- Email: [email protected]
Fluid dynamical studies on generation of propulsive forces in swimming a breast stroke
Abstracts-InternationalSocietyof BiomechanicsXIV Congress1993 PROBLEMS AND DIFFICULTIES IN ANALYSIS OF FENCING LUNGE T. Szllagyi Departmentof Biomechanics HungarianUniversity of PhysicalEducation 1123 Alkotas u. 44. BudapestXII. Hungary H-l 123 The author tested the displacement,the period of time, the averagevelocity and the highest velocity of the fencing lunge. We studied how the kinematic parameters depend on the type of combinations of the movements.We determinedthe selectedparametersof lungesin all the specifiedcombinationgroups. Then we calculatedthe averagestypical for the groups. We evaluatedthe executionsof fencing lunge in two manner. In the first evaluation method we verified the beginning of the lunge by examinationof the path/time curves. In the secondevaluation method we verified the beginning of the lunge by examinationof the angle/time curves. The determinationof the kinematic parametershad done independentlyfrom one another in the two cases,but the raw data file was the samein both cases.The two different evaluationmethod yielded two different results. The first reason of this fact, that executions of the footworks were diierent from the classical technical descriptions, On the other hand it is an unsettled question, when the fencing lunge starts in not perfect executions.
FLUID DYNAMICAL STUDIES ON GENERATION OF PROPULSIVE FORCES IN SWIMMING A BREAST STROKE H. Takagi, Y. Shimizu, T. Macda, T. Goya, T. Nomura and A. Matsui Mie University, Kamihama-thou 1515 Tsu city, Mie, 514, JAPAN. This study aims at consecutivemeasurementof the relation betweenthe swimming form, in particularof the breaststroke,and the generatedpropulsiveforce and collection of the fundamentaldata to establishan efficient swimming form. Comparisonbetweenthe skilled swimmers and the unskilled swimmers showsthat the unskilled swimmerskeep larger angleof attackrelative to the moving direction, and generatethe propulsiveforce mainly by the drag. On the other hand,the skilled swimmersseemto obtain large propulsive force not by pushing back the water but by generatingmore lift when they strokethe water inside. The unskilled swimmersdid not show much changein the moving speedof the hand,while the skilled swimmersacceleratedthe moving speed from the phaseof starting the stroke to the phaseof stroking inside. Therefore,it is important to obtain the propulsiveforce by the resultantforce of the drag and the lift to generatethe propulsive force efficiently, by generatingnot only the drag but also the drag in appropriatemanner.For this purpose,it is suggestedthat an appropriateangle of attack of the hand be kept to acceleratethe moving speed.
TWO VAULTING TYPES OF THE WORLD-CLASS POLF VAULTERS AT THE 3RD IAAF WORLD CHAMPIONSHIPS IN ATHLEl-ICS J. Takamatsul, M. Ae1, T. Fuchimoto2, and T. Kotohl 1. Institute of Health and Sport Sciences, University of Tsukuba,Tennoudai 1-l - 1, Tsukuba City, Ibaraki, Japan 2. OsakaUniversity of Physical Education,Osaka,Japan We analyzedthe trials of the elite pole vaulterswith a 3D cinematographyat the 3rd IAAF World Championshipsin Athletics, 1991Tokyo. We found that there were two vaulting types which were polerecoihng type and pole-rotationtype. Thesevaulting techniqueswere typically employedby Bubka (USSR) and by Bagyula (HUN), respectively.Bubka’smaximum pole bend (708%) was greaterthan Bagyula (75.2%). but Bagyula’stake-off angle (19.7deg)was greaterthan that of Bubka (164deg). From take-off (TO) to maximum pole bend (MPB), Bagyula’smean vertical velocity of the center of mass(CM 2.76m/s) was greaterthan that of Bubka (2.44m/s).But, from MPB to Pole straight, Bubka’smean vertical velocity of CM (4.7Om/s)was greaterthan that of Bagyula (437m/s). This meansthat Bubka more dependedon the pole-recoiling,while Bagyula more dependedon the pole-rotationto obtain the vertical velocity of CM. Bubka’smean accelerationand decelerationof CM during vaulting was large (8.9Om/sz).In the caseof the pole-recoiling type, it will be difficult to control the movementof the whole body. On the other hand, Bagyula’smean accelerationand decelerationof CM (7.18m/sz)was smaller than that of Bubka. IO the case of the pole-rotationtype, the force applied on the uPperbody will be smaller. But, smaller pole bend will reduceadvantagesof the pole bend. This study was supportedby BiomechanicsProjectTeam of JapanAmateur Athletic Federationand by IntematiooalAthletic Foundation. l
691
FLUID DYNAMICAL STUDIES ON GENERATION OF PROPULSIVE FORCES IN SWIMMING A BREAST STROKE H. Takagi, Y. Shimizu, T. Macda, T. Goya, T. Nomura and A. Matsui Mie University, Kamihama-thou 1515 Tsu city, Mie, 514, JAPAN. This study aims at consecutivemeasurementof the relation betweenthe swimming form, in particularof the breaststroke,and the generatedpropulsiveforce and collection of the fundamentaldata to establishan efficient swimming form. Comparisonbetweenthe skilled swimmers and the unskilled swimmers showsthat the unskilled swimmerskeep larger angleof attackrelative to the moving direction, and generatethe propulsiveforce mainly by the drag. On the other hand,the skilled swimmersseemto obtain large propulsive force not by pushing back the water but by generatingmore lift when they strokethe water inside. The unskilled swimmersdid not show much changein the moving speedof the hand,while the skilled swimmersacceleratedthe moving speed from the phaseof starting the stroke to the phaseof stroking inside. Therefore,it is important to obtain the propulsiveforce by the resultantforce of the drag and the lift to generatethe propulsive force efficiently, by generatingnot only the drag but also the drag in appropriatemanner.For this purpose,it is suggestedthat an appropriateangle of attack of the hand be kept to acceleratethe moving speed.
TWO VAULTING TYPES OF THE WORLD-CLASS POLF VAULTERS AT THE 3RD IAAF WORLD CHAMPIONSHIPS IN ATHLEl-ICS J. Takamatsul, M. Ae1, T. Fuchimoto2, and T. Kotohl 1. Institute of Health and Sport Sciences, University of Tsukuba,Tennoudai 1-l - 1, Tsukuba City, Ibaraki, Japan 2. OsakaUniversity of Physical Education,Osaka,Japan We analyzedthe trials of the elite pole vaulterswith a 3D cinematographyat the 3rd IAAF World Championshipsin Athletics, 1991Tokyo. We found that there were two vaulting types which were polerecoihng type and pole-rotationtype. Thesevaulting techniqueswere typically employedby Bubka (USSR) and by Bagyula (HUN), respectively.Bubka’smaximum pole bend (708%) was greaterthan Bagyula (75.2%). but Bagyula’stake-off angle (19.7deg)was greaterthan that of Bubka (164deg). From take-off (TO) to maximum pole bend (MPB), Bagyula’smean vertical velocity of the center of mass(CM 2.76m/s) was greaterthan that of Bubka (2.44m/s).But, from MPB to Pole straight, Bubka’smean vertical velocity of CM (4.7Om/s)was greaterthan that of Bagyula (437m/s). This meansthat Bubka more dependedon the pole-recoiling,while Bagyula more dependedon the pole-rotationto obtain the vertical velocity of CM. Bubka’smean accelerationand decelerationof CM during vaulting was large (8.9Om/sz).In the caseof the pole-recoiling type, it will be difficult to control the movementof the whole body. On the other hand, Bagyula’smean accelerationand decelerationof CM (7.18m/sz)was smaller than that of Bubka. IO the case of the pole-rotationtype, the force applied on the uPperbody will be smaller. But, smaller pole bend will reduceadvantagesof the pole bend. This study was supportedby BiomechanicsProjectTeam of JapanAmateur Athletic Federationand by IntematiooalAthletic Foundation. l
691