The Serve: Probation!

[Frida1]

yes minimal

[johnyandell]

Seano,

Yep it's a great view! Hopefully gets you over BG withdrawal...

[stotty]

Yeah what do guys make of Tiafoe's downward wrist position in the wind up? He does the same on his forehand.

Quite like it. A lot of serves I have seen with flexion in the wrist during the wind up seem to be good ones. I've never discouraged that kind thing.

[seano]

John -

I think the aerial view of the serve is fascinating, gives a different but important view. Can really study the downward and upward parts of the swing, great stuff.

Sean

[johnyandell]

Yeah what do guys make of Tiafoe's downward wrist position in the wind up? He does the same on his forehand.

[seano]

Is it me? but I feel like I'm going through withdrawl w/o a video from Brian.

[doctorhl]

Brian, John Yandell’s revealing overhead view of Tiafoe’s service path to the hesitation point sure seem to push the limits of biomechanical efficiency.

[nickw]

Thanks Brian, I really appreciate you delving into those issues. What you say makes sense to me, and improves my understanding further.

[BrianGordon]

Hi Everyone -

Interesting points here. The main thing I've discovered in researching and teaching the strokes is that there are infinite ways a player can ultimately get the racquet to the ball. Even at a very high level we see a variety of ways so these discussions often go to this one or that produces big shots this way so it must be ok or even better.

My approach has always been to look at the full array of options and assess the biomechanical attributes in such a way that I feel comfortable teaching it to my young players because I know this will provide a sound (and safe) foundation. That foundation may morph to individual expansion into areas that work for them - but I still would not have taught it to them initially - I teach the base by which I know they can build their own interpretations - which I encourage.

The reason I start with this pedological explanation is that the points discussed are by and large individual interpretations. The racquet facing forward around the hesitation point is a case in point. In moving the racquet into a hesitation point type position obviously the racquet facing forward reduces the moment of interia of the racquet during the elevation (depending on the windup type and especially for continuous transitions). And this advantage can continue between the hesitation point and the initial instants of descent - however as the racquet begins the descent a diagonal swing plane of the type desired (by me) is not possible unless the racquet is more or less squared to the side fence - this is the case for many of the examples given. Keeping it facing forward creates the mechanical problems I already described. Do some some players pull it off - yes. Would I build a serve that way - never in a million years.

The method by which the body attains the hesitation point is an interesting discussion but I'll leave it to you guys and for the most part my players.

nickw - thanks and great questions - a 20 degree drop is the most I'll allow because anymore tends to change the backswing plane unless it is re-elevated first which a waste of motion in my book. Also, if you accept that the ESR in the backswing is a function of the leg drive then the rotational effect on the arm/racquet due to the force applied to the arm by the torso accelerating (from the leg drive) up would be optimized if the axis of ESR (roughly the humerus) is at a 90 degree angle to the line of the force (ESR axis in line with the shoulders). 20 degrees below is less efficient and more than 20 unacceptable to me.

The cartwheel is a torso event and independent of that arm orientations though many try to get past the coaches eye by manipulating the arms rather than using the torso lol. The left arm (stretched and timed) is an important factor in leveraging (term used loosely) the cartwheel of the TORSO through distributing load on the back leg and I suppose attaining the tilted position of the torso but I've yet to see that explained in a mechanically correct way and it is beyond the scope here.

By to the right of the player I assume you refer to an internally rotated humerus. I proposed a 20-30 degree internal rotation. The rotational consequence of the leg drive to the hitting arm structure doesn't occur functionally until that structure is moving vertically down. The 20-30 ISR is to provide a muscular boost in acquiring acquiring ESR before the leg drive takes over. I've found that that enhancement becomes counter productive if the ISR goes much past 30 as the lower to upper body synchronization becomes too complicated for most. Despite recent popularity of the idea (up to 90) I would NEVER teach it. 20-30 does about the same job without the sychronization baggage. And I realize Roddick pulls it off beautifully - personal interpretation.

Thanks all for considering my presentation. I've enjoyed the discussion and applaud the extent to which other mechanics junkies have thought about these issues.

[lovati4]

If the player can synchronize knee extension with the beginning of the backswing every time like that, good for him. You need excellent coordination and timing.
But for most players it might be better to decelerate the racquet head smoothly almost to a stop (v=0) by the trophy position. In addition have the racquet head at an angle to a vertical line. This allows for some extra time for the beginning of the knee extension (which actually takes a lot of time) before the racquet head drops into the backswing.

[postpre]

Sorry, I need to go back to the point that many big servers do not have their strings facing the right (side fence) at the trophy position (or as they pass through trophy if it's a continuous motion). They display a bit of forearm supination at this point, and often get more of an "on edge" racquet drop than Sampras and Federer. Below is another clip of Marius Copil's serve. Watch the slow motion in the middle of the video:

https://www.youtube.com/watch?v=fT9dbmuwf4g

I am not here to argue whether severs like Copil have a better serve than Sampras and Fed (they most certainly do not when all things are considered). Instead, I see this as very practical in terms of coaching and development, and knowing when to correct sub optimal biomechanics. Thus far, I am not convinced that a serve like Copil's lacks anything from a biomechanical perspective. But I am open to hearing viewpoints that challenge my current understanding.

[bottle]

Yes one can clearly see it in the Roddick. My other idea was that racket might get going the 20 degrees during the slow part of the serve to build a little momentum before the legs speed everything up.

[nickw]

Thanks for digging out my article don_budge

Hi Brian, when you have a moment, I'd really appreciate your thoughts on a couple of issues regards what's going on at the hesitation point. By the way, fantastic article, and series as I've mentioned before. I'm a huge fan of your work.

First issue is the position of the elbow. You said that if this falls much below 20 degrees in relation to the shoulder, then it will start causing problems. There are examples of players who drop the elbow well below 20 degrees in the hesitation point, yet it seems to me this position almost helps them get more power by generating a deeper starting position to the cartwheel motion. I wonder is there any truth in that, and to what extent this is less efficient bio-mechanically? Does maintaining a straight line between the shoulders, by extending the tossing arm to point more directly upwards, allow this deeper elbow position to function better? You can see this in the Isner and Dent examples, by finding the point where the legs first start to push up. I took screenshots, but couldn't upload them.

Taylor Dent: https://www.tennisplayer.net/members...stSAdRear2.mov

John Isner: https://www.tennisplayer.net/members...2%20240fps.mp4

Second issue is the position of the racket being to the right of the player in the hesitation point. Logic would suggest that if the racket is positioned to the right of the player (ie a little short of the traditional trophy position), then the hitting arm can benefit even more from the accelerating effect of the leg drive, because it has a little further to travel enabling a little more racket speed to be generated. I wondered your thoughts? Would this be the case, or might this have negative implications on how well the racket gets in and out of the drop position? Perhaps it depends on the flexibility of the shoulder too. Roddick is an example of the racket to the right at the moment his legs start to push up, and Isner exhibits this to some extent too.

Andy Roddick: https://www.tennisplayer.net/members...DeuceRear1.mp4

[lovati4]

In the initial phase of a serve I like allowing the racquet head go down first, slowing it down at the bottom without a full stop then letting the racquet head accelerate a little on the way to the trophy position.
In this case the racquet head accelerates without much effort. You really have to slow it down at the bottom.
Then it accelerates again on the way up before slowing down again. Here I like the analogy with slowing down a train. If you want to stop the train at a station you need to begin slowing it down very early, long before the station and keep doing it. Only then the train will slow down smoothly, in time. The same way players should learn to begin the deceleration of his (her) hand and the racquet long before the trophy position.
Some players use a different sequence. They completely stop the racquet head before pulling it up to the trophy position. Surprisingly many good players serve like that. May be even for them this acceleration-deceleration sequence is not easy to synchronize with the knee extension.
On the other hand some players do not slow down the racquet head at the bottom of the path. This may lead to poor timing of the knee extension and the beginning of the backswing (the key element of a good serve).

[don_budge]

Article by Nick Wheatley...1:2 Rhythm: The Serve

I would say the solution is to keep the acceleration of the hand to as little as possible. The less speed the hand builds up, the easier and more natural it is to decelerate it. Smooth and deliberate through this phase of the serve, as per my 1-2 rhythm concept (articles on this site). It never looks right when players rush the racket to trophy position, which often leads to poor timing and lack of acceleration through the hitting phase. The slower and smoother you can make it, the better you prepare for phase 2 which of course starts with the explosive driving up of the legs. It's like very slowly pulling back a slingshot, and then release...BANG! Maybe that makes some sense

https://www.tennisplayer.net/members/classiclessons/nick_wheatley/1-2_rhythm_serve/