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  • Linear momentum

    Originally posted by emeralda View Post
    Thanks. First I need to check those references from the ITF book. Regards, Don
    There is a full chapter ( 3 ?) on this subject


    There are 3 possible issues to address:

    1.a choice between an open stance and square stance for
    modern forehand

    2.a decomposition of forehand into
    a) linear movement
    b) angular movement
    c) brushing/lifting movement

    3.conversion of energy between LINEAR MOVEMENT and
    ANGULAR MOVEMENT

    See as well
    Last edited by uspta146749877; 07-08-2008, 10:59 AM.

    Comment


    • brushing movement

      Originally posted by emeralda View Post
      John,

      Linear momentum in the forehand is considered significant by some and also crops up in threads as you probably know. Do you have any views on this and are there any articles which support the 'linear plus angular' concept? Once the forehand is in motion I only see angular momentum and torque.

      Don
      There is brushing/lifting movement as well -see Nadal

      Comment


      • coria's serve

        John... I think it would be fascinating if you were to review coria's current strokes versus how he was hitting before he became, in his own words, "lost on the wrong road....without a map".

        Perhaps an analysis of his serve by you would even get the magician back on track!

        kurt

        Comment


        • Haven't seen him play much less filmed him since before that French Open final. I suspect though that you wouldn't see technical problems. I think the issues are probably mainly emotional for him. If he makes it in front of the camera somewhere where we are filming I'll take a look.

          Comment


          • coria

            yeah John, I agree that it is probably a mental more than a technical thing, but in his latest match (on clay vs. schwank in stuttgart) he double faulted 19 times! (scores were 0-6,6-1,6-2).....there must be something technically wrong there as well....

            kurt

            Comment


            • Like I said I wouldn't necessarily agree. The mind can easily have that type of effect. If he comes across a court where we're filming we can check.

              Comment


              • A reference text

                Originally posted by emeralda View Post
                Thanks. First I need to check those references from the ITF book. Regards, Don
                Any luck with a getting a reference text?

                Comment


                • References

                  Thanks for the additional comments. 'Biomechanical Principles of Tennis Technique' and the ITF book are accessible but I don't have yet.

                  Comment


                  • Please stay in touch

                    Originally posted by emeralda View Post
                    Thanks for the additional comments. 'Biomechanical Principles of Tennis Technique' and the ITF book are accessible but I don't have yet.
                    Please stay in touch

                    Comment


                    • From the ITF book.
                      "...forward linear momentum is crucial in the development of racquet head speed"
                      "forward movement of the trunk increases the linear velocity of the shoulder and also helps in pre-stretching the shoulder musculature."
                      "...it appears square stance stokes can create slightly higher racquet head speeds" (about 1 m/s for professionals, 21.2m/s to 22.3m/s)

                      So forward linear momentum is crucial yet the increase in the racquet head speed is minimal and the authors do not make a definitive commitment to open or square stance.

                      Comment


                      • Originally posted by emeralda View Post
                        From the ITF book.
                        "...forward linear momentum is crucial in the development of racquet head speed"
                        "forward movement of the trunk increases the linear velocity of the shoulder and also helps in pre-stretching the shoulder musculature."
                        "...it appears square stance stokes can create slightly higher racquet head speeds" (about 1 m/s for professionals, 21.2m/s to 22.3m/s)

                        So forward linear momentum is crucial yet the increase in the racquet head speed is minimal and the authors do not make a definitive commitment to open or square stance.
                        Don,
                        please see
                        a very simple quotation from Page 66 of the same book-
                        "Open stance forehands have been shown to have court coverage and other
                        tactical advantages"
                        I believe that recovery time for open stance is smaller.
                        See

                        See as well


                        See as well the middle part of Page 68 for comments related to your post
                        regards,
                        julian usptapro 27873
                        Last edited by uspta146749877; 07-30-2008, 11:51 AM.

                        Comment


                        • Originally posted by uspta146749877 View Post
                          Don,
                          please see
                          a very simple quotation from Page 66 of the same book-
                          "Open stance forehands have been shown to have court coverage and other
                          tactical advantages"
                          I believe that recovery time for open stance is smaller.
                          See

                          See as well

                          Speed numbers quoted above are twice higher than in the ITF book-
                          hard to understand why.Maybe JY knows why
                          See as well the middle part of Page 68 for comments related to your post
                          regards,
                          julian usptapro 27873
                          Julian,
                          Quotes from


                          "For the professional players, the actual racquet head velocity for the open stance was about 47mph. For the closed stance it was about 50mph"

                          "These are relatively small differences, about 5%. They were less than the error factor in the measurements..."

                          My enquiry may be unrealistic as I was considering a 'standard' topspin FH with time not a factor and then comparing stances from a purely technical perspective. Is there a preferred stance?
                          You have shown forward linear momentum is defined and described but if the racquet head speeds are as stated then the benefits of forward linear momentum may be over-stated.
                          Regards,
                          Don

                          Comment


                          • Open stance is preferable

                            Originally posted by emeralda View Post
                            Julian,
                            Quotes from


                            "For the professional players, the actual racquet head velocity for the open stance was about 47mph. For the closed stance it was about 50mph"

                            "These are relatively small differences, about 5%. They were less than the error factor in the measurements..."

                            My enquiry may be unrealistic as I was considering a 'standard' topspin FH with time not a factor and then comparing stances from a purely technical perspective. Is there a preferred stance?
                            You have shown forward linear momentum is defined and described but if the racquet head speeds are as stated then the benefits of forward linear momentum may be over-stated.
                            Regards,
                            Don
                            Don,
                            Open stance is PREFERABLE for me because a QUICKER RECOVERY time
                            regards,
                            julian

                            Comment


                            • Originally posted by uspta146749877 View Post
                              Don,
                              Open stance is PREFERABLE for me because a QUICKER RECOVERY time
                              regards,
                              julian
                              OK, fair enough. Thanks also for all the references. I've been curious about this subject since my junior days where I survived with a less than average FH.

                              Comment


                              • Sorry

                                Originally posted by emeralda View Post
                                OK, fair enough. Thanks also for all the references. I've been curious about this subject since my junior days where I survived with a less than average FH.
                                Sorry that you are disappointed by my answers

                                Comment

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