Does Weight or Swingweight add more power?

[BC1]

Just curious - Which racquet has more power (assuming the swing speed is the same). Does the higher weight in "B" make it more powerful, or does the Balance and higher SW in "A" make it more powerful? Or will they be about the same?

Racquet A
Head Size:100 sq. in. / 645 sq. cm.
Length: 27 inches / 69 cm
Strung Weight: 11oz / 312g
Balance: 4pts Head Light
Swingweight: 320
Stiffness: 69
Beam Width: 22-24 mm Tapered Beam

Racquet B
Head Size:
100 sq. in. / 645.16 sq. cm.
Length: 27 inches / 68.58 cm
Strung Weight: 11.4oz / 323.18g
Balance: 8 pts HL
Swingweight: 302
Stiffness: 70
Beam Width: 23mm/24mm/23mm/

By the way - Racquet A is the Volkl PB8 295; Racquet B is the PB8 315.

 

[el sergento]

Just curious - Which racquet has more power (assuming the swing speed is the same). Does the higher weight in "B" make it more powerful, or does the Balance and higher SW in "A" make it more powerful? Or will they be about the same?

Racquet A
Head Size:100 sq. in. / 645 sq. cm.
Length: 27 inches / 69 cm
Strung Weight: 11oz / 312g
Balance: 4pts Head Light
Swingweight: 320
Stiffness: 69
Beam Width: 22-24 mm Tapered Beam

Racquet B
Head Size:
100 sq. in. / 645.16 sq. cm.
Length: 27 inches / 68.58 cm
Strung Weight: 11.4oz / 323.18g
Balance: 8 pts HL
Swingweight: 302
Stiffness: 70
Beam Width: 23mm/24mm/23mm/

By the way - Racquet A is the Volkl PB8 295; Racquet B is the PB8 315.

Why don't you just plug those racquets into the TW power calculator in the TW university?? Seems easier no?

 

[cellofaan]

That's an interesting question.

I plugged both specs into the twu customisation worksheet (starting from a 27", 13" balance, 250 gram, 250SW base racquet, and then working to the specs of both racquets)
According to the worksheet, Racquet A has a 40% power increase and 25.9% more plowthrough.
Racquet B has a 38% power increase, and 22.8% more plowthrough.

So, Racquet A should have more power than racquet B. This doesn't include the differencce in stiffness though, and since the balance also affects power, it's difficult to draw any conclusions.

Hopefully, there's someone on the forums that actually knows how these things work, like the twu prof.

Edit: Ha, two people thinking the same thing

 

[stufflebean]

On preview: sort of scooped by cellofaan

Why don't you just plug those racquets into the TW power calculator in the TW university?? Seems easier no?

Before you get all snide, I tried this. Unfortunately the power calculator doesn't let you use arbitrary specs for whatever reason. You have to use a known racquet.

Anyway, that aside, I imagine this is a difficult question to answer (more on why after I take a first crack at it).

Based on what I see in the TWU trajectory compare tool, for the same racquet speed, the first racquet (i.e., the one with the greater swingweight) is going to add more power. I used the racquet finder to find a racquet with specs as close to the new PB8 315 as possible and found that the PB9 is actually pretty close: 98 sq in, 27", 11.3 oz, 6 pts HL, 306 SW, 66 stiffness. When I put that into the trajectory compare tool, with the same set of initial conditions (racquet speed/angle), the PB8 295 imparts more speed to the ball (72.3 mph vs 71.3 mph).

This would seem to indicate that SW adds more than weight. However, there are some complicating factors here. First, it's difficult to isolate this variable. Rarely do two racquets differ only by weight and balance without changing something else like stiffness. Second, and probably more importantly, this comparison only matters if you're capable of swinging both racquets at the exact same speed, which seems unlikely. More likely, swinging a racquet with a higher SW is going to slow you down (maybe not at the very low end of the SW range, where you're limited by other factors). This means that any increase in ball speed you get from the higher SW (and from a physics point of view, more kinetic energy to transfer) is going to be counteracted by the heavier SW slowing you down. (And in fact, since kinetic energy is proportional to mass, but proportional to the square of velocity, any decrease in speed is going to hurt you more than the same increase in mass)

What does this all mean, then? (I'm tempted to say "Just demo them!" here, but you knew that ;-)) If you're capable of swinging both racquets at the exact same speed, then the higher SW will give the ball more power. If you're human, then I would guess that the physics would dictate that the lower SW (and correspondingly higher racquet velocity) would be more beneficial.

 

[Agent Orynge]

I'm sure this has been asked and answered many times over in the not-too-short history of these boards. I dug this one up from the past not too long ago;

http://tt.tennis-warehouse.com/showthread.php?t=193776

It takes a while to build momentum (no pun intended), but eventually gets around to discussing the same point. It's well worth a read in it's entirety.

 

[BC1]

Thanks for the feedback guys - this is obviously a debatable and ongoing question. I guess the best thing to do is stop reading and demo, demo, demo.

 

[eigers]

Power = Speed X Inertia

Here's my opinion, based on what I've read in a book titled "Technical Tennis."

The power of the racquet will be described by its momentum.

The swingweight of the racquet is it's inertia

Momentum = Speed X Inertia.

If you assume that both racquets are moving at the same speed, its all about the swingweight.

The assumption that they both have the same speed is a pretty big assumption, though. Lower swingweight means faster swing (but lower inertia). Higher swingweight means slower swing (but higher interia). Power is the product of both speed and inertia, so the extremes are a bit of a problem. If the racquet is too head-heavy, you won't be able to swing it fast enough to get enough power. If it's too head-light, it won't matter how fast you swing it.

This all sounds impossible, but there's an optimum range where the weight of your racquet ends up being about 6X the weight of the tennis ball (and about 1/6 the weight of your arm.)

This 6-to-1 ratio also works for baseball, meaning that a baseball bat weighs 6X more than a baseball and is about 1/6 the weight of both arms.

Bottom line--Demo a bunch of racquets.

 

[Agent Orynge]

Here's my opinion, based on what I've read in a book titled "Technical Tennis."

The power of the racquet will be described by its momentum.

The swingweight of the racquet is it's inertia

Momentum = Speed X Inertia.

If you assume that both racquets are moving at the same speed, its all about the swingweight.

The assumption that they both have the same speed is a pretty big assumption, though. Lower swingweight means faster swing (but lower inertia). Higher swingweight means slower swing (but higher interia). Power is the product of both speed and inertia, so the extremes are a bit of a problem. If the racquet is too head-heavy, you won't be able to swing it fast enough to get enough power. If it's too head-light, it won't matter how fast you swing it.

Or you could read what I linked above, which says almost the same thing - only more accurately.

 

[Don't Let It Bounce]

This would seem to indicate that SW adds more than weight. However, there are some complicating factors here. First, it's difficult to isolate this variable. Rarely do two racquets differ only by weight and balance without changing something else like stiffness. Second, and probably more importantly, this comparison only matters if you're capable of swinging both racquets at the exact same speed, which seems unlikely.

Third, or perhaps more properly 2a, even a given player will not swing the racquet at the same speed for every stroke. It seems intuitively plausible that the high static wt/low SW racquet might have higher rebound velocity on a volley (limited linear rqt movement, no swing), and on other blocked/semi-blocked shots (RoS, approach, emergency).

 

[stufflebean]

Third, or perhaps more properly 2a, even a given player will not swing the racquet at the same speed for every stroke. It seems intuitively plausible that the high static wt/low SW racquet might have higher rebound velocity on a volley (limited linear rqt movement, no swing), and on other blocked/semi-blocked shots (RoS, approach, emergency).

I would think that would depend on whether the racquet is pivoting at your wrist or rebounding laterally. If it's rebounding laterally, then it should be dependent on the static weight, but if it's pivoting, the swingweight would probably have more of an effect.

To further complicate this, if you're holding the racquet relatively sturdily (i.e., disallowing a substantial portion of the racquet's rebound), then I would think that factors like string tension/composition and racquet stiffness would have a more significant impact than the weight or swingweight of the racquet.

 

[Don't Let It Bounce]

I would think that would depend on whether the racquet is pivoting at your wrist or rebounding laterally. If it's rebounding laterally, then it should be dependent on the static weight, but if it's pivoting, the swingweight would probably have more of an effect.

Exactly. I am using "linear rqt movement" the same way you are using "rebounding laterally", and I am suggesting that variation in the ratio of linear to angular (by which I mean what you mean by "pivoting") racquet movement–and therefore the relative importance of mass and swingwt–is inherent to, among other things, the stroke being executed.

 

[stufflebean]

Exactly. I am using "linear rqt movement" the same way you are using "rebounding laterally", and I am suggesting that variation in the ratio of linear to angular (by which I mean what you mean by "pivoting") racquet movement–and therefore the relative importance of mass and swingwt–is inherent to, among other things, the stroke being executed.

I have a feeling we may be thinking too hard about this. And this is coming from a guy who has an Excel sheet for his racquet demos...

I agree with what you're saying, though.

 

[0d1n]

The TW University studies and graphs show that the most direct correlation is between swing weight and power...not mass and power.
I tend to go with that as well as a "trend", but exceptions will always exist based on other factors (construction...stiffness...head size ....etc).

 

[dParis]

A good question the OP brings up, but I'm still scratching my head about the 302 swingweight of the PB8 (315). I mean, come on! I've seen, from other sources, static weight of 11.8oz and sw of 308. I don't know that says about Volkl's QC... Either way, it seems Volkl reduced the swingweight quite a bit which is somewhat disappointing to me. Imo, a low swingweight didn't do any favors for the PB9.

 

[BC1]

A good question the OP brings up, but I'm still scratching my head about the 302 swingweight of the PB8 (315). I mean, come on! I've seen, from other sources, static weight of 11.8oz and sw of 308. I don't know that says about Volkl's QC... Either way, it seems Volkl reduced the swingweight quite a bit which is somewhat disappointing to me. Imo, a low swingweight didn't do any favors for the PB9.

Exactly my thoughts and concerns. However, in the TW racquet description it says...
Volkl Power Bridge 8 315 (compared to the regual PB8 )
New With the added weight comes more power, stability and comfort which makes this a great choice for intermediate through advanced players. Big hitters will hit even bigger with this one.

I guess only a good demo of the two will tell.

 

[TW Professor]

That's an interesting question.

I plugged both specs into the twu customisation worksheet (starting from a 27", 13" balance, 250 gram, 250SW base racquet, and then working to the specs of both racquets)
According to the worksheet, Racquet A has a 40% power increase and 25.9% more plowthrough.
Racquet B has a 38% power increase, and 22.8% more plowthrough.

So, Racquet A should have more power than racquet B. This doesn't include the differencce in stiffness though, and since the balance also affects power, it's difficult to draw any conclusions.

Hopefully, there's someone on the forums that actually knows how these things work, like the twu prof.

Edit: Ha, two people thinking the same thing

I've fixed the Customization Worksheet so that you don't have to do anything tricky to get your power specs. Just fill in the starting specs and it will calculate the power and plowthrough.

 

[Don't Let It Bounce]

I have a feeling we may be thinking too hard about this. And this is coming from a guy who has an Excel sheet for his racquet demos...

Heh. I've got one comparing specs, pre- and post-customization, for the racquets I'm considering demoing.

I'm cool with it, though, and in no sense do I kid myself that it is a priority for playing good tennis. I indulge in overanalysis and racquet geekery for the same reason I play tennis: it's fun!

 

[MuscleWeave]

A more helpful question might be:

For a given amount of power, how much [swingweight] or [balance+static weight] do I want the racquet to have?

The racquethead speed will be a seperate concern. The higher sw racquet will swing slower and the lower balance racquet will swing faster , with the same amount of effort. All other things being equal, energy will be conserved and the ball speed will be the same. It just depends on how you want to get there (your technique.)

Sorry about my scientific tongue. Too much Physics textbook reading, I suppose. I would have gone for the PHD if I could have afforded it. I love this stuff!

 

[stufflebean]

A more helpful question might be:

For a given amount of power, how much [swingweight] or [balance+static weight] do I want the racquet to have?

The racquethead speed will be a seperate concern. The higher sw racquet will swing slower and the lower balance racquet will swing faster , with the same amount of effort. All other things being equal, energy will be conserved and the ball speed will be the same. It just depends on how you want to get there (your technique.)

Sorry about my scientific tongue. Too much Physics textbook reading, I suppose. I would have gone for the PHD if I could have afforded it. I love this stuff!

As I thought more about what I had said previously, I started to come to the same conclusion. Really, I think SW or balance + static weight affects things other than power (specifically the stability/maneuverability spectrum) more than power itself.

 

[MuscleWeave]

As I thought more about what I had said previously, I started to come to the same conclusion. Really, I think SW or balance + static weight affects things other than power (specifically the stability/maneuverability spectrum) more than power itself.

That's why you have to isolate what things you are considering, and ignore the other factors by calling it an 'otherwise perfect system' or 'all else being equal.' Trying to describe everything that is going on would be a fruitless endeavor.

 

[corners]

Racquet A:

Hittingweight at 21" from butt :170 grams
Power Potential at 21" :40.04

Racquet B:

Hittinweight at 21" from butt :160 grams
Power Potential at 21" : 38.11


Swingweight is nearly proportional to hittingweight and hittingweight is proportional to ACOR, or power potential. Therefore, this question is easy: assuming the swingspeed is the same, racquet A has more power, significantly more.

You could add another 20-30 grams to the handle of racquet B, and as long as it didn't change the swingweight too much, B still wouldn't be as powerful as A. Swingweight is MUCH more important to racquet power than static weight. This is the whole principle behind the hammer concept.


BTW, are you sure that racquet B is the PB8 heavy? That swingweight looks unstrung to me (would be ~330 strung).

 

[stufflebean]

That's why you have to isolate what things you are considering, and ignore the other factors by calling it an 'otherwise perfect system' or 'all else being equal.' Trying to describe everything that is going on would be a fruitless endeavor.

'Assuming a spherical cow...'? I'm an engineer; I know how approximations and simplifications work. ;-)

 

[BC1]

BTW, are you sure that racquet B is the PB8 heavy? That swingweight looks unstrung to me (would be ~330 strung).

Yes - according to the TW description/specs in the volkl racquet section.

 

[corners]

Yes - according to the TW description/specs in the volkl racquet section.

Ah, now I see why you asked the question. Odd specs, in fact very similar to the PB9, but more headlight. Also similar to Wilson's old K Pro Tour and Bab's Pure Storm Ltd.

Now I see why you asked this question using the PB8295 and PB8315 as examples. TW's blurb says the heavier, lower swingweight one is more powerful. Hmm, inherently - not.

But it's likely you can swing PB8315 faster, given it's significantly lower swingweight. All the studies done to date (and there haven't been a great many) show that swingweight, and not static weight, determine how fast you can swing a racquet. But, these studies use swingweight at the wrist axis, and some include the weight of the hand in the swingweight calculation. When you measure swingweight at the wrist the static weight gets into the figure, but the swingweight spec is still the most important.

I'm guessing that many people can swing the 315 version faster, which would make up the difference in inherent power, but only just. You'd have to swing about 4mph faster on your forehand to make up that difference.

However, if you have a wippy swingstyle the lighter version may be easier to whip (despite the higher swingweight) and thus give you higher swingspeed for your swingstyle. Racquets with less weight in the handle (and relatively more in the head) are easier to whip, for reasons that Rod Cross explains in this very cool article (in my experience they're lousy at net though):

http://www.racquetsportsindustry.com/articles/2006/04/racquet_handle_weighting_and_m.html

 

[Don't Let It Bounce]

I just came across a good Rod Cross article that seems to settle the OP's question:

http://www.racquetsportsindustry.com/articles/2006/02/raw_racquet_power.html

In short, there is some correlation between increased mass and increased rebound power (ACOR), but the correlation between increased swing weight and increased rebound power is pretty much a straight line. So, SW will generally add power more efficiently than mass does, as Corners points out above.

The tests were done on a stationary racquet, so the distinction I made upthread between linear momentum (i.e., volleys) and angular momentum (i.e., GS and serves) appears not to matter.