Discussion in 'Tennis Tips/Instruction' started by luvforty, Feb 28, 2013.
wow maybe i had a twin separated at birth!
run with it, cheetah
I'm with you - both.
this. /end of thread
you need both to square the racket up.
actually I agree that both ISR and pronation happens.
i just have problem with the 'swinging on edge' part, not so much with how the face is squared.
I don't know and don't know how to get hand pressure from high speed videos. (Pressure sensitive gloves that can measure hand pressure exist and may have been used for tennis serve research. ??)
The racket appears to accelerate mostly angularly with the axis of rotation of the arm. To give that acceleration to the racket handle might involve mostly a torque with balanced pressures, for example, mostly equal pressures on both bevels 3 & 7 with the pressure on bevel 3 being closer to the racket head.
You can get a sensation by holding the racket in the impact position at an angle to the straight arm. Rotate it using ISR. That is what happens before impact but the angle between the arm and racket is rapidly changing from ~90° to the angle at impact,"β". Be careful not to do this very forcefully or with a poor shoulder orientation as explained in the Ellenbecker video and Jim McClellan videos or there could be impingement.
^^ right, so if you need pressure on bevels 3 and 7..... why would you teach 'swing up on edge' - which implies pressure on bevel 1.... right?
I don't know much about the bevels and hand pressure and was speculating.
'Edge on' and other service motion check points:
1) Edge On. I find it useful to make sure that my racket has an edge on orientation in my service motion. I tend to leave that out. I want the transition from edge on to impact to be relaxed and to be a result of muscle memory from practice.
2) Wrist Flexion & Racket Handle Pointing at the Ball. I also want the racket handle to point at the ball at a point in the motion. I tend to leave that out too. I believe the joint motion of wrist flexion - listed right behind ISR as contributing the most to racket head speed - while it might be a rapid joint motion is the result of ISR and not wrist muscles. In my opinion, pointing the racket handle to the ball is important so that wrist flexion occurs.
3) Angle Between the Arm & Racket at Impact - β. I also use too little β.
IMO you are right.
When pros hit flat serve they often use intense wrist extension and then wrist flexion. The wrist extension brings the racquet in semi open position, so they cannot ‘swing up on edge’, see figure below and post http://tt.tennis-warehouse.com/showthread.php?p=5276723#post5276723. :shock:
thank you toly -
arche3 go double up on that xanax !
^ Just cuz toly says it, doesn't make it so. I will address several points later.
You are welcome. There is one more example - Chanelle Scheepers hits slice serve with extreme wrist flexion and brings the racquet in semi open arrangement. That’s why she also cannot ‘swing up to edge’.
Again, I'm confused.
The "on edge" portion of the swing is fairly small for most serves. All the stills shown are from just before contact, if the racket were on edge at this point it wouldn't be able to hit the ball.
Are people really arguing that the racket face stays on edge until just before contact?
This whole discussion has me confused. It seems that the whole issue is that luvforty seized on the "on edge" part of somebody's description of how to serve and it messed up his form.
Why not just drop the description and watch the motions that good servers make?
Federer has very little pronation on serve and overhead IMO, so not the best example.
@Wild - my serve used to be weak.... this on edge thing didn't hurt, but didn't help at all....
look at the good serves - easier said than done..
Instruction ‘on edge’ is a little bit confusing. This suggests that we need to hold constantly the racquet string bed in a vertical position during upward swing. So, this doesn’t allow us to use wrist extension/flexion to produce additional RHS. If we want to use wrist extension/flexion for extra speed creation, I believe it could be better to forget about ‘swing up on edge’. This is really not big deal.
Deleted due to it not adding to the discussion.
Look at slow motion video of the professionals on the tube. Put a camera on a tripod and then video your serve during the next practice. Compare it to the professional and see what you are doing wrong. The preceding is easy.
The hard part is then getting your body to adopt the changes you know you need to make.
But if you don't have the money to hire a good coach, I can't recommend using video highly enough. Seriously, the mental image we have of what we are doing is over-rated. The camera will show you the truth and then allow you to make real improvement.
Disagree with this. When this wrist is c0cked, it is not "intense wrist extension" (whatever that means). The c0cking of the wrist is partly wrist extension and partly radial deviation. On the upward swing to contact, the wrist moves from the c0cked position to a fairly neutral position at contact. I would not characterize this wrist action as a "wrist snap".
The problem with that phrase is that it is very misleading. Many/most players mistakenly assume that the wrist will be in flexion (position) either before or after contact when told to "snap the wrist". The wrist should not be in a position of flexion before contact or after contact. It is not even necessary to assume a position of flexion after contact either. However, some elite players may have a slight flexion well after contact.
The racket does move up on edge. However, for a flat serve,most of this "on edge" motion is prior to the big L (prior to image #1 in your sequence). For a spin serve, the racket moves "on edge" longer.
do you realize the arm is already straight in each of these frames?
Chanelle Scheepers definitely has straight arm, post 62.
I think Kevin Anderson hits the ball with slightly bend elbow, see explanation in post http://tt.tennis-warehouse.com/showthread.php?p=5276723#post5276723
Here is Chas Tennis post about “Definition & usage of Pronation & Supination.
IMO we can say that the wrist is in maximum extension position (or minimum flexion position) when it has angle -90°. Similarly, the wrist is in maximum flexion position (or minimum extension position) when the angle is +90°. Start point of motion can be arbitrary within the range from -90° to +90°. So, according to proper definitions of these motions I can use the term wrist flexion to describe the wrist unbending progression.
Duplicating these frames makes for a very nice demonstration of ISR and its relation to the "edge on" discussion. Stand anywhere holding a racket, no ball -
1) Tilt shoulders, one high and one low as the server is doing in all frames. (Important to minimize impingement risk as discussed earlier.)
2) Straighten the arm, keep straight throughout (as in all frames).
3) Racket 90° to arm to start and pointed back (as in frame #1) or as far back as it goes since you cannot get as much stretch in the demo as in a real serve. Racket is "edge on" to the imaginary ball position (as in frame #1).
4) Now internally rotate the shoulder as shown in frames 1-7.
5) As ISR rotates the upper arm for, say, ~90° of ISR, decrease the angle between the arm and racket from about the 90° of frame #1 to say, 30°, at impact (estimate of racket-arm angle in frame #7).
6) The racket had an approximate edge on orientation in frame #1 and with about 90° of ISR will be square to the back of the ball.
All angles are very approximate, will vary between serve types, etc. .
With No Wrist Motion. Notice that starting in the position of frame #1, without any wrist motion, that about 90° of ISR would take an edge on racket to flush on the back of the ball at impact.
Question - In frame #1 the ball must be closer to the camera than the racket head even though they appear to be in the same plane. Maybe the edge on racket location in that frame is not directly toward the ball but displaced to the side. ??
The frames also show the relative amount of forward hand motion and forward racket head motion.
Do not try to pronate the wrist. That's impossible. Only try to realize the truth.
There is no wrist. Then you'll see, it is not the wrist that pronates, it is only yourself.
I'm looking at ways of hitting a fake drop shot.
If I pronate my entire torso at the last moment, will it turn my
dropshot into a power baseline drive?
Only if you are the One.
Quite a few times in the past 5-6 years I have indicated that flexion, extension, etc. can be applied to both position and to an action/movement. I have never said that the unbending that you talk about is not a flexion action. I completely agree that a motion from an extended position to a neutral position is a flexion action -- I have indicated this many times previously.
What I have said is that the term "wrist snap" is misleading. In my mind and in the minds of many other students of the game, it implies a an extreme wrist action where the wrist ends in a fully flexed position. To some it also implies that the wrist is in a flexed position at contact. Both are incorrect conclusions that derive from a misleading instruction.
The other thing that I do not agree with is that the wrist assumes a full wrist extension on the serve. For normal ROM, the wrist can be extended up to ~70 degrees. From my observation (of your images), the wrist is not extended to this degree for the serve. What I see is that the wrist is radially deviated with something less than full extension.
Fed's pancake serve !! for real.
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