swing. The AMG guys have shown that most amateurs can generate close to the same amount of hand speed that pros do, but pros generate their max hand speed a lot earlier in the down swing. I'd think one factor in generating max hand speed as early as possible is grip strength, given the force needed to be applied from the top. It has also been shown that a quicker transition (i.e. the opposite of a pause at the top) leads to more club head speed -- this also requires more force at the top to generate max hand speed earlier given you are redirecting the force backwards rather than letting it first come to a stop before transitioning down.

Personally, I find this topic interesting because I've always had issues with my driver moving around in my hands as I transition into the downswing. One factor for sure is that my driver is probably a little too long (as most stock shafts are nowadays), but I've always been curious about how much of a factor my grip strength could be.

I think hand shape and size and how you grip the club also influences where exactly you need "grip strength" as I presume it can exist in a variety of different ways. For instance, rock climbers tend to have unusually strong fingers, which I'd think could manifest itself as overall grip strength in the same way someone else might manifest overall grip strength with more palm/forearm.

[clevited]

Good thoughts regarding where your strength is at in your hands. I never thought of that. I think at the very least, what I ended up doing was providing some insight as to just how much the grip strength required can fluctuate given the condition of your glove and grip. Mass of the club certainly matters as well as the location of the clubs CG. If we assume that even more force is needed besides what is required for handling just the centripetal forces generated (you mentioned the force from redirecting your hand direction from the top), then I think it might give some insigth into an often overlooked aspect of the golf swing. Essentially, I think you can never have too strong of hands and is one of the easiest things to work on. I arguably don't need any more handstrength but I have a whole set of strength trainers that I can easily do at work. I am doing sort of a self experiment to see if I see any club speed/control improvement as my hands get stronger. Thanks for your input.

[Arthur_Vandelay]

I'd definitely be curious to see the results of your grip strength training.

[Stuart_G]

Question: what thread are you referring to that has the discussion about the determination of friction coefficients? Thanks.

EDIT - also one observation. For human males, did you realize a normal grip strength is considered in the range of 80-120 lbs.

 

 

 

[Stuart_G]

Haven't read through it yet, but sounds like you might find this relevant:https://repository.lboro.ac.uk/articles/Measurement_and_analysis_of_grip_force_during_a_golf_shot/9567140

[clevited]

This discussion popped up in this thread https://forums.golfwrx.com/discussion/1835377/why-size-matters-as-it-pertains-to-distance#latest

As far as the coefficients, the highest of .8 was directly measured by me, which is relatively easy to do. There is of course error with this but also many other grips and glove combinations I just can't test. That is one of the reasons for this discussion. It would be interesting to have people with the means to join in on this and help quantify what the best friction value a person can get out of what is available on the market.

As far the grip strength data you presented. I did post some information about that in the other thread. I have pasted it below."Just for reference, according to topendsports.com (no idea if reputable) an average man's grip strength in his prime is right around 104 lbs, and an average woman's grip strength in her prime is around 74 lbs. A "strong" grip strength for men is 127 lbs, and a "strong" grip strength for a woman is 91 lbs. "

This information I found seems to jive well with your information in my opinion.

[clevited]

Just started reading it. So far looks very interesting. Thank you!

Edit: Read quickley through it as it is quite a short report. 2 things I found quite interesting. 1) Left hand saw the most pressure generated, and 2) the points during the swing where the grip pressure applied peaks as shown in the image below. I am going to read through it more carefully and take it in and really think about it but for now, I am left with at least a couple of things I hope is in there somehwere. The speed at which these players swung to get the results they did, as well as the skill level of each player on the graph.

[Stuart_G]

Only scanned it myself, but main takaway I'm getting from that first look is that max total force seems to more commonly happen in transition. Which means as far as slippage goes, the linear acceleration of the club in transition may be the bigger limiting factor more often than the centripetal acceleration during the release and impact.

 

[clevited]

Yes, I noticed that. Very interesting and was actually something I tried to model in a simulation. It is almost impossible without a ton of work to reproduce a swing with the software I have. I would have to have a spline of data points from an actual player. Not sure where I can nab that.

 

Edit: Even then, I doubt I can capture everything going on. Too many little things to account for that woudl be hard to model imo.

[cardoustie]

I have crazy grip strength and have only lost a couple of arm wrestling matches in my life. Can't swing above 111. Yesterday, 107.5 max, though I do have bicep tendonitis in both arms

I don't think it is strength in hands or overall strength is what I am saying to have the ability to really rip at it like the tour pro's. You can add some speed with lifting but I think downswing sequencing is more the answer

I think it is more about rotational ability between the lower body going first and the upper body (like a Justin Thomas)

 

[clevited]

I agree, but that wasn't what I was getting at with my post. My thoughts are that it can be "A" limiting factor. You having very strong hands means you don't necessarily have a limiting factor as far as grip strength is concerned, but like you said, it could be sequencing or something else. I just have a hypothesis that most very fast swinging players have quite above average grip strength and I attempted to quantify what that would need to be the best I could. Btw, 107-111 is quite fast imo!

[clevited]

@Stuart_G Read through it a little more thoroughly, will be reading through it some more later when I get a chance so I can soak it all in. Doesn't look like they show swing speed, but they do separate test subjects by handicap which was nice. The image I posted in an above post is the zero handicap guy. He looked to me to have the highest peak forces. The actual peak value they get is around 84 lbs force total. That is quite low compared to what I estimated from just centripetal force alone for my club and assumed friction values. Would be nice to know the total weight of the club, CG location, and peak swing speed for each subject. It does at least give some good insight as to where the peak forces happen like you said, and that the left hand had more force than the right. Interesting stuff. Thanks again for posting that.

Edit: Actually I am unsure of which graph shows actual peak force. I am going to have to read through this a few times to decipher their technical jargon better. I will try and get a complete understanding and post a bit of a summary in here. Feel free to critique my summary, I am sure I will misunderstand at least something from that report.

[Stuart_G]

What software are you using?
While I agree it's not something that's easy to model, all you really need are some peak acceleration data. Sorry don't have any links but I've run across several biomechanics analysis papers that have done inverse dynamics on 3d motion captured swings. Obviously it can vary a lot depending on how the player transitions, but it would be a decent starting place.
@clevited said: Actually I am unsure of which graph shows actual peak force
All of them do.
Fig 4 - shows total force from the grip sensor - each graph is for a different player, each graph holds mulitple shots for that player
Fig 5 - left 3 graphs are total force from finger sensors for 3 golfers, right side graphs is just thumb senser
Fig 6 - normalized total force from both sensors, 1 graph per player
Fig 7a and 7b - mean total for different fingers plotted together on one graph for 8 players

[clevited]

I use Solidworks Simulation software. Have to model everything and assign motors and motion timing. It can be done if I have better motion timing so if you ever come across that data, let me know. Otherwsie I will try and dig it up again.

As far as the graphs are concerned, I had which sensors were which mixed up. The grip sensor is what I am most interested in. Hopefully I am interpretting what they mean by total force correctly, if I am, it looks like 1100 N (257 lbs force) peak for worst case (both hands total). Who knows if its because they swing faster or apply more pressure than they should.

I had a thought about the drop in grip force at impact. Do you think that is a result of the vibrations at impact? If you ever miss hit a ball badly, its pretty easy to drop a hand off the grip as a result. Stings and almost feels like it shakes your hands off the grip. Does it happen to a lesser extent when just feeling the vibration of a good impact? Intersted in your interpretation.

[Stuart_G]

@clevited said it looks like 1100 N (257 lbs force) peak for worst case (both hands total). Who knows if its because they swing faster or apply more pressure than they should.
Considering it only got that high for one player - who was a 15 handicap - my guess is way more pressure than he really needed. Or maybe an overly aggressive transition.@clevited said I had a thought about the drop in grip force at impact. Do you think that is a result of the vibrations at impact?
No, I don't think so. Those vibrations are high frequency and likely would be filtered out by the sampling hardware/firmware or averaged between the peaks and valley's of the vibrations.
More likely from the stalling of the hands through impact. The player is no longer able to keep up with the speed of the club and apply any more force to continue acceleration. Remember you're looking at forces not just to hold onto the club but also the forces that are used to accelerate the club.

[SirFuego]

It would be interesting to see the videos of each player. I have struggled with over-the-top/EE for most of my golfing career. I've made huge improvements, in the past couple years, but video evidence shows that I went from a huge over the top move to a slight over the top move. Only recently have I made some swings where (with video) I verified that I was actually shallowing the club in transition. In those swings, it felt like it was a lot easier to hold onto the club than when I come over the top. Swing speeds actually went up, too, when I shallow the golf club.

I'd imagine that if the 15 handicap had some of the highest grip forces, it's because he's swinging the club in an inefficient way and he needs to grip harder to counteract that inefficiency. So perhaps it's a double whammy for amateurs -- not enough grip strength coupled with inefficient motion. Although the latter could at least be fixed with some lessons and might make the former less of a problem...

[Stuart_G]

Yes the efficiency of the swing can be one of many factors that will influence the grip force. So it's certainly one (of many) possibilities). But it's interesting to note that there were also higher handicaps and even a couple that had never swing a golf club before included in the paper that didn't see even close to that much force.

[games]

Really good thread here! My favorite grip is a Lamkin Crossline ACE 3Gen in oversize. I've never had a grip that felt so good in my hand from a size, shape, texture, and tack perspective. It's also fairly substantial at 80g.

I do wonder how much grips can affect shaft fitting. And, for that matter, how clubfitters can fit large hands or those who prefer large grips from fitting cart shafts with nothing but standard grips.

[clevited]

I wouldn't be surprised if grip fitting became a thing. By that I mean finding the size that your hands can apply the most pressure easiest and gives you the most tack. This will sound absurd, but I have contemplated machining a knurled aluminum grip and seeing how that goes. It will chew up gloves no doubt, but it would last forever and the grippiness (is that a word?) would never really change with use. Also might have the side benefit/detriment of making a shaft behave a little more stiff but I am not for sure on that.

[games]

Knurled? You mean kind of like an arthritic grip, but made of aluminum? Oh wow. Wet weather might be an issue...

You know, about 10-20 years ago, 3M made a golf grip and golf glove "system" designed to maximize traction. (The marketing guys at 3M apparently forgot to consult the USGA on their idea because it flat out violated the rules of golf.) The glove on its own was actually decent, IIRC...

[Stuart_G]

Grip size is critical. If a fitter can't accommodate changing grips for the player they are fitting - then (IMO) they shouldn't really be calling themselves a fitter.

But I agree it's a wide spread problem, most people who call themselves fitters really shouldn't for lots of reasons. And most customers don't understand enough about fitting to know the difference. Retail store "fitters" typically being the worst.

 

[braveheart]

I totally agree. I have very strong hands. In fact, I think some of us with strong hands have a tendency to grip everything too hard and have less touch or feeling for things. Being able to rely on them, a tendency is to overuse them. People I know, that I can crush their hands in a handshake, I've seen hit a ball with as much authority and even more power than me. Makes me realize, that other things, such as what caroustie mentions are much more important.

 

[clevited]

Keep in mind, I brought up this thread to discuss what hand strength might mean for swing speed. For some, hand strength could be a limiter to them reaching faster swing speeds. For others, it won't be and some other aspect of their swing is limiting them including gripping too hard. This discussion was meant to try and validate or provide more detail regarding just how much hand strength is needed to swing a typical driver at various speeds. You might have comfort knowing your hand strength is likely enough to swing 150+ lol if you are crushing hands.

[cardoustie]

Braveheart may have a point, maybe too much hand strength can be bad?

I know it helps A LOT out of the rough, thats been proven for years across different tours and at the Am level

[clevited]

I personally don't think you can have too much, but you need to be in control of it probably for it to be put to good use. That is just my opinion anyway. I could be totally wrong on that.

I can provide me as an example though. I crush hands, can close a 200 lb hand trainer, and I am able to swing in the mid to high 120s with driver. Who knows if they correlate or not. That is something I want to figure out.

[xmanhockey7]

Yeah if they're not willing to do a quick grip change in the fitting they shouldn't even be in the business. If I can't get my CP2 wrap with 3 extra wraps under the right hand in a fitting I'll take my money elsewhere.

[clevited]

I was reading back through a bit and had some more thoughts on this particular post of yours. That drop in hand pressure right at impact is what most interests me again. You attribute that to the release and hands not needing to apply as much pressure if I understand correrctly. My issue with that thought is that the club should be reaching peak velocity during the release correct? I know my math above is sound at least as far as calculating centripetal force at peak velocity. Because of that, I can't stop thinking that the dip in grip pressure is from the impact with the ball. It is so momentary that to me, it really does seem like it could be caused by the impact vibration momentarily shocking the hands enough for them to not be able to appy the same amount of force.

I say this because in my own swing, I feel this happening. When my grip is needing cleaning, it because very apparent at least feel wise to me. I feel the club accelerating and just before impact I can feel the grip slipping. I then feel the hit of the ball which is much more noticeable when struck badly. During the bad strike, my hands quiver and let go, sometimes to the point where I take a hand off because of the sting. Right after impact I feel myself grabbing the club hard again. I don't recall much grip pressure before that, accept at the transition at the top.

This is all just my own feels for my own swing and could certainly be false feedback I am deciphering but I think this particular item would be really interesting to know about regarding what is happening and why. I think I will look through that paper again and see if they mention anything about the curves and why grip pressure is what it is at each moment in time of the swing.

[ColdOkieGolf]

Very interesting!

Another consideration is wrist extension (also known as cupping) at the top of the backswing. Our grip strength is at its peak when the wrist is in a slightly extended position (bent backwards). As you flex your wrist, you lose the ability to firmly grasp objects. Now think about someone like Dustin Johnson with how bowed his left wrist is at the top.

Wrist extension (cupping) = more gripping force with less muscle activation

Wrist flexion (bowed) = less gripping force, or requires more muscle activation to achieve the same level of grip vs. neutral.

[Stuart_G]

@clevited said You attribute that to the release and hands not needing to apply as much pressure if I understand correrctly.
Close but not exactly, it's not so much not needing to but rather not being able to - but the main point being that impact is when the least amount of force is applied to the club in the context of accelerating the club@clevited said My issue with that thought is that the club should be reaching peak velocity during the release correct?
For a good swing, yes. For a bad swing, maybe not.@clevited said I know my math above is sound at least as far as calculating centripetal force at peak velocity.
I can't say. You didn't show your complete work or derivation. Did you assume a fixed (zero velocity) point at the hands when calculating rotational velocity of the club based on club head speed? Or did you account for the actual velocity of the hands through impact? If not, that would result in a higher centripetal acceleration than what's really happening. @clevited I feel the club accelerating and just before impact I can feel the grip slipping. I then feel the hit of the ball which is much more noticeable when struck badly. During the bad strike, my hands quiver and let go, sometimes to the point where I take a hand off because of the sting.
Sounds to me more like a self developed habit. One that probably started as a concious reaction to pain but over time and repatition has become more habitual. It would be interesting to see actual force/time plots for you when that happens but I'm guessing that it's a bit delayed and I doubt very much that it's a normal reaction. I might not be surprised to see it in an occasional player but not something that's consistent to all the players in the study. Pain at impact just isn't a normal part of the golf swing for most and individuals reaction to pain can vary quite a bit, especially when the pain or even the potential for pain is anticipated.
Now for off center hits, there will also be a need to resist slipage from torsional forces as well as axial, but not sure I've seen anyone attempt to measure what those torsional forces are when they get to the hands so hard to say how much force is needed relative to the force needed to resist the axial slip.