Mystery of kick serve swing path

AnyPUG

Rookie
Is there an easy to understand explanation on how the ball goes forward towards the net when the swing path is almost parallel to the baseline? You would think the ball should fly towards the side fence instead of the net.
Is it just the racket face angle at contact or anything more significant to it?
 

Shroud

G.O.A.T.
Is there an easy to understand explanation on how the ball goes forward towards the net when the swing path is almost parallel to the baseline? You would think the ball should fly towards the side fence instead of the net.
Is it just the racket face angle at contact or anything more significant to it?
Ball is tossed in to the court so there is a forward component and yes racquet face angle. Try dropping a ball for your fh and hit it in the air with a completely vertical swingpath. Where does the ball go if you hit the strings? Straight up or forward and up?
 

user92626

G.O.A.T.
Is there an easy to understand explanation on how the ball goes forward towards the net when the swing path is almost parallel to the baseline? You would think the ball should fly towards the side fence instead of the net.
Is it just the racket face angle at contact or anything more significant to it?
Is it really almost parallel to the baseline or it is kinda like 45 degree cut into the court? Think about that.
 

Injured Again

Hall of Fame
Is it really almost parallel to the baseline or it is kinda like 45 degree cut into the court? Think about that.
When I hit a kick serve, the main thing in my mind is to not rotate my shoulders, so that when I actually make contact with the ball, my body is still side on to the direction I'm hitting the ball. The racquet's path is just a small bit into the court, maybe a 15 degree angle in relation to the baseline, but it feels like that the forearm pronation creates a bit of additional racquet motion into the court that generates the forward ball speed.
 

sureshs

Bionic Poster
If you a rightie, and you contact the ball on the right on the equator as you look up, it has to move forward into the court. Why? Because a purely tangential contact which in theory occurs at a single point on the ball is not practically possible. Any other kind of contact on the right side on the equator of the ball will have a forward and sideways component of force. And as pointed out above, the swing is actually also not quite parallel to the baseline. Both factors mean that the ball will go more forward than sideways to the fence.
 

AnyPUG

Rookie
Ball is tossed in to the court so there is a forward component and yes racquet face angle. Try dropping a ball for your fh and hit it in the air with a completely vertical swingpath. Where does the ball go if you hit the strings? Straight up or forward and up?
If I try to hit completely vertical and avoid all forward motion, I frame everytime and the ball goes in random direction.
 

user92626

G.O.A.T.
If I try to hit completely vertical and avoid all forward motion, I frame everytime and the ball goes in random direction.
Even if your arm swing up "completely vertical", the forearm pronates if you do it correctly and should give some forward component. From there, you can play with grips and adjust the racket face to give you the desired ball direction.
 

Chas Tennis

G.O.A.T.
Is there an easy to understand explanation on how the ball goes forward towards the net when the swing path is almost parallel to the baseline? You would think the ball should fly towards the side fence instead of the net.
Is it just the racket face angle at contact or anything more significant to it?
The meanings of word descriptions of tennis strokes are the subject of many threads, 50%? You can search back to the beginning of TT and see very similar threads as many posters have various undefined tennis terms to use in very similar threads.

See the thread Junior Twist Serve. The OP's serve is compared to Stosur's in a clear high speed video. They were very close in racket path.

"Swing path is almost parallel to the baseline" is a misleading simplification for what you see in the videos and the Frank Salazar kick serve taken with an overhead camera view. See Toly's composite picture of Salazar's kick serve for the hand or racket path of a kick serve and its angle to the baseline. Unfortunately, those overhead camera views are hard to find.

The racket face is tilted at about 14 degrees closed just before impact for the kick serve - much more than for the flat and slice serves.

Many posters remember tennis terms that are show-stoppers when it comes to describing and understanding the 3D complex service motion.

I can't remember what servers do in spatial detail, but I can view a video and see what they do in a few minutes.

The above discussion is limited to before impact because it is easier to describe than after first touch.
 
Last edited:
Is there an easy to understand explanation on how the ball goes forward towards the net when the swing path is almost parallel to the baseline? You would think the ball should fly towards the side fence instead of the net.
Is it just the racket face angle at contact or anything more significant to it?
Because the force applied is tangential, not towards the target as with a flat serve.

Think of spinning a basketball on your finger. After the initial spin energy has dissipated, you have to keep feeding more energy into the ball in order to keep it spinning. If you hit it straight on, you will knock the ball off your finger. The only way to apply force and keep it on your finger is tangentially.

I would suggest that, way more important than understanding it, is actually being able to do it. Yes, understanding it is nice. But if it's interfering with your ability to execute, I'd throw understanding out the window for now and concentrate on execution.
 

Chas Tennis

G.O.A.T.
Because the force applied is tangential, not towards the target as with a flat serve.

Think of spinning a basketball on your finger. After the initial spin energy has dissipated, you have to keep feeding more energy into the ball in order to keep it spinning. If you hit it straight on, you will knock the ball off your finger. The only way to apply force and keep it on your finger is tangentially.

I would suggest that, way more important than understanding it, is actually being able to do it. Yes, understanding it is nice. But if it's interfering with your ability to execute, I'd throw understanding out the window for now and concentrate on execution.
What is to be executed?

I have mentioned the 13-15 degrees closed racket many times and there have been few comments from forum readers. I have not seen it discussed in other places except in Technical Tennis indirectly. Do you think the OP's beliefs about how closed the racket face is at first impact are true or false? How else can he "execute"? Use trial and error with no video observations for guidance? Why not see the video evidence?
 
What is to be executed?

I have mentioned the 13-15 degrees closed racket many times and there have been few comments from forum readers. I have not seen it discussed in other places except in Technical Tennis indirectly. Do you think the OP's beliefs about how closed the racket face is at first impact are true or false? How else can he "execute"? Use trial and error with no video observations for guidance? Why not see the video evidence?
Actually, I didn't read your post before responding to the OP. You went into it in much greater detail. I simply tried to explain how the swing path leads to tangential force and how that leads to the serve going in a different direction.

As far as his beliefs, I see 2 [one a hypothetical]:

"You would think the ball should fly towards the side fence instead of the net."

This is obviously false because the ball does not go towards the side fence. But I think he's just making a hypothetical.

"Is it just the racket face angle at contact or anything more significant to it?"

It can't just be the racquet face angle because if I used that angle but had a swing path towards my opponent, the ball would travel a different arc.

So it must be a combination of swing path and racquet face angle. How much of either I can't say. My knowledge of the serve does not extend that far. I do know at least how to correlate my results with my actions but I wouldn't know, for example, to change my angle by 2 degrees more open and I'll get 14% more RPMs.
 

AnyPUG

Rookie
Because the force applied is tangential, not towards the target as with a flat serve.

Think of spinning a basketball on your finger. After the initial spin energy has dissipated, you have to keep feeding more energy into the ball in order to keep it spinning. If you hit it straight on, you will knock the ball off your finger. The only way to apply force and keep it on your finger is tangentially.

I would suggest that, way more important than understanding it, is actually being able to do it. Yes, understanding it is nice. But if it's interfering with your ability to execute, I'd throw understanding out the window for now and concentrate on execution.
Not sure if I understood how to finger a basketball, but it's okay.

Why do you think being able to execute is way more important than actually understanding it? quite a few "what ifs" to consider.
too many assumptions here my friend?
 
Last edited:
Not sure if I understood how to finger a basketball, but it's okay.
Probably tongue-in-cheek but on the off-chance it wasn't:


Notice the direction their hand is moving relative to the ball: tangentially. Why is the ball not falling off of their finger? Because of the tangential force direction.

Same reason why the kick serve doesn't travel into the side fence.

Why do you think being able to execute is way more important than actually understanding it?
Because someone can tie themselves in knots trying to understand something when it would be a lot easier working on execution.

Can you hit topspin? Can you explain what topspin is and why the ball does what it does? Do you need the latter to do the former?

quite a few "what ifs" to consider.
too many assumptions here my friend?
If they don't apply to you, don't consider them.
 

Kevo

Legend
Is there an easy to understand explanation on how the ball goes forward towards the net when the swing path is almost parallel to the baseline? You would think the ball should fly towards the side fence instead of the net.
Is it just the racket face angle at contact or anything more significant to it?
The basic principal is the ball travels in the direction perpendicular to the strings at contact and it spins in the direction the strings were traveling at contact. You can pretty much develop any stroke by deploying those two principles conceptually to create a reasonable swing path and then training up the swing to make it actually function at speed during play.

I think this is where S&V-not_dead_yet's focus on execution is absolutely correct. We are well built for learning physical skills just by simple feedback loops. You can have a very bad mental model for a skill you possess but still be excellent at that skill. I find all the time when teaching people that many people have a very loose mind to body mapping and often think they are doing one thing when they are doing something very different. They can all still learn the techniques though. It might just take a little longer for some than others.
 

Chas Tennis

G.O.A.T.
The basic principal is the ball travels in the direction perpendicular to the strings at contact .........................
Rackets might be rotating at about 2500 degrees per second at first contact. That's in the side-to-side or azimuthal direction. That's 2.5 degrees per millisecond.

Since contact lasts about 4 milliseconds, the racket would rotate 10 degrees if it did not impact the ball, the strings and ball distort significantly, other variables, ................it's too complicated.......

Maybe there are publications on racket face angle at first contact vs serve direction. Please post.
 

Kevo

Legend
Since contact lasts about 4 milliseconds, the racket would rotate 10 degrees if it did not impact the ball, the strings and ball distort significantly, other variables, ................it's too complicated.......
Exactly. That's why you start slow with the basic principles. You can teach anyone who is reasonably coordinated and listens well to hit a kick serve in 30 minutes. It will be a slow loopy kick serve, but it will be a good base to start with. From there it's just lots of practice building speed and making adjustments to keep things moving in the right direction. Eventually, with enough training, you just decide what you want to hit and hit it. You don't think about how to hit it exactly, because you can't. Things happen too fast.

That doesn't mean the basics have to be complicated. The basics usually aren't. What happens at speed in the real world is different. Our brains aren't equipped to process that consciously, but they are equipped to learn it and execute it automatically.
 

big ted

Hall of Fame
i think the online tennis coach peter freeman relates the swing to a sideways tomahawk type stroke
which can be helpful
 

Chas Tennis

G.O.A.T.
Exactly. That's why you start slow with the basic principles. You can teach anyone who is reasonably coordinated and listens well to hit a kick serve in 30 minutes. It will be a slow loopy kick serve, but it will be a good base to start with. From there it's just lots of practice building speed and making adjustments to keep things moving in the right direction. Eventually, with enough training, you just decide what you want to hit and hit it. You don't think about how to hit it exactly, because you can't. Things happen too fast.

That doesn't mean the basics have to be complicated. The basics usually aren't. What happens at speed in the real world is different. Our brains aren't equipped to process that consciously, but they are equipped to learn it and execute it automatically.
I like specifics.

Comparing high speed videos provides useful feedback on what a server is doing for the kick serve. The ATP servers provide a high performance reference standard for comparison. You then have one technique that works for sure with clarity.

For the first few years of studying the serve, I could not understand the racket motion for the kick serve and looked for videos that would show the racket motion on the ball. Thousands of finds but no clear videos............ I could not find any. I learned the signature of the kick serve from studying high speed videos and taking a few of my own. I recommend that everyone else do the same to add to other thoughts that they may have about the kick serve.

If you find clear videos of the kick serve, please post so that they will become more widely known. Especially needed is the racket on the ball.
 
Last edited:

Jake Speeed

Rookie
I like specifics.

Comparing high speed videos provides useful feedback on what a server is doing for the kick serve. The ATP servers provide a high performance reference standard for comparison. You then have one technique that works for sure with clarity.

For the first few years of studying the serve, I could not understand the racket motion for the kick serve and looked for videos that would show the racket motion on the ball. Thousands of finds but no clear videos............ I could not find any. I learned the signature of the kick serve from studying high speed videos and taking a few of my own. I recommend that everyone else do the same to add to other thoughts that they may have about the kick serve.

If you find clear videos of the kick serve, please post so that they will become more widely known. Especially needed is the racket on the ball.
I first discovered the "kicker" by looking at an instructional tennis book by Pancho Gongales. I believe the book was published in the early 60's. My guess, this was probably 1969 or 1970? Interesting book with great photos AND this book can still work today.

Sure some of the strokes are a bit different, but the learning stages start with the basics. Basics are so important and they are generally skipped over in the teaching process of today. Only with solid basic strokes, using proper technique, can you then eventually progress into more complicated stroke production.

I don't see a good service motion, racket/ball placement or a technique which will deliver or render properly, the high bounce kicker?

But I didn't view all these videos.

Only on the receiving end can you really tell how well someone is hitting the kicker.

Anyone remember Poncho Gongales?
 

TennisCJC

Legend
The swing path isn't parallel to the baseline for a 2nd serve. Sometimes it feels parallel but in reality it isn't. The 2nd serve swing path is more up and to the side than a first serve. See about 1:45 and you'll see the swing up and through contact in the video below. Federer's 1st serve on the left and his 2nd serve on the right. Chest is slightly more closed and swing path is slightly more to right for 2nd serve. Notice his 1st serve swing path also moves to the right of the intended line of flight for spin and his 2nd serve move up and more to the right for more spin and a more topspin angle on the spin. Also look at the angle front the hitting hand to contact. On the 1st serve, the racket head is to the left of the hand but on the 2nd serve, it is more severely to the left. The steeper angle on the 2nd serve allows the racket head to move up more than on the first serve.


 
Last edited:

Jake Speeed

Rookie
From my vantage point,

That second serve is a "slice" and not the kicker.

Or, his attempt is a poor kicker,

I must add this. Or I'll be in a lot of trouble instead of a little trouble. :)
 
Top