When you analyze tennis serve technique in slow motion from the top view and compare the flat, slice and topspin serve techniques, a new perspective emerges.
I've recorded myself serving all types of serves using a drone and then analyzed them in slow motion pointing out the key technical elements of the serve that are the most obvious from the top down view.
I have also made top down view videos for other tennis strokes, feel free to check out videos on one-handed backhands and forehands.
1. Flat Serve Technique Analysis
While a complete flat tennis serve has many technical elements, we'll focus just on the 4 keys of the flat serve technique that are the most interesting to observe:
- body rotation (in preparation and into the ball)
- weight transfer (most players get this wrong)
- loop behind the back (which is where we accelerate the racket)
- pronation (and showing that there is no wrist snap)
a) Body Rotation
Most recreational tennis players learn to serve with the simple "pancake / waiter's tray" technique where the body does not rotate at all.
All the power that comes into such a serve comes from the arm pushing forward in a straight line.
Most tennis players learn to serve like this without any body rotation.
And even when players start working on a more advanced tennis serve technique they will still tend not to rotate enough into the serve because of the old habits.
So what we can observe really well in the top down view of the flat serve is how much coiling / body rotation is there in the preparation.
I turned 110 degrees away from the direction I will be hitting at.
While in the ready position to execute the serve, I was facing forward. However as I toss the ball up, I bring up my racket to load up the swing for the serve.
While doing this, I coiled my upper body by turning more than 90° away from the target, about 110° of rotation actually.
Note how much rotation / uncoiling has happened from my initial coiled position in the first picture.
All that stored energy can then be released into the ball and that is what generates a lot of power of the serve.
b) Weight Transfer
The reason why I would like to point out the weight transfer on the serve is because players tend to execute it incorrectly.
Leaning too much back and not "seeing" the right weight transfer is a common problem.
A tennis serve seems to have just a back and a forward motion but that is just an illusion and it tends to deceive the player into a wrong mental image.
The right way to transfer weight when serving is to go from FRONT to BACK to FRONT foot again.
The weight is mostly on the front at the start of the serve.
At the beginning, notice that my weight is on my front foot. As I started the motion to serve, I slowly transferred the weight back.
The weight shifts to the back foot as I initiate the backswing and the toss...
However, once I tossed the ball up into the air, I started to shift my weight forward again - this is despite me leaning slightly towards the back.
... the weight starts to shift back to the front foot again well before the uncoiling begins.
If you observe closely, you can notice the knee bending while in the ‘trophy’ position. That is when I started to shift my body weight to the front foot at the same time.
c) Loop Behind The Back
As I mentioned in the body rotation, most players start hitting their serves with the simple "pancake" serve where the arm and the racket just move in a linear fashion back and forward.
That of course does not create any loop behind the back and again this old habit may trouble you even though you are working on a more advanced serve.
That's why it's important to really see how much the racket loops around in a semi-circle as the arm & racket follow the body rotation.
Start of the loop...
... end of the serve loop.
The racket will of course continue to move from the "end of the loop" stage but it will now move in a linear way towards the ball as the body will now slow down the rotation.
What is also interesting to observe using the timer is that the forearm pronates in 6-7 hundredths of a second (yes, 0.066 seconds!) from the racket aligned with the edge to the ball to the racket facing the ball and hitting it flat.
It takes just 6-7 hundredths of a second for a racket to go from edge to flat alignment on the ball.
We obviously cannot consciously control our body parts in such a small amount of time therefore we need to develop the skill of pronation through drills.
d) No Wrist Snap
One last thing to bring up here is that after the serve, observe that I did not perform any wrist snap. As I complete my follow through, my wrist is completely aligned with my forearm.
There is no wrist snap on the serve, the wrist is in fact very firm through contact.
Many players assume that a wrist snap usually follows up in a serve, as they see that the racket seems to be at an angle from the arm and because amateur tennis coaches keep saying so.
I have dispelled the myth of the wrist snap previously; just follow the link.
2. Flat vs Slice Serve Comparison
For slice and topspin serve, the motion is largely the same, with some changes on the swing and ball toss.
Ball Toss: In a flat serve, the ball was tossed closer to my head, while for the slice serve, further to the right of my head. Tossing more to the right for a slice serve makes it easier to hit the ball slightly on the side to impart sidespin.
Note the differences in the contact point and the racket angle.
Contact: Another thing to notice is the way the racket face contacts with the tennis ball. For a flat serve, the racket face contacts the ball on a straight face. For a slice serve however, the racket face has a bit of an angle which is what creates a sidespin.
Even though I am hitting a slice serve more to the left, I swing more to the right initially.
Swing Path: For a regular flat serve, my swing path is closer towards my head. For a slice serve however, the path is further away. This may not seem logical at first since I am serving out wide to the deuce side but that's how an advanced serve with pronation works.
3. Flat vs Topspin Serve
The changes between a flat and topspin serve are bigger than between flat and a slice serve, let's observe...
Body Orientation: You may notice that I angle my body more towards the court sidelines when serving the topspin serve, while keeping a straighter line (with a bit of angle) for flat serve.
There is more coiling for the topspin serve as the swing path will be more to the side.
The reason here is because when performing a topspin serve, I will swing with a bit more angle than a flat serve. To do this, I use my body orientation to create more contact angle.
Contact: I also contacted the racket with the ball at a different point, in both serves. For the flat serve, my racket contacts the ball almost right on the top of my head, whereas for a topspin serve the contact is behind my head.
Note the differences in the contact between the flat and the topspin serve.
Swing Path: The flat serve swing path is more forward, closer to the direction of the ball flight whereas the swing path of a topspin serve is more to the side.
This concludes the top view analysis of the tennis serve technique and the main comparisons with the slice and topspin serves.
My question to you now is: what else would you like to see in relation to the serve technique when it comes using the drone and the top view perspective? Let me know in the comments below!
As usual brilliant analysis.