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By understanding the normal humeral and scapular kinematics during the kayak stroke, inferences about the relationship of kayaking technique and shoulder injury may be established. The purpose of this study was to describe scapular and humeral kinematics and to compare dominant versus non-dominant symmetry in healthy whitewater kayakers performing the forward stroke. Twenty-five competent whitewater kayakers (mean age: 34.1±9.4 years, mean height: 1.768±0.093 m, mean mass: 78.2±13.0 kg) underwent humeral and scapular kinematic assessment, using an electromagnetic tracking device, while kayaking on a kayak ergometer. Paired t-tests were used to determine symmetry. Scapular and humeral kinematic means and standard deviations at six time points during the kayak stroke were described. Scapular and humeral kinematics were shown to be similar upon bilateral comparison. The greatest potential for injury during the forward stroke may be at thrust paddle shaft vertical when the humerus is maximally elevated in internal rotation and adduction as subacromial structures may be mechanically impinged. The relationship between scapulohumeral kinematics related to injury at other time points are also described.

Title: Selected parameters of gait and foot in consideration of the individual's body height Objectives: This thesis deals with a dependence of the selected gait and foot characteristics on a person's body height. These parameters are compared between a group of men and a group of women. In addition, a validity of selected formulas used for a determination of body height is evaluated. Methods: Mutual relation among the gait and foot characteristics and the individual's body height is observed. The thesis is a descriptive - association research, the comparative method is chosen in the practical part of the thesis. For an objectification of the research, the Plantograph and the 3D kinematic gait analysis performed by Qualysis system was used. Results: It was found out that the selected formulas used for a determination of body height are valid. The best results are brought by the formulas which count with a length of a bare foot, the length of a step and a double-step. On the contrary, the worse results are achieved by using the formulas which count with the dimension of shoe print. A tight dependence of the foot length and the length of the step / double-step on the body height was proven. A minimum dependence of the foot width on the body height was proven. Nevertheless the foot width is verifiably...

Four wheeler is one type of the transportation vehicle which be widely used. Good or bad performance of the vehicle steering system has the decisive influence regarding security of the driver operation and the vehicle travel. Therefore, the purpose of this article is to establish the kinematic analysis theories of the vehicle steering system. And an improvement design theory of size synthesis are proposed to develop a set of user-friendly computer aided analysis and design program. At First, this article collects the related literatures and papers to understand the research technique and the design direction of vehicle steering mechanism. Second, establish the location analysis theory, the rotation torque analysis theory, the mechanical advantage theory and other performance¡¦s calculation formula with regard to ¡§Rocker Shaft Type Connecting Rod Vehicle Steering¡¨ and ¡§Rack and Pinion Type Connecting Rod Vehicle Steering¡¨ which are the most widely used. Third, establish a set of user-friendly computer aided kinematic analysis program by using the VB.NET computer programming language. And then propose a systematized movement design procedure, and establish the optimization size synthesis design theory by using the gene calculation method. Afterwards, carry on the sensitivity analysis in view of the each design variable of the steering mechanism with the orthogonal array table, and establish the kinematic improvement design program. Finally, separately aim at the two Vehicle Steering mechanisms, design a new group mechanism¡¦s size, whose steering performance is better than the original mechanism¡¦s size.

Multibody dynamics plays the key role in the modeling, simulation, design, and control of many engineering problems. In practice, such problems may be encountered with the existence of uncertainty in the system's parameters and/or excitations. As the complexity of these problems in terms of the number of the bodies and kinematic loops (chains) increases, the effect of uncertainty in the system becomes even more significant due to the accumulation of inaccuracies. Therefore, considering uncertainty is inarguably a crucial aspect of performance analysis of a multibody problem. In fact, uncertainty needs to be propagated to the system kinematics and dynamics for the better understanding of the system behavior. This will significantly affect the design and control process of such systems. For this reason, this research presents a detailed investigation on the use of the Polynomial Chaos Expansion (PCE) method for both control and kinematic analysis of nondeterministic multibody systems.

京都大学 / 0048 / 新制・課程博士 / 博士(人間健康科学) / 甲第21706号 / 人健博第72号 / 新制||人健||5(附属図書館) / 京都大学大学院医学研究科人間健康科学系専攻 / (主査)教授 澤本 伸克, 教授 木下 彩栄, 教授 渡邉 大 / 学位規則第4条第1項該当 / Doctor of Human Health Sciences / Kyoto University / DFAM

Title: Kinematic Analysis of Tennis Serve. Objectives: To evaluate tennis serve realization in the selected performance category, to review speed of particular serve types and define the differences. To create detailed movement analysis of the slice serve from the right side of the court and set up a trajectory of the centre of gravity. Methods: Case study using kinematic 2D and 3D analysis was made. Results: We found out that the flat serve is the fastest type of serve. There are differences in the body centre of gravity trajectory by comparison with elite tennis players. We also found out that serving from the right side of the court is being hit higher, than from the left side. We assume there is a very close connection between serve speed and the point of impact. Keywords: tennis, serve, kinematic analysis, 2D, 3D

The purpose of the study was to compare the kinematics of the barbell back squat between two footwear conditions and to evaluate the results with respect to recommendations put forth in the National Strength and Conditioning Association position statement for proper squat technique. Twenty-five subjects with 5 - 7 years of resistance training experience participated. Selected kinematics were measured during a 60% of 1RM barbell back squat in both barefoot and athletic shoe conditions. Paired-samples T tests were performed to compare the two footwear conditions. Significant differences were found in trunk (50.72±8.27 vs. 46.97±9.87), thigh (20.94±10.19 vs. 24.42±11.11), and shank segment angles (59.47±5.54 vs. 62.75±6.17), and knee joint angles (81.33±13.70 vs. 88.32±15.45) at the peak descent position. Based on the kinematic analysis of the barefoot squat, two kinematic advantages are countered by two disadvantages. Coaches and instructors should acknowledge these results with respect to a performer's capability, and be aware the advantages and disadvantages of barefoot squat from a kinematic perspective.

The purpose of the study was to compare the kinematics of the barbell back squat between two footwear conditions and to evaluate the results with respect to recommendations put forth in the National Strength and Conditioning Association position statement for proper squat technique. Twenty-five subjects with 5 - 7 years of resistance training experience participated. Selected kinematics were measured during a 60% of 1RM barbell back squat in both barefoot and athletic shoe conditions. Paired-samples T tests were performed to compare the two footwear conditions. Significant differences were found in trunk (50.72±8.27 vs. 46.97±9.87), thigh (20.94±10.19 vs. 24.42±11.11), and shank segment angles (59.47±5.54 vs. 62.75±6.17), and knee joint angles (81.33±13.70 vs. 88.32±15.45) at the peak descent position. Based on the kinematic analysis of the barefoot squat, two kinematic advantages are countered by two disadvantages. Coaches and instructors should acknowledge these results with respect to a performer's capability, and be aware the advantages and disadvantages of barefoot squat from a kinematic perspective.

The geometric alteration of slopes is a reality that can be observed in several districts of the Peruvian capital. The construction of houses, roads, and other infrastructure can produce some slope instability and cause tragic events. Thus, a stability analysis was carried out for a slope located in the San Juan de Lurigancho district, specifically in the Virgen de Fátima sector. Therefore, for the present investigation, two models were made with the help of Phase2 software to identify the resistance reduction factors (SFR), which is a finite element-based program. To start the analysis, possible failures were identified, demonstrating that the slope does not present any possibility of failure. For the first model, we worked with a dip of 30° and identified an SFR = 19.26 for static conditions and an SFR = 9.66 for pseudo-static conditions. For the second model, we worked with a dip of 55°, this change in slope geometry shows a possible wedge failure, according to the kinematic analysis. Also, an SFR = 0.89 was identified for static conditions and an SFR = 0.48 for pseudo-static conditions. The results show very considerable changes and are due to the geometry of the slope, the presence of discontinuities, and the participation of seismic forces.