Discussion in 'Tennis Tips/Instruction' started by luvforty, Jan 31, 2013.
Maybe Toly's thinking of the root deligo, which means he loves tennis more than anyone else does.
toly is talking about the delicate sense of touch and feel in his volleys, as in "soft hands."
In reality I’m very harsh. To restrict myself I decided to use this “crazy” signature. :cry:
We should apply forehand pronation/supination before active ISR, see pictures of Federer and Henin in post #26. There must be no forearm supination around impact.
Can you explain please why nobody can understand my explanations about this so simple stuff, unbelievable???
I agree with you. If we apply extreme forearm supination and extreme ESR, these actions can probably stimulate SSC for forearm pronation and ISR. So, they could increase angular speed of the racquet, but also can destroy completely azimuth control. At least I’ve never seen that pros use extreme forehand supination at the start of forward swing, but all of them exploit excessive ESR.
"For instance, in the power serve, pronation is primarily responsible for racquet orientation,.............."
From Biomechanics and Tennis, B. Elliott, See also Table 2, quote above in paragraph below the table.
I've already seen this and the reference you provided talks about velocity only.
There is no mention or implication in that paper supporting Toly's claim that 'all scientific research shows that ball direction is controlled by supination'.
Definitions & Usage of Pronation & Supination
Maybe these arguments on supination & pronation are made worse by the seriously different definitions of terms. I know I have had a very hard time....believing ISR was pronation for decades until 2011, etc.
1) Position. The anatomical definitions of pronation and supination are defined for position of the forearm and not movement of the forearm. They reference 0° as a defined position of the "anatomical position". It is very clearly defined. You can search and find these definitions on the internet. In this video the forearm pronation and supination are measured.
2) Common Usage for Rotational Motion in a Direction. For motion, for a right handed person looking out along the axis of the forearm, pronation is elbow-to-wrist rotation in the counter-clockwise direction and supination is forearm elbow-to-wrist rotation in clockwise direction. That usage is very common, including in biomechanical references. The forearm rotation direction is toward the the same positions as shown in the video above so this usage is closely related to the anatomical definition of #1. You might search and find on the internet, maybe not. If you think this usage is defined please search and provide some links.
3) Tennis Usage of 'Pronation'. The term is broadly used for the considerable arm rotation that can be seen by eye at the wrist especially at the end of the follow through. This motion in the follow through is mostly pronation (the rotation usage of #2). Leading up to impact, however, there is very little forearm pronation but a lot of internal shoulder rotation (ISR) to provide the largest component of racket head speed. The tennis usage of the term 'pronation' can not be searched on the internet. A dinosaur from the 1970s when people looked at tennis strokes by eye .....I even head Elliott use 'pronation' after his research and publications explained ISR. Since pronation is not a good term for the ISR of the serve you can't search and find an internet definition to describe how it is being used - its only in the collective tennis wisdom of....
There is a conflict if you think about the definition of #1 and the common usage of #2. If the angle of the forearm as defined is, say, in a position of 40° of supination but the forearm is rotating in the direction of pronation- are we sure what everybody means by pronation or supination?
"The Anatomical Position" - in this position all joints of the body are in their reference positions including supination and pronation at 0°.
chas I am confused..... #1 and #2 are the same thing, no?
there are actually some guys in baseball that think pre supination (and especially early humeral external rotation) prevents tommy john surgery.
the reasoning behind that is that every throw at some point reaches maximum external rotation (ER). before maximum ER the whip of the forearm cannot really start. a lot of pro pitchers start the arm with a pronated position (similar to the modern FH) and then "bounce" into ER as the arm lays back.
this bounce can be very violent and over time damage the UCL (but they also say that pronation in the forward motion helps saving the UCL).
people said that this motion had something to do with strasburgs injury. Google strasburg+ inverted W and you will find some articles.
there was also a former pitcher called mike marshall who did some researchon this topic.
#1 is an angluar position such as 42° of supination or 13° of pronation. Stationary. No angular motion.
#2 is an angular motion such as rotation toward the pronation side at 300°/ sec. No angular position.
Where are you standing? (#1)
What direction and how fast are you walking? (#2)
I think Raonic 'pre-supernates'? he seems to have a very closed racquet head during take back. His serve turns out fine so it's probably worth trying
Supination Pre-Stretches Pronator Muscles
Raonic at some point in his serve probably supinates by both using some forearm muscles and, most importantly, by using leg thrust and other large muscle, strong, slow motions to supinate and pre-stretch his pronator muscles. Later in the serve he can use that pre-stretch to pronate. Pronation and supination motions & positions are difficult to identify at times in high speed videos. Pronation is easy to see after impact in the follow through.
Matched Muscle Pairs, Agonist & Antagonist - The muscles always work in matched pairs at a joint (really multi-muscle groups). Agonist muscle shortening is opposed in the other joint direction by antagonist muscle shortening. If I understand the terms, the agonist is the one, by definition, providing most force for a movement and it stretches the antagonist. The muscles groups that supinate and pronate are agonist and antagonist.
The motion of supination will stretch the forearm muscles that can soon after be used for the motion of pronation. This pre-stretch of the pronator muscles can be used during the forward swing (if used within tenths of a second after which pre-stretch potential dissipates and is lost).
Totally Separate Stretch - Internal Shoulder Rotation. The main contributor to racket head speed at impact is ISR. The leg thrust and other body motions, by external shoulder rotation, are also stretching the internal shoulder rotator muscles, mainly the pec and lat. The lat is the largest muscle attached to the arm. When the shoulder joint is held up as it is on the serve the pre-stretched lat and pec can work together to internally rotate the shoulder very rapidly and forcefully.
Supination Reached Before Elbow Extension
This video has a good viewing angle along the forearm to show supination angle when the elbow is bent at about 90°.
Find thumbnail frame shown after 3 sec by pressing pause-play as fast as possible.
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