How young is too young for polyester?

[10shoe]

For the past decade or so I have been cautioning parents to avoid polyester for their kid's racquets until they are at least 14. Now, 14 yrs old, I didn't just pull this number out of my butt. My shop is not too far from the National Tennis Center and the junior development program there came up with the number 14 and were advising parents to stick to multis...at least they were 10 yrs ago when I had several customers with kids in the program.

Lately I am getting a lot of requests for poly for kid's under the age of 10. I think a number of the coaches in my area are under the impression that whatever they are using is what everybody should be using, regardless of age or level. So, if the coach is using Tour Bite 16, everybody should use Tour Bite 16. And I'm sure if you have a young student who is having trouble keeping the ball in the court, switching them to poly will make a coach look like a coaching genius when suddenly everything is landing in the court.

How do YOU feel about poly for 8 and 9 yr olds?

What about strings that contain poly...like Tecnifibre Triax?

 

[am1899]

That is too young IMO.

“14ish” is generally my comfort zone. I’m willing to bend a little younger if the kid in question is an outlier in terms of physical and technical development and can obviously benefit from utilizing such string. Regardless, there is zero chance I would recommend something as stiff Tour Bite 16 right out of the gate. That is insanity.

IME unfortunately coaches are more often than not poorly educated on this subject, which makes our jobs even harder.

For me strings like Triax, Isospeed axon, etc. potentially make good “stepping stone” strings to transition a player from multi to polyester - dipping a toe in the pool, without fully jumping in all at once.

 

[esgee48]

Insane! I recommend polys only for players that break their strings within 4-6 hours of hitting. Kids generally don’t meet this criterion. Most adults don’t meet this criterion either. I don’t have any clients younger than their twenties. But using gradually harder string setups would be the preferred method rather than jumping anyone to something like TB 16.

 

[A Defenseless Creature]

Never too young. Polys installed in the mid to upper 30s provide excellent pocketing and plenty of comfort. I would suggest getting players used to polys at low tensions as they are getting started in the sport, is a long term service to both their game and arm health.

 

[travlerajm]

Kids growing up in most tennis countries don’t really have access to non-poly strings these days.

 

[Wes]

Kids growing up in most tennis countries don’t really have access to non-poly strings these days.

^^^

What? Huh?

I'm not going to speak for all of the other "tennis countries", but kids in the U.S. most certainly have access to non-poly strings.

So, you're telling us that kids in the U.K., France, Italy, Australia, Japan, etc. don't have access to non-poly strings??

 

[Irvin]

Kids growing up in most tennis countries don’t really have access to non-poly strings these days.

LMAO I would not consider a country that only has access to poly string a tennis country.

 

[travlerajm]

LMAO I would not consider a country that only has access to poly string a tennis country.

Tennis is huge in Paraguay. It’s the #2 sport after fútbol.

 

[Irvin]

If you say so.

 

[travlerajm]

If you say so.

You can get a high-quality stringjob with 2h turnaround for 4 USD there.

 

[illzoni]

Does concern about poly strings remain valid?
Or have modern poly strings improved to the point that no concern is warranted?

 

[Irvin]

You can get a high-quality stringjob with 2h turnaround for 4 USD there.

I can? I doubt that, it will take me longer than 2 hours to get to the Atlanta airport gate, and the ticket required to get to the gate will be a lot more than $4 USD.

 

[10shoe]

Never too young. Polys installed in the mid to upper 30s provide excellent pocketing and plenty of comfort. I would suggest getting players used to polys at low tensions as they are getting started in the sport, is a long term service to both their game and arm health.

My personal experience is that I got tennis elbow playing with poly at 30 lbs in a racquet with a tension range of 57-67 lbs. But I am a senior citizen. BTW, the string I was using was Luxilon Alu Power Fluoro which was supposed to be relatively soft.

 

[10shoe]

I am currently stringing for an 8 yr old who is using Yonex Rexis Speed 1.25. At first I thought: "okay it's a multi, no worries" but since it was brought to me on a reel there was scant info on the spool. Yesterday though someone brought me a pre-cut set of it and looking at the package I was kind of surprised to see the word polyester on there and now I am at least a little concerned.

 

[bobleenov1963]

Natural Gut is the best string for kids 16 years old or younger. I used Luxilon NG for my son when he was that age.

 

[kkm]

I am currently stringing for an 8 yr old who is using Yonex Rexis Speed 1.25. At first I thought: "okay it's a multi, no worries" but since it was brought to me on a reel there was scant info on the spool. Yesterday though someone brought me a pre-cut set of it and looking at the package I was kind of surprised to see the word polyester on there and now I am at least a little concerned.

You needn’t worry. Far as I can tell it has nylon and polyester filaments. I’ve played with it, and it’s got a lot of give.

 

[johnmccabe]

Everyone is so different. Nothing wrong with trying poly-sgut poly-multi hybrid at low tension and restring after 20hrs. Go back to full bed multi immediately if any sign of problems. Know some nationally ranked 12 yr olds playing poly sgut the whole time.

 

[ryohazuki222]

I was playing with Kevlar / syn gut hybrid at 13-14. Loved it. Never any issues, still to this day.

Personally, I think it’s not just age, but also technique dependent.

 

[Yamin]

High school

 

[travlerajm]

I was playing with Kevlar / syn gut hybrid at 13-14. Loved it. Never any issues, still to this day.

Personally, I think it’s not just age, but also technique dependent.

I switched from syn gut to kevlar age 17, never looked back. I occasionally use poly, but always come back to kevlar mains. Cross with zx, poly, or syn gut depending on head size and pattern openness.

Kevlar guy for 34 years and counting.

 

[netlets]

I would say you could put good players in a multi/poly hybrid at 13 and if their game style warrants it, into a thin poly at 14. I never agreed with using poly at lower tensions for young kids. The reason you avoid that is because softer string with more feel helps their development. It’s easier to feel the ball on volleys, slices, serves, etc. when using a multi. If the strings start moving then go to a hybrid. Once they start breaking a hybrid quickly go to a thin poly only if they are using modern technique and hitting heavy topspin.

 

[PRS]

I would NEVER recommend poly in any capacity to sometime under 10 years old. Most players (think average high school player not at a big tennis school) should wait till they're 16-18 years old to start poly (I didn't start poly till the summer before my freshman year of college and walked on to a mid D2 team). Advanced juniors who are very serious about tennis I would start around 14 assuming they have good technique and, preferably, are also breaking non-poly in under 6 hours consistently. Good technique is a must though.

Triax or similar strings that contain poly, I would still wait till they're at least 12, and only if they're breaking other strings in under 10-ish hours and they want them to last longer.

I'm more traditional in my thinking, I know. But poly isn't nearly as game-changing as most people think, especially for younger kids. And why risk it if you don't have to? Using a multi or synthetic gut isn't going to prevent a player from competing at a high level and improving greatly. There is not a single shot that you can hit with poly that you can't hit with non-poly. Yes, it has advantages, but it's not going to make a world of difference, and it comes with an increased risk of injury. To me, the slight increase in performance is not worth the increase injury risk as a junior.

 

[10shoe]

You needn’t worry. Far as I can tell it has nylon and polyester filaments. I’ve played with it, and it’s got a lot of give.

I'm just gonna flesh out this particular case with a bit more detail. This 8 yr old blew through an entire reel of Yonex Rexis Comfort 1.25 in 3 months. So, about 5 days per stringing. I suggested Dynawire 1.30 but instead Yonex sent them this reel of Rexis Speed 1.25 which I installed on 2 racquets about a week ago. Personally, I think the Dynawire would have been safer and probably more durable. I don't think adding poly to a multi makes it more durable. When I've used strings like that I got better control but the durability was pretty much the same as a regular multi. So, I'm kind of surprised at Yonex sending him this multi/poly reel. I mean, if they think highly enough of an 8 yr old to sponsor him why risk doing any damage to his arm?

 

[kkm]

I'm just gonna flesh out this particular case with a bit more detail. This 8 yr old blew through an entire reel of Yonex Rexis Comfort 1.25 in 3 months. So, about 5 days per stringing. I suggested Dynawire 1.30 but instead Yonex sent them this reel of Rexis Speed 1.25 which I installed on 2 racquets about a week ago. Personally, I think the Dynawire would have been safer and probably more durable. I don't think adding poly to a multi makes it more durable. When I've used strings like that I got better control but the durability was pretty much the same as a regular multi. So, I'm kind of surprised at Yonex sending him this multi/poly reel. I mean, if they think highly enough of an 8 yr old to sponsor him why risk doing any damage to his arm?

Have the kid’s parents ask Yonex about Multi-Sensa. It was a multifilament, all polyester - no nylon. Dunno if it’s still in production. I think you’ll have a hard time finding anything with more stretch. IMHO Rexis Speed > Multi-Sensa.

 

[fuzz nation]

For the past decade or so I have been cautioning parents to avoid polyester for their kid's racquets until they are at least 14. Now, 14 yrs old, I didn't just pull this number out of my butt. My shop is not too far from the National Tennis Center and the junior development program there came up with the number 14 and were advising parents to stick to multis...at least they were 10 yrs ago when I had several customers with kids in the program.

Lately I am getting a lot of requests for poly for kid's under the age of 10. I think a number of the coaches in my area are under the impression that whatever they are using is what everybody should be using, regardless of age or level. So, if the coach is using Tour Bite 16, everybody should use Tour Bite 16. And I'm sure if you have a young student who is having trouble keeping the ball in the court, switching them to poly will make a coach look like a coaching genius when suddenly everything is landing in the court.

How do YOU feel about poly for 8 and 9 yr olds?

What about strings that contain poly...like Tecnifibre Triax?

I'll also register a pretty firm "no" on the question of poly for 8-9 year olds.

To get any real "help" from a poly, the player in question needs to have enough swing speed - generated from proper technique - to bend that string and get its potential performance benefits happening. Kids in the 8-9 year old range just aren't there yet.

Multi is relatively expensive for what it delivers. I'll install that string for folks who already use it or in cases where somebody needs a shift to a substantially softer layout. Otherwise I'm routinely recommending syn. gut. Some are a little more stiff and durable. Other syn. guts are rather soft and very easy to live with once the right tension is sorted out. Even if 8-9 year old kids are popping strings now and then, syn. gut should be able to give them everything they need at many dollars less than the "premium" multis.

I string for the high school kids on the teams that I coach and although a few of them have switched into a poly or poly hybrid as they've grown and developed their games, I can honestly say that it's not rare for one or another to find benefits after switching away from poly into a softer string type during their high school years. I've noticed the same thing among a few kids on other teams that we compete with every year. Some do okay with poly, some absolutely do not.

Also pretty sure that there's a big difference between some strings which are poly monofilaments and others that are "infused" with poly - one example of that (if I'm remembering it right) is Tecnifibre X-One Biphase. That's a soft multifiber, but poly is somehow added to the bundle of tiny strands that primarily compose the fundamental string. Perhaps Triax has a similar construction going on...

 

[LOBALOT]

Having been around junior tennis quite a bit I have not seen a kid playing 10 and under tournaments that required the use of a full bed of poly. I don't recall seeing a kid in that age group using a hybrid either. They just don't have the racquet head speed / strokes / size to benefit from it.

That said I have seen plenty of junior players require a transition to a hybrid in 12s and make the switch to full poly by 14s. I have also seen 16s and 18s go without poly all along but that is very rare for tournament kids.

Coaches, players, and parents must monitor their kids progress and evaluate where their kid is at to determine next steps for strings be it full bed multi, hybrid or and for some full poly setups. For sure most advanced juniors in 14s are using full poly strings without issues.

There are so many polys with varying characteristics today that I think a blanket statement that juniors can't use polys simply because 15 years ago those options didn't exist is not adjusting to what the marketplace provides and what advanced juniors are able to produce. It is like the blanket statements I used to see out here that if you aren't a 4.0 you shouldn't use poly.

 

[Bambooman]

I'll also register a pretty firm "no" on the question of poly for 8-9 year olds.

To get any real "help" from a poly, the player in question needs to have enough swing speed - generated from proper technique - to bend that string and get its potential performance benefits happening. Kids in the 8-9 year old range just aren't there yet.

Multi is relatively expensive for what it delivers. I'll install that string for folks who already use it or in cases where somebody needs a shift to a substantially softer layout. Otherwise I'm routinely recommending syn. gut. Some are a little more stiff and durable. Other syn. guts are rather soft and very easy to live with once the right tension is sorted out. Even if 8-9 year old kids are popping strings now and then, syn. gut should be able to give them everything they need at many dollars less than the "premium" multis.

I string for the high school kids on the teams that I coach and although a few of them have switched into a poly or poly hybrid as they've grown and developed their games, I can honestly say that it's not rare for one or another to find benefits after switching away from poly into a softer string type during their high school years. I've noticed the same thing among a few kids on other teams that we compete with every year. Some do okay with poly, some absolutely do not.

Also pretty sure that there's a big difference between some strings which are poly monofilaments and others that are "infused" with poly - one example of that (if I'm remembering it right) is Tecnifibre X-One Biphase. That's a soft multifiber, but poly is somehow added to the bundle of tiny strands that primarily compose the fundamental string. Perhaps Triax has a similar construction going on...

I think you are confusing polyester as a strand and polyurethane the "varnish".

There's many variations of "poly" materials.

Multifilament strings could be polyester fibers like Dacron bowstring or fishing line which is then soaked or coated in polyurethane to tie the fibers together.

Tecnifibre x One is infused with polyurethane.

 

[Stringway Official]

Never too young. Polys installed in the mid to upper 30s provide excellent pocketing and plenty of comfort. I would suggest getting players used to polys at low tensions as they are getting started in the sport, is a long term service to both their game and arm health.

This is very true!
Using polys on low tensions has only pros, not only for youngsters:
It is important to understand that the player feels the string bed stiffness much more than the stiffness of the string.
The low sbs provides more comfort and more power.
This results in less injuries and a higher “stroke efficiency”.
It is important for young players that they learn to use the “spring back effect” of the string bed so that they need less force to generate the maximum speed of the ball.
This is what modern pros do also, they play on sbs between 30 and 40 kg/cm while the Lendls and Agassi used over 40.

The advantage of the poly compared to the multi is that the elasticity is 2 times lower so the control on the speed is better.

Our advise:
String on a sbs of 28 kg/cm and lower this as long as the player can control the speed.

You can use our Tension Advisor (page 3) to calculate the tensions for this stiffnessk for every racquet with every string pattern.
https://www.stringwaynederland.nl/SW-TA-online/SwingCalc/tad-en.php

 

[Stringway Official]

There is one more advantage of the Poly on low tension:
Because of the higher remaining elongation many polys loose tension quickly.
The lower the tension the slower the loss of tension

 

[10shoe]

@Stringway Official

Again, as I stated in post #13, I personally got tennis elbow with poly strung at 30 lbs in a racquet with a 57-67 recommended range. This has left me with an "unsafe at any speed" kind of attitude toward poly. Don't get me wrong, I string lots of poly and recommend it more often than you might imagine. But always with a warning that it is not "arm-friendly". It is not easy to dissuade folks though and getting harder all the time.

It's interesting that you bring up Lendl. I don't recall him needing arm surgery in spite of the exceptionally high tensions he used ...but then he strung with gut. And back in those gut days, it was pretty rare to hear that someone on the tour needed arm surgery. Can you think of anybody who played with gut and needed arm surgery?

Today, things are different. Arm surgeries seem to abound on the tour.

Djokovic has needed arm surgery. Del Potro has needed arm surgery and bye-bye career. Thiem has needed arm surgery and bye-bye career. CeCi Bellis has needed arm surgery and bye-bye career. I don't think it's a short list.

 

[Bambooman]

Both Agassi and Connors had wrist surgery.

 

[Irvin]

@10shoe poly string goes bad quickly, but many will continue playing with it past its life. In fact many will continue playing with it until it breaks, or their arm starts hurting. I think you can continue playing with nylon, multi, or gut string much longer, but not to the point where the string breaks.

Poly hybrid string jobs are good too. You get to play with the benefits of poly a little longer without hurting your arm. But even poly hybrid string jobs should be restrung more often IMO.

 

[Rabbit]

I'm just gonna flesh out this particular case with a bit more detail. This 8 yr old blew through an entire reel of Yonex Rexis Comfort 1.25 in 3 months. So, about 5 days per stringing. I suggested Dynawire 1.30 but instead Yonex sent them this reel of Rexis Speed 1.25 which I installed on 2 racquets about a week ago. Personally, I think the Dynawire would have been safer and probably more durable. I don't think adding poly to a multi makes it more durable. When I've used strings like that I got better control but the durability was pretty much the same as a regular multi. So, I'm kind of surprised at Yonex sending him this multi/poly reel. I mean, if they think highly enough of an 8 yr old to sponsor him why risk doing any damage to his arm?

Have the kid’s parents ask Yonex about Multi-Sensa. It was a multifilament, all polyester - no nylon. Dunno if it’s still in production. I think you’ll have a hard time finding anything with more stretch. IMHO Rexis Speed > Multi-Sensa.

I'm currently using Yonex Rexis Speed 1.25 and really like it. According to TWU, it's actually (admittedly barely) softer than Rexis Comfort despite being infused with poly. I find it to be uber comfortable and has great playing characteristics and long life.

Both Agassi and Connors had wrist surgery.

Agassi did use kevlar. To my knowledge, Connors never used anything but natural gut in a reasonable gauge and tension. Stuff happens I reckon. I do agree though that poly is causing a higher incidence of injury among even pros.

We had a pro at our club who was a retired ATP professional. He won the 35s at Wimbledon and was/is a great player. He recommended poly to 50+ 3.5 women. Just because someone is very good at playing doesn't mean they know beans about gear!

 

[kkm]

@10shoe poly string goes bad quickly, but many will continue playing with it past its life. In fact many will continue playing with it until it breaks, or their arm starts hurting. I think you can continue playing with nylon, multi, or gut string much longer, but not to the point where the string breaks.

Poly hybrid string jobs are good too. You get to play with the benefits of poly a little longer without hurting your arm. But even poly hybrid string jobs should be restrung more often IMO.

For many weekend warriors until it breaks = never, so they play with it forever.

 

[LOBALOT]

For many weekend warriors until it breaks = never, so they play with it forever.

Juniors and College kids too. It is nuts how long some keep a string setup in their racquet before they restring.

 

[10shoe]

Both Agassi and Connors had wrist surgery.

As @Rabbit pointed out Agassi may have played during the gut era but he played with Prince Pro Blend a Kevlar hybrid, at least until his surgery.

 

[DropWideShot]

Lets not forget there are 20 gauge and 19 gauge polys out there as the first step for someone young (or old I guess) to try them out. Definitely no reason for any kid to be using anything thicker than 18 gauge unless their level warrants it.

 

[Rabbit]

Lets not forget there are 20 gauge and 19 gauge polys out there as the first step for someone young (or old I guess) to try them out. Definitely no reason for any kid to be using anything thicker than 18 gauge unless their level warrants it.

Great point, the thinner gauge, newer polys do deflect more and provide a lot of the same playing characteristics. I used Timo 1.10 and did so without pain or detriment. The newer polys are a good option for younger (and a lot of older) players.

 

[PRS]

Thin poly strings just go dead quicker, and once they go dead, it doesn't matter how thin they are.

 

[Irvin]

For many weekend warriors until it breaks = never, so they play with it forever.

Agree or sometimes just a few years or until their arm starts hurting.

 

[DropWideShot]

Thin poly strings just go dead quicker, and once they go dead, it doesn't matter how thin they are.

Just re-string once they go dead. Unless your budget is super tight, nothing beats playing the right string at the right gauge. I was so hesitant towards "thin" poly for a while until I actually tried 18 gauge (1.15) hyper g soft. Maybe I got 2-3 hours of extra life from the 17g but it could not compete with the 18 or 19 on feel and comfort. I probably string about 4 times extra per year with 18 gauge but I never wake up or leave a tennis match/session with my arm feeling it.

 

[PRS]

Just re-string once they go dead. Unless your budget is super tight, nothing beats playing the right string at the right gauge. I was so hesitant towards "thin" poly for a while until I actually tried 18 gauge (1.15) hyper g soft. Maybe I got 2-3 hours of extra life from the 17g but it could not compete with the 18 or 19 on feel and comfort. I probably string about 4 times extra per year with 18 gauge but I never wake up or leave a tennis match/session with my arm feeling it.

Yeah, you definitely can, but then you're restringing extremely often. I just don't see the benefit from poly for such a short period when you can just use a multi or synthetic gut and use it 2-3 times as long with no risk of injury from the string.

If you're older, that's fine, but I'm specifically talking about juniors under the age of 14 (when I said I start recommending poly to some advanced kids with good technique).

 

[devoker]

LMAO I would not consider a country that only has access to poly string a tennis country.

In poor countries people tend to string with poly and play for months or years to avoid restringing costs. When theyare earning a few $ per hour they don't want to spend a few days of salary to restring.

 

[Irvin]

In poor countries people tend to string with poly and play for months or years to avoid restringing costs. When theyare earning a few $ per hour they don't want to spend a few days of salary to restring.

Just because they play tennis in poor countries it does not make them a tennis country.

 

[Stringway Official]

Agassi did use kevlar. To my knowledge, Connors never used anything but natural gut in a reasonable gauge and tension. Stuff happens I reckon. I do agree though that poly is causing a higher incidence of injury among even pros.

MONOS AND INJURIES !
I am afraid I forgot a very important aspects when it comes to monos and injuries:

It makes a huge difference which mono you take.

The force of the impact on the arm depends on the deflection of the string bed and the more the string bed deflects the more you feel the difference in elongation of the strings.
On impact you feel the total elongation of the string when the ball goes into the string bed.

As you can see in this list the difference in total elongation (totale rek) between the polys is huge: from 9,6 % for and Sxc string to 1,6 % for and S4 mono.
http://www.stringwaynederland.nl/pdf/Snarentest 2014-1-op-tot-rek.pdf

This list shows the strings sorted on name and in English.
http://www.stringwaynederland.nl/pdf/EN/Snarentest2015-1opnaam-ENG.pdf.

So if convenience and injuries are of major importance it is important to take an S1 or S2 mono.
(The Sxc monos have so much remaining elongation that they loose tension quickly.)

 

[Stringway Official]

DIFFERENCE IN FEEL OF THE STRING.

This is what modern pros do also, they play on sbs between 30 and 40 kg/cm while the Lendls and Agassi used over 40.

A player only feels the elongation quality of the string when the string stretches on impact because the string bed deflects.
The more the string stretches, the more the player feels the stretch quality of the string.
The sbs of Lendl and Agassi's was so high that they did not really feel the difference in string.

We then tested strings for Rucanor and also strung them at the high tensions.
The players felt little difference between the strings even though they were very different in terms of elongation

 

[Rabbit]

Just because they play tennis in poor countries it does not make them a tennis country.

You mean like Serbia?

 

[drakulie]

If the user of the poly string is playing 2-4 times a week, and the poly doesn't break well inside of three weeks, then age doesn't matter.

 

[AM Stringing]

For the past decade or so I have been cautioning parents to avoid polyester for their kid's racquets until they are at least 14. Now, 14 yrs old, I didn't just pull this number out of my butt. My shop is not too far from the National Tennis Center and the junior development program there came up with the number 14 and were advising parents to stick to multis...at least they were 10 yrs ago when I had several customers with kids in the program.

Lately I am getting a lot of requests for poly for kid's under the age of 10. I think a number of the coaches in my area are under the impression that whatever they are using is what everybody should be using, regardless of age or level. So, if the coach is using Tour Bite 16, everybody should use Tour Bite 16. And I'm sure if you have a young student who is having trouble keeping the ball in the court, switching them to poly will make a coach look like a coaching genius when suddenly everything is landing in the court.

How do YOU feel about poly for 8 and 9 yr olds?

What about strings that contain poly...like Tecnifibre Triax?

Aloha 10shoe,
Juniors under 10 are skilled and physically ready to play with a full bed of polyester strings. In most cases, juniors using polyester strings are being told by their coach (non-stringer) or copying what the pros are playing with. This idea also applies to beginning 2.5 adults.

Using the wrong string at the wrong time can be a player's downfall without even knowing. The wrong string can harm their game, leading to subpar performance and potential injury.

However, once players can "improve and prove" their skills by breaking nylon strings, they are ready to move up to the next level.

I devised two comprehensive Stringing Guidelines to assist in selecting the ideal string setup and determining the frequency of stringing for juniors and adults, both recreational and competitive.

 

[SavvyStringer]

I'm currently using Yonex Rexis Speed 1.25 and really like it. According to TWU, it's actually (admittedly barely) softer than Rexis Comfort despite being infused with poly. I find it to be uber comfortable and has great playing characteristics and long life.



Agassi did use kevlar. To my knowledge, Connors never used anything but natural gut in a reasonable gauge and tension. Stuff happens I reckon. I do agree though that poly is causing a higher incidence of injury among even pros.

We had a pro at our club who was a retired ATP professional. He won the 35s at Wimbledon and was/is a great player. He recommended poly to 50+ 3.5 women. Just because someone is very good at playing doesn't mean they know beans about gear!

I find the last comment about being good at tennis and not knowing about gear very common. I have a 12 year old girl who recently went from the Ultra 100 UL to the Vcore 100 L. Her pro has had her switch back to the 100 UL because he thinks the Vcore is too heavy and asked her mom to bring them to me to make the Ultras match the TW specs of 285g strung while also not adding swing weight or changing the balance. Typically TW rackets are strung with a 16L. This girl has a 20g TB main and 16g TNT2 cross so the weight isn't the same. Add to that the racket is out of spec and she needed like 20g to get to the 285g strung weight. I told mom it couldn't be done effectively without changing the swing weight or really changing the balance. I can't count how many times I see teaching pros tell parents and adult players dumb things about weight, string, and tension. Teaching pros need to figure out their lane and stay in it.