Quantifying Shot Outputs

[johnyandell]

Let's discuss Brian Gordon's article, "Quantifying Shot Outputs"

[klacr]

That Playsight system is an awesome tool. Brian knows his stuff and he is right. If looking to make a change in a student's technique its important to actually test it with measurable performance goals. Brian is fortunate to have that facility and he deserves it. He has worked extremely hard and is beloved by many. Numerous clients of mine have worked with him and have a profound respect for his knowledge and expertise. But man...those poor hips. Healthy recovery Brian!

Kyle LaCroix USPTA
Boca Raton

[stotty]

Playsight seems a scientific way of breaking down and working on a stroke's capabilities. It's certainly nothing like the way I have gone about the same process in the past.

I judge strokes over a period of time by watching matches. It can be a lengthy way to make judgements, but in the end, sooner or later, I end up knowing exactly what a shot's capabilities are and where its weaknesses lie. What I like about playsight is the way a coach can work on a stroke and measure accurately its progress within lesson time; and, one would think, get quite close to knowing how that stroke might stand up in a match. It's the 'measuring' capacity of Playsight which I feel is very useful. Being able to analyse the outcome of, say, a 20-ball drill in so many ways seems so useful.

With my method I work on stroke purely by intuition and with no reliable way to measure the outcome of success within a lesson. I tend to have to wait and see how the stroke stands up in matches, which is actually fine but long winded. Playsight seems interesting. I assume it costs a fortune?

[johnyandell]

A small fortune! Think about $15K USD give or take a couple of K.

[BrianGordon]

Thanks Kyle, that is very kind of you to say and our mutual clients have nothing but very positive things to say about you as well. Hips now work great!

Stotty - the ultimate test of our work is definitely the highest level of complexity which is performance in competition - that will always be the gold standard. I've found shot quantification systems useful in training at the lower levels of complexity like racquet fed drilling because it provides benchmarks, introduces accountability, and allows me to apply pressure scenarios. I've found that my players focus harder and the payoff to performance in matches is accelerated - or at least so it seems thus far.

The systems are not cheap and there have been many developmental bugs. The process by which 3D ball locations are determined is not trivial and subject to breakdown. That said, system performance and up time has been improved quite a bit since I start using it and the drilling options are being expanded pretty regularly - almost to what I used to have manually with yoga mats and trajectory ladders lol.

[seano]

Brian - If you have a moment to answer a few questions about your student Sarah, just curious. Taking into account that technique is only one part of the puzzle.
Where is Sarah's forehand and backhand in terms of development for the strokes you ultimately want her to have? What did they look like when you first started with her? What is your hope for the finished product?

Looking at her forehand - She keeps the swing on the outside (Type 3) Has slight elbow loop with racquet tip pointed forward in the backswing. Looks to have a somewhat of a hybrid backswing you discussed previous but reaches the ideal hand position to the outside going into the flip. Definitely uses double bend FH, you can see some instability of the elbow at contact, particularly as the elbow/contact gets closer to the body. You can see some evidence of releasing her wrist in the follow through.

Backhand - Type 1 BH where you see the lateral component of racquet behind the hands. Bent/Bent hitting arm structure with right elbow collapsing really close to the body on at least 2 of them. Don't know if going for more angle or a flaw. Are you trying to make a change to more of a type 3 BH?

Can't get enough of your video series and hoping for more. Really appreciate you taking the time to answer our questions, adds a tremendous amount.

[arturohernandez]

Did BrianGordon answer your questions seano? I'd like to know his thoughts as well.

[seano]

If he does, he would in this post.

[BrianGordon]

Thanks seano. Sarah started with me a few years back sporadically and full time from the beginning of this year. She came as a typical junior with hideously inside loops on both sides. Her recent rise through the metrics by which the establishment judges competitive performance has been very impressive. By my mechanical and output standards her forehand is at 80% and backhand 70% of the goal on most days which roughly correlates to her 10.64 rather than 13.5 UTR - but she is young.

On her forehand the elbow breakdown and/or lack of attaining the desired elbow angle by the end of the backswing is the problem, as you note, especially on higher balls or when positioning is poor (too often for such a great mover). The elbow problem (and racquet orientation at the unit turn) relates in part to her "need" to drop the arm at the shoulder in the backswing which I tolerated for awhile but no more - very inefficient and caused problems against the "slappers".

She is capable of producing a perfect type 3 backhand. As the level of complexity increases, however, she tends to break the racquet from the set position into what I term a pre-roll or secondary swing - different from the type 1 swing. If you saw it from multiple views at high speed I believe you would not classify it as type 1 but rather a flawed type 3 execution - but even then it would be difficult to differentiate what is flip and what is pre-roll without 3D. It has improved quite a bit from when that video was taken but the pre-roll still rears its ugly head - maybe it always will at some level. That aside, at this point she is bent/straight which is the classic type 3 contact configuration.

Hope that answers your questions. BG

[seano]

Brian -

Thanks for the answers, I really get into the science of the technique. If you wouldn't mind to answer a little more, i'd greatly appreciate it, thanks )

Could you describe pre-roll a little more? And why it's different than a Type 1 swing?

When stressed and the BH breaks down, Is the "pre-roll" from:
a) old habits from the former technique?
b) lack of stretch of the right shoulder in the backswing?
c) lack of "pull" of the right hand forward? The proper technique would be the pull of the right hand then the push of the left hand in the forward swing.
d) something else?

Is the pre-roll considered a "bubble loop" as Rick Macci would describe it?

[don_budge]

Brian...I have a question for about about your feeding style. I notice that you do not bounce the ball when you feed and I question what kind of variety of spin and speed you can generate. I like to bounce he ball on the feed and hit the ball on the way up...on the rise so to speak. I feel that I am using the speed of the ball on the shorter hop and better able to control the three elements of power...speed, spin and placement. Doesn't it take more energy on your part to hit the ball out of the air? Any thoughts from the realm of science to my theory.

Thanks for your contributions and your excellent follow up discussion with forum members. You are a fascinating character and best of luck to you.

[seano]

Another good feed to replicate more of a heavy ball, is to hit the ball out of your hand with heavy topspin and have the ball bounce on your side first then it bounces on the other side with much more force.

[BrianGordon]

seano:

I differentiate backswing attributes by the motion of the hand(s) (technically the wrist articulation) OR motion of the racquet relative to the hand(s) created by wrist joint motion but most often twisting rotation of the forearm and/or upper arm. A loop in my world is defined by a circular motion (often pretty big) of the hand(s).

The type 1 backhand possess a lot of circular hand motion starting from a relatively elevated "unit turn" position. A pre-roll refers to racquet motion relative to a stable-ish hand position at what is generally typical at the end of the type 3 backswing - roll referring to the twisting rotation that causes it - pre referring to the fact that it occurs prior to the pull that initiates the forward swing.

The loop variations (full being type 1) usually result from an incomplete stretch position at the end of the type 3 backswing. I should note that less than the full stretch position (what I call the 3/4 set - high or low) may be intentional to deal with some incoming ball attributes. None-the-less a small spherical motion of the hands that can be present from the 3/4 set to the start of the pull is a bubble loop. A hemisphere hand path over the same interval is a hook loop. Both are contraindicated on the type 3 BH.

The cause for Sarah (and most) that come from an extensive type 1 swing is, I suppose, a motor pathway artifact.

The bounce-over feed does provide some challenging incoming balls - as I work on clay I find it is a lot work as the surface mitigates some of it's devastation.

don_budge:

Two firsts in your post.

I've never been asked about feeding technique. I like to think mine is pretty versatile as it is about the only thing I can do on a court anymore and I get a lot of practice. I suppose I can produce about 80 mph and 3000 rpm (not necessarily at the same time) and throw in a respectable slice or side-spin offering. Bouncing or hitting out of the air is probably a personal choice with both producing the desired result with enough practice. I've no empirical evidence to back that up either with regard to mechanics or energetics - I'll have to test it out.

Don't think I've ever been called fascinating - crazy for sure. Is the latter a subset of the former?

Thanks for your post!

[don_budge]

Don't think I've ever been called fascinating - crazy for sure. Is the latter a subset of the former?

Thanks for your post!

No...I would say that the two are mutually exclusive.

[don_budge]

don_budge:

Two firsts in your post.

I've never been asked about feeding technique. I like to think mine is pretty versatile as it is about the only thing I can do on a court anymore and I get a lot of practice. I suppose I can produce about 80 mph and 3000 rpm (not necessarily at the same time) and throw in a respectable slice or side-spin offering. Bouncing or hitting out of the air is probably a personal choice with both producing the desired result with enough practice. I've no empirical evidence to back that up either with regard to mechanics or energetics - I'll have to test it out.

Don't think I've ever been called fascinating - crazy for sure. Is the latter a subset of the former?

Thanks for your post!

Thanks for the reply.

I think that it would be tremendously interesting to quantify the bounce technique (hitting the ball on the rise or short hop) versus the plucking the ball out of the air technique in terms of feeding balls. When you think about it...the ramifications are big time when it comes to teaching. Qualitatively thinking I tend to think (feel) that the bounce allows for more options. Perhaps less strain on the feeder.

While you are at it...quantify seano's technique as well. I had never thought of that one although I have seen some tennis drill sort of employing that technique where both players bounce the ball on their side of the court first and then over the net.

Fascinating versus obsessive. Obsessive is crazy and perhaps in a sense you have become obsessed with "quantification versus qualification". Numbers versus feeling. Technology versus sensitivity. But I find you more fascinating for a number of reasons. Number one is how you seem to resonate with my fellow forum participants. Number two...more importantly to me is that your studies and findings are very interesting to me. This is fascinating because ordinarily I tend to not be too concerned with the why and more concerned by how does it feel.

Great work and thanks for sharing...off of the court.