Forehand Loop against UNDERSPIN Technique

**Der_Echte** · 01-19-2021

As far as describing a lot of the finer points of impact dynamics and some adjustments... I know it is SERVES, but look at MaTT's series on serving he started in March 2020... He went as far to show how the different changes in bat angle before impact and how fingers work when.

A lot of that stuff in concept is transferale to understanding loop impact.

**Der_Echte** · 01-19-2021

Locally, 2150ish Sergey Scoobie Doo is very well known for pushing a short ball with much underspin, (just daring you to loop - he can do that as he has good footwork and can retrieve well) so much underspin that the unlearned players will fail to get it even to the net...the ones who learned have many ways to get the ball over... some go way back behind on backswing like Brian shows in his dry run before the practice... some do it like the girl in the vid with backswing just behind the knee, some do it like Baal was shown how to adjust and open bat some more and go down to ground with backswing and dip...

I use all of these ways and even open bat some more take ball early and go forward/finish upwards vs his heavy underspin and i do all three loops - slow/extrm heavy, med/heavy, fast/heavyish

One really has to figure out how to get good position, leverage, coordination of muscles, explosion, timing, and control of bat angle and grip in order to consistently land your loop vs underspin... once adapted and ready, one can be very high percentage and consider the loop vs an underspin that the opponent is taking it easy on you and inviting you to attack and win the point... or at least gain the advantage in the rally as a minimum.

**latej** · 01-19-2021

Originally Posted by Brian Zhao

Hey all, here's a video about looping underspin. It's only 10 minutes, but I tried to pack as much information as I could in. Please let me know what you think and share the video/subscribe if you like it!

https://youtu.be/myijNgE2Pv0

This is good video, and you put a lot of work into it. I like Andrew's technique. There is couple of things, some you may disagree with, these are my opinions.

First, you concentrate too much on the contact point, also mentally, when you speak about it in the video, and I think it holds you back. Try for the moment just ignore it. I think it is all about racket movement speed, one movement, the hit is just an accidental detail. The angle will find itself. Try to think what you do when you want to throw a spear, whole movement, full power, in this sense. In TT a bit more control, but it will find itself.

Second is to try to hold your spine straight and the head in the same line. It is a rotation axis. If it is not straight it is hard to rotate effectively. You can experiment with it. You can try to over rotate the body first, all in the goal of maximizing the hand speed. Thinking more about the whole of the movement, than the contact. I think Andrew does that better than you in the moment. But you can free it, release the dragon :-)

P.S. BB tells things straight, right away as he sees it. I can assure you he means well.

**yogi_bear** · 01-19-2021

1. brokenball seems to be still fixed on the issue that material testing for table tennis player and opting the equipment for his individual style should be done on a scientific way and on a level of manufacturing wherein you have to measure everything. I never claimed that I am a materials expert this is the reason why i did not address his irrelevant claims about testing. Up until now, he does not realize that I am testing equipment for a wider audience and also simplifying the test which involves playing and making recommendations on which the readers can relate. He, on the other, is persistent to force people to accept that his way is the only correct way. In the first place, he does not even have the feel of a proper player in terms of playing. which leads me to point 2. Yes I saw his video looping and it is a beginner's loop and no that is not the proper way looping the ball.
3. This confuses me until now knowing a lot of players who are in the engineering field and 3 of even reaching National level. One of which is even a bronze medalist in the SEA Games for doubles. That mechanical engineer friend of mine never lectured about physics when coaching because 1. it is a waste of time (it eats up the vital time in which he is supposed just be spent on teaching the strokes and all components of the game) 2. you can go away with physics while learning and training TT. If you want to include physics lecture go lecture on a scientific paper or a class.
4. no and no sane coach well pair with brokenball on a TT seminar. the participants go on a TT seminar to learn table tennis and not physics. This is the reason why instead of physics, mental conditioning, physical conditioning are taken up because these are vital to good training. Again broken ball will just dismiss it and ignore the fact because it does not support his wild theory.
5. and seriously, countries as advanced as korea, japan and china in terms of TT did not even thought of teaching physics to players and all the while brokenball was the one who thought of this therefore this is a very important discovery that will affect TT????? the answer is obvious, brokenball's idea is useless and a waste of time.

**Baal** · 01-19-2021

Originally Posted by brokenball

I can loop very well.

I think you should post that video you mentioned again on this thread so we can all see your, er technique. I think it would put all your comments in a proper context.

**Music&Ping** · 01-19-2021

Originally Posted by Baal

The "accelerate on contact" thing is a purely mental construct the player uses to increase racket speed. The effect of trying to accelerate on contact is to accelerate somewhat before contact, while still managing to actually make good contact. It is a mental approach that may help some people.

There are all sorts of mental tricks athletes use to get a desired result that don't exactly correspond to what is really happening. Good coaches know all sorts of ways to convey an effective technique. They may say "it's sort of like....", or "think of it like..."

This is sports, not physics. There is psychology, motor learning, and all the other things about PEOPLE actually playing a sport. People aren't robots.

So bringing physics into it is, as is almost always the case in these threads, utterly pointless.

Ask Dan when he met Damien Eloi for the Andro blades video: as Damien Eloi uses a short stroke, he also uses his wrist to generate extra spin, most pro player know that technique, it’s exactly the same as accelerating at contact point. I know how to train with beginners for example: no wrist action. When I play with more advanced players, then I use the wrist, and it’s easy to control, and a quite fast action to process. Everyone at the club has told me the difference was obvious.

**latej** · 01-19-2021

Originally Posted by yogi_bear

1. brokenball seems to be still fixed on the issue that material testing for table tennis player and opting the equipment for his individual style should be done on a scientific way and on a level of manufacturing wherein you have to measure everything. I never claimed that I am a materials expert this is the reason why i did not address his irrelevant claims about testing. Up until now, he does not realize that I am testing equipment for a wider audience and also simplifying the test which involves playing and making recommendations on which the readers can relate. He, on the other, is persistent to force people to accept that his way is the only correct way. In the first place, he does not even have the feel of a proper player in terms of playing. which leads me to point 2. Yes I saw his video looping and it is a beginner's loop and no that is not the proper way looping the ball.
3. This confuses me until now knowing a lot of players who are in the engineering field and 3 of even reaching National level. One of which is even a bronze medalist in the SEA Games for doubles. That mechanical engineer friend of mine never lectured about physics when coaching because 1. it is a waste of time (it eats up the vital time in which he is supposed just be spent on teaching the strokes and all components of the game) 2. you can go away with physics while learning and training TT. If you want to include physics lecture go lecture on a scientific paper or a class.
4. no and no sane coach well pair with brokenball on a TT seminar. the participants go on a TT seminar to learn table tennis and not physics. This is the reason why instead of physics, mental conditioning, physical conditioning are taken up because these are vital to good training. Again broken ball will just dismiss it and ignore the fact because it does not support his wild theory.
5. and seriously, countries as advanced as korea, japan and china in terms of TT did not even thought of teaching physics to players and all the while brokenball was the one who thought of this therefore this is a very important discovery that will affect TT????? the answer is obvious, brokenball's idea is useless and a waste of time.

Hi Yogi, I can see your perspective. And thanks for posting more than your usual 1-liner :-)

Talking physics seems like a waste of time for young players. They may not even know what the .... are you talking about. But at the same time, we should not be afraid of physics. It is just a name. Sometimes the fear feels like inherited/translated from school years. BB is right that the physics tries to describe how the world works. This may sound distant, but all your movements do follow the rules. We should not be negligent. I'm sure CNT isn't either. Another "tabu" world is energy. We want to maximize the spin, yet we can't use the word "energy". For me the body is like couple of bones stick together via joints. Certain movements you can't do, if you want to stay alive. And other movements are optimal, natural, for hitting the ball - or for energy transfer to the ball - and ruled (or foretold) by physics - and they are aesthetic - all of those at once. I don't think we should exclude anyone of those, especially not physics. I'm not arguing for equations. I stop here, shut up and train :-)

**Brs** · 01-19-2021

Not sure what all the long post argy-bargy is about. Content seems pretty standard stuff everybody agrees with. To the OP, pls don't say "...only ten minutes." Ten minutes is abt 5 minutes too long. I have many lolcat vids to get to, can't spend all day on your loop vs backspin.

**Music&Ping** · 01-19-2021

Originally Posted by Brs

Not sure what all the long post argy-bargy is about. Content seems pretty standard stuff everybody agrees with. To the OP, pls don't say "...only ten minutes." Ten minutes is abt 5 minutes too long. I have many lolcat vids to get to, can't spend all day on your loop vs backspin.

LMFAO

Means "next time do a 20 mn vid plz" right ?

**zeio** · 01-19-2021

What a pain. How about some actual substance, folks?

Table tennis strokes are like multistage rockets, where different parts of the body work in succession at different segments of the stroke. It can be broken down into 2 stages:
primary acceleration, in which the lower body accelerates from rest and then transition to;
secondary acceleration, in which the upper body accelerates until the desired final velocity.

After some trial and error, most normal human beings should, by intuition, understand "accelerate upon contact" to mean secondary acceleration. Now for some real data.

In one Chinese paper from 2010 on the FH loop stroke against backspin ball, it's found that MLin and WH complete the forward swing within ~180ms and ~170ms, respectively. That's less than the typical human reaction speed of 200-250ms and close to the blink of an eye of 100-150ms. In terms of human perceptions, you could say it happens almost instantaneously.

For the most part, the lower body finishes the primary acceleration first and the upper body follows with the secondary acceleration, yet the order of joint motion does not always follow the kinetic chain principle. In 6 tries, their 3 fastest moving joints are consistently and progressively the elbow, wrist and hand. These 3 joints all reach their maximum velocities near the end of the forward swing, right before, upon or after impact and within 0-35ms apart.

MLin achieves maximum velocity 5ms before impact 4 times, right upon impact 1 time, 10ms after impact 1 time. WH achieves maximum velocity 5ms before impact 2 times, right upon impact 2 times, 10ms after impact 2 times.

Code:

Backswing(s)		0.65±0.10, 0.75±0.04
Forward swing(s)	0.18±0.01, 0.17±0.01
Followthrough(s)	0.34±0.01, 0.27±0.04
Recovery(s)		0.4±0.06, 0.34±0.05

MLin
Order		Forward swing(m/s)	Time(s)	Followthrough	Time
1
Right elbow	6.67			1.42	6.36		1.445
Right wrist	11.95			1.425	11.03		1.445
Right hand	13.82			1.44	13.79		1.445
2
Right elbow	6.99			2.995	6.81		3.015
Right wrist	13.31			3	12.73		3.015
Right hand	14.15			3.01	14.16		3.015
3
Right elbow	6.71			4.505	6.48		4.525
Right wrist	12.12			4.51	11.59		4.525
Right hand	13.63			4.52	13.67		4.525
4
Right elbow	6.81			6.075	6.42		6.11
Right wrist	10.74			6.09	10.03		6.145
Right hand	13.66			6.095	13.51		6.11
5
Right elbow	7.40			7.665	7.34		7.675
Right hand	14.35			7.67	14.46		7.675
Right wrist	10.73			7.67	10.86		7.68

6
Right wrist	13.36			9.27	12.92		9.285
Right elbow	7.21			9.27	7.07		9.285
Right hand	14.17			9.28	14.25		9.285

WH
1
Right hand	13.86			2	13.86		2.005
Right elbow	6.20			2	6.21		2.005
Right wrist	13.23			2	13.66		2.01
2
Right hand	12.05			3.53	11.60		3.545
Right elbow	13.68			3.54	13.77		3.55
Right wrist	6.18			3.54	6.21		3.55
3
Right wrist	11.62			5.105	1.39		5.125
Right hand	13.41			5.12	10.90		5.125
Right elbow	5.87			5.12	13.39		5.125
4
Right hand	11.44			6.655	11.04		6.675
Right elbow	6.20			6.655	6.19		6.675
Right wrist	13.77			6.67	13.76		6.675
5
Right wrist	10.67			8.16	10.47		8.175
Right hand	12.93			8.17	13.01		8.18
Right elbow	5.84			8.17	5.87		8.18
6
Right hand	13.56			9.795	13.58		9.8
Right elbow	6.16			9.795	6.18		9.805
Right wrist	9.96			9.76	10.37		9.825

**zeio** · 01-19-2021

Players always say things that, more often than not, do not match what actually takes place but what's more important is to figure out what they really mean rather than "I have the best loops!"

https://www.tabletennisdaily.com/for...l=1#post259179

**yogi_bear** · 01-19-2021

Originally Posted by Brian Zhao

I agree with you, in that playing TT is based on feeling the ball. I was just refuting a point to defend myself from being called “completely bogus”

Originally Posted by Baal

Something Eric Owens used to tell me is that if you're having to dip THAT low (e.g. when looping really heavy underspin) you are better off just opening the racket angle a little bit*. My initial response was, "but then I won't get enough spin". His response was, "try it and see". And sure enough, the shot had power and plenty of spin.

* but not too much!!

Originally Posted by latej

Hi Yogi, I can see your perspective. And thanks for posting more than your usual 1-liner :-)

Talking physics seems like a waste of time for young players. They may not even know what the .... are you talking about. But at the same time, we should not be afraid of physics. It is just a name. Sometimes the fear feels like inherited/translated from school years. BB is right that the physics tries to describe how the world works. This may sound distant, but all your movements do follow the rules. We should not be negligent. I'm sure CNT isn't either. Another "tabu" world is energy. We want to maximize the spin, yet we can't use the word "energy". For me the body is like couple of bones stick together via joints. Certain movements you can't do, if you want to stay alive. And other movements are optimal, natural, for hitting the ball - or for energy transfer to the ball - and ruled (or foretold) by physics - and they are aesthetic - all of those at once. I don't think we should exclude anyone of those, especially not physics. I'm not arguing for equations. I stop here, shut up and train :-)

I am not afraid of physics but only putting into perspective on what is actually needed and what works best in a training. As what people have said hard headed engr has a hard time compartmentalizing. Everything around us is ruled by laws of science but the obvious and useful ones are given emphasis in a certain sport. When you become a serious coach you will understand this. I think you will understand even now.

**Brian Zhao** · 01-19-2021

Originally Posted by latej

This is good video, and you put a lot of work into it. I like Andrew's technique. There is couple of things, some you may disagree with, these are my opinions.

First, you concentrate too much on the contact point, also mentally, when you speak about it in the video, and I think it holds you back. Try for the moment just ignore it. I think it is all about racket movement speed, one movement, the hit is just an accidental detail. The angle will find itself. Try to think what you do when you want to throw a spear, whole movement, full power, in this sense. In TT a bit more control, but it will find itself.

Second is to try to hold your spine straight and the head in the same line. It is a rotation axis. If it is not straight it is hard to rotate effectively. You can experiment with it. You can try to over rotate the body first, all in the goal of maximizing the hand speed. Thinking more about the whole of the movement, than the contact. I think Andrew does that better than you in the moment. But you can free it, release the dragon :-)

P.S. BB tells things straight, right away as he sees it. I can assure you he means well.

Thanks for the input. I do have a different opinion on the part about ignoring contact point. The contact is very critical, and all my coaches throughout my life who are world class players have emphasized that point. One of the essentials of TT is explosive acceleration, which many CNT coaches are always talking about. That explosiveness must be applied at the moment of contact to generate power. Also, my coaches have always emphasized "eating the ball" which which means to really grab it. If your acceleration isn't timed near the contact point, you won't be grabbing the ball as effectively.

I do appreciate the input, and I hope my explanation makes some sense. Much of TT is hard to put into words...

**LordPippington** · 01-19-2021

Ah yes, good ol' brokenball!

I like his world famous 'coefficient of the restitution' explanation

Across all sports, you find coaches babbling about what happens and what you should do... and rarely does it line up on the molecular level or scientific fact!

When I try teaching people, I'll say things like: imagine giving the ball a buzz cut or slicing off a very thin piece of ham from your favorite cut of meat

If I were to go on about 'force needs to be applied with 50% velocity at the precise moment of angular torque, when adjusted perpendicularly to the apex of the anticipated trajectory all while coefficient of the restitutions must align' ...

Or when teaching the backhand pip technique. I make it even simpler, I go full rick james and tell them to imagine you are 'smacking a bitch.' Just wap! Pop 'em in the nose. Voila! Their stroke flattens out

**SpinSquid** · 01-19-2021

Originally Posted by Brian Zhao

Thanks for the input. I do have a different opinion on the part about ignoring contact point. The contact is very critical, and all my coaches throughout my life who are world class players have emphasized that point. One of the essentials of TT is explosive acceleration, which many CNT coaches are always talking about. That explosiveness must be applied at the moment of contact to generate power. Also, my coaches have always emphasized "eating the ball" which which means to really grab it. If your acceleration isn't timed near the contact point, you won't be grabbing the ball as effectively.

I do appreciate the input, and I hope my explanation makes some sense. Much of TT is hard to put into words...

My coach is Chinese and also emphasizes the the contact point, explosive acceleration powered through the ground, and eating the ball (吃球).

Every coach and every player plays quite differently, but your video made a lot of sense to me (almost 90% of it is what my coach has explained to me before).

Keep up the good work!

**latej** · 01-19-2021

Originally Posted by Brian Zhao

Thanks for the input. I do have a different opinion on the part about ignoring contact point. The contact is very critical, and all my coaches throughout my life who are world class players have emphasized that point. One of the essentials of TT is explosive acceleration, which many CNT coaches are always talking about. That explosiveness must be applied at the moment of contact to generate power. Also, my coaches have always emphasized "eating the ball" which which means to really grab it. If your acceleration isn't timed near the contact point, you won't be grabbing the ball as effectively.

I do appreciate the input, and I hope my explanation makes some sense. Much of TT is hard to put into words...

Sure thing. I tried to give my perspective. Also given how the thread evolved, it could be a bit discouraging, but you seem to handle that pretty well.

I don't feel like competing with your coaches. I am trying to formulate my thoughts :-) and as you say, it's hard to put into words. The contact between the bat and the ball, just from the definition, must be important, but, it is a point, and I am interested in the line. It is the most important point, but only a point in the whole movement. At least for me it is liberating to see it that way.

I agree that TT is a lot about explosive acceleration. But when you say that "that explosiveness must be applied at the moment of contact to generate power", then I think it would be too late. Explosive acceleration powered through the ground, as SpinSquid put it, is better. You started to accelerate already there, on the ground, and your hand reaches certain speed at contact. That speed is important. What I want to say that at the contact you have already reached max. speed and nothing extra happens, just the hit. Perhaps you also mean it that way, but I can only react on what you say, and when you say "your acceleration isn't timed near the contact point", then I must mention, that acceleration at contact point doesn't matter. What matters is the speed, acceleration already happened. Also when I hear "accelerate upon contact" then it implies like someone is trying to do something extra at that point, but you can't really do anything anymore there, apart from the hit, almost like a by-product. I hope this perspective can be helpful to you.

Thanks to Zeio we now have hard numbers, and we can hope we'll reach 50% someday :-).

The "eating the ball" is killing me :-) I should not argue... For me more important is where on the bat the ball has contact. I'd like to improve it, to have more contacts closer to the optimal place on the bat. On BH perhaps I can feel like the bat grabbed into the ball, but not always. To put differently, it is more important to go full power and reach good hand speed for me, and obviously put the ball on the other half, than trying to "feel" how the ball was grabbed at that contact. Maybe I'm right and maybe also I'll see it differently later. Good luck!

**brokenball** · 01-19-2021

[QUOTE=zeio;33579
MLin achieves maximum velocity 5ms before impact 4 times,
[/quote]
This definitely is not accelerating through the ball but hitting the ball with 5ms is very good. That takes precise timing.

right upon impact 1 time,

This is optimal.

10ms after impact 1 time.

This is still pretty close but any acceleration after the ball is hit will not affect the ball.

WH achieves maximum velocity 5ms before impact 2 times, right upon impact 2 times, 10ms after impact 2 times.

These times are also pretty close to as optimal s a human can get.

A few milliseconds give or take from optimal is pretty good.
It is obvious to me that someone went through a lot of trouble to get this data just to check where in the stroke the ball is hit. It sure looks to me the ball is hit within a few millisecond plus or minus of the maximum speed, not maximum acceleration.

This backs up what I said in my first post about maximum speed is reached when the acceleration is 0 and and you want to hit the ball close to the maximum speed of the stroke otherwise you are wasting energy or time.
The best players must be playing close to optimal.

I understand most people, especially students, don't understand physics. However, I don't think it is right to fill their heads with myths like the first video does. I once asked a high school kid how far does a TT ball traveling at 10 m/s go in one millisecond and I got a blank stare. Can't bet past phy101.

**Baal** · 01-19-2021

The shark has been jumped.

**IB66** · 01-19-2021

I like both ways at looking at things!! Touchy feely and the science !!

**Baal** · 01-20-2021

Originally Posted by Brian Zhao

Realized I should just ignore that guy lmao

If you value your sanity.

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