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

[JohnB]

I made a mistake about the mass of the arm. Travlerajm, as you mentioned, was talking about the forward part of the stroke where the weight of the arm would be of influence.

Since airpressure and temperature are not covered in the formula, I am pretty sure it not relevant for the formula. In reality in might be of a very, very small influence. Because the rackettip has a longer way to travel from top to bottom than the arm, the speed of the rackettip will be higher if it is in tune with your arm, therefore the rackettip will be more influenced by airresistance than the arm. But, I think that because of the relative low speed of the arm and rackettip at the high to low part of the stroke, the influence would be small. In the part of the forward segment of the forehand, the rackettipspeed will much higher. So airresistance will play a greater part.

You are supposed to let the racket drop by gravity at the beginning of the forehand, so the lenght of the arm is important and not how strong or how fast you can swing.

This is my personal experience. With thinner grips I am more able to play wristy shots and those stretchshots you mentioned. I think with thinner grips, if you play not on your optimum value, you can "correct" the swingpath easier than if you play with a thicker grip.

I don't know about the wristband location. Maybe a simple way to test is: take a racket close to optimum Mgr/I and put a watch or something on your wrist and play. Then move that watch to your upperarm and play and check if the timing/direction of your forehands differ. My guess is that the higher up the arm, the higher the optimum value.

By the way, the Mgr/I concept is only a part of tuning a racket. What really helped me was a thread by Stoneage (Combining weight, balance and swingweight)

[newyorkstadium]

Stoneage mentioned air pressure and temperature in his critique of mgr/i. Just found out stoneage was being sarcastic about this. Never mind.

[cmendez79]

Originally Posted by JohnB

I made a mistake about the mass of the arm. Travlerajm, as you mentioned, was talking about the forward part of the stroke where the weight of the arm would be of influence.

Since airpressure and temperature are not covered in the formula, I am pretty sure it not relevant for the formula. In reality in might be of a very, very small influence. Because the rackettip has a longer way to travel from top to bottom than the arm, the speed of the rackettip will be higher if it is in tune with your arm, therefore the rackettip will be more influenced by airresistance than the arm. But, I think that because of the relative low speed of the arm and rackettip at the high to low part of the stroke, the influence would be small. In the part of the forward segment of the forehand, the rackettipspeed will much higher. So airresistance will play a greater part.

You are supposed to let the racket drop by gravity at the beginning of the forehand, so the lenght of the arm is important and not how strong or how fast you can swing.

This is my personal experience. With thinner grips I am more able to play wristy shots and those stretchshots you mentioned. I think with thinner grips, if you play not on your optimum value, you can "correct" the swingpath easier than if you play with a thicker grip.

I don't know about the wristband location. Maybe a simple way to test is: take a racket close to optimum Mgr/I and put a watch or something on your wrist and play. Then move that watch to your upperarm and play and check if the timing/direction of your forehands differ. My guess is that the higher up the arm, the higher the optimum value.

By the way, the Mgr/I concept is only a part of tuning a racket. What really helped me was a thread by Stoneage (Combining weight, balance and swingweight)

Do you have the link to stoneage thread?

[newyorkstadium]

never mind

[JohnB]

Originally Posted by newyorkstadium

Arm length can vary among people of the same height. Also, some rackets claim to have increased air resistance. Bearing this in mind, shouldn't everybody find there own mgr/i? Should you re-tune the mgr/i every time you buy a new racket?

Stoneage mentioned air pressure and temparature in his critique of mgr/i. This is a question that travlerajm hasn't answered yet.

I thought you are supposed to play with a relaxed wrist for mgr/i. This seems at odds with a smaller gripsize, which is about using more wrist.

From what i've read on smaller grips, they improve spin and spin serves, but they reduce consistency, volleys and flat serves.

Mgr/I is indeed very personal. I've heard some success stories where people played with different rackets, but had the same Mgr/I value and they played the same timing wise.

Oh I thought Stoneage was being ironic about the airpressure and temperature.

[newyorkstadium]

never mind

[Midguytenis]

I have read some threads here and there for a long time, I don't have much time for forums and stuff, however this caught my eyes.

I read through part when I could, I had 2 different rackets with completely different result that i liked, so I don't really believe this can work, different rackets, different power level.

I also agree with someone else who posted here about swing weight, which is measured only in short distances, so when I choose a new racket (i usually play with them for 2-3 years at least) I don't base my choices on measurements at all.

[ben123]

lmao learn to play tennis

[newyorkstadium]

deleted...

[newyorkstadium]

bump........

[newyorkstadium]

bump......

[travlerajm]

Originally Posted by newyorkstadium

bump......

DH,
I replied to your challenge message post and left a number.
give me a call if you're in Seattle and this week and want to set something up.

[newyorkstadium]

Hi travlerajm. I was only in Seattle for the week. I thought I could fit a game in against you, but I didn't hear back from you until too late.

Could you look at my questions please? Sorry for the volume of questions.

[newyorkstadium]

1) Arm length varies in people of the same height. So, should everybody find there own personal mgr/i?

2) Some rackets claim to have increased air resistance. Does this affect mgr/i? Should you re-tune mgr/i for a new racket?

3) What if you wore the wristband further up the arm, so that it wasn't affecting the pivot point of the wrist? Would it affect mgr/i?

4) Is the 0.2 wristband calculation based on large wristbands? I wear a small, single wide wrist band.

5) Are you still planning on publishing a book on mgr/i?

6) Should you use your correct grip size for mgr/i? I think you are supposed to play with a relaxed wrist for mgr/i. This seems at odds with a smaller grip-size, which is about using more wrist.

From what I've read on smaller grips, they improve spin and spin serves, but reduce shot consistency, volleys and flat serves.

[travlerajm]

Originally Posted by newyorkstadium

1) Arm length varies in people of the same height. So, should everybody find there own personal mgr/i?

Yes.

Originally Posted by newyorkstadium

2) Some rackets claim to have increased air resistance. Does this affect mgr/i?

I doubt it.

Originally Posted by newyorkstadium

Should you re-tune mgr/i for a new racket?

Yes.

Originally Posted by newyorkstadium

3) What if you wore the wristband further up the arm, so that it wasn't affecting the pivot point of the wrist? Would it affect mgr/i?

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

Originally Posted by newyorkstadium

4) Is the 0.2 wristband calculation based on large wristbands? I wear a small, single wide wrist band.

The one I tested was medium - I suggest you try your own experiment.

Originally Posted by newyorkstadium

5) Are you still planning on publishing a book on mgr/i?

Yes, but I am more focused on my medical device startup for now. The tennis racquet customization book probably won't happen until I have more free time.

Originally Posted by newyorkstadium

6) Should you use your correct grip size for mgr/i? I think you are supposed to play with a relaxed wrist for mgr/i. This seems at odds with a smaller grip-size, which is about using more wrist.

I think everyone should use a grip size that feels most comfortable and relaxed.

Originally Posted by newyorkstadium

From what I've read on smaller grips, they improve spin and spin serves, but reduce shot consistency, volleys and flat serves.

Again, my opinion is that a grip size that feels most comfortable will be best for all-around performance. If the grip is too small, you may fatigue your wrist by needing to grip too tightly. Same problem if it's too big to hold securely. I have smaller than average hands (9" pinkie to thumb full stretch, 7-1/2" base of palm to tip), but prefer grips in the 4-1/2 to 4-5/8 range.

[newyorkstadium]

Originally Posted by travlerajm

I doubt it.

You doubt that the some rackets have increased air resistance, or you doubt that air resistance affects mgr/i?

Is it true that if your mgr/i is tuned, you hit the ball with a more relaxed wrist? I thought using more wrist enhanced spin.

[newyorkstadium]

I have some final questions on lead placement:

1) I've noticed you recommend 1/4 inch lead tape. Is 1/2" lead tape okay at 7 inches? Will this affect dynamic stiffness/spin?

2) Lead tape under or over the grip, at 7 inches, increases the grip size. Do you place lead inside the handle?

3) Does hand size affect mgr/i?

[travlerajm]

Originally Posted by newyorkstadium

You doubt that the some rackets have increased air resistance, or you doubt that air resistance affects mgr/i?

I doubt that a difference in air resistance between racquets would have much effect on the optimum MgR/I value.

Originally Posted by newyorkstadium

Is it true that if your mgr/i is tuned, you will hit the ball with a relaxed wrist,? I thought using more wrist enhanced spin.

Yes - the whole idea with optimizing MgR/I is that it allows you to hit the ball without needing to use the wrist muscles to control the angle of your racquetface as you come through the hitting zone. The racquetface of a perfectly tuned racquet will stay aligned toward your target longer. Thus, the perfectly tuned racquet is more accurate because your swing will be less sensitive to small errors in timing.

Also, you can take advantage of a much higher swingweight racquet if it is properly tuned because your forearm will not get tired if you don't need to exert those muscles. And it is much easier to hit a heavy ball with a lot of spin if you use a higher swingweight racquet that is well-tuned.

Originally Posted by newyorkstadium

I have some final questions on lead placement:

1) I've noticed you recommend 1/4 inch lead tape. Is 1/2" lead tape okay at 7 inches? Will this affect dynamic stiffness/spin?

It doesn't matter what width of tape you use. It just matters how much mass you use and where you put it.

Originally Posted by newyorkstadium

2) Lead tape under or over the grip, at 7 inches, increases the grip size. Do you place lead inside the handle?

I try to avoid putting lead inside, since it's more difficult to change later. If I need to add a lot of lead, if possible I use the lead to sculpt the upper part of the handle so that the grip profile shape is extended up longer for good feel on the 2hb. If the placement needs to be lower on the handle, then I spread it as thinly as possible. There is some art to it.

Originally Posted by newyorkstadium

3) Does hand size affect mgr/i?

If you have bigger hands, you will have more mass effectively added to the grip. So someone with very large hands might have a lower optimum MgR/I value than someone with very small hands, all else being equal.

[newyorkstadium]

Originally Posted by travlerajm

Yes - the whole idea with optimizing MgR/I is that it allows you to hit the ball without needing to use the wrist muscles to control the angle of your racquetface as you come through the hitting zone. The racquetface of a perfectly tuned racquet will stay aligned toward your target longer. Thus, the perfectly tuned racquet is more accurate because your swing will be less sensitive to small errors in timing.

So you don't need to rotate your wrist, like rafa , to increase spin?

Originally Posted by travlerajm

It doesn't matter what width of tape you use. It just matters how much mass you use and where you put it.

Is it okay to use 1/2" lead tape rising form 7" up to 7.5"? Will this affect dynamic stiffness/spin? If not, how high can I go without affecting dynamic stiffness/spin?

Anyway, I'm off now. Thanks for answering my many questions.

[travlerajm]

Originally Posted by newyorkstadium

So you don't need to rotate your wrist, like rafa , to increase spin?

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

Originally Posted by newyorkstadium

Is it okay to use 1/2" lead tape rising form 7" up to 7.5"? Will this affect dynamic stiffness/spin? If not, how high can I go without affecting dynamic stiffness/spin?

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.