Coco Gauff Second Serve:
A Technical Analysis
Sean O’Neil
There's been a lot of interest in Coco Gauf since she exploded on to the tennis scene as a young teenager, and in her ascent to the top levels of the game, culminating in her 2023 U.S. Open victory.
Her game is built around power and she uses it well on both serves and groundstrokes. But, even though she's able to hit with impressive power, her serve has come under scrutiny, particularly her 2nd serve.
After analyzing her 2nd serve motion using high speed slow motion video, I've discovered some very interesting aspects of her technique. It's amazing how little the human eye sees versus the reality of super slow motion video motion.
So I will focus my attention on multiple aspects of her motion and also compare her technique with two of the great servers in the game: Milos Raonic and Jannick Sinner. On balance when we look at her technical motion it's amazing she serves as well as she does.
Toss
Notice how Coco has released the ball and her legs have barely begun to bend. This disconnect between her upper and lower body plays havoc with her rhythm and the synchronization of the kinetic chain.
The teaching cue has always been: the legs go down as the arm goes up. As you can see with Sinner and Raonic, their legs are bending to load for the ground reaction forces as their arms are tossing the ball. Not a good start to Coco's service motion.
Back Bend
Notice how soon and how much Coco bends her back compared to Milos and Jannik. Big difference. This, over time, will put lots of stress on her lower back and possibly lead to injury. Ideally, the back should be as straight as possible for as long as possible.
Notice how much straighter Sinner and Raonic's backs are--big difference. Ideally, you should bend your knees keeping your back relatively straight.
Racquet Drop
Next the racket drop. Look at Coco's racquet head on the entrance into the backswing. The tip of the racquet goes past her left shoulder. This much of a forward entry severely limits her ability to externally rotate her shoulder (ESR). At the full drop, the racket often isn't even on edge with her right side. Instead the face of the strings are actually flat and pointing at her back.
Compare that that the Milos and Jannik. Their rackets are on edge to the body, with the arm externally rotated even further so the tip of the racket actually tilts slightly to the players' right.
Upward Swing and Followthrough
The goal on both 1st & 2nd serves is to achieve maximum internal shoulder rotation. The racquet travels up on "edge" and rotates 90 degrees to contact, then rotates an additional 90 degrees to finish on the opposite "edge" in the followthrough. This means a full 180-degree rotation of the arm, hand, and racquet as a unit from the shoulder joint. (For more on ISR, Click Here.)
Notice the lack of internal shoulder rotation Coco has after contact. Her strings are parallel to the ground after contact and not on "edge". She achieves only 90 degrees of ISR, half what it could be.
Compare Coco's motion to Jannick and Milos. It's is amazing how quickly after contact the "long axis rotation" of these two players reaches a full 180 degrees of ISR. The amount of racquet head speed they achieve is incredible.
It's very reminiscent of Pete Sampras and Andy Roddick's ISR.
Contact Point
At contact look at Coco's head. H collapsed and her head is pointing down to the ground. Compare this to Sinner and Raonic with the head looking up at the contact point.
Coco's pull down of her head is very similar to what Venus Williams used to do. Besides limiting racquet head speed and her ability to create an upward swing trajectory, the pulling down puts more stress on her shoulder and abdomen. Venus was constantly having to deal with abdominal issues.
A second point. At contact the hand should be tilted inwards at contact to allow for proper internal rotation of the shoulder (ISR). If the arm, wrist and hand are in-line and pointing straight up like Coco, you further limit ISR and put stress on the shoulder. Look at the shoulder problems that Kei Nishikori has had to deal with over his career. John Yandell has pointed out this problem with Kei's serve. (Click Here.)
Because of all these unnecessary movements that Coco has developed in her swing, she's been having a difficult time maintaining a dependable, repeatable swing under pressure.
Notice the amount of internal shoulder rotation Coco has achieved after contact. Her strings are pointing towards the ground after contact and not on "edge". She'll achieves only 90 degrees of ISR, half what it could be.
Compare Coco's motion to Milos Raonic's serve. It's is amazing how quickly after contact his "long axis rotation" reaches a full 180 degrees of ISR. The amount of racquet head speed he achieves is incredible. It's very reminiscent of Pete Sampras and Andy Roddick's ISR. It's no coincidence that Raonic, Sampras and Roddick are 3 of the best servers of all-time.
Because of all these unnecessary movements that Coco has developed into her swing, she's been having a difficult time maintaining a dependable, repeatable swing especially under pressure.
My hope is this article will stimulate hearty discussion about Coco's serve and in the Forum as well as thoughts about how these problems have developed and suggestions about corrections.
