Power potential of lower tension

Discussion in 'Strings' started by PKfan1, Oct 12, 2012.

  1. PKfan1

    PKfan1 Semi-Pro

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    Has anyone found any study on the potential increase in ball speed from decreasing string tension. Example (completely theoretical): If I can consistently serve @120 mph strung @62 lbs is there a measurable amount of increase in ball speed if tension is decreased to 52 lbs?

    I know power comes easier at lower rhs but I'm not sure I notice too much difference when I take a full swing at the ball and I don't have a radar prove my theory. Any knowledge would be helpful.
     
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  2. UCSF2012

    UCSF2012 Hall of Fame

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    Do your own testing. It means more.

    It's hard to compare 55 vs 57 lbs, but you can readily see the difference between 65 and 55 lbs. Even more so 65 vs 45lbs.
     
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  3. fortun8son

    fortun8son Hall of Fame

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    The actual ball speed difference is very small, however there is a perceived difference in power due to the change of trajectory.
     
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  4. Hi I'm Ray

    Hi I'm Ray Hall of Fame

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    At higher tensions with poly, when it gets boardy and dead (even w/fresh strings) I'll notice a drop off in power, but I don't really notice it as much with other types of strings. I don't really see a difference in power between 53lbs vs 36lbs (poly) on groundstrokes, but on serve I'm seeing an increase in power and spin.
     
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  5. Povl Carstensen

    Povl Carstensen Legend

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    When I tried 15 kg (33lbs) in my K90, I had the surprising experience of loosing too much power. It was as if the string was to loose to transmit impact to the ball...
     
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  6. Bartelby

    Bartelby G.O.A.T.

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    There was a chart up here once upon a time that did show that the optimum tension for polys was in the forties, but higher for nylons and higher again for gut.
     
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  7. morten

    morten Hall of Fame

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    imo, lower tension=deeper shots. i loose control if i string too tight as i overhit to get the desired length...
     
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  8. TennisFan1337

    TennisFan1337 New User

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    This is true.

    From my own experience I can tell, that when you go lower in tension, you will get more depth on your shots. The tighter you go, the more depth you will loose.

    The change in ball speed is not that noticeable. It's just easier to generate the needed depth (and also some more spin).
     
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  9. filphil

    filphil Rookie

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    These two quotes are directly related.
     
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  10. TonyB

    TonyB Hall of Fame

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    I remember that chart -- it was in the "Low, low tensions (20 lb.)" thread that Chris Edwards started.

    I think the power curve had a peak around 40 lb. for most polys and any tension higher or lower than that dropped off in power. But I'm just guessing, you'd have to check out the original thread and find the chart to be sure.
     
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  11. TonyB

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    #11
  12. Rozroz

    Rozroz Legend

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    #12
  13. Federerkblade

    Federerkblade Professional

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    What about indoors and poly tensions ?
     
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  14. tlm

    tlm Legend

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    I don't pay attention to what some chart says, because I have found it to be the exact opposite. With syn. guts and most multi's I have found that I don't need to go as high as I do with poly string.

    There is a point were syn. gut or multi's will board out and become dead at to high of tension, were poly will still have pretty good power.

    In the the last few rackets that I was using I found that most mult's or syn. would become to dead at a little below 60 lbs. Were with poly I could go with at least 66 lbs. with no problem.
     
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  15. Bartelby

    Bartelby G.O.A.T.

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    #15
  16. Logic Dude

    Logic Dude New User

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    I never found lower tensions to be more powerful, they just launch the ball higher.
     
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  17. Bartelby

    Bartelby G.O.A.T.

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    #17
  18. corners

    corners Legend

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    According to the physicists who study these things, if you reduce the stiffness of your stringbed by half you increase the apparent co-efficient of restitution (the percentage of racquet speed and incoming ball speed that is returned by your strings as outgoing ball speed) by 3 percentage points. Those 3 percentage points translate to roughly 3 miles per hour on a groundstroke. But it's impossible to halve your stringbed stiffness by lowering strung tension.

    For example, let's say you normally string Luxilon Alu Power Rough 16L at 60 pounds. But you drop it to 50 pounds to get more "power." That drop of 10 pounds will feel significant (reduced shock, increased dwell time, etc.) but you've only decreased the stiffness of your stringbed by about 11%, which would give you about .3 mph extra on your groundstrokes. Not much. If you drop to 40 pounds next time you restring you'll get an extra half a mph. Whoopee. But you'll also find that the launch angle of the ball off your strings changes as you drop tension. All other things (swingspeed, racquet-face angle, swing angle, incoming ball speed, trajectory and spin, etc.) being equal, a ball will bounce off looser strings at a higher angle than off tighter strings. So even though your shots at 40 pounds are only marginally faster than at 60, they might land significantly deeper in the court because a higher launch angle mean a higher trajectory and thus more depth. This is what most people are talking about when claiming that they get a "power" boost from looser strings.

    And this is why going purely by what you experience on the court can be deceptive, and why using a radar gun would be essential to confirm any perceived increase in speed of shot attributed to a drop in string tension.

    The only way to significantly increase pace with string changes is to switch to a significantly more flexible and elastic string. For example, natural gut at 60 is less than half as stiff as Alu Power Rough is at 60, and it is more elastic, meaning that if you made that switch you would get more than 3 extra miles per hour on your shots, maybe 4 or even 5. But that's as good as it gets. Going from Alu to a syngut or multi might get you 1.5 mph extra, at most, which in many people's experience is not enough to offset the loss Alu's famously awesome spin boost.

    IMHO, the impact of string changes is greatest in terms of comfort, feel and spin, and least in terms of pace. Pace, just like everything else in tennis, is primarily a matter of skill, talent and fitness.
     
    Last edited: Oct 13, 2012
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  19. TonyB

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    Ummm, what??? That makes absolutely no sense. Poly is incredibly stiff and boardy at medium or high tensions. There is no "give" in the string. That's just a fact due to the material and construction of the string.

    Why would you have to string multis and syn guts lower?? Multis are very powerful by comparison to polys. Syn guts are also fairly powerful (made from nylon, mostly), but lose tension quickly. Polyester is by far the lowest powered string material on the market. It absolutely makes no sense that you would have to string it higher than syn gut or multis.

    I've been playing with strings for at least 6 years now, and nothing that I have experienced supports your theory of stringing poly higher than syn guts or multis. On the whole, poly is dead-feeling, low-powered, and offers no feel whatsoever. Syn gut and multi strings are virtually the exact opposite.

    Wow.
     
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  20. TonyB

    TonyB Hall of Fame

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    I think what you are referring to is the "dwell time". The longer the dwell time, the higher the launch angle. As you can see from the charts, the dwell time of poly at very low tensions if quite high. Higher, in fact, than other materials at the same tension. So, the pocketing is increased with low tensions, but the depth of shot is also increased, even with only a minor increase in power.

    I've noticed this in my own experiments. With low tension poly, I definitely see more power, but I also notice that I get incredible depth with a "normal" stroke. This speaks more to "control" than power. People sometimes mistake "control" for "increased depth without increase in power". However you want to think of it, poly can offer good depth control without much loss in power if you either swing hard or string your frame at lower tension. With polys at low tensions, I can swing out freely without worrying about hitting the ball too deep, because while the depth of shot increases, the power doesn't increase all that much. It takes some adjustment, but all in all, the net "gain" from poly is much less than other strings. That is, for the same stroke, the variance in depth or placement is much less. This can be called "control".
     
    Last edited: Oct 13, 2012
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  21. PKfan1

    PKfan1 Semi-Pro

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    Thanks corners! That's the info I was looking for. I was speaking more about actual ball speed on a flat serve so that would take the launch angle out of the equation, and you answered my question. I also got to wondering about different types of strings and you covered that as well!
     
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  22. tlm

    tlm Legend

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    Poly is not even close to the lowest powered string on the market, kevlar is way less powerful. Then you can state that there is no give in the string and say that is a fact. Now that is hilarious no give at all, well I didn't know that poly was the same as having solid steel rod in the racket.

    So do you string yourself? How many different strings have you experimented with at a wide range of tensions? I will bet not even close to what I have. You mentioned about some experimenting let me guess with poly you have probably never tried many if any at around 60 lbs. or more.

    I have tried many many string types and tensions over the years, way more than a good % of the players here. There are so many here that keep repeating the same things that they have heard but have never really tried experimenting that much so even though they really don't know if these theories are true it becomes the gospel.

    At lower tensions syn. can be more powerful than poly at the same tension that I will agree with. But once you start increasing the tension there is a point where the syn. will board out so bad that they have no power left but the poly can still provide good power.

    But you would have had to actually tried this instead of going by what you have heard so many times that you accept it as fact. The last racket I was using was a blx 90 asian version I ended up playing with rpm blast between 65 and 68 lbs. and it played great, It was low powered but not anywhere as most would think, plus I could still get good pop out of this set up. But again most have never tried it because according to them you would not have any power and your arm would fall off.

    Now the same racket with nxt tour 18 gauge at 58 lbs. had very little power, it had great control but no bite off the court. It was just to dead compared to the rpm at the higher tension. I know you will never believe this but if you ever tried it you would see what I am talking about. Or going by the never ending charts and lab tests that really are not that close to what a person actually experiences.

    I would love to take some of these guys that think they know so much and string their favorite rackets at different tensions with different strings and let them actually feel the difference instead of just talking about something they really don't know that much about.

    I would be willing to bet good money that many syn. or multi strings will reach a point of no power at a lower tensions than a lot of the poly strings would. But guys like you will never know because you think you know about things that you have never tried.

    One of my good friends uses a blx 90 with lux 18 gauge bb ace at 70 lbs. thats right 70 lbs. And he has been using this set up for years with no problems. And believe me this set up has plenty of power, I hit with it once in a while and am always surprised at how much power it has. This guy is around 5' 7" and weighs 150 lbs. and can flat out rip the ball with poly at that high tension.

    So please let me hear from you after you really have experienced a lot of different strings at a broad range of tensions.
     
    Last edited: Oct 13, 2012
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  23. tlm

    tlm Legend

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    So are you saying that a higher launch angle will not cause more shots do go long?
     
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  24. jmnk

    jmnk Professional

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    If I may ask - how did you measure 'the pop' and 'the deadness'?
     
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  25. tlm

    tlm Legend

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    I don't have lab testing equipment on the court which I guess some would need to be convinced. But a big part of my game is hitting high bouncing top spin and it is more than obvious that if the set up is not popping up much and it becomes almost impossible to hit the ball by your opponent and tough to get any depth that there is no pop and the string job is dead.

    Plus my hitting partners will tell me the difference, I have had some set ups that I thought were pretty good because of the excellent control I was achieving but my partners would tell me the shots had nothing on them and no bite off the court.

    Again this is achieved by experimenting and going out with 2 or 3 different set ups and hitting all of them and actually trying them and asking your partner what they notice. This beats the hell out of any lab tests.
     
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  26. jmnk

    jmnk Professional

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    thanks.
    in short 'in your opinion', which is as good as any other opinion but it is not backed up by any objective measurements whatsoever, certain setups provide more 'pop' and are less 'dead'.
    Let me ask you another question. Could you define what exactly you mean by 'pop' and 'deadness'? As in if one wanted to spent time to measure it - what exactly would he be measuring?
     
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  27. Hi I'm Ray

    Hi I'm Ray Hall of Fame

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    You'll get a much better idea if you just string two of the same rackets and strings at different tensions and see for yourself. Lab tests are good for some things and misleading in others. PS 85 was rated as having more power than a PDGT in the sweet spot in lab tests and I think there was some test that showed 1-3% difference in power across string types, both just don't come through that way on the court.

    I'm talking about poly here though, say 54lbs vs 36lbs. I tried low tension poly, kevlar, and syn gut - the first two played well at low tension but the syn gut felt like rubber bands.
     
    Last edited: Oct 13, 2012
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  28. tlm

    tlm Legend

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    The comparison you give of the PS 85 against the PDGT is a great example of lab tests being one thing and playing on the court the complete opposite. I know that the heavier smaller head rackets can produce surprising power, but there is no way in hell that the average player is going to get anywhere near the power from a PS 85 that they would out of a PDGT. This shows many of these lab tests to be nothing but comical.

    Also I agree that to make comparisons you need to have big differences in tensions like your example of 54 vs 36 lbs. And yes sy. gut or multi's at low tensions will feel like rubber bands. But try them at 64 lbs. or higher and they are the complete opposite boardy and super dead.
     
    Last edited: Oct 14, 2012
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  29. Logic Dude

    Logic Dude New User

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    Assuming you take the same swing you would with full polyester at 68, sure. Having been a lurker here for a while, and having read many of your posts, you don't seem to realize that people have different swings. Some are grooved to higher tensions (such as Querrey, Isner, and Blake), and some are grooved to lower tensions (Sock, Falla, Belucci, and Volandri). I remember you saying that since pros restring every half hour, the low tensions don't count. That's a ludicrous statement. Logic dictates that regardless of how long they keep the strings in there, they still string significantly lower than those whose string at 68 pounds, and still do just as well.

    The logic of the statement I quoted would then suggest that none of my shots would ever make it over the net with poly strung as high as you do. The simple fact is that people have different swing paths, different rackets, racket head speeds, and different body builds. To say that stringing low=hitting long all the time would be perfectly equitable to saying stringing high=hitting into the net all the time. To make those sweeping generalizations is nonsensical, especially in a sport with such varied swings as in tennis.

    Now, your retort might be something along the lines of "Stringing high still gives you plenty of pop and power to hit it over the net and not long." In this case, I could simply point to my own racket strung at 40 and say, "It still gives me plenty of control as well as increased spin, not to mention it gives me the extra height over the net so I don't have to worry about hitting into the net."

    Another point: having watched the videos of you playing, the stroke you take is obviously going to feel better to you with high tensions. You hit straight up on the ball, providing your own high launch angle, so naturally you prefer higher tensions to bring that angle down and give you the "control" you feel.

    I, on the other hand, hit topspin with a more linear stroke, hitting through the ball with racket head acceleration. I generate the spin and power, but naturally my launch angle is lower than yours. Even when I string low, my problem is always hitting the tape of the net, not hitting it long. Do I hit it long sometimes? Of course. The thing you say that galls me is that you think my problem when hitting long is that I string too low, that if I string as high as you, that problem will go away. Imagine how uncomfortable you would feel playing with a racket strung at 40 pounds. That's how uncomfortable I would be with a racket strung at 68 pounds, if not more so due to the inevitable tennis elbow that would ensue.

    The simple flaw in your reasoning is that you think everyone has the same strokes as you. They don't. End of story.
     
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  30. tlm

    tlm Legend

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    I think you make some really good points in this post. But believe me I definitely realize that there are many different stroke styles. I am in no way saying that everyone should us high tension. Where did you see that? According to most here everyone should use no more than 45 lbs. when stringing poly.

    I have used poly at a wide range of tensions and I say use whatever works and the lower tension you can use the better feel and comfort you will get. But it does not mean that many players can not benefit from higher tensions also.

    Also where did I say that stringing low would mean hitting long all the time? I have said for me with to low of tension I have a hard time with depth control. I never said that stringing low = hitting long all the time and string high will fix every problem. But so many here claim that there is more control with poly at lower tensions than at higher tensions, this is laughable at best.

    And as you said the racket the type of poly the strength and swing style all come into play. But on average the same racket strung at 40lbs. compared to 65 lbs. will have more power and less depth control. This is what all my hitting partners have concluded, it is pretty obvious if you actually go out on the court and try it.

    You are twisting my comment about the pro players changing strings every half hour around. The point was that many here say that fed only uses 54 lbs. tension and that is what I use. Well okay you are using the same tension as him for the first half hour, but not the next day and the next week and on and on. Most players do not change their strings that often so comparing their tensions to a pro that uses their string job for a very short time is what I would classify as ludicrous.

    Not to mention the pro player has great foot work set up and timing that no club players will ever have. The pro does not need as much help with control as the club player does and again there is a huge difference in 54 lbs. brand new as compared to a day or week or more later.

    You state that imagine how uncomfortable I would be playing with only 40 lbs. of tension. Well unlike a lot of people here I have used that low of tension and everything in between. I have found that with some rackets poly in the 40's can have decent control, but you lose the precise feel and control that a somewhat tighter tension will give in match conditions.

    That is when you have to hit all the different shots from bad positions and not always having the time that you need to execute a good stroke. For me that is when the help of the higher tensions built in restricted flight helps.
     
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  31. corners

    corners Legend

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    Yes, that's what I was talking about. This is also why people find their shots going long with "dead" copoly, even though they claim the strings have lost their "resilience". The dead copoly has simply lost so much tension, and the dwell time increased so much, that the launch angle puts the ball too deep. There is also the factor of string scuffing and tension loss impeding the snapback effect, resulting in less spin which again puts the ball too deep.

    Yeah, I think you've got this about right. Usually when people are talking about power they are talking about control, not pace. You hear this all the time with racquets - someone will say they want a racquet with less power, which is ridiculous as the actual power differences between racquets, on fast swings, is negligible. And who wouldn't want a couple extra miles per hour on their shots, as long as they remain in control of those shots? Here again, they are talking about depth and directional control factors having to do with stiffness, dwell time, string pattern, etc., and not the inherent power potential of the racquet.
     
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  32. corners

    corners Legend

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    Great. Cheers.
     
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