# Questions on Spin

Discussion in 'Tennis Tips/Instruction' started by Gogg, Oct 21, 2008.

1. ### GoggNew User

Joined:
Oct 20, 2008
Messages:
82
I know there's 3 known types of spin, Topspin, Backspin, and side spin. Twist is a combination of sidespin and topspin. What do you call backspin with side spin (if that exists)? Also, what you do you call the spin when the ball rotates sideways on a horizontal axis? (what I mean by this is like drawing a 2D circle, that's the rotation of the ball)

Also, how do you achieve the ball to go sideways rather than forward? I once hit a ball that bounced sideways towards the edge of the court rather than the ball moving towards my opponent's baseline (if the first statement was unclear).

Thank you.

2. ### AlphaCDjkrRookie

Joined:
Sep 29, 2008
Messages:
310
Location:
West Covina, CA
Well... I wouldn't consider topspin and backspin two different spins, because they're on the same axis. They're just rotating differently. Since there's 3 dimensions to a ball, there's 3 ways it can spin. Theres Topspin/Backspin, Sidespin, and then another sidespin.. (I have no idea what this is called. Does it even have a name?) I'll elaborate in the next part because your next question refers to this sidespin that I don't think has a special name.

A combo of topspin/sidespin is merely Topspin-slice. This spin becomes "twist" when you alter the axis of rotation so that the topspin-slice serve is no longer traveling along its axis.. if you can understand this.

Backspin with sidespin.. It exists but I don't think its anything really. It's just a shot. Lol.

That sidespin I mentioned previously, the one I don't think has a name, refers to this. I think it's just referred to "sidespin". The sidespin in a "Slice serve" refers to the first type of sidespin I mentioned. The sidespin in a sidespin slice is like the one you're mentioning.

This follows the same concept of slicing along the axis that I don't know the name of.

If you hit a ball that bounced towards the sides rather than straight along the balls path, you hit a sidespin slice. Basically, instead of imparting backspin, you imparted a kind of underspin sidespin.. um... You take your racquet, and brush UNDERNEATH the ball in a horizontal fashion.. I don't know how to describe this shot, and ironically it's one of my favorite shots to do.

I can take a video of me doing it and upload it here tomorrow; maybe that would explain it better.

3. ### SystemicAnomalyG.O.A.T.

Joined:
Feb 25, 2006
Messages:
15,478
Location:
Stuck in the Matrix somewhere in Santa Clara CA
Don't know of any special spin names for various spin combinations. For serves (& underhand strokes), you can have an underhand sidespin or a reverse underhand sidespin than can have both underspin & sidespin components. If hit in an extreme manner, some very wicked bounces can be produced with these combinations.

As Alpha has indicated (above), a Twist (serve) does not simply refer to a combination of topspin and sidespin. A standard topspin-slice serve employs this combination, but does not result in a twist. Even most topspin kick serve have some sidespin component but will not necessarily twist either. The Twist is actually a special version of the kick serve (according to my definition of the Twist).

For most spins in tennis, the axis of rotation will be pretty much perpendicular to the flight direction of the ball. However, for a Twist action, the axis of rotation deviates by a fair amount from this right angle relationship. (There is/was an excellent graphic of this on Operation Doubles, but that site does not appear to be up right now. Hopefully, a temporary situation).

The 3rd type of spin would be referred to as Roll in flight dynamics. This would be the same type of spin imparted to a football (American football), known as a spiral spin. This spin, about the longitudinal axis, is also the rotation seen with bullets (due to the rifling of the barrel) and some arrows. The longitudinal axis is in the same direction of the (normal) flight of a projectile (ball) or aircraft. The other types of spins (topspin, underspin, sidespin) are perpendicular to the normal direction of ball flight.

I believe that that there may very well be some amount of spiral (helix) spin imparted to a tennis ball on some type of strokes. We don't speak much of this type of spin in tennis probably because it is not as obvious or as easy to see as topspin, underspin (backspin), and sidespin. There may be some spiral spinning when we hit certain combination spins -- like when hitting on the "outside" or the "inside" of the ball when imparting topspin or backspin.

Perhaps there is a significant longitudinal (spiral) spin on Twist serves. This spiral spin component may be responsible for the axis of rotation being offset from the right angle relationship seen on other types of spins and combination spins. It may be the very thing that gives the Twist serve that "twist".

4. ### SystemicAnomalyG.O.A.T.

Joined:
Feb 25, 2006
Messages:
15,478
Location:
Stuck in the Matrix somewhere in Santa Clara CA
^ en.wikipedia.org/wiki/Tait-Bryan_angles#Definition ^

In one sense, topspin & backspin are 2 flavors of the same type of spin as you state. They are both rotations about the transverse axis (left/right orientation & perpendicular to the ball flight).

However, they are different spins in so far as they act very differently on the trajectory of the ball and its court interaction - the bounce. These differences are due to gravity acting on the ball and fluid dynamics of the air surrounding the ball. The high & low pressure systems around the ball are opposite for these two flavors of spins. For a ball with topspin, it see a higher air pressure at the top part of the ball than at the lower part. For underspin, the situation is reversed. This cause the ball to fly differently for topspin and backspin.

wings.avkids.com/Tennis/Project/windr-06.html

The 2 different flavors of transverse spin also causes the ball to interact or grab the court in a different manner. The amount of spin relative to its linear speed and the angle of incidence will also affect the manner in which the ball bounces. A heavy topspin (relative to speed) will tend to have a higher trajectory & kick up more than a ball with less topspin relative to its speed. An high trajectory underspin ball (colliding with the court at greater than 45 degrees), will tend to sit up and not advance forward as much after the bounce and other balls. A low trajectory backspin ball will tend to skid on the court and stay low (before and) after the bounce.

5. ### fuzz nationG.O.A.T.

Joined:
Oct 20, 2006
Messages:
10,060
Whoa... S-A, you're makin' my head hurt dude!

Actually I routinely enjoy/appreciate your in-depth info and explanations.

As for Gogg's inquiry, my pals and I often refer to that funky under/side spin as snakeoil!

6. ### SystemicAnomalyG.O.A.T.

Joined:
Feb 25, 2006
Messages:
15,478
Location:
Stuck in the Matrix somewhere in Santa Clara CA
Yeah, if I hadn't written it, it would probably make my head hurt, too.

For those still playing along... Pitch would be the flight dynamics analogue of topspin & backspin; Yaw is the flight equivalent of sidespin (both left & right flavors).

7. ### GoggNew User

Joined:
Oct 20, 2008
Messages:
82
Thanks for the info! As for this "sidespin slice" is this refering to the slice groundstroke?

8. ### oldhackerSemi-Pro

Joined:
Feb 8, 2007
Messages:
414
To get the ball to bounce sideways rather than forward you need to hit it with little pace but lots of spin on an axis which is perpendicular to the baseline and parallel with the court surface. The only time I do it is when I am at full stretch to reach a low short ball (usually the result of a mis-hit or net cord by my opponent) and the only way I can get it back is to swing sideways across and underneath the ball.

9. ### LuckyRLegend

Joined:
Jun 2, 2006
Messages:
6,402
Location:
The Great NW
There are essentially 2 axes of spin since the third axis (spinning like a spiral thrown football) is not used in tennis.

10. ### GPBProfessional

Joined:
Mar 24, 2008
Messages:
1,186
Location:
Jacksonville, FL
Meh, I submit that twist serves have some of this third axis of rotation.

Joined:
Oct 16, 2008
Messages:
112
i would like to know whats a backspin a twist spin and a side spin..if anyone has videos

12. ### LuckyRLegend

Joined:
Jun 2, 2006
Messages:
6,402
Location:
The Great NW
Mathematically you are correct. Any shot that is not 100% flat or 100% of one of the two common spin axes technically has a smidge of the third axis spin. But it is essentially negligible.

13. ### SystemicAnomalyG.O.A.T.

Joined:
Feb 25, 2006
Messages:
15,478
Location:
Stuck in the Matrix somewhere in Santa Clara CA
How would you account for the relationship of the spin axis to the flight direction for a twist serve? If you accept the notion that the spin axis is not perpendicular to the flight of the ball for this serve, then there must be somewhat more than a negligible amount of longitudinal (3rd axis) spin. Granted, it is not very much, but it seems that it could be significant in some cases (such as the twist serve and perhaps some other radical spin situations).

14. ### SystemicAnomalyG.O.A.T.

Joined:
Feb 25, 2006
Messages:
15,478
Location:
Stuck in the Matrix somewhere in Santa Clara CA
Something of interest for a few of you out there:

The rotation for a badminton shuttle is the 3rd axis (longitudinal) spin that we've been talking about. The normal direction of that spin is dictated by the nature of its construction -- for non-synthetic shuttles, the feather are overlapped in a fashion to produce this stabilizing spin; synthetic shuttles are constructed to imitate the natural spin of a feather shuttle.

When hitting a net (hairpin) drop, the shuttle can be made to tumble end-over-end by imparting a backspin action to the cork, much as one would do for a dropshot or drop-volley in tennis.

A badminton shuttle can also be sliced much as one would do for a slice serve in tennis. However, instead of producing the sidespin seen with a tennis ball, the shuttle experiences additional spiral rotation -- it can be made to spin much faster than its natural spin or it can even be made to spin in the opposite direction than the natural spin of the shuttle.

15. ### winksRookie

Joined:
Apr 7, 2004
Messages:
279
My thinking...

If you take the assumption that the racquet/ball contact point is essentially at the back of the ball (point opposite the direction the ball is traveling) I don't see how any significant spin or than variations of topspin/slice (i.e spins on a "perpendicular axis") could be applied. The only obvious exception I see to this would be certain volleying situations, where contact is made under the ball.

I've always been confused about the "twist" serve. I think the term gets thrown around a lot and can mean different things to different people, much like "kick" serve. I do remember reading somewhere that it was much like a extreme slice serve, with so much spin that it somehow caused it to move after in the opposite direction of the after the bounce. If this definition is correct, the spin axis is still perpendicular to flight. I have never faced a twist serve playing myself, nor do I ever remember witnessing one in a televised pro match.

Last edited: Oct 24, 2008
16. ### LuckyRLegend

Joined:
Jun 2, 2006
Messages:
6,402
Location:
The Great NW
The vast majority of the twist serve spin is more or less evenly distributed between the 2 major axes. Yes, it is true there is a tiny amount of spin, in reality, in the third axis, however a twist serve can be produced with absolutely zero rotation about the third axis.

17. ### S H O W S T O P P E R !Hall of Fame

Joined:
Aug 17, 2008
Messages:
1,937
Location:
In your thredz, stealin ur bukkits
Slice and sidespin combine to make what is known as the dropshot.

18. ### LuckyRLegend

Joined:
Jun 2, 2006
Messages:
6,402
Location:
The Great NW
Your second paragraph is a perfect description of the third axis and rightly attrubutes this spin to the irregular shape of the bird (in comparison to the almost spherical tennis ball). This third axis spin is completely indifferent to the racquet's work in striking the bird.

19. ### SystemicAnomalyG.O.A.T.

Joined:
Feb 25, 2006
Messages:
15,478
Location:
Stuck in the Matrix somewhere in Santa Clara CA
Not really (if I understand what you are saying. If the shuttle is hit flat, w/o a slicing or cutting motion, the shuttle will assume its natural rotation about the longitudinal axis. However, it the shuttle is struck with a side brushing motion the spin speed or even the direction of the rotation of the shuttle is significantly altered.

For a tennis twist serve -- still wondering how you would account for the axis of rotation not being at right angle to the flight direction as it is for typical spins on a tennis ball.

BTW, when I refer to a Twist serve, I am not talking about the more common topspin kick (which bounces up for the most part rather than kicking to the opposite direction of the original trajectory).
.

Last edited: Oct 24, 2008
20. ### AlphaCDjkrRookie

Joined:
Sep 29, 2008
Messages:
310
Location:
West Covina, CA
What? There are plenty of cases where you can contact the ball at any place, not just the back. If you decide to hit underneath the ball (The motion is as though you were 'catching' it.)

There are sidespin slice groundstrokes, volleys, and almost ANYTHING that jolt sideways upon bounce. I think.. that you might not have ever tried hitting underneath the ball.

Absolutely not, more slice just means more skid and more curve. Maybe if you make a ball spin in the manner you're speaking of but drop it straight down, it would indeed twist. However, as you impart this spin in a serve, the sideways velocity of the ball due to the slice would be too strong for the sidespin to twist the ball. There is not enough 'bite' into the court for an extreme sidespin serve to twist.

Research a bit more, that longitudinal spin is indeed possible and is used. I personally use it myself.

21. ### AlphaCDjkrRookie

Joined:
Sep 29, 2008
Messages:
310
Location:
West Covina, CA
Well yes and no. It really just depends if you put a sidespin on the slice; otherwise, a traditional slice groundstroke involves backspin and very little, if any, sidespin.

Actually not really. You're right in a sense. Since a twist is merely a 7-1 swing impacting the left side of the ball, there is only spin on the 2 major axes. Topspin, and sidespin. However, since you're essentially hitting the twist at an incorrect axis of rotation (Though impact is at left of ball, the directional impact is still straight), if you realign your perspective to the twisted axis, you'll see that a twist involves all 3 axes. There is topspin, some sidespin, and underhanded sidespin.

Topspin= Main component of the twist
Sidespin= Any curve generated in midair
Longitudinal Sidespin = The cause of the twist effect on bounce.

22. ### SystemicAnomalyG.O.A.T.

Joined:
Feb 25, 2006
Messages:
15,478
Location:
Stuck in the Matrix somewhere in Santa Clara CA
^ Good posts Alpha.

winks, while many topspin groundstrokes are hit directly on the back of the ball, not all shots in tennis are hit at that point. In other recent threads, I have spoken about hitting slightly to the "outside" or the "inside" of the ball on topspin shots to add a little bit of curve to the trajectory -- due to some sidespin and, possibly, a little bit of spiral (3rd axis) spin. Underspin shots can also be hit in such a manner as seen in the pictures below from a Tennis mag article:

Altho' I don't use them in serious play very often, I can hit some very exaggerated (sideways) undercut balls that have a huge amount of spiral (3rd axis) spin as well underspin. These balls will have a fair amount of bend in the trajectory and will bounce off more to the side than forward. Can drive an opponent crazy sometimes as they are trying to figure out which way the ball will bounce.

That definition is not correct. I view the Twist as a specific type of kick serve, not a variation of a slice serve. However, it can be regarded as an extreme variation of a topspin-slice serve, with a heavy topspin component. I have seen a number of reliable sources that indicate the the spin for a twist serve, unlike other serves, is not in the same direction as the flight path of the ball. This is another way of saying that the spin axis is not perpendicular to the ball's flight path. Check this description here:

American Twist/Twist serve

I believe that the reference used for the link above is Operation Doubles. On that web site, Kathy Krajco provided an excellent graphic and explanation of this relationship of the spin to the flight path for the Twist & other serves. (Unfortunately, altho' Kathy's tennis blog pages are still up, the Operation Doubles pages have been down for a few days now. Sadly, Kathy passed away earlier this year. Don't know if the OD site will return). I also believe that Dave Smith (CoachingMastery) of TennisOne.com and Tennis Mastery has spoken of the spin axis of the twist serve.
.

Last edited: Oct 25, 2008
23. ### AlphaCDjkrRookie

Joined:
Sep 29, 2008
Messages:
310
Location:
West Covina, CA
Yeah, they are really good shots when used sparingly. However, I've thrown them at my friends so much that they've learned how to read the spin instantly from my body language and racquet motion; though I still have certain idiotic friends who never adjust to it ;-)

Yeah, it's been depressing without that website. I used to read it for a lot of the strategic tips, and now it's not even there =(. It feels like it won't come back though, because at first it was only a few pages of the site that were down; as though the bandwidth was being eaten up and only a few pages could be shown. Now, they're all blocked. It feels like nobody is taking care of the page, so it's dying off :cry:

24. ### GoggNew User

Joined:
Oct 20, 2008
Messages:
82
While you debate about the twist serve, I would like to ask a question. Is it possible to hit a serve with sidespin slice?

25. ### AlphaCDjkrRookie

Joined:
Sep 29, 2008
Messages:
310
Location:
West Covina, CA
Which kind of sidespin?

A regular sidespin slice is just that; A slice serve, where the motion of the racquet brushes across the ball in a (mostly) 9 o clock to 3 o clock fashion (for a righty, for a lefty its 3-9).
---
If you're talking about that longitudinal sidespin, the one that causes the ball to jump left/right upon bounce, then.. yes but not really. It is theoretically possible to have a serve that's 100% topspin, 100% backspin, 100% sidespin, but not for a longitudinal sidespin. That is because, for a topspin/backspin/sidespin shot, you have the option of hitting right at the back of the ball, which allows you to hit forward. However, when you want to impose a longitudinal spin, the contact point of the ball may never be the back. It will be at the bottom, left, top, or right. Basically, these are the spots that will not allow the ball to have any forward momentum at all. Whenever you apply longitudinal spin, you must also add a forward momentum in order to even make the ball go forward; this implies that you will ALWAYS be forced to add another type of spin (topspin, backspin, sidespin) to allow the contact point to come closer to the back of the ball.

Basically yes, you can hit a serve with this type of sidespin, but it will not be perfect, as it will contain another spin as well. Also, it would be difficult for the longitudal spin to be the majority of the spin; Twist serves are usually composed of all 3 types of spin, but the longitudinal spin is often one of the smaller components. Whenever you find someone doing the twist serve with a huge break, that means the main component of the serve was the longitudinal spin.

Umm.. Does this make sense to you? :???:

26. ### SystemicAnomalyG.O.A.T.

Joined:
Feb 25, 2006
Messages:
15,478
Location:
Stuck in the Matrix somewhere in Santa Clara CA
I called the customer service number,703-986-3116, that is listed when you attempt access the Operation Doubles website. They informed me that it was suspended because there is an overdue balance (over \$300) on the account. Perhaps Tennis Warehouse or some other benefactor can pay this and take over running the website.
.

Last edited: Oct 26, 2008
27. ### AlphaCDjkrRookie

Joined:
Sep 29, 2008
Messages:
310
Location:
West Covina, CA
Ah, so that's it. Would Tennis Warehouse (or anywhere) take it though? That was an excellent site, so much work was put into it

28. ### GoggNew User

Joined:
Oct 20, 2008
Messages:
82
Yes it does make sense, but if you were to hit a serve using backspin or sidespin with sidespin slice, wouldn't that create a "dropshot" type serve? In other words, a very powerful weapon?

29. ### AlphaCDjkrRookie

Joined:
Sep 29, 2008
Messages:
310
Location:
West Covina, CA
Essentially yeah. It would create a dropshot-esque serve. However, the fact that it is a serve, where the receiver is ready for almost anything, will give the receiver plenty of time to retrieve that kind of serve. Especially since, to make it a dropshot-like serve, you'd have to hit it with plenty of backspin and a rather slow pace; those two combined would result in a very floaty,slow shot; that's just too much time.

It could be useful against inexperienced players or.. something.

30. ### GoggNew User

Joined:
Oct 20, 2008
Messages:
82
I think it would be good in combination with other serves. For topspin, if you hit more spin into it rather than power, the ball moves slowly as well and kicks up too. If you used these two in combination, you'd be able to trick your opponent.

31. ### AlphaCDjkrRookie

Joined:
Sep 29, 2008
Messages:
310
Location:
West Covina, CA
Well, there are alot of serves intended to trick the opponent. Twist serve, R. Twist serve, Underhanded sidespin, underhand backspin, blahblah.

For a topspin serve, If you put too much spin and not enough power, unless you aim high enough, the ball will dive into the net ;-)