排序方式： 共有6条查询结果，搜索用时 265 毫秒
1
1.
Homma M Homma M 《Sports biomechanics / International Society of Biomechanics in Sports》2005,4(1):73-87
We investigated coaching points for the technique of the eggbeater kick in synchronized swimming. The movements of the eggbeater kick for six female synchronized swimmers, all the top-ranking members at the Olympics and World Championships, were analyzed by using three-dimensional motion analysis. By comparing the movements of higher eggbeater-skilled swimmers with lower eggbeater-skilled swimmers, the coaching points for techniques of the eggbeater kick in synchronized swimming are clarified as follows. First, to hold the knees as high and as near the water surface as possible and to keep the heels close to the hips. Secondly, to keep the knees as wide as possible. Thirdly, to kick sideways producing lift force, and not to kick downward. Fourthly, to pull up the heels to nearly the water surface at the out-kick, with strong internal rotation of the thighs. Lastly, to move the feet as if treading water, with strong dorsiflexion and plantar flexion and adduction of the foot; that is to move the feet like the motion of the hands when sculling. Moreover, the movements of higher eggbeater-skilled swimmers can be termed 'horizontal kick type' and the movements of lower eggbeater-skilled swimmers can be termed 'vertical kick type'. 相似文献
2.
Abstract The frequency of one-legged stance and two-legged stance differs considerably among sports. We therefore expect the balance ability of athletes from different sports to vary. This study compared the sway characteristics during a static one-legged stance of soccer players, basketball players, swimmers, and non-athletes. The centre of pressure sway during one-legged stance of ten male participants representing each of the four groups was measured using a stabilometer. Centre of pressure sway was assessed by four sway factors: sway velocity, anterior-posterior sway, horizontal sway, and high-frequency sway. None of the four groups of participants showed significant differences in body sway between standing on the dominant leg and standing on the non-dominant leg. The soccer players had more high-frequency sway and less anterior-posterior sway and horizontal sway than the basketball players, swimmers, and non-athletes. These results suggest that soccer players have superior ability to maintain a stable one-legged stance. Further study is required to determine how much of the superior balance ability in soccer players is innate and how much is developed through training, as well as to determine the relationship between balance ability and playing performance. 相似文献
3.
Two experimental tests of three-storied reinforced concrete structural walls having large openings were performed.Based on an original macro model,a multiple modified macro-model was proposed to develop a simple method to design a reinforced concrete structural wall with large openings and various opening locations.The interaction between reinforcement ties and concrete struts formed along the perimeter of openings was neglected in the original model.However,the strut-and-tie node was proposed to take account of such interaction in the proposed model.The predicted behavior of two specimens using such a proposed model was compared with the experimental results.It is shown that the behavior of structural walls with large openings could be modeled well using the proposed model.Moreover,the study indicates that the proposed model is applicable even in cases of multi-story structural walls having large openings and various opening locations. 相似文献
4.
Stroke phase discrimination in breaststroke swimming using a tri-axial acceleration sensor device 总被引：3，自引：1，他引：2
Yuji?OhgiEmail author Hiroshi?Ichikawa Masanobu?Homma Chikara?Miyaji 《Sports Engineering》2003,6(2):113-123
Our previous study has demonstrated that the swimmer’s wrist acceleration in the crawl stroke and the breaststroke had distinctive
characteristics between subjects (Ohgiet al. 2000). In addition, stroke phase discrimination could be achieved for the crawl stroke by using the swimmer’s wrist acceleration.
This study provides evidence that the swimmer’s tri-axial wrist acceleration could be used for stroke phase discrimination
in the breaststroke. Swimmers’ triaxial wrist accelerations were measured and their underwater stroke paths calculated. The
authors examined the characteristics of the wrist acceleration, such as a local maximum or minimum, with reference to the
swimmers’ stroke paths. As a result, it was suggested that the three phases of the breaststroke, the recovery, the insweep
and the outsweep, could be distinguished using thex-axis (ulnar-radial axis) and they-axis (distal-proximal axis) acceleration. This methodology allows us to identify which stroke phase would be changed in skill
training or over training, and the acceleration sensor device has the potential to become a precise stroke pedometer or stroke
monitoring tool in the near future. 相似文献
5.
The frequency of one-legged stance and two-legged stance differs considerably among sports. We therefore expect the balance ability of athletes from different sports to vary. This study compared the sway characteristics during a static one-legged stance of soccer players, basketball players, swimmers, and non-athletes. The centre of pressure sway during one-legged stance of ten male participants representing each of the four groups was measured using a stabilometer. Centre of pressure sway was assessed by four sway factors: sway velocity, anterior-posterior sway, horizontal sway, and high-frequency sway. None of the four groups of participants showed significant differences in body sway between standing on the dominant leg and standing on the non-dominant leg. The soccer players had more high-frequency sway and less anterior-posterior sway and horizontal sway than the basketball players, swimmers, and non-athletes. These results suggest that soccer players have superior ability to maintain a stable one-legged stance. Further study is required to determine how much of the superior balance ability in soccer players is innate and how much is developed through training, as well as to determine the relationship between balance ability and playing performance. 相似文献
6.
报道了我国丝瓜藓属Pohlia两新种，即产自云南的明齿丝瓜藓 P．hyaloperistoma Zhang,Li &; Higuchi和产自西藏的疏叶丝瓜藓P．macrocarpa Zhang,Li&;Higuchi。前者主要特征为蒴齿透明无疣，后者孢子体大型且雌雄异株。 相似文献
1