Purpose. The start is treated as one of the most important technical elements in all sliding sports, as it is the only phase when athletes can actively contribute to increasing sled velocity. Nevertheless, start kinematics in luging have seldom been addressed in literature. Therefore, the aim of this study was to analyse hip and shoulder movement of lugers during one of the essential start phases-the pull and push-off from the start handles-to further understanding of the velocity development process at its initial stage. Methods. Three experienced female lugers volunteered to take part in the case study. A number of start attempts were filmed and analysed using a motion tracking method. Results. The study found that an athlete and the sled do not move as a whole rigid system, and a hip movement relative to the sled was found to exist. The study participants used two techniques for achieving high sled velocity: by initially pulling on the start handles with a powerful back extension, and sliding the hips forward on the sled in an attempt to increase forward momentum; a combination of both techniques might provide increased performance. Athletes featured two weaknesses in terms of where horizontal sled velocity was lost-at the end of the initial pull on the handles and during the final moment of the push-off from the handles. The latter was previously believed to be another option at gaining increased sled horizontal velocity. Conclusions. As found in the results, athletes have at least two possibilities of increasing horizontal sled velocity. Hip movement relative to the sled appeared to be important for gains in velocity. Additional studies that analyse larger pulls are necessary for understanding the role of hip and sled relative movement in start technique and its impact on increasing initial velocity.

Development of new techniques and appropriate equipment for treatment of long bone fractures in bovines has been an objective of recent veterinary research. Accurate estimates of body segment inertial parameters (BSIP) are essential for determination of forces acting on limbs and play an important role in an appropriate prosthesis development. The aim of the present study is to examine the mass distribution properties and to suggest a geometric model of bovine right pelvic limb based on these mass distribution properties. Four Holstein breed male calves were filmed by one high-speed camera while walking on a force plate. The animals and two cadaveric specimens were examined in axial computer tomography scanner and the images were exported in DICOM (Digital Imaging and Communication in Medicine) format into a set of software and a computational model was obtained. This model provided information for geometric model construction. Measures of segmental mass, positions of segmental center of mass (CoM) and longitudinal moment of inertia (MoI) of segments of the right pelvic limb were estimated based on the proposed model. These estimates were compared with measurements obtained from a computational model and showed consistent accuracy. This study not only presents a technique that may be applied to other body segments and to different species, but also provides insight into bovine musculoskeletal system necessary to improve the models for dynamic analysis of movement and our understanding of bovine gait.

For safety reasons, wood strength values are calculated based on their characteristic values. Brazilian national standard (NBR, in Portuguese "Norma Brasileira Regulamentadora") 7190 (1997) establishes ratios for characteristic strength estimation and three forms of wood characterization, with an emphasis on the simplified procedure for common species, which allows obtaining the strength characteristic values through equations correlating different mechanical properties. The present work evaluates the accuracy of the relation proposed by NBR 7190 (1997) of shear strength along the grain (f v0,k) to compression strength along the grain (f c0,k) (f v0,k =0.12 f c0,k). 960 experimental measurements of shear and compression strength values were performed for 40 hardwood species, and the precision of the relation proposed by the Brazilian standard was evaluated using the analysis of variance (ANOVA) method. Linear, exponential, logarithmic, and geometric regression models were used as an alternative to the NBR relation for shear strength estimation. The statistical analysis revealed that the geometric regression is the model of best fit.

The aim of this study was to determine whether there are significant differences in timing of start elements that lugers perform on a sliding track and an iced start ramp built for training purposes. Male and female lugers with different competitive experience performed starts on the start ramp and on the luge track. Timing of start elements was measured from high-speed video records and compared between start facilities. Most of the athletes showed different timing of start phases at the track and the ramp. These differences partially arise from a necessity to assume a riding position in-time on the track. Though training on the start ramp does not represent exactly start performance on a luge track, it is a convenient way for practicing technical elements of the start.

The aim of this study was to determine whether there are significant differences in timing of start elements that lugers perform on a sliding track and an iced start ramp built for training purposes. Male and female lugers with different competitive experience performed starts on the start ramp and on the luge track. Timing of start elements was measured from high-speed video records and compared between start facilities. Most of the athletes showed different timing of start phases at the track and the ramp. These differences partially arise from a necessity to assume a riding position in-time on the track. Though training on the start ramp does not represent exactly start performance on a luge track, it is a convenient way for practicing technical elements of the start.