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-   -   The arm is not dragging by the body (http://tt.tennis-warehouse.com/showthread.php?t=407618)

albesca 12-31-2011 12:55 AM

The arm is not dragged by the body
 
Start by saying that this is only the opinion of a tennis lover, I have the pleasure to share that opinion with you.

I think that pushing more with legs or turning fast the trunk will not help on producing more arm speed.

The speed of the arm is produced by the arm.

The important thing is to understand the body posture significantly affects the ability to swing fast the arm.

Searching the perfect distance and taking the perfect posture at a certain time, here is what the body does. During the search for the ball, the positioning of the feet, the body coiling ...the arm doesn't exist. But when it's time to hit the arm becomes the master, and the body simply has to follow his will.

Happy new year to all
Al

papa 12-31-2011 05:06 AM

Well, first of all we're interested in racquet "head" speed and its not just generated by the arm - far from it. Most lower level player use way too much arm in playing this sport and as a result either end up with arm/shoulder injuries, are totally inconsistent, can't generate much pace, etc. When just the arm is involved, there is excessive lateral movement into the ball as compared with rotation. When just lateral movement is involved the stroke is very sluggish and just won't hold up.

So, in my opinion, you have this a little bit backwards.

albesca 12-31-2011 08:01 AM

Tank you Papa for ur opinion. I don't talk about all the stroke .. i'm talking only about the forward swing. Before, body works hard for positioning and loading... but as the forward swing starts I think the body must reduce its role about to do the correct footwork and upper body would have to uncoils following the arm, and not driving it.

rkelley 12-31-2011 08:26 AM

Quote:

Originally Posted by albesca (Post 6200714)
Tank you Papa for ur opinion. I don't talk about all the stroke .. i'm talking only about the forward swing. Before, body works hard for positioning and loading... but as the forward swing starts I think the body must reduce its role about to do the correct footwork and upper body would have to uncoils following the arm, and not driving it.

Well, I would advise the opposite of what you're saying here. The legs, trunk, and shoulders provide the power. They start the swing. The arms and the racquet whip around and the head of the racquet whips into the ball. The arms and wrist do some fine tuning as to exactly when the whip is cracked and exactly where the racquet head goes - that's why you keep your eye on the ball through impact - but the legs, trunk, and shoulders start the swing and provide the power.

spacediver 12-31-2011 08:28 AM

Just because the arm is swinging around joint X doesn't mean that the momentum is generated at joint X.

Think of a whip - the tip of the whip breaks the speed of sound, but all the momentum is generated in the heavy handle.

toly 12-31-2011 12:33 PM

Quote:

Originally Posted by rkelley (Post 6200772)
Well, I would advise the opposite of what you're saying here. The legs, trunk, and shoulders provide the power. They start the swing. The arms and the racquet whip around and the head of the racquet whips into the ball. The arms and wrist do some fine tuning as to exactly when the whip is cracked and exactly where the racquet head goes - that's why you keep your eye on the ball through impact - but the legs, trunk, and shoulders start the swing and provide the power.

When we rotate trunk with acceleration, IMO the passive arm will never whip around the body. Thus, the arm and its parts should be active, or we should slow down trunk acceleration. Does it make any sense?
If trunk doesn’t rotate at all, the arm by itself still can rotate around shoulder joint etc. I believe that good athlete can hit 100 mph FH without trunk rotation, by using just active arm motions. He will never be able to do that with passive arm relying on whip effect. I tried it many times and always got pathetic FH.:)

maxpotapov 01-01-2012 02:39 AM

Quote:

Originally Posted by toly (Post 6201073)
When we rotate trunk with acceleration, IMO the passive arm will never whip around the body. Thus, the arm and its parts should be active, or we should slow down trunk acceleration. Does it make any sense?
If trunk doesn’t rotate at all, the arm by itself still can rotate around shoulder joint etc. I believe that good athlete can hit 100 mph FH without trunk rotation, by using just active arm motions. He will never be able to do that with passive arm relying on whip effect. I tried it many times and always got pathetic FH.:)

My experience, pretty much. But all those exercises helped me to improve my body positioning, posture, core and back muscles etc.
Now I simply add arm/wrist/fingers action to turn racquet head around, once I got fundamentals (lower/upper body) right.

It is simple physics: during body rotation centrifugal forces pull racquet forward/away, not around the body. There is no physical way racquet shaft will bump against your left shoulder on follow through if your hitting arm is all passive during upper body rotation.

albesca 01-01-2012 03:41 AM

Quote:

Originally Posted by rkelley (Post 6200772)
Well, I would advise the opposite of what you're saying here. The legs, trunk, and shoulders provide the power. They start the swing. The arms and the racquet whip around and the head of the racquet whips into the ball. The arms and wrist do some fine tuning as to exactly when the whip is cracked and exactly where the racquet head goes - that's why you keep your eye on the ball through impact - but the legs, trunk, and shoulders start the swing and provide the power.

Obiouvsly there are many ways to hit the ball on the other side of the court. What I believe is that it is impossible or so to produce an heavy ball without producing an high raquet head speed... and by dragging the arm whit the trunk i don't believe it is reliable.

Sure, the more fast we want to swing the arm, the more we have to be able to rotate the trunk fast, that mean great body and legs work .. but not the opposite.

Ironically, a too fast trunk rotation can disturb the swinging of the arm instead to help it on swinging fast.

Quote:

Originally Posted by toly
When we rotate trunk with acceleration, IMO the passive arm will never whip around the body. Thus, the arm and its parts should be active, or we should slow down trunk acceleration. Does it make any sense? If trunk doesn’t rotate at all, the arm by itself still can rotate around shoulder joint etc. . I believe that good athlete can hit 100 mph FH without trunk rotation, by using just active arm motions. He will never be able to do that with passive arm relying on whip effect. I tried it many times and always got pathetic FH

Agree Toly, exactly what I would say.


Quote:

Originally Posted by maxpotapov
Now I simply add arm/wrist/fingers action to turn racquet head around, once I got fundamentals (lower/upper body) right.

Absolutely agree Max.

rkelley 01-01-2012 08:09 AM

Quote:

Originally Posted by toly (Post 6201073)
When we rotate trunk with acceleration, IMO the passive arm will never whip around the body. Thus, the arm and its parts should be active, or we should slow down trunk acceleration. Does it make any sense?
If trunk doesn’t rotate at all, the arm by itself still can rotate around shoulder joint etc. I believe that good athlete can hit 100 mph FH without trunk rotation, by using just active arm motions. He will never be able to do that with passive arm relying on whip effect. I tried it many times and always got pathetic FH.:)

When folks talk about "passive arm" it's not to say the muscles in the chest, arm and wrist are not being used, but the majority of the power is coming from the core rotation that starts with the legs, then through the hips and shoulders. Assuming that the arm is still attached to the shoulder at this point it has to whip around the body.

Check out this video, 0:36. This is what's happening: http://www.youtube.com/watch?v=EMNtq...eature=related

And here's a video that shows the whipping action in the full forehand stroke: http://www.youtube.com/watch?v=EMNtq...eature=related

If you try to hit 100 mph forehands with just your arms, assuming that's even possible, I think you'll tear your shoulder apart pretty quickly.

rkelley 01-01-2012 08:30 AM

toly, maxpotapov, and albesca, here are some video links to pro forehands.

Here's Fed's forehand with some good analysis: http://www.youtube.com/watch?v=ydMHJGpypQE

Here's Djokovic's forehand: http://www.youtube.com/watch?v=y8AJY...eature=related
No analysis on this one but you can see (or at least I can) the same action of the shoulders whipping the arm around. Note that Djokovic is using a Western grip.

And then there are the two Lock and Roll videos that explain the concept and teach the forehand:
http://www.youtube.com/watch?v=Wwg9DB8S8a8
http://www.youtube.com/watch?v=EMNtq...eature=related

Give this stuff a try.

5263 01-01-2012 08:30 AM

Quote:

Originally Posted by toly (Post 6201073)
When we rotate trunk with acceleration, IMO the passive arm will never whip around the body. Thus, the arm and its parts should be active, or we should slow down trunk acceleration. Does it make any sense?
If trunk doesn’t rotate at all, the arm by itself still can rotate around shoulder joint etc. I believe that good athlete can hit 100 mph FH without trunk rotation, by using just active arm motions. He will never be able to do that with passive arm relying on whip effect. I tried it many times and always got pathetic FH.:)

IMO you and the OP make some good points here and that maybe the
body does more to position the arm so that then the arm can create the
acceleration of the racket. Oscar often talks of how much the biceps are
involved.

papa 01-01-2012 08:46 AM

Quote:

Originally Posted by rkelley (Post 6202125)
When folks talk about "passive arm" it's not to say the muscles in the chest, arm and wrist are not being used, but the majority of the power is coming from the core rotation that starts with the legs, then through the hips and shoulders. Assuming that the arm is still attached to the shoulder at this point it has to whip around the body.

Check out this video, 0:36. This is what's happening: http://www.youtube.com/watch?v=EMNtq...eature=related

And here's a video that shows the whipping action in the full forehand stroke: http://www.youtube.com/watch?v=EMNtq...eature=related

If you try to hit 100 mph forehands with just your arms, assuming that's even possible, I think you'll tear your shoulder apart pretty quickly.

Well, this is certainly how I see this whole process. I know, and frequently see, other attempts at hitting the forehand but I just don't happen to agree with them.

I know for example of a guy that can absolutely smack the ball and he stays on the rear foot throughout the stroke. For him, "maybe" it works to a degree but I honestly believe that as good as he presently is (I'm taking forehand) he would be that much better if he used the example provided by rkelley. Can he hit the ball with more pace than me - yeah, probably but I'd win hands down when it comes to consistency and placement. He isn't all arm by the way and is able to generate wicked racquet head speed coming across the body which I like - I just like more weight transfer.

I know some don't care to move away from their all arm approach and I realize that for them, it might work. Many have learned this game when racquet/string technology didn't play such a significant role - that's just not the case anymore.

rkelley 01-01-2012 10:26 AM

I've learned this whole modern forehand "thing" and letting my arm whip around in the last year. It's been an adventure.

I'll say that for me it's taken a fair number of hours of practice to get the feel of it. At first, when I did it correctly, it felt great, but other times I'd miss time it. I wasn't feeling the arm whip and I wasn't getting any power. Some days I'd really have it, and then I'd struggle the next time out. I kept at it, practiced on the wall, and now it's pretty automatic.

Relative to my old school forehand the two biggest improvements are greater spin and consistently hitting with more power - and they're linked. I can get a lot more topspin than I used to be able to. This is critical for getting shots to land in that would otherwise go out. I can also hit with greater power in all positions on the court. When I have to I can just stay in a totally open stance, reach across with my left arm and take the racquet back, and rip a pretty decent forehand. But without the topspin all that extra power would launch balls long.

As I've gotten better at hitting this forehand it really cool how much racquet head speed I can get without really swinging that hard. The racquet head just naturally whips around. I can control the swing path so that I can control the amount of topspin verses hitting through the ball.

toly 01-01-2012 10:38 AM

Quote:

Originally Posted by rkelley (Post 6202125)
... but the majority of the power is coming from the core rotation that starts with the legs, then through the hips and shoulders.

This is a very bold statement. You are a Mechanical Engineer. Can you prove your claims using the scientific approach? Please feel free to employ any formula, the laws of physics, math, etc.

Happy New Year!:)

albesca 01-01-2012 10:53 AM

Quote:

Originally Posted by rkelley
If you try to hit 100 mph forehands with just your arms, assuming that's even possible, I think you'll tear your shoulder apart pretty quickly.

No doubt, agree with this point 100 percent. Only I think the trunk doesn't drag..

Dragging the arm, trying to maintain a constant angle at the elbow joint, results in an isometric or so biceps action that stiffens the swing.

This is ok if I have to manage an hard ball .. but I'd clearly divides the cases where our priority is to accelerate the racket head from where our priority is to maintain a stable head of the racket, and this depends, at first, on the speed of the incoming ball.

By me seems to have great raq. head acceleration, the elbow needs some independence form the shoulder joint.. this mean, at the end, to have active biceps during the forward swing.

Quote:

Originally Posted by 5263 (Post 6202178)
IMO you and the OP make some good points here and that maybe the body does more to position the arm so that then the arm can create the acceleration of the racket. Oscar often talks of how much the biceps are involved.

I don't know so much about the Oscar Wegner method, only here I read something, but agree , biceps , forearm pronator and fingers tendons .. imho have the control of the raquet head acceleration.

ho 01-02-2012 05:42 AM

Quote:

Originally Posted by toly (Post 6202356)
This is a very bold statement. You are a Mechanical Engineer. Can you prove your claims using the scientific approach? Please feel free to employ any formula, the laws of physics, math, etc.

Happy New Year!:)

1/Leg and core rotation provide the major power in rotational movement
2/Arm whip around shoulder provide the most racket speed in linear movement.
(1) provide speed if you hit with body and arm as one unit. Not the racket speed that give you the ball speed, but the compression of the ball against a solid object self create the ball speed.
(2) provide racket speed but their is only the arm weight behind the racket, law of physic on colliding will indicate that ball speed will not always as much as (1) particular when ball coming in great speed.

The best way is to combine both:
You hit with arm and body as one unit
Right by the time after contact, whip out your arm forward for more speed and spin.
Saying it is easy, but doing it need great timing and accuracy:
You extend your arm out by:
1/ keeping your arm loose
2/ time the push out of your arm by using your left hand: drop to the chest early will launch your right shoulder at the right moment.

rkelley 01-02-2012 07:00 AM

Quote:

Originally Posted by rkelley (Post 6202356)
... but the majority of the power is coming from the core rotation that starts with the legs, then through the hips and shoulders.


Quote:

Originally Posted by toly (Post 6202356)
This is a very bold statement. You are a Mechanical Engineer. Can you prove your claims using the scientific approach? Please feel free to employ any formula, the laws of physics, math, etc.

Happy New Year!:)

Hi Toly. I don't think of this statement as being bold or controversial. Go to just about any instruction site and you'll see something similar said. It's completely consistent with what I see when I watch pros and high level players hit, and it's completely consistent with my own personal experience.

Meaning no disrespect, but it just seems really obvious to me. Yes, I am a mechanical engineer. As an engineer I'd tell you that muscles groups in your legs and core are far stronger than the muscles in your shoulder alone. Wouldn't it make sense to utilize those stronger muscle groups in generating power? An analytical analysis would need to take into account.

Seriously, just go out and hit some balls. Can you hit it harder when you use just your arm, or when you use your legs and body too? Do what works for you and have fun.

toly 01-03-2012 11:23 AM

Quote:

Originally Posted by ho (Post 6203499)
1/Leg and core rotation provide the major power in rotational movement

It’s true that leg and core rotation provide the major power, but with very low efficiency, from ball/racquet speed point of view. Most of this energy is wasted for rotation of 200 pounds and just a little bit is going to the ball.

Quote:

Originally Posted by ho (Post 6203499)
2/Arm whip around shoulder provide the most racket speed in linear movement.

If arm is passive and moves like the whip, it cannot produce decent linear racquet speed.

Quote:

Originally Posted by ho (Post 6203499)
(1) provide speed if you hit with body and arm as one unit.

It cannot provide a lot of speed because body and arm as one unit has very big mass. Thus, this unit would be relatively slow, compare with elbow or wrist motions.

Quote:

Originally Posted by ho (Post 6203499)
Not the racket speed that give you the ball speed, but the compression of the ball against a solid object self create the ball speed.

The ball speed approximately is

Vballspeed = Vracquetspeed x (1 +K), (1)

Where K is coefficient of restitution.

If the racket has speed 80 mph, K is around 0.3. So, the compression of the ball cannot be the main factor. According to formula (1), the racquet speed is the main factor of the ball speed.


Quote:

Originally Posted by ho (Post 6203499)
(2) provide racket speed but their is only the arm weight behind the racket, law of physic on colliding will indicate that ball speed will not always as much as (1) particular when ball coming in great speed.

See please my posts: http://tt.tennis-warehouse.com/showt...60#post5892760, http://tt.tennis-warehouse.com/showt...80#post5895380

DavaiMarat 01-03-2012 11:37 AM

Quote:

Originally Posted by albesca (Post 6200714)
Tank you Papa for ur opinion. I don't talk about all the stroke .. i'm talking only about the forward swing. Before, body works hard for positioning and loading... but as the forward swing starts I think the body must reduce its role about to do the correct footwork and upper body would have to uncoils following the arm, and not driving it.

You are partly right about this accessment but also partly wrong. I would have to agree with papa, the body plays an importantly role in coiling, the body also uncoils as you bring the racquet out of the slot and forward unto the ball. If you look from the slot and contact the arm doesn't really move that much save for the forearm. As you continue into the forward swing the body stops rotation to allow the arm to 'snap' around the shoulder axis finishing the 2nd to last part of the kinetic chain (wrist being the last). Not very often will you find players extending the fully 180 degrees. Djokovic may be an exception to this rule.

So yes the body rotation stops acts like a fulcrum against the arm but it's the body who initializes the forward swing.

Read the article 'The arms swings the least' at tennisone.com...you will grasp the concept.

I like to think of this way. The arm lifts, the body hits!

toly 01-03-2012 11:38 AM

Quote:

Originally Posted by rkelley (Post 6202125)
When folks talk about "passive arm" it's not to say the muscles in the chest, arm and wrist are not being used,

If arm and wrist are being used actively, there is no reason to talk about the whip. In whip, only handle is active and the rest of whip must be passive. IMO, you are using wrong terminology and got me completely confused.:???:


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