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View Full Version : How important are legs (viz. knee bend) in the serve?


Eph
04-06-2008, 02:24 PM
How important is the knee bend in your serve? And being able to use your legs fully.

I'll explain why I ask after someone answers.

dave333
04-06-2008, 02:29 PM
They don't actually add that much speed to your serve. People in wheelchairs can serve 100+. The difference between men and women on their serve is the upper body muscles, where men are considerably stronger.

But I guess that by exploding up, your contact point goes higher, so you have a better angle.

Eph
04-06-2008, 02:36 PM
They don't actually add that much speed to your serve. People in wheelchairs can serve 100+. The difference between men and women on their serve is the upper body muscles, where men are considerably stronger.

But I guess that by exploding up, your contact point goes higher, so you have a better angle.

Ah, so the angle is important?

I ask because I wear a knee brace (that while my knee surgeon says this is what he gives to the pro hockey players [he's a sports surgeon for a pro hockey team] so it fits over their gear, it is really causing me hell). I can't bend properly and I can't get a little jump off the ground.

I decided to take off the brace today (just to practice serves) and I was serving at 70% 1st serve and about 8/10 were hitting the fence with just one hop (what's the approximate speed of that, btw? some were down the T, some in the middle, and even a few the were on the side line) and I felt actually *fluid*. When serving with my knee brace, I would be lucky to get 3 out of 10 shots in the box and it's *really* affecting my game. But I can't take off the brace to play - that would be suicide with the state of my knee.

So, can I safely say my ****** serve is because of my knee brace?

Supernatural_Serve
04-06-2008, 02:48 PM
So, can I safely say my ****** serve is because of my knee brace?Yes, but it doesn't have to remain that way. Any change to basic serve mechanics is going to set you back until you make natural adjustments throughout your entire service motion to accommodate your brace and less knee bend.

Eph
04-06-2008, 02:49 PM
Yes, but it doesn't have to remain that way. Any change to basic serve mechanics is going to set you back until you make natural adjustments throughout your entire service motion to accommodate your brace and less knee bend.

Well, the thing is, I have only been playing tennis since I've been wearing the knee brace (unless you count the times when I was 10). And yet, when I take off the brace, I can serve properly. When it's on, I serve like **** - it either goes straight into the net (80% of the time) or flies ten feet high.

Eph
04-06-2008, 02:50 PM
I really don't like making excuses for poor playing, but this is setting me back. I've dealt with bad knees and a bad back for a long, long time, and I basically said F*CK the docs, and am just enjoying life, which includes playing tennis.

Bungalo Bill
04-06-2008, 03:12 PM
How important is the knee bend in your serve? And being able to use your legs fully.

I'll explain why I ask after someone answers.

In a properly executed serve you send power upward from the ground by throwing that energy up threw your legs, torso, and arm upward. It is the knee bend that helps thrust this energy and your body upward.

So the legs are important for transferring power upward. Otherwise, if you do not use your lower body properly, you wil have to generate it all from the upper body which could conflict with your ability to relax the hitting arm and the flexibility in this arm because you might have a tendency to contract the muscles for more power.

dakels
04-06-2008, 03:55 PM
As previously stated, the knee bend helps facilitate the spring upward and forward. While you can achieve good rotational force with little to no knee bend, your serve becomes more limited by lower height of contact, momentum, and also the propensity to slap at the ball using only upper body strength. Legs also allow you to spring into the court better for approach on serve and volley. Knee bend also helps you sweep up on the ball for a topspin or twist serve.

One of the key things about knee bend and jumping into a serve is properly transitioning that power through the ball. So many times I see people with a good knee bend and poor transfer of weight into the contact point. You need to keep the movement fluid with arm fully extended at contact. Your contact point need to be into the court and above you, not to the side or too far behind.

About the ball hitting the back fence... It's hard to say how fast that is. Depends on so many factors. Depth, spin, surface all affect how far the ball bounces. It's probably going at least 60-70mph but then again, who cares. Quality of the serve is, of course, so much more important. I used to serve about 110mph but frankly, that serve sucked. It was very flat and sat up about waist level. A better placed serve 10mph slower with more movement/spin gave me much better result and more unreturnable serves.

chess9
04-06-2008, 03:56 PM
Also, a properly timed upward thrust of the legs will open the chest and slightly accentuate the 'drop' element of the arm motion, increasing racquet head speed.

So, do it.

-Robert

Bungalo Bill
04-06-2008, 04:08 PM
Also, a properly timed upward thrust of the legs will open the chest and slightly accentuate the 'drop' element of the arm motion, increasing racquet head speed.

So, do it.

-Robert

Agreed. However, do you think that the chest opens only from the use of the legs? Or that the legs contribute to an easier opening of the chest and drop? Read your comment above because that is what it seems to imply.

dave333
04-06-2008, 04:09 PM
[QUOTE=Eph;2229566]Ah, so the angle is important?

QUOTE]

The higher your contact point, the higher over the net your serve will go over, letting you need less spin to make it over. It also gives you more places you can put your serve. This is part of why servers like Isner and Karlovic can get so many aces; they can put their serves in really wide parts of the court without needing a lot of spin to bring the serve back in.

Bungalo Bill
04-06-2008, 04:13 PM
[quote=Eph;2229566]Ah, so the angle is important?

The higher your contact point, the higher over the net your serve will go over, letting you need less spin to make it over. It also gives you more places you can put your serve. This is part of why servers like Isner and Karlovic can get so many aces; they can put their serves in really wide parts of the court without needing a lot of spin to bring the serve back in.

Dave, I am not disagreeing with you and I do understand what you are saying. However, I do know that even with hieght (for example I am 6'2"), the serve may not pass over the net so well. This could be because of a brought down arm due to a players head moving down before contact.

Vic showed us a video, of how the head of a player can cause a slight alteration in the swing path of the racquet. It showed that when a persons head went down, so did their shoulder and ultimately their racquet.

dave333
04-06-2008, 04:23 PM
^^^ I was sort of talking about guys with excellant technique, where extra height can make a pretty big difference.

chess9
04-06-2008, 04:38 PM
Agreed. However, do you think that the chest opens only from the use of the legs? Or that the legs contribute to an easier opening of the chest and drop? Read your comment above because that is what it seems to imply.

No, not only from the use of the legs. You can't be in a proper drop position if the chest isn't fairly well open before the upward thrust. The difference though is that by thrusting upward with an already somewhat open chest, one stretches the pecs and shoulder girdle and loads them to add to the explosiveness of the serve. In Roddick's case, for instance, I think pec and shoulder girdle loading is a larger component of his power than one normally finds even in very good pro servers. He is a unique individual obviously, with loads of power, great timing, and great shoulder flexibility.

-Robert

Bungalo Bill
04-06-2008, 05:23 PM
No, not only from the use of the legs. You can't be in a proper drop position if the chest isn't fairly well open before the upward thrust. The difference though is that by thrusting upward with an already somewhat open chest, one stretches the pecs and shoulder girdle and loads them to add to the explosiveness of the serve. In Roddick's case, for instance, I think pec and shoulder girdle loading is a larger component of his power than one normally finds even in very good pro servers. He is a unique individual obviously, with loads of power, great timing, and great shoulder flexibility.

-Robert

Okay, just wanted to clarify. Good post.

Bagumbawalla
04-06-2008, 06:03 PM
Imagine you have a straight stick about 9' long with a with a 1' leather "whip" at the end.

You also have a "bull-whip" that has a 1' handle and 9' of flexable, braided leather.

With which one will you be most likely to make that familiar cracking sound (that is the tip breaking the speed of sound).

Exactly so.

Also like skaters holding hands in a long "whip-chain" the central, slower, skaters may only move a small bit, but by the time the action is carried/transfered to the outside/farthest skater, it is enough to fling that person across the rink.

Likewise, although the legs are only a small part in the cumulative chain of actions that is the serve, without that action the racket head speed will be diminished to some extent (physics majors out there?).

I don't know exactly to what extent, but here is an experiment. Have someone throw a baseball as far as they can using the full force of every muscle available to them. Mark the landing point.

Then have them stand absolutely still on stiff legs and repeat the toss.

That will indicate the importance of the legs to the total action.

Having said that, depending on your opponents and level of play, a good sports-quality knee brace shouldn't ruin your serve.

Bungalo Bill
04-06-2008, 06:16 PM
^^^ I was sort of talking about guys with excellant technique, where extra height can make a pretty big difference.

Yes, I know you were. Which is why I said I agree with you figuring you might be implying that.

Eph
04-06-2008, 08:50 PM
In a properly executed serve you send power upward from the ground by throwing that energy up threw your legs, torso, and arm upward. It is the knee bend that helps thrust this energy and your body upward.

So the legs are important for transferring power upward. Otherwise, if you do not use your lower body properly, you wil have to generate it all from the upper body which could conflict with your ability to relax the hitting arm and the flexibility in this arm because you might have a tendency to contract the muscles for more power.
When you say relax the hitting arm, by not relaxing it, are you at a greater risk of losing your grip on the racquet?

Hooooon
04-06-2008, 08:54 PM
it's about more than extra height.... think of yourself as a projectile shooting into the air. the faster you are going up the more upward momentum the ball has coming off your racquet... giving you more net clearance and allowing you to hit "down" more

Bungalo Bill
04-06-2008, 08:58 PM
When you say relax the hitting arm, by not relaxing it, are you at a greater risk of losing your grip on the racquet?

Eph,

Show me where I said that because I lost the context in which I said something like that. Normally, I talk about relaxation of the hitting arm alone.

The grip on the racquet should be very light to allow the wrist to be very flexible. However, you need to have slight pressure in your grip so the racquet doesnt fly out of your hand.

Eph
04-06-2008, 09:01 PM
Eph,

Show me where I said that because I lost the context in which I said something like that. Normally, I talk about relaxation of the hitting arm alone.

The grip on the racquet should be very light to allow the wrist to be very flexible. However, you need to have slight pressure in your grip so the racquet doesnt fly out of your hand.

Well, I mainly ask because I am developing a blister around my knuckle on my thumb and it causes me to sometimes lost the racquet when serving and either A) missing completely or B) hitting it way out (more often than A). I tried popping the blister when I got home, but it doesn't want to pop and now has built up with blood around it. I put neosporin on it hoping it would start healing.

spiritdragon
04-06-2008, 09:06 PM
They don't actually add that much speed to your serve. People in wheelchairs can serve 100+. The difference between men and women on their serve is the upper body muscles, where men are considerably stronger.

But I guess that by exploding up, your contact point goes higher, so you have a better angle.

wow, that's amazing. is this really true?

Bungalo Bill
04-06-2008, 09:07 PM
Well, I mainly ask because I am developing a blister around my knuckle on my thumb and it causes me to sometimes lost the racquet when serving and either A) missing completely or B) hitting it way out (more often than A). I tried popping the blister when I got home, but it doesn't want to pop and now has built up with blood around it. I put neosporin on it hoping it would start healing.

A loose grip is needed for the serve. It is a bit looser then the forehand because you really want the wrist area to be loose and floppy. So I dont know what to tell you about the blister.

Eph
04-06-2008, 09:23 PM
A loose grip is needed for the serve. It is a bit looser then the forehand because you really want the wrist area to be loose and floppy. So I dont know what to tell you about the blister.

Sorry if I am asking rather naive questions, but there's no where else to ask them, and I can't afford a coach at 60/hour (who isn't any good, in the first place).

My other question is, how do I work on putting spin on the first serve?

Bungalo Bill
04-06-2008, 09:26 PM
Sorry if I am asking rather naive questions, but there's no where else to ask them, and I can't afford a coach at 60/hour (who isn't any good, in the first place).

My other question is, how do I work on putting spin on the first serve?

In a nutshell? Slowly. If you know the serve you want to hit or the spin you want to create (like topspin) then practice your motion slowly and deliberately. Once you see the action you want on the ball. Speed up the motion and see if you can do the same with a faster motion.

Eph
04-06-2008, 09:28 PM
In a nutshell? Slowly. If you know the serve you want to hit or the spin you want to create (like topspin) then practice your motion slowly and deliberately. Once you see the action you want on the ball. Speed up the motion and see if you can do the same with a faster motion.

I really need to ask my surgeon about getting a brace that isn't quite as strong (I'm also a ski racer and that's what he intended this for), so I can actually bend my knees. There *is* a difference in my serve.

The thing is, I don't know how to create topspin on a serve (or any type of spin on a serve, for that matter).

THSBOI
04-06-2008, 09:28 PM
I think its important because then you would throw more power at the ball and it would go faster thats IMO

vndesu
04-06-2008, 10:01 PM
I think its important because then you would throw more power at the ball and it would go faster thats IMO

it plays an important part but you also got to use your b ody shoulder etc.

Trinity TC
04-12-2008, 03:05 PM
How important is the knee bend in your serve? And being able to use your legs fully.

I'll explain why I ask after someone answers.
I've coached players that have had a history of knee problems and it is possible to have a reliable and powerful serve without the type of knee bend that the pros use. You can still get a good enough leg drive and upper body torque with more subtle movements.

Keep working on the grip and arm motion...and stay away from anymore injuries. :)