This Really Works-Keeping Eye on Ball

[SystemicAnomaly]

Originally Posted by 5263

I've also heard the frame rate references as it relates to calling lines.
Like if a hard serve hits the back of the line, then as it rolls or skids well off the line before bouncing up. In this situation your eyes may capture a frame of it on the back part of the line or maybe after it has left the line (appearing to be out), or miss the contact portion of the bounce completely, leaving the brain to fill in and decide where the ball hit.

Not heard this either. Any references?

The only mention that I've come across with respect to seeing the world in frames is with certain neuropsychological disorders, such as akinetopsia (motion blindness). There is also the matter of saccadic suppression (or saccadic masking). With this phenomenon the brain suppresses visual information when the eye performs a saccade.

With regards to calling lines, I've spoken to several lines persons (certified for pro tennis). They have been taught, not to track the ball when it is bouncing near or on a line. Anytime a ball appears to be encroaching a line of interest, the lines person may track the ball long enough to determine the approx part of a line the ball may bounce. However, before that ball reaches the line, the lines person quickly shifts their gaze to that part of the line so that both the head and the eyes are not moving when the ball bounces. If either the head or the eyes are moving as the ball bounces, it has been found that the ability to accurately detect the bounce point is severely hampered.

Originally Posted by nabrug

Do you recognize players "spacing out" like jswinf posted? If so how do you help them?
If other people like to comment. Please!

Will try to come back to this later today (and will explain convergence insufficiency).

[nabrug]

Originally Posted by SystemicAnomaly

Not heard this either. Any references?

The only mention that I've come across with respect to seeing the world in frames is with certain neuropsychological disorders, such as akinetopsia (motion blindness). There is also the matter of saccadic suppression (or saccadic masking). With this phenomenon the brain suppresses visual information when the eye performs a saccade.

With regards to calling lines, I've spoken to several lines persons (certified for pro tennis). They have been taught, not to track the ball when it is bouncing near or on a line. Anytime a ball appears to be encroaching a line of interest, the lines person may track the ball long enough to determine the approx part of a line the ball may bounce. However, before that ball reaches the line, the lines person quickly shifts their gaze to that part of the line so that both the head and the eyes are not moving when the ball bounces. If either the head or the eyes are moving as the ball bounces, it has been found that the ability to accurately detect the bounce point is severely hampered.

Can you give your sources? Where did you study? What literature did you read? Did you write articles about this? etc..

[SystemicAnomaly]

Originally Posted by nabrug

Can you give your sources? Where did you study? What literature did you read? Did you write articles about this? etc..

My area of university study was actually in Engineering Technology (Calif Polytechnic, SLO). My knowledge & study of the human visual system is something of a personal obsession/hobby. I engaged in a sports vision training program with a behavioral optometrist in the late 1980s. Learned quite a bit about vision & visual tracking, during that training. However, my knowledge of the subject is hardly comprehensive -- there is quite a bit that I don't know about this stuff.

I have skimmed thru various journal articles on vision-related studies. However, for the most part, much of these are somewhat over my head. If you are interested in those types of sources on akinetopsia, you might take a look at the following:

http://www.jneurosci.org/cgi/reprint/11/2/454.pdf
http://www.jneurosci.org/cgi/reprint/9/5/1628.pdf

If that is more than you were looking for then you might try some google searches on some of the keywords that I've mentioned. Some information can also be gleaned from wikipedia (some articles are better than others). Here are a couple that may be of interest:

http://en.wikipedia.org/wiki/Motion_...europsychology
http://en.wikipedia.org/wiki/Phi_phenomenon
.

[SystemicAnomaly]

Another couple of related articles:

http://www.hhmi.org/senses/b210.html

http://en.wikipedia.org/wiki/Saccadic_masking
.

[5263]

Originally Posted by SystemicAnomaly

With regards to calling lines, I've spoken to several lines persons (certified for pro tennis). They have been taught, not to track the ball when it is bouncing near or on a line.

Your use of the term "tracking" may be consistent with the science community, but I think track is an excellent word for what actually happens with the eye following something smoothly when it can, then shifting to pick it up in spots once it can't follow it continuously. If you are tracking a deer and lose the trail for a moment, then pick it up a little farther down, that is all part of tracking the animal. Just cause it couldn't be followed for awhile didn't mean you were not still tracking in the overall situation of tracking the animal, as that is part of Tracking. Or like tracking a package with Fedex. It just gives you a shot of where the package has been at times, not where it is continuously.

Seems what you say should be watching or seeing, which is continuous, vs tracking, which accounts for spaces of no data. Also this important since we are not working with vision phd's too often, so tracking would be a good term for making this point with the avg Joe based on the normal uses of the word.

[TenniseaWilliams]

Overall, most studies suggest that the human eye has no intrinsic "frame rate".

This http://www.100fps.com/how_many_frame...humans_see.htm page is a pretty easy read through the subject.

The http://en.wikipedia.org/wiki/Wagon-wheel_effect has some references to recent human eye temporal sampling theory and studies. (near the end of the article) The article is fairly easy to wade through and makes some interesting points.

[W Cats]

TennisOne had a series of articles about what S.A. is referring to. I don't currently have a subscription so I can't accurately reference it . But as I recall one of the issues beside what the eye can track accurately at speed is how fast the eye/brain can process the information. One type of vision allows for the brain to tune into detail of an oncoming object such as: brown, almond shape, two white strips, football, direction of travel approximate speed and trajectory. The other more peripherally oriented vision the brain processes at several times the speed of the previously mentioned by only tuning into the speed and trajectory of the object. Jump saccade allows the eye/brain to tap into the second type of faster processing.

[SystemicAnomaly]

Originally Posted by 5263

Your use of the term "tracking" may be consistent with the science community, but I think track is an excellent word for what actually happens with the eye following something smoothly when it can, then shifting to pick it up in spots once it can't follow it continuously. If you are tracking a deer and lose the trail for a moment, then pick it up a little farther down, that is all part of tracking the animal. Just cause it couldn't be followed for awhile didn't mean you were not still tracking in the overall situation of tracking the animal, as that is part of Tracking. Or like tracking a package with Fedex. It just gives you a shot of where the package has been at times, not where it is continuously.

Seems what you say should be watching or seeing, which is continuous, vs tracking, which accounts for spaces of no data. Also this important since we are not working with vision phd's too often, so tracking would be a good term for making this point with the avg Joe based on the normal uses of the word.

Seriously? You are taking issue with my use of the word "tracking" in that context. Slow posting day or are you just trying to get in the last word (CYA)?

If you've really been reading & following my posts, it should be apparent that I am primarily using this word to mean smooth pursuit tracking (it's a bit tedious spelling out the whole phrase all the time). Most English words have multiple meanings or connotations. It should be fairly obvious, even to non-PhD's, that I'm using the word in a specific way.

I meant what I said in the previous post. A good lines person will actually stop tracking (or watching) the ball before the ball bounces on or near a line of interest. Their eyes fixate on a portion of the line, laying in wait for the ball to come into view & bounce. The foveal (central) vision is trained on the outside edge of that line segment, with the head kept very still.

Does this sound familiar? This is very similar to what Federer and other pros do when they are playing a shot? As the player commences their forward swing they actually stop tracking, or stop watching, the ball. Their eyes lose sight of the ball shortly before contact and they do not make an attempt to follow the ball coming off the strings. If they are still watching (or trying to watch) the ball as people suggest, the head & eyes would move as soon as contact is made in a (futile) effort to see the ball. This is not the case -- I'll say it again -- elite players will stop watching the ball during their forward swing.

[SystemicAnomaly]

Originally Posted by TenniseaWilliams

Overall, most studies suggest that the human eye has no intrinsic "frame rate".

This http://www.100fps.com/how_many_frame...humans_see.htm page is a pretty easy read through the subject.

The http://en.wikipedia.org/wiki/Wagon-wheel_effect has some references to recent human eye temporal sampling theory and studies. (near the end of the article) The article is fairly easy to wade through and makes some interesting points.

Originally Posted by W Cats

TennisOne had a series of articles about what S.A. is referring to. I don't currently have a subscription so I can't accurately reference it . But as I recall one of the issues beside what the eye can track accurately at speed is how fast the eye/brain can process the information. One type of vision allows for the brain to tune into detail of an oncoming object such as: brown, almond shape, two white strips, football, direction of travel approximate speed and trajectory. The other more peripherally oriented vision the brain processes at several times the speed of the previously mentioned by only tuning into the speed and trajectory of the object. Jump saccade allows the eye/brain to tap into the second type of faster processing.

Thanks for this great feedback guys. W Cats, do you recall when TennisOne presented these articles? Is it possible that some or all of it is posted in archives of their free newsletter?

[5263]

Originally Posted by SystemicAnomaly

Seriously? You are taking issue with my use of the word "tracking" in that context. Slow posting day or are you just trying to get in the last word (CYA)?

No need to be rude. I realize that you think tracking is mostly for the smooth aspect. I agreed that your terms were probably correct from a science use, so no need to be ultra sensitive and lash out. But since you did, maybe the issue of you coming in on any discussion related to vision, and correcting other peoples terms to conform to that you have read on your hobby subject may not be the best way to approach it in this medium.
Especially since tracking is probably the best word (based on common usage of it) to describe the whole event, moving from smooth to the jump saccade.
And of course no one else is going to get the last word on "eye on the ball" as long you are on the forum, so no, I had no illusions of that.

[W Cats]

S.A. This was a series of articles on Parallel Processing written by Scott Ford. He also wrote a book called In the Zone. It was pretty interesting stuff.

Here is a link to an accompanying article that he wrote. It does not however contain the information about prcessing speed of detail vs. speed/trajectory.

http://www.tennisone.com/magazine/cl...allel/mode.php

[SystemicAnomaly]

Originally Posted by nabrug

This is a question to all readers:

Do people recognize this? Or are you always watching the ball? Without any effort. Besides that I want to know what teachers say to you to help you if you are distracted? Or if you are a teacher how do you help a player who has problems concerning concentration?

The larger question is, are you watching the ball when it should be watched and fixating on the contact zone (with the head kept still) during the appropriate time (usually during the forward swing)? I'm fairly certain that I almost always watch the ball when I should. However, the 2nd part is the more difficult one. I'm usually very good about fixating on the contact zone with the head still for 2 or 3 sets, but this tends to break down for a couple of reasons.

The primary reason for this breakdown is a combination of convergence insufficiency and visual/mental fatigue. I'll come back to this a bit later. The other reason for the breakdown is because I'm teaching a lot more than I am playing these days. The problem is something of a occupational hazard. I am usually feeding balls to students and watching their actions rather than focusing on the flight of the ball. I will often hit balls back without fixating on the contact zone so that I can clearly see what they (the student) is doing -- are they recovering? split-stepping as I make contact? are they still moving as I am about to make contact? are they in balance? the appropriate location? etc?

So, when I go back to playing, I've got to retrain myself not to do this. I constantly find myself practicing the "quiet eye" when I warm up and between points (before the ball is put into play).

Convergence insufficiency (CI) is a visual problem where my eyes prefer not to converge -- the outside muscle of the eyes win out over the eye muscles that are used for convergence. I have a very difficult time sustaining eye convergence for near and even mid-range objects in my field of vision. This is a congenital problem that is not uncommon. I do not have any figures on how common this disability is but I do know several other people with the same disorder. I did not find out about this learning disability until I had already graduated from college. Because of CI, my eyes fatigue easily when reading printed material or when using a computer monitor. In 10-15 minutes of reading, I will feel considerable eye strain due to close convergence.

The CI problem was discovered when I engaged in sports vision training some 20+ yrs ago. It explained why I got headaches when reading a book or monitor and why my hand-eye coordination seemed to be slightly off when playing sports such as tennis. The vision training did not cure the CI but it did improve my visual stamina in this regards. After the training, I was able to read a book for nearly 30 minutes at a time instead of only 10-15 minutes.

My hand-eye and visual stamina improved for sports as well. However, after a couple of sets or so, I start feeling the eye fatigue which, in turn, produces mental fatigue. Even for those people that do not have CI, visual and mental fatigue will play a role in the ability to sustain the proper ball tracking and "quiet eye" techniques.
.

[5263]

Originally Posted by W Cats

S.A. This was a series of articles on Parallel Processing written by Scott Ford. He also wrote a book called In the Zone. It was pretty interesting stuff.

Here is a link to an accompanying article that he wrote. It does not however contain the information about prcessing speed of detail vs. speed/trajectory.

http://www.tennisone.com/magazine/cl...allel/mode.php

Also a book call Design B.

[RafaBrain]

Originally Posted by kenshireen

I have played for 40 years and having watched Federer slo-motion videos saw that he kept his head down on the ball as close as humanly possible until it struck his racket.

Most of us have a tendency to follow the ball but not TRY to watch it hit the racquet head.
We tend to look up at where the ball is going as we strike it..

What I am going to say is very subtle and difficult to do because of the inclination to see where the ball is going after you strike it. But I have been doing the following lately and it has significantly increased my consistency.

I follow the ball as it strikes the opponents racket and as it is crossing the net and coming to either my BH or FH I take a snapshot of the court and decide where I am going to attempt to hit the ball (i.e. DTH, CC, Drop, etc.) Now here is the most important and difficult part (only difficult due to habit). I watch the ball hit my racket head and only after I strike it do I look up.. I agree that there is only a millisecond difference between this technique and the other way where you strike and look up almost simultaneously.

But for me I find that I hit the ball much more consistently and have fewer frame shots.
It also stops me from lifting up my shoulder when striking the ball which tends to keep the ball from flying deep.

Now, I am a 3.5 player so take that into consideration..

Ken

.
I have learned some nice things about when to keep eyes on the ball from book <Tennis Kung Fu>.

[5263]

Originally Posted by RafaBrain

.
I have learned some nice things about when to keep eyes on the ball from book <Tennis Kung Fu>.

Could you share some of those points?