Optimum Racquet Balance for Performance II - MgR/I Data for ATP Pros

[newyorkstadium]

Originally Posted by travlerajm

Your wrist will naturally rotate effortlessly to generate the spin if your racquet is tuned for it.

So the belief that a smaller grip increases wrist flexion, rotation and pronation, which increases spin, is wrong?

Originally Posted by travlerajm

Any amount of weight added anywhere will affect the dynamic stiffness and spin. It is up to you to experiment and find what you like best.

I'm sure I remember reading a post where you said lead at 9" increases stiffness. How high can I go above 7" without affecting stiffness, to increase mgr/i?

What is your views on racket technologies? Is an increase in power/sweetspot even a good thing for a decent player, who can generate there own power? Do the Exo3 port-holes really increase power, control, sweetspot, comfort and spin?

I have been placing all of my lead at 12' to decrease mgr/i. Should I be adding some at 10/2, 3/9 etc?

Does muscle strength/ fast twitch muscle fiber's have an effect of mgr/i? This is based on the belief that a person with the same muscle mass can have more muscle strength/more fast twitch type muscles.

The wrist is pretty heavy and people differ in wrist's mass substantially. What about wide vs narrow wrists? Add to this people of the same height can have different arm length/hand size. I'm not sure you should be advising people there is an optimal mgr/i per height. I think you should advise everyone to find their own personal mgr/i.

[newyorkstadium]

never mind

[travlerajm]

Originally Posted by newyorkstadium

So the belief that a smaller grip increases rotation of the wrist, wrist snap and range of motion, which increases spin, is wrong?

Some players might prefer small grips. If they feel it gives them more spin, maybe it does.

Originally Posted by newyorkstadium

I'm sure I remember reading a post where you said lead at 9" increases stiffness. How high can I go above 7" without affecting stiffness, to increase mgr/i?

Adding mass at either location will increase dynamic stiffness. But adding mass at 9" will increase dynamic stiffness much more than adding mass at 7".

Originally Posted by newyorkstadium

What is your views on racket technologies? Is an increase in power/sweetspot even a good thing for a decent player, who can generate there own power? Do the Exo3 port-holes really increase power, control, sweetspot, comfort and spin?

I think increasing the sweetspot is always a good thing. But I don't think O-ports of exo-ports make much difference in sweetspot size - instead they just increase the effective size of the stringbed. I string tighter to compensate.

Originally Posted by newyorkstadium

I have been placing all of my lead at 12' to decrease mgr/i. Should I be adding some at 10/2, 3/9 etc?

If you want, sure. I prefer extra mass spread out around the entire upper half of the hoop.

Originally Posted by newyorkstadium

Does muscle strength/ fast twitch muscle fiber's have an effect of mgr/i? This is based on the belief that a person with the same muscle mass can have more muscle strength/more fast twitch type muscles.

MgR/I has nothing to do with strength or fast twitch fibers.

Originally Posted by newyorkstadium

The wrist is pretty heavy and people differ in wrist's mass substantially. What about wide vs narrow wrists? Add to this people of the same height can have different arm length/hand size. I'm not sure you should be advising people there is an optimal mgr/i per height. I think you should advise everyone to find their own personal mgr/i.

I do advise people to find their own personal optimum MgR/I value. I refer again to this post:

http://tt.tennis-warehouse.com/showp...8&postcount=17

[newyorkstadium]

Edit: I found an answer using the search function.

[newyorkstadium]

Again, I found an answer using the search function.

[newyorkstadium]

deleted...

[newyorkstadium]

Originally Posted by travlerajm

I think increasing the sweetspot is always a good thing. But I don't think O-ports of exo-ports make much difference in sweetspot size - instead they just increase the effective size of the stringbed. I string tighter to compensate.

Sorry, what does "increase the effective size of the stringbed" mean?

Originally Posted by travlerajm

I do advise people to find their own personal optimum MgR/I value. I refer again to this post:

http://tt.tennis-warehouse.com/showp...8&postcount=17

Could you include this link in your OP?
I've noticed some people on here think MgR/I=21 is optimal, instead of fine tuning their racket. I assume these people have just read the OP, not the entire thread.

Originally Posted by travlerajm

If you wear a wristband near your elbow, I doubt that it would make much difference.

What about if you wear it midarm/forearm? Would it affect Mgr/I?I moved my wristband up to midarm and noticed a difference in swingspeed.

I think weightlifting increases hand and wrist muscle mass. Should mgr/i be re-tuned if you lift weights?

[travlerajm]

Originally Posted by newyorkstadium

Sorry, what does "increase the effective size of the stringbed" mean?

The region of stringbed deflection on O3 frames extends to the outer edge of the frame. With conventional frames, the region only goes to the grommet, which are on the inside of the frame. I suppose this does increase sweet spot a tad, but also means you need to string tighter to compensate.

Originally Posted by newyorkstadium

Could you include this link in your OP?
I've noticed some people on here think MgR/I=21 is optimal, instead of fine tuning their racket. I assume these people have just read the OP, not the entire thread.

Ok, I can do that.

Originally Posted by newyorkstadium

What about if you wear it midarm/forearm? Would it affect Mgr/I?I moved my wristband up to midarm and noticed a difference in swingspeed.

I don't know how much it would affect timing - I have never tried that.

Originally Posted by newyorkstadium

I think weightlifting increases hand and wrist muscle mass. Should mgr/i be re-tuned if you lift weights?

If you are Bruce Banner, then I suppose you should re-tune your racquet after you transform into your alter ego.

[newyorkstadium]

Ok, that's all. Thanks for all your help, travlerajm.

[newyorkstadium]

I've tried to tune my racket on three separate occasions now, for a sum total of 4.5hrs. Unfortunately I got nowhere. My shot's were going to the right, to the left and exactly where I wanted. I've also tried tuning by height and it didn't improve my accuracy. Maybe I have abnormally large arms, like djokovic. It would be great if we could sort MgR/I by arm/torso length. Although, that would take a large focus group and lots of money to pay them.

It's frustrating as I now am back to the interminable demoing racket's process. It's also frustrating, as I had planned some experiments. These were:

1) Test how switching from eastern to a extreme eastern, and SW, grip impacts MgR/I?
2) Test the effect of wristband location. I was going to check at the elbow, upper forearm, lower forearm and at the wrist.
3) Test the impact of choking down the handle. I was going to check a 0.5 inch movement, then 1" and finally 2 inches.

Anyway, although MgR/I was a failure for me, I'm nerdy enough to stil have some questions on it.

This thread suggests the racket face should be closed by 10 degrees for optimal top spin. Does MgR/I impact whether the racket is closed/open at impact?

You have told me that muscle mass doesn't affect MgR/I much. If you went from skinny guy to Arnie (not that I intend to), how much would the MgR/i change? Does leg and torso mass/length have an impact?

Sorry for the constant questions. I'm just trying to further understanding of MgR/i.

[newyorkstadium]

I've edited my last post to add some questions and info.

[travlerajm]

Originally Posted by newyorkstadium

I've edited my last post to add some questions and info.

If you are having difficulty tuning against the wall, remember that you need to fully relax the wrist in order to tune.

Another way to tune MgR/I (albeit a little rougher) is to swing the racquet in your living room through a big high-to-low-to-high pendulum sweep, using your normal weight transfer as if you are hitting a forehand (but with a golf style swingpath).

The thing to look for is what type of couple you feel the handle applying to your hand as your racquet passes through the low point of the arc.

If you feel the handle pressing against the base knuckle of your index finger, that means MgR/I is too low. Conversely, if you feel the handle pulling forward on the distal portion of your fingers, then MgR/I is too high.

If MgR/I is perfect, you will not feel any torque acting in either direction on your hand. You may find it useful to experiment with choking up (which will increase MgR/I) and choking down (which will lower it) in order to feel the different types of torque. For any racquet, there exists a certain hand position along the handle where the torque is zero (where MgR/I is optimized).

[mykoh]

awesome stuff trav.

any particular grip required when you do this? or do you hold your normal forehand grip (SW for me)?

[newyorkstadium]

I was fully relaxing my wrist throughout the wall test's. My shot's were going to the right, left and exactly where I intended.

Originally Posted by travlerajm

If you feel the handle pressing against the base knuckle of your index finger, that means MgR/I is too low. Conversely, if you feel the handle pulling forward on the distal portion of your fingers, then MgR/I is too high.

I tried the rough method. I could feel the racket pressing against the knuckles. Unfortunately, no matter how much lead I added at 7", I couldn't feel the handle pulling forward on the distal portion of the fingers. I tried swinging quickly and slowly.

Originally Posted by travlerajm

You may find it useful to experiment with choking up (which will increase MgR/I) and choking down (which will lower it) in order to feel the different types of torque. For any racquet, there exists a certain hand position along the handle where the torque is zero (where MgR/I is optimized).

My aim with experimenting on choking down the handle was to get an exact number of how much choking down affects MgR/I. If we can work out how much different equipment factors affect MgR/I, then people don't have to return to the practice wall every time they make a change.

With most of these questions I could have found out the answers for myself, but I got nowhere with the wall tuning. Thanks muchly for answering my questions.

[mykoh]

You are one curious dude

[newyorkstadium]

Bump. I must start posting my questions in american time, since this is predominantly an american forum. Starting from now I will do this.

[newyorkstadium]

Last bump then I'll give up.

[Relinquis]

no you won't...

[BlueB]

Just a recent observation of mine...
While I'm not a firm believer in this theory, I keep this information in the spread sheet of my racquets' specs and mods. I noticed something interesting and re-confirmed it today by adding and reducing weight from a specific point on the racquet while playing/serving. The balance optimised for groundie forheand constantly served worse then the one that had 0.2 lesser MgR/I.
Anyone else noticed this?
Anyone worked on optimal numbers for serve?

[travlerajm]

Originally Posted by BlueB

Just a recent observation of mine...
While I'm not a firm believer in this theory, I keep this information in the spread sheet of my racquets' specs and mods. I noticed something interesting and re-confirmed it today by adding and reducing weight from a specific point on the racquet while playing/serving. The balance optimised for groundie forheand constantly served worse then the one that had 0.2 lesser MgR/I.
Anyone else noticed this?
Anyone worked on optimal numbers for serve?

Optimization for serve is complex - it depends not only on the the swing dynamics, but on the hitting weight and dynamic stiffness as well. If you tell me the two sets of specs you are comparing (and what point on the racquet you were adding/reducing weight), I might be able to shed some insight on why one was better than the other.