We’ll discuss the term throw angle in table tennis.
The term throw angle is usually based on the arc with which the ball leaves the blade after the impact. Given the same stroke, the rubber with the higher arc would be labelled as high throw.
The problem with the above definition is that a single rubber doesn’t have a single throw angle, but many different ones. Based on the incoming ball(spin and speed) and your stroke (blade angle, stroke direction) you get a unique throw angle for every ball. As we can see (or later see since the explanations follow below), we can only compare different rubbers throw angles on certain stroke types.
However, people aren’t stupid and we’ll see later on why this infamous term enjoys such a high popularity, how and why the usual rubber reviewer labels a rubber as high or low throw and how you can still benefit from these (false or inexact) reviews to make a good decision.
2. How a rubber works
In the picture below we see a ball penetrating a sponge. At this point I’d like to remind every reader that you owe me a new kitchen cleaning sponge, a Battle I topsheet and some TT glue.
Sadly my kitchen sponge isn’t that elastic, so some effects can’t be seen properly. However, at the 3 minute mark in the following video there’s a nice model of the ball rubber impact.
Let’s go back to our model (click to open bigger version in a new tab).
We saw the the throw is the result of different forces and their relation to each other, in particular the relation between the upward and forward forces.
Below we see a high throw (blue) and a low throw(red) and the explanation which forces result from which phenomenons (compare with our model above).
We can also see, that certain manipulations of the spin/speed ratio are possible. By using less forward speed we need less upward force to get a similar high throw angle.
3. What makes a rubber high or low throw on a certain stroke with a certain incoming ball spin and speed?
As seen above, different things influence the forward and upward forces. The aspects a rubber can influence are:
- topsheet tacky or nontacky
- the sponge hardness
- the sponge thickness
- the pimple structure(type, width, distance to each other)
In the next section we’ll do a little case study on these options.
3.1 Case study: Tenergy rubbers T64,T05 and T25
We previously saw how the sponge and the stroke type lead to different types of outgoing ball trajectories. So far we didn’t consider the different pimple types, although they play a major role for describing the rubbers throw.
Sadly I wasn’t able to get a complete list of all ITTF licensed rubbers and their pimple measurements as listed and enforced on the ITTF sheet for rubber approvals.
I even send an E-Mail to Mr. Darren Leong (ITTF equipment coordinator) but he just kindly told me that its a trade secret. That’s a bit strange considering that every firm can measure a competitors rubber easily to a very high accuracy. So my guess is that it’s just another method of keeping the usual ‘stupid’ costumer stupid and robbing him of the ability to discover a similar and possibly cheaper rubber.
Gladly, one of the most used and well known companies published some of their pimple measurements and you might have already guessed it, it’s Butterfly.
We start with the comparison between T05 and T64. According to Butterfly, they have the same pimple type and width, but the pimples are further apart and taller at the Tenergy 64.
Imagine we apply a certain force onto the rubber. This force gets distributed among all pimples below the topsheet which are influenced by the ball. Let’s say the force is distributed among 10 pimples on the T05.
The same force is then distributed among fewer pimples on the T64, because they are further apart, which means that each individual pimple has to withstand more force on the T64. This makes it easier to let them dive into the sponge compared to the T05
, especially since the T05 has a harder sponge. It’s thus easier to compress the sponge on the T64 and hence also easier to let the rubber ‘eat’ the ball and get more upward energy out of it.
Now the big question is: If it’s easier to get an upward force out of the T64, why it’s shown in the video at the beginning to have a lower throw?
The answer lies in the different incoming and applied forces and how the rubber can handle them (you might remember the trampoline example from the chemistry article).
For low forces the T64 is sufficient and creates a high arc or throw. But as soon as more force is applied the longer pimples of the T64 can’t withstand the force applied to them and do not bend but rather get smashed without to much resistance. The topsheet failed. Now we lose much of the upward force and can only rely on the ball eating force(yellow in one of our above examples). At the same time, the
softer sponge of the T64 is strongly compressed (or even bottomed out) and then applies a great forward force to the ball. Thus the ball goes long instead of high.
The Tenergy 05 on the other hand can handle this high forces, because the pimples are closer together and hence less force is applied to each pimple. Furthermore, the pimples aren’t as tall as the T64 ones and are less susceptible to getting smashed without properly realigning.
Last but not least, the hard sponge can handle the incoming force better and provides sufficient upward lift while limiting the forward force.
(Many thanks to reddit user /u/anchorschmidt for pointing out that T05 and T64 have the same sponge hardness, I looked in the wrong column ;).)
The description above already hints at the fact, that different rubbers have a range where they shine. The T64 at low forces and the T05 at medium to medium high forces.
We close the gap for very high forces by introducing the Tenergy 25. This rubber has really massive wide pips which are close to each other. Thus the force applied from the topsheet can be distributed among a great pip surface and can be handled even for very high forces. Additionally they almost never fail to realign themself after being compressed because they are so massive.
Another question might appear at this moment: Why professional players even bother with playing the T64 and T05 and don’t simply to move to T25 since it handles high forces better?
You might have read it a thousand times here already, but again, nothing in life is free. The ability to handle high amounts of spin on the T25 comes at a price. The price is the fact, that you need a very high energy to compress the pimples and the sponge. If you try to make a thin brush loop against a slow ball, you won’t get any upward force. The sponge won’t get compressed because the low incoming force is distributed among the massive pimples and the pimples won’t bend. Hence intermediate players might say the T25 is a low throw rubber, because for them, on most of their ‘weak’ strokes it doesn’t create any arc. However, on power strokes, the arc is higher than the arc of the Tenergy 05 and T64 as correctly shown in the Butterfly video at the beginning.
These thoughts immediately lead us to the next section.
4. Making sense of people and their ratings
On tabletennisdb people rate their rubbers regarding many aspects. Luckily they also rate the throw angle and therefore we can try to understand:
- which rubbers are rated high,
- why they are rated high,
- and what we can do with this information.
Sorting by the throw angle value and accepting rubbers with more than 15 ratings we get the list of the following first 6 entries:
- DHS H3 (tacky,pro)
- Sanwei T88-I (tacky)
- Donic Bluefire M3 (soft)
- Butterfly Tenergy 05 (pro)
- Butterfly Sriver G3 FX (soft)
- Donic Baracuda ()
The words behind the rubber are
- pro: rubber is used by pro players so the rating might be flawed
- tacky: rubber has a tacky surface
- soft: rubber has a soft sponge and rather small pimples
If we remember our statement of the ratio of upward and forward energy and how to manipulate it, we see why tacky rubbers are rated as being high throw.
They reduce the forward forces significantly and hence the ball appears to have a higher throw. The picture above also explains why tacky rubber users should stay close to the table.
4.2 The Sanwei Case
The Sanwei rating is interesting because it a clone of the T25, which has a lower throw angle rating. It has massive pimples aswell. However, the tackiness seems to help people to overcome the lack of a lifting force for brush loops and weak balls in general.
4.3 Soft rubbers
Soft rubbers with rather small pimples bend easily on slower strokes and thus provide a good upward force (ball ‘eating’ /dwell time) even on weak strokes.
However, as previously stated, they fail at higher impact energies. Nevertheless most amateurs would give their left leg to say that they can generate a higher throw with these rubber types.
4.4 How to use the rubber throw ratings
At first remember the reasons why people give rubbers a high throw rating. They give the rubber a high throw rating, if they get an high arc on most of their shots. Depending on their skill level the same rubber might vary from low throw to high throw ratings (T25 case). If a rubber is neither too soft nor tacky, there’s a high chance that this rubber indeed creates a good arc on most shots (T05,Baracuda).
If you like tacky rubbers (H3,T88), there’s nothing wrong with playing them, but consider the advantages and disadvantages as written on the tacky rubbers article. Also note that the H3 might produce an on average higher throw than the Sanwei rubber because the pimples of the H3 aren’t as massive.
If you know that your playing level isn’t too high, there’s no need to play really hard rubbers which need a high impact energy (T25) to produce a high arc. Then softer rubbers are your choice.
The throw throw angle measures how closely a ball follows a high or low arc as it leaves the blade. The arc is determined by the amount of energy the rubber can store to push the ball forward or upward once it leaves the topsheet. Hence a rubber doesn’t have a single throw angle, but a throw angle which is dependant and hence different based on the incoming ball and our stroke.
If a rubber still gets a throw angle rating it’s usually referring to its average throw on all shots. Hence the T64 was labelled as low throw, although it has a higher throw than the T05 if the impact is rather small. The Tenergy 05 gets a higher throw angle in general, although the T25 produces a higher throw on high energy balls, but fails to produce higher arcs on lower energy balls.
Beside the incoming balls energy and the stroke type, the sponge hardness, the sponge thickness, the pimple type and the tack of the topsheet play an important role.