Power potential of lower tension

[PKfan1]

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.

[UCSF2012]

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.

[fortun8son]

The actual ball speed difference is very small, however there is a perceived difference in power due to the change of trajectory.

[Hi I'm Ray]

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.

[Povl Carstensen]

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...

[Bartelby]

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.

[morten]

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

[TennisFan1337]

Originally Posted by morten

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

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).

[filphil]

Originally Posted by fortun8son

The actual ball speed difference is very small, however there is a perceived difference in power due to the change of trajectory.

Originally Posted by TennisFan1337

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).

These two quotes are directly related.

[TonyB]

Originally Posted by Bartelby

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.

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.

[TonyB]

After a few minutes of searching, here it is:

http://tt.tennis-warehouse.com/showp...&postcount=164

[Rozroz]

Originally Posted by TonyB

After a few minutes of searching, here it is:

http://tt.tennis-warehouse.com/showp...&postcount=164

this is too complicated!!
can you maybe summon up the conclusion for me?

[Federerkblade]

What about indoors and poly tensions ?

[tlm]

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.

[Bartelby]

Thanks for finding that as its one of the most useful posts on this board.

Originally Posted by TonyB

After a few minutes of searching, here it is:

http://tt.tennis-warehouse.com/showp...&postcount=164

[Logic Dude]

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

[Bartelby]

More particularly, I found the first one useful:



http://tt.tennis-warehouse.com/showp...&postcount=271

[corners]

Originally Posted by PKfan1

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.

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.

[TonyB]

Originally Posted by tlm

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.

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.

[TonyB]

Originally Posted by corners

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.

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".