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International journal of sport biomechanics最新文献

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The Gliding and Push-Off Technique of Male and Female Olympic Speed Skaters 奥运会男女速度滑冰运动员的滑行和推举技术
International journal of sport biomechanics Pub Date : 1989-05-01 DOI: 10.1123/IJSB.5.2.119
R. D. Boer, K. Nilsen
{"title":"The Gliding and Push-Off Technique of Male and Female Olympic Speed Skaters","authors":"R. D. Boer, K. Nilsen","doi":"10.1123/IJSB.5.2.119","DOIUrl":"https://doi.org/10.1123/IJSB.5.2.119","url":null,"abstract":"The 1988 Winter Olympic Games provided a unique opportunity to study large numbers of optimally prepared speed skaters during ideal ice and weather conditions for all the competitors (indoor Olympic Oval in Calgary). In this study a kinematic analysis was conducted of the gliding and push-off technique during the Men’s and Ladies' 1,500-m and 5,000-m races. Statistical analysis showed that factors such as trunk position, preextension knee angle, and peak knee and hip angular velocities failed to correlate with mean lap speed. Within such a homogeneous group of elite athletes it was found that the higher work per stroke of the faster skaters was correlated to a longer gliding phase and a more horizontally directed push-off. All skaters showed plantar flexion at the end of the stroke, which is undesirable and indicates the complex nature of the gliding and push-off technique in speed skating.","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"45 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117063306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 19
A Multisegment Dynamic Model of Ski Jumping 跳台滑雪的多段动态模型
International journal of sport biomechanics Pub Date : 1989-05-01 DOI: 10.1123/IJSB.5.2.258
M. Hubbard, R. Hibbard, M. Yeadon, A. Komor
{"title":"A Multisegment Dynamic Model of Ski Jumping","authors":"M. Hubbard, R. Hibbard, M. Yeadon, A. Komor","doi":"10.1123/IJSB.5.2.258","DOIUrl":"https://doi.org/10.1123/IJSB.5.2.258","url":null,"abstract":"This paper presents a planar, four-segment, dynamic model for the flight mechanics of a ski jumper. The model consists of skis, legs, torso and head, and arms. Inputs include net joint torques that are used to vary the relative body configurations of the jumper during flight. The model also relies on aerodynamic data from previous wind tunnel tests that incorporate the effects of varying body configuration and orientation on lift, drag, and pitching moment. A symbolic manipulation program, “Macsyma,” is used to derive the equations of motion automatically. Experimental body segment orientation data during the flight phase are presented for three ski jumpers which show how jumpers of varying ability differ in flight and demonstrate the need for a more complex analytical model than that previously presented in the literature. Simulations are presented that qualitatively match the measured trajectory for a good jumper. The model can be used as a basis for the study of optimal jumper behavior in flight which ...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"128 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124346176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 38
A Method for Obtaining Three-Dimensional Data on Ski Jumping Using Pan and Tilt Cameras 一种利用平移和倾斜相机获取跳台滑雪三维数据的方法
International journal of sport biomechanics Pub Date : 1989-05-01 DOI: 10.1123/IJSB.5.2.238
M. Yeadon
{"title":"A Method for Obtaining Three-Dimensional Data on Ski Jumping Using Pan and Tilt Cameras","authors":"M. Yeadon","doi":"10.1123/IJSB.5.2.238","DOIUrl":"https://doi.org/10.1123/IJSB.5.2.238","url":null,"abstract":"A method is presented for the three-dimensional analysis of ski jumping using two pan and tilt cameras. In each film frame two reference markers are digitized and identified so that a pseudo focal length and three angles defining camera orientation can be calculated from a knowledge of the positions of camera and markers. In each film frame 12 body landmarks are digitized and the films taken by the two cameras are synchronized using the digitized displacement data. The time histories of the center of mass location and 15 angles describing the orientation and configuration of the jumper are calculated. Digitization errors lead to an error of 0.05 m in center of mass location and an error of 1° in orientation angles.","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115656061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 56
Twisting Techniques Used in Freestyle Aerial Skiing 自由式空中滑雪中使用的扭转技术
International journal of sport biomechanics Pub Date : 1989-05-01 DOI: 10.1123/IJSB.5.2.275
M. Yeadon
{"title":"Twisting Techniques Used in Freestyle Aerial Skiing","authors":"M. Yeadon","doi":"10.1123/IJSB.5.2.275","DOIUrl":"https://doi.org/10.1123/IJSB.5.2.275","url":null,"abstract":"At the 1988 Calgary Winter Olympics, six triple somersaults with three twists or four twists were filmed using two cameras. Angles describing body configuration and orientation were determined and were used as input into a computer simulation model of aerial movement. It was found that the twist angle of each simulation deviated from the corresponding angle obtained from film by less than 0.08 revolutions during the first somersault of each movement. Contributions to the tilt angle after one somersault were determined using simulations based on modifications of the film data. It was found that of the six competitors, two initiated the twist during the takeoff phase, two initiated the twist during the aerial phase, and two used a combination of both methods.","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121742096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 15
Factors Influencing Performance in Bobsledding: I: Influences of the Bobsled Crew and the Environment 影响雪橇运动成绩的因素:1:雪橇队员和环境的影响
International journal of sport biomechanics Pub Date : 1989-05-01 DOI: 10.1123/IJSB.5.2.208
M. Morlock, V. Zatsiorsky
{"title":"Factors Influencing Performance in Bobsledding: I: Influences of the Bobsled Crew and the Environment","authors":"M. Morlock, V. Zatsiorsky","doi":"10.1123/IJSB.5.2.208","DOIUrl":"https://doi.org/10.1123/IJSB.5.2.208","url":null,"abstract":"The performance in bobsledding is influenced by several factors. This study concentrated on influences of the environment and the bobsled crew on the final time of a bobsled run. The analysis was performed with data collected during the four-man competition at the 1988 Winter Olympic Games in Calgary. It was shown that the start order, the ice temperature, and the push time together explain about 50% of the variance in the performance (α=0.05). It is suggested that the existing rule concerning the start order in a heat be modified to guarantee a fair competition. Selected speed and turn time variables were shown to give an indication of the characteristics and the important sections of the bobsled track at Canada Olympic Park. It is speculated that the optimization of turn times is more important than the increase in speed in a turn.","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115203010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 23
The Takeoff Forces in Ski Jumping 跳台滑雪的起飞力
International journal of sport biomechanics Pub Date : 1989-05-01 DOI: 10.1123/IJSB.5.2.248
M. Virmavirta, P. Komi
{"title":"The Takeoff Forces in Ski Jumping","authors":"M. Virmavirta, P. Komi","doi":"10.1123/IJSB.5.2.248","DOIUrl":"https://doi.org/10.1123/IJSB.5.2.248","url":null,"abstract":"This study measured the takeoff forces exerted by jumpers during the 70-m ski jumping competition of the 1988 Winter Olympics in Calgary. Instrumentation consisted of four force plates installed under the snow of the takeoff platform. The results indicated that the greatest force was already exerted 149±9 ms before the release. The second force peak appeared closer to the edge of the takeoff platform. The correlations between the variables measured in this study were generally weak but some were considered important. The official approach velocity of the first round and relative maximum force as well as the mean relative force during the whole takeoff sequence of the second round correlated to length of jump. The mean relative forces at the end of takeoff and for the whole takeoff sequence were significantly higher among the best jumpers. It is concluded that although the force analyses among the jumpers do not reveal conclusive interrelationships, the fast development of the takeoff forces may be an impo...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126698018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 34
Techniques Used by Elite Women Gymnasts Performing the Handspring Vault at the 1987 Pan American Games 1987年泛美运动会优秀女子体操运动员手翻跳马技术
International journal of sport biomechanics Pub Date : 1989-02-01 DOI: 10.1123/IJSB.6.1.29
Y. Takei
{"title":"Techniques Used by Elite Women Gymnasts Performing the Handspring Vault at the 1987 Pan American Games","authors":"Y. Takei","doi":"10.1123/IJSB.6.1.29","DOIUrl":"https://doi.org/10.1123/IJSB.6.1.29","url":null,"abstract":"The purpose of this study was to determine mechanical factors, through development of the deterministic model, that govern successful performance of the handspring vault. The subjects were 40 elite male gymnasts participating in the 1987 Pan American Games. A motion-picture camera placed with its optical axis at right angles to the runway was used to record the subjects’ performances. Significant correlations indicated that the following were important determinants for success: (a) large horizontal velocity and angular momentum at takeoff from board, (b) shorter time of preflight and smaller relative height of takeoff in preflight, (c) large horizontal breaking force and large vertical force exerted as well as a large loss of angular momentum during horse contact, and (d) large vertical velocity of takeoff from horse. Significant correlation of “on-horse” factors with the judges’ scores indicated that the more the gymnast focused on horse contact and the more vertical the direction of his effort at takeof...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129765554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 49
Biomechanical Characteristics of Jumping 跳跃的生物力学特征
International journal of sport biomechanics Pub Date : 1989-02-01 DOI: 10.1123/IJSB.5.1.89
O. Aura, J. Viitasalo
{"title":"Biomechanical Characteristics of Jumping","authors":"O. Aura, J. Viitasalo","doi":"10.1123/IJSB.5.1.89","DOIUrl":"https://doi.org/10.1123/IJSB.5.1.89","url":null,"abstract":"Four track and field athletes were subjects in a study that analyzed seven jumping exercises and flop-style high jump takeoffs for ground reaction forces, knee angular kinematics, and electromyographic activities of knee extensor musculature. The ground contact times varied between 177 ±13 (flop) and 278 ±25 ms (standing five jumps). The peak ground contact forces were from 5002±130 N (special drop jump) to 8202±901 N (ranning five hops). Average knee angular velocities were highest in the eccentric phase of the flop takeoff (ω = 7.1 ± 2.1 rad × s-1). Electromyographic activities before the ground contact and during the eccentric phase of contact were highest in the flop-style high jump, while during the concentric phase of contact a special drop jump exercise showed the highest activity. Preactivity IEMG correlated with the eccentric IEMG, force, and knee angular velocity positively and with the contact time negatively (p<0.001), while eccentric IEMG correlated with the eccentric force and angular veloci...","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134125593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 56
Kinetic and Kinematic Characteristics of 10-m Platform Performances of Elite Divers: II-Reverse Takeoffs 优秀跳水运动员10米平台动作的动力学和运动学特征:2 -反向起跳
International journal of sport biomechanics Pub Date : 1989-02-01 DOI: 10.1123/IJSB.6.3.283
D. I. Miller, I. Jones, Marc A. Pizzimenti, E. Hennig, R. C. Nelson
{"title":"Kinetic and Kinematic Characteristics of 10-m Platform Performances of Elite Divers: II-Reverse Takeoffs","authors":"D. I. Miller, I. Jones, Marc A. Pizzimenti, E. Hennig, R. C. Nelson","doi":"10.1123/IJSB.6.3.283","DOIUrl":"https://doi.org/10.1123/IJSB.6.3.283","url":null,"abstract":"Takeoffs for 10-m platform dives from the reverse group at the 1986 World Championships and 1989 FINA Cup were analyzed to provide insights into their kinetic and kinematic characteristics. As with back takeoffs, the major changes in both linear and angular momentum occurred during final weighting (i.e., upward acceleration). Vertical velocities at last contact were higher for reverse dives than reverse multiple somersaults, and different moment-of-force patterns were associated with increased rotational requirements. Last-contact vertical velocities were less for reverse rotating dives than corresponding dives from the back group. Although last-contact horizontal velocities for the two groups were not statistically different, the horizontal acceleration patterns of the three composite body segments were near mirror images of one another. Finally, implications of a resultant head velocity of 10 m/s when passing the leading edge of the platform in reverse multiple somersaulting dives were considered.","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125741920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 23
Effect of Vibrations on Javelin Lift and Drag 振动对标枪升力和阻力的影响
International journal of sport biomechanics Pub Date : 1989-02-01 DOI: 10.1123/IJSB.5.1.40
M. Hubbard, Christy D. Bergman
{"title":"Effect of Vibrations on Javelin Lift and Drag","authors":"M. Hubbard, Christy D. Bergman","doi":"10.1123/IJSB.5.1.40","DOIUrl":"https://doi.org/10.1123/IJSB.5.1.40","url":null,"abstract":"The theory of crossflow aerodynamics is used to estimate the effect of thrower-induced vibrations on javelin mean lift and drag. Vibrations of all modes increase both lift and drag from the vibration-free condition. Percentage in-creases in lift and drag are largest at small mean angles of attack, large vibrational amplitudes, and large relative wind speeds. Thus the consequences of vibration effects on aerodynamics may be most significant for elite throwers.","PeriodicalId":308877,"journal":{"name":"International journal of sport biomechanics","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115324504","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 14
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