The Forehand: Busting misconceptions once and for all

[sureshs]

Originally Posted by dominikk1985

I asked "our" pro filip peliwo about that.

he said he thinks that he usually hits with a slightly closed face (but is not sure because he doesn't have slow mo-we don't know if he is experiencing the closing after contact or actual contact since that happens so fast), but he is pretty sure that he doesn't hit the ball below Center. of course this is just an anecdote because he is not a scientist and many pros actually don't know what they are doing in Detail since that happens so fast and they do it intuitively since their childhood (a lot of MLB Players think they swing down to contact) but I think it's still interesting to read.

If some shots are hit below center, it is probably as a by-product of other factors like closed face and whether the ball is rising or falling , etc.

[Chas Tennis]

You can do some analysis with a DVR when a high speed video with small motion blur is shown. With the Motorola controller pause just before ball impact, then press the pause button again to advance a single frame. Works great.

I was watching the Australian Open yesterday and they had a slow motion of Tipsaravic hitting a forehand. Contact was very close to the centerline.

Interpretation of Videos - For the Tipsaravec video the racket was rising so rapidly that just one frame time after impact, the ball appeared distinctly below the racket centerline. I do not know the frame rate (and there was a degree of double imaging (interlacing?) in my DVR stop action display of the broadcast). But frame rate could be an issue that causes errors that would falsely skew the data to below center hits if you catch the ball later, say, when it has just left the strings. That error would falsely add to counts below the centerline. This issue applies, of course, to all high speed video analysis.

Toly, those are great pictures, the perfect display for this issue. I would like to learn how to do that. Since you have found a great way to display frames could you tell us the expert's way to capture an image from video, assemble images, label, and post them into the forum?
Such as
1) View Youtube or other?
2) Use some kind of YT frame capture or download video and use which other software to capture a single frame from the video.
3) What video software or other software did you use to assemble the selected frames and label them?
4) Did you prepare the assembled pictures and upload them to an internet photo site and then entered the URL link in the box available ("Image Insert") on the TW forum reply page?

[corners]

Originally Posted by tommyfr

What a sample, 12 pictures and all middle or above middle!

I have seen 100s of videos and pictures, in my estimate about 50 % are below longitude midline. So I think this sample is not at all closely to being random....very selective...Cheating, in short. Argumentation the Ugly way.

Wait a minute, who's cheating? At least he posted his evidence, as scanty as it may be. You simply refer to the "100s" of videos you have seen and that we have not, of which you estimate that 50% are below the longitudinal axis. Toly has no agenda here, he's just looking at some video and posting what he finds, which takes some time BTW, even though its only a small sample. You do appear to have an agenda, or at least some investment into this idea, an investment you're trying to protect apparently. Presumably you've spent some time trying to figure out if you're correct or just fooling yourself, right? But you haven't even taken an accurate count of the "100s" of below center impacts you claim to have observed. Is that good enough to convince you you're right? It's not gonna convince anyone else, that's for sure.

[corners]

Originally Posted by Chas Tennis

I was watching the Australian Open yesterday and they had a slow motion of Tipsaravic hitting a forehand. Contact was very close to the centerline.

You can do some analysis with a DVR when a high speed video with small motion blur is shown. However, the racket was rising so rapidly that just one frame time later, the ball appeared distinctly below the centerline.

Yeah, the ball will always be below the impact point immediately after impact on topspin shots because the ball is sliding along the strings at that phase of impact. But the lab evidence found that balls that strike below center rebound with more spin, not balls that slide down there. So when viewing video the only thing that counts, given the information we have currently, is where the ball first touches the strings, because that corresponds with where the ball was aimed in the lab.

Again, for those who haven't seen it, the lab evidence I'm referring to: http://twu.tennis-warehouse.com/lear...r/location.php

[corners]

Originally Posted by dominikk1985

I asked "our" pro filip peliwo about that.

he said he thinks that he usually hits with a slightly closed face (but is not sure because he doesn't have slow mo-we don't know if he is experiencing the closing after contact or actual contact since that happens so fast), but he is pretty sure that he doesn't hit the ball below Center. of course this is just an anecdote because he is not a scientist and many pros actually don't know what they are doing in Detail since that happens so fast and they do it intuitively since their childhood (a lot of MLB Players think they swing down to contact) but I think it's still interesting to read.

Peliwo gives a very astute and educated response. He's not 100% sure about most of this stuff because he hasn't analyzed the video. Smart guy. But the takeaway, as far as this thread goes, is that he dosen't aim below center, or at least he doesn't aim below center consciously. Sample size = 1, yes, but now we know that one pro does not hit below center on purpose.

[Relinquis]

ultimately what are you going to do with this knowledge? apply it, right?

why don't you guys go out to a court and try your theories? see what happens trying to hit below or above or on the centre during practice rallies and then during a match. Report back, maybe with a bit of video.

this forum isn't a peer reviewed academic journal. you're just arguing without having done a controlled experiment nor have you gathered empirical data systematically. What are you trying to prove apart from being keyboard warriors?

You're not advancing anyone's understanding with your tone and arguments.

[Chas Tennis]

The pros impact first on the strings above, on, or below the racket centerline. The stats are out there now in the high speed videos, on your DVR or even in a sample of still photographs of forehand ball impacts. It is a simple enough observation that with some care we might get a preliminary result.

Why not?

Even better, someone might find and present some existing research on this interesting question.

[toly]

Originally Posted by Chas Tennis

Toly, those are great pictures, the perfect display for this issue. I would like to learn how to do that. Since you have found a great way to display frames could you tell us the expert's way to capture an image from video, assemble images, label, and post them into the forum?

1) View Youtube or other?
Mostly YouTube, but also some different websites.

2) Use some kind of YT frame capture or download video and use which other software to capture a single frame from the video.
Use RealPlayer (it is free) to download and trim video.
Use Kinovea (it is free) to save particular frame of video as picture with JPEG extension.


3) What video software or other software did you use to assemble the selected frames and label them?
That can be any drawing application, for example: PaintBrush, PowerPoint, and Photoshop.

4) Did you prepare the assembled pictures and upload them to an internet photo site and then entered the URL link in the box available ("Image Insert") on the TW forum reply page?
I use tinypic.com (it is free).

[sureshs]

I did a minor adjustment today which fixed a backhand issue (for good I hope). I consciously made sure that the racket face was closed on take back. It seems much easier to start with a closed face and go more open later, than vice versa. I realized that I always had a closed face on my forehand, but not on my backhand. Then I noticed several players today making the same mistake and hitting weak or long backhands (but I did not tell them about it).

[luvforty]

this below the sweetspot stuff, may have merit, but practically useless..

i be happy if i put the racket on the ball.

[corners]

Originally Posted by luvforty

i be happy if i put the racket on the ball.

LOL. Me too.

[Chas Tennis]

MYTH: Step forward to put your 'weight' into the shot.

REALITY: Your weight is the magnitude of the force from earth's gravity that attracts you to earth. [A vector has both magnitude and direction.] The force is a vector that is always directed toward the center of mass of the earth, down. How am I putting 200 lbs into the shot?

SPECULATION: You move your mass into the court by stepping forward while and at the same time rotating or moving some body parts back in the backswing. In this way you pre-stretch some useful muscles using the inertia of both body parts & the racket relative to your center of mass and deliberate muscle activation. Those pre-stretched muscles can then forcefully, rapidly, smoothly and maybe more reproducibly shorten to produce a large portion of the racket head speed. If you don't get you mass moving into the court by stepping the pre-stretching of some of these muscles is much less effective.

[luvforty]

no.. gravity always down doesn't mean it can't help creating forward momentum.

from standing still, how do you start walking forward? you don't just start pushing with your feet..... you actually first move your CoG forward by 'falling forward', the you move your feet to 'catch yourself' to start walking.

you can put you weight into the shot... not the entire 200lbs though.

[Chas Tennis]

Originally Posted by luvforty

.................................................. ..
you can put you weight into the shot... not the entire 200lbs though.

Roughly how much of my weight do you think I can put into my shot?

[10isfreak]

Originally Posted by Relinquis

ultimately what are you going to do with this knowledge? apply it, right?

why don't you guys go out to a court and try your theories? see what happens trying to hit below or above or on the centre during practice rallies and then during a match. Report back, maybe with a bit of video.

this forum isn't a peer reviewed academic journal. you're just arguing without having done a controlled experiment nor have you gathered empirical data systematically. What are you trying to prove apart from being keyboard warriors?

You're not advancing anyone's understanding with your tone and arguments.

Well, I doubt that they can really go out on a court and test their hypotheses. By the way, the concept of "theory" in a scientific context involves a test or a series of test: a theory is a validated hypothesis or a collection of these.

But I agree with your point. Without data, we cannot make the right call. When I initiated this thread, I used the blog of a researcher to present simple principles that we can all apply in our everyday lives. As a fact lower contact do lead to higher spin rate, but whether this is manageable for a player to get is a different question... maybe they are results of slight differences in the player's movement as "dominik" suggests, maybe not.

The only important point is that what the best pros do on the court to hit good forehands differs a lot from what we read on this forum or even hear by sometimes famous coaches and knowing these distinctions between the factual reality and the doctrines which are professed by people such as Wegner can enable you to make a difference in your game.

[10isfreak]

Originally Posted by Chas Tennis

MYTH: Step forward to put your 'weight' into the shot.

REALITY: Your weight is the magnitude of the force from earth's gravity that attracts you to earth. [A vector has both magnitude and direction.] The force is a vector that is always directed toward the center of mass of the earth, down. How am I putting 200 lbs into the shot?

SPECULATION: You move your mass into the court by stepping forward while and at the same time rotating or moving some body parts back in the backswing. In this way you pre-stretch some useful muscles using the inertia of both body parts & the racket relative to your center of mass and deliberate muscle activation. Those pre-stretched muscles can then forcefully, rapidly, smoothly and maybe more reproducibly shorten to produce a large portion of the racket head speed. If you don't get you mass moving into the court by stepping the pre-stretching of some of these muscles is much less effective.

The vast majority of strokes do not involve forward movement, although it is clear that you can more easily hit a better shot by moving forward. As you pointed out, the wording is both confusing and wrong regarding this phenomenon.

As a matter of fact, many micro movements enable players to benefit of specific muscular reflexes that makes it easier to reproduce the stroke every time, all the while making themselves more powerful. A muscle which is fully extended will contract faster, provided that this extension doesn't last long: you have a window of half a second to use it to enhance your performances.

We call this phenomenon a stretch-shortening cycle because the muscle goes through a cycle of eccentric and concentric contraction which enables the individual to shorten the amount of time required to perform the concentric contraction. It seems complicated, but eccentric and concentric just means "toward the exterior" and "toward the center." A muscle eccentrically contracts when the antagonist muscle forces the muscle into extension (for instance, your biceps forces your triceps into eccentric contraction when you use them to lift a weight). Isometric just means holding stuff into place, like trying to sit on a fake chair to train your leg muscles.

End of the parentheses. Your point does present an issue... You do not have to be moving forward to benefit of these cycles. Some of them involve muscles which have nothing to do with your body's position or where it is heading. In fact, you can hit just as hard while moving backward than moving forward... just as you hit a 100 mph running forehand.

The only difference is that moving backward involves a different set up which is, upfront, less usual or common. If you practice it, you can do it right, though and it's pretty similar to hitting an airborne forehand such as what Federer likes to do. The key is that you find a way to use your last step to begin your motion. On every version of the running forehand, of the airborne forehand, of the forehand approach shot or while moving back... every one of them can be hit with the same overall motion. The point is that you need, as if you were standing still, to begin with your racket leg -- you need to use it in order to begin your hip rotation. That's the key to ALL forehand strokes which involve complex footwork.

In terms of hitting it, you're still rotating just the same and you're still enjoying plenty of sources of power. It simply requires a more complex sequence of action and it can be more easily thrown off than, say, if you were hitting forehand without having to move.

[10isfreak]

Originally Posted by sureshs

I did a minor adjustment today which fixed a backhand issue (for good I hope). I consciously made sure that the racket face was closed on take back. It seems much easier to start with a closed face and go more open later, than vice versa. I realized that I always had a closed face on my forehand, but not on my backhand. Then I noticed several players today making the same mistake and hitting weak or long backhands (but I did not tell them about it).

It's a simple thing which makes a lot of difference in terms of control and pace. With the safety of additional spin, people can hit out a lot more loosely. Furthermore, spin confers control over the ball's placement.

[sureshs]

Originally Posted by 10isfreak

It's a simple thing which makes a lot of difference in terms of control and pace. With the safety of additional spin, people can hit out a lot more loosely. Furthermore, spin confers control over the ball's placement.

The spin was there - it was more like the closed face made it easier to be consistent than sometimes starting with a slightly open face and then closing it. By always closing it, or leading with the edge as Oscar says, you can open it up a little if you want to.

[Chas Tennis]

Originally Posted by 10isfreak

.................................................. ..........
.........................A muscle which is fully extended will contract faster, ....................... See the Hill Muscle Model and Velocity vs Force for passive and active muscle shortening. The main point may be that the stretched muscle can passively shorten faster than it can actively shorten using deliberate activation. This implies you always want to use stretch in preference to active shortening for the fastest part of your strokes. That's how I interpret recent descriptions of the stretch-shortening cycle.
..............................................A muscle eccentrically contracts when the antagonist muscle forces the muscle into extension (for instance, your biceps forces your triceps into eccentric contraction when you use them to lift a weight). ........................The antagonist muscles are matched in size to the agonist muscles. Antagonists contribute to stretch but bigger muscles can cause the joint itself to translate up in a serve or forward or up in a tennis forehand. Along with inertia of body parts & racket that translation of the joint forward in the case of stepping in can pre-stretch the muscle.

........................... You do not have to be moving forward to benefit of these cycles. Some of them involve muscles which have nothing to do with your body's position or where it is heading. In fact, you can hit just as hard while moving backward than moving forward... just as you hit a 100 mph running forehand. .....I see how translating the joint forward or up for a forehand can stretch muscles and add to the pace of a forehand. I guess that a backward motion or other could be used to stretch useful muscles but can't yet visualize how.

...........................to hitting an airborne forehand such as what Federer likes to do. The key is that you find a way to use your last step to begin your motion. On every version of the running forehand, of the airborne forehand, of the forehand approach shot or while moving back... every one of them can be hit with the same overall motion. The point is that you need, as if you were standing still, to begin with your racket leg -- you need to use it in order to begin your hip rotation. That's the key to ALL forehand strokes which involve complex footwork.
I think that the leg thrust is another form of big-slow muscles stretching smaller-faster muscles. My interpret of what you are saying is that the force of leg thrust can be in various directions and still result in stretched muscles and a strong forehand. I guess that Federer is putting his 'weight' up into the shot for those airborne forehands.
.........................................

Better to say- Translate you body and your joints in a way to stretch the muscles used for the forehand.

[Kevo]

Most people use weight and mass interchangeably. So moving forward to put your weight into the shot is fine IMO. It's not necessarily the new school way to hit the ball, but it does work quite well. I've hit many winners while moving forward into the shot.

Also, hitting the ball with your weight(mass) moving forward rather than swinging makes for some of the most spectacularly power volleys I have ever hit. It's amazing really how much hurt you can put on the ball with a step forward and a slight forward movement of the racquet. It's really a shame I don't typically move properly up to net and I like to swing too much.