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  • LJ and Wind?

    Anybody done any work with regard to how much a tailwind helps in the long jump? Any rough guesstimates? I just reviewed S. Bayer's 8.71 indoors and thought wow what a jump. Wonder how that would rate on the outdoor list with wind correction - if such a thing is possible?

  • #2
    I have some ideas about how to go about doing it. It will not be particularly "clean" because the mostly likely mechanism is to get a ton of data about wind speeds and jumps across jumps in a series, jumps across similar series time and competitive season-wise.

    There are statistical models for fixed and variable effects that are similar to what I used in my dissertation but stuff has advanced since then. I am not great at collecting the appropriate data and you would want to have as much clean data as possible.

    You also have to develop rules to cut out jumps that are "off" for reasons other than wind and they will make your data 'noisy'. Such rules have to be developed before you start working on the data used for the analysis for the statistics to be valid, although this should not be too hard if you have a ton of data because you use a modest subset to try to figure out what makes sense. Included in this 'making sense' is talking with people here on the board (lonewolf, gh, flumpy, JRM, Olorin, and a lot more would have useful insights). Also, talking with coaches and athletes.

    My impression is that the Big Gold Book, in its early incarnations developed wind adjustments using empirical data primarily (also altitude effects might have been estimated this way; they were probably larger than the 'conventional wisdom' prior to 1968). JRM's approach is considerably different but dovetails quite well.

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    • #3
      I have to assume that body size (amount of surface area) will greatly affect the aid, and therefore is nigh on impossible to 'factor'. Esp. since the surface area is constantly changing in the run-up and jump.

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      • #4
        IMO, there are so many variables affecting the effect of a tail wind it is impossible to ascribe a meaningful percentage. Suffice it to say a tail wind helps... unless it causes you to foul at the board... or negates what would have been a record jump without tail wind by exceeding allowable wind speed.

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        • #5
          Originally posted by Atticus View Post
          I have to assume that body size (amount of surface area) will greatly affect the aid, and therefore is nigh on impossible to 'factor'. Esp. since the surface area is constantly changing in the run-up and jump.
          Why would body size matter a lot? Remember that momentum scales with mass, and the bigger cross-section of a larger jumper has more mass. And, what I am suggesting is not fitting an equation to some hypothetical body etc. Rather it goes in to a multiple variable, fixed/variable effects model that estimates the impact of wind speed on jump distance while controlling for other factors and how good the model is will show in how noisy the parameter estimates are for wind and for wind interaction with anything that can be reliably measured and recorded in the data set. It takes a lot of data to get decent estimates of the effect but I doubt size is a significant factor.

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          • #6
            Originally posted by 26mi235 View Post
            Why would body size matter a lot? Remember that momentum scales with mass, and the bigger cross-section of a larger jumper has more mass. And, what I am suggesting is not fitting an equation to some hypothetical body etc. Rather it goes in to a multiple variable, fixed/variable effects model that estimates the impact of wind speed on jump distance while controlling for other factors and how good the model is will show in how noisy the parameter estimates are for wind and for wind interaction with anything that can be reliably measured and recorded in the data set. It takes a lot of data to get decent estimates of the effect but I doubt size is a significant factor.

            Here are a couple of interesting reads..........on wind and long jumping...


            https://ojs.ub.uni-konstanz.de/cpa/a...File/2720/2562


            https://www.researchgate.net/publica...ring_Long_Jump
            Last edited by cajun5150; 03-23-2018, 02:56 PM.

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            • #7
              Originally posted by cajun5150 View Post
              Here are a couple of interesting reads..........on wind and long jumping...
              https://ojs.ub.uni-konstanz.de/cpa/a...File/2720/2562
              https://www.researchgate.net/publica...ring_Long_Jump
              Ain't math grand?
              The 1st one demonstrates that a +2.0w increases a jump 2 inches.
              The 2nd one demontrates that a +2.0w increases a jump 6 inches.
              I believe . . . neither. The answer is much more nuanced: it depends.
              Variables include body type, take-off speed, take-off angle, and even attitude of the jumper towards the wind.

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              • #8
                I think altitude (say for instance Mexico City) and wind (say for instance 2mps) has to be worth at least 1 ft.

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                • #9
                  Originally posted by lonewolf View Post
                  IMO, there are so many variables affecting the effect of a tail wind it is impossible to ascribe a meaningful percentage. Suffice it to say a tail wind helps... unless it causes you to foul at the board... or negates what would have been a record jump without tail wind by exceeding allowable wind speed.
                  Another variable is that all wind readings are an average (mean) over a set period of time, albeit a shorter period in a long jump than for a track event. Therefore 2m/s might sometimes be made up of a short spell of much stronger wind and another of lesser wind. When that stronger gust happens may affect the actual benefit gained. There is also the factor of wind direction - while a low wind reading may mean there is very little wind it could also mean there is a sidewind which would not be helpful or a wind that switches direction and the positive and negative elements largely cancel themselves out arithmetically.

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                  • #10
                    Originally posted by Atticus View Post
                    Ain't math grand?
                    The 1st one demonstrates that a +2.0w increases a jump 2 inches.
                    The 2nd one demontrates that a +2.0w increases a jump 6 inches.
                    I believe . . . neither. The answer is much more nuanced: it depends.
                    Variables include body type, take-off speed, take-off angle, and even attitude of the jumper towards the wind.
                    Then clearly it is 4 inches!

                    Comment


                    • #11
                      Originally posted by Atticus View Post
                      Ain't math grand?
                      The 1st one demonstrates that a +2.0w increases a jump 2 inches.
                      The 2nd one demontrates that a +2.0w increases a jump 6 inches.
                      I believe . . . neither. The answer is much more nuanced: it depends.
                      Variables include body type, take-off speed, take-off angle, and even attitude of the jumper towards the wind.
                      Atticus said it for me.. too many known and unknown variables, was it a clutch jump, did jumper take off a foot before the board?
                      You can torture the math and get different results, all meaningless.. it is what it is at the moment and as useless as guessing what distance or time would have been under optimum conditions.. or trying to pick a GOAT
                      Last edited by lonewolf; 03-23-2018, 07:18 PM.

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                      • #12
                        Yeah - I think math and physics are almost irrelevant. Is all about how athletes respond to it. I’ve seen some athletes PR into a wind and foul with a tailwind. I always over adjusted my run back with a tailwind and had good jumps. My best jumps were driving into a small headwind and pushing harder.

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                        • #13
                          math and physics most certainly not irrelevant. If (and it's admittedly a big IF) you are able to hit the board properly with no stutter-stepping, you'll go farther with a tailwind because you're moving faster. That's incontrovertible.

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                          • #14
                            I had never bothered to ask any officials, but I always wondered about how and when long jump readings were initiated, so I went to the IAAF site and looked up their Competition Rules.

                            RULE 184

                            Wind Measurement
                            10. The wind gauge shall be the same as described in Rules 163.8 and
                            163.9. It shall be operated as described in Rules 163.11 and 184.12 and
                            read as per Rule 163.13.

                            11. The relevant Field Events Referee shall ensure that the wind gauge is
                            placed 20m from the take-off line. The measuring plane shall be positioned 1.22m ± 0.05m high and not more than 2m away from the
                            runway.

                            12. The wind velocity shall be measured for a period of 5 seconds from the time an athlete passes a mark placed alongside the runway, for the Long Jump 40m from the take-off line and for the Triple Jump 35m. If an athlete runs less than 40m or 35m, as appropriate, the wind velocity shall be measured from the time he commences his run.

                            https://www.iaaf.org/about-iaaf/documents/technical

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                            • #15
                              It is not math and physics that are the source of useful knowledge on the effects of wind, it is statistics - a very different beast. It is an empirical question and I will hazard a guess that handled correctly the chances that the estimated values are positive but really the effect is zero is probably on the order of less than one in a trillion. Now it might be a noisy estimate if you cannot get the right data and a lot of it (100,000 observations might be brought in to the analysis, although keeping towards more elite competitions with higher quality data will cut that a lot. In the earth and at the level of a building there are lots of random variations and vibrations, on the order of possibly up to tenths of a millimeter. However, lots of technical, physical and statistical tricks allow measurement that are 10^15 small than that. Just because there are lots of things that affect an individual jump does not mean that there is not a systematic effect of wind.

                              Someone brought up that you could close or far from the board, but that is essentially irrelevant unless the effect of the wind is different if you are 12cm from the line than if you are 2cm from the line. And while your estimates might be better if you could include exactly how close the the line you are, if you have enough measurements without bias it matters little.

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