CONTRIBUTION TO THE BIOMECHANICAL ANALYSIS OF THE LONG JUMP

The Austrian national outdoor-record for men’s long jump is 8.30 m. This record was set in 1988. Since then the national record has not been broken. Therefore the purpose of this study was to examine the various parameters affecting performance during the last support phase of the long jump. The current work is an attempt to help both the coaches and the athletes to improve performance

MEASURING DYNAMIC SKI BEHAVIOR WITH STRAIN GAUGES

The performance of a ski is influenced not only by geometric properties such as length, width, camber height, side cut and thickness; but also by the deformation behaviour caused by the mechanical properties (Kaps et al. 2001). The purpose of this work was to evaluate the influence of flexural and torsional stiffness on the deformation of a ski during turns

Estimation of Joint Moments During Turning Maneuvers in Alpine Skiing Using a Three Dimensional Musculoskeletal Skier Model and a Forward Dynamics Optimization Framework

In alpine skiing, estimation of the joint moments acting onto the skier is essential to quantify the loading of the skier during turning maneuvers. In the present study, a novel forward dynamics optimization framework is presented to estimate the joint moments acting onto the skier incorporating a three dimensional musculoskeletal model (53 kinematic degrees of freedom, 94 muscles). Kinematic data of a professional skier performing a turning maneuver were captured and used as input data to the optimization framework. In the optimization framework, the musculoskeletal model of the skier was applied to track the experimental data of a skier and to estimate the underlying joint moments of the skier at the hip, knee and ankle joints of the outside and inside leg as well as the lumbar joint. During the turning maneuver the speed of the skier was about 14 m/s with a minimum turn radius of about 16 m. The highest joint moments were observed at the lumbar joint with a maximum of 1.88 Nm/kg for lumbar extension. At the outside leg, the highest joint moments corresponded to the hip extension moment with 1.27 Nm/kg, the knee extension moment with 1.02 Nm/kg and the ankle plantarflexion moment with 0.85 Nm/kg. Compared to the classical inverse dynamics analysis, the present framework has four major advantages. First, using a forward dynamic optimization framework the underlying kinematics of the skier as well as the corresponding ground reaction forces are dynamically consistent. Second, the present framework can cope with incomplete data (i.e., without ground reaction force data). Third, the computation of the joint moments is less sensitive to errors in the measurement data. Fourth, the computed joint moments are constrained to stay within the physiological limits defined by the musculoskeletal model

A Model-Based Approach To Predict Neuromuscular Control Patterns That Minimize ACL Forces During Jump Landing

Jump landing is a common situation leading to knee injuries involving the anterior cruciate ligament (ACL) in sports. Although neuromuscular control is considered as a key injury risk factor, there is a lack of knowledge regarding optimum control strategies that reduce ACL forces during jump landing. In the present study, a musculoskeletal model-based computational approachis presented that allows identifying neuromuscular control patterns that minimize ACL forces during jump landing. The approach is demonstrated for a jump landing maneuver in downhill skiing, which is one out of three main injury mechanisms in competitive skiing

A graph-based approach can improve keypoint detection of complex poses: a proof-of-concept on injury occurrences in alpine ski racing

For most applications, 2D keypoint detection works well and offers a simple and fast tool to analyse human movements. However, there remain many situations where even the best state-of-the-art algorithms reach their limits and fail to detect human keypoints correctly. Such situations may occur especially when individual body parts are occluded, twisted, or when the whole person is flipped. Especially when analysing injuries in alpine ski racing, such twisted and rotated body positions occur frequently. To improve the detection of keypoints for this application, we developed a novel method that refines keypoint estimates by rotating the input videos. We select the best rotation for every frame with a graph-based global solver. Thereby, we improve keypoint detection of an arbitrary pose estimation algorithm, in particular for 'hard' keypoints. In the current proof-of-concept study, we show that our approach outperforms standard keypoint detection results in all categories and in all metrics, in injury-related out-of-balance and fall situations by a large margin as well as previous methods, in performance and robustness. The Injury Ski II dataset was made publicly available, aiming to facilitate the investigation of sports accidents based on computer vision in the future

Improved 2D Keypoint Detection in Out-of-Balance and Fall Situations -- combining input rotations and a kinematic model

Injury analysis may be one of the most beneficial applications of deep learning based human pose estimation. To facilitate further research on this topic, we provide an injury specific 2D dataset for alpine skiing, covering in total 533 images. We further propose a post processing routine, that combines rotational information with a simple kinematic model. We could improve detection results in fall situations by up to 21% regarding the [email protected] metric.Comment: extended abstract, 4 pages, 3 figures, 2 table

Analysis of a severe head injury in World Cup alpine skiing

Traumatic brain injury (TBI) is the leading cause of death in alpine skiing. It has been found that helmet use can reduce the incidence of head injuries between 15% and 60%. However, knowledge on optimal helmet performance criteria in World Cup alpine skiing is currently limited owing to the lack of biomechanical data from real crash situations. Purpose: This study aimed to estimate impact velocities in a severe TBI case in World Cup alpine skiing. Methods: Video sequences from a TBI case in World Cup alpine skiing were analyzed using a model-based image matching technique. Video sequences from four camera views were obtained in full high-definition (1080p) format. A three-dimensional model of the course was built based on accurate measurements of piste landmarks and matched to the background video footage using the animation software Poser 4. A trunk-neck-head model was used for tracking the skier's trajectory. Results: Immediately before head impact, the downward velocity component was estimated to be 8 m.s(-1). After impact, the upward velocity was 3 m.s(-1), whereas the velocity parallel to the slope surface was reduced from 33 m.s(-1) to 22 m.s(-1). The frontal plane angular velocity of the head changed from 80 radIsj1 left tilt immediately before impact to 20 rad.s(-1) right tilt immediately after impact. Conclusions: A unique combination of high-definition video footage and accurate measurements of landmarks in the slope made possible a high-quality analysis of head impact velocity in a severe TBI case. The estimates can provide crucial information on how to prevent TBI through helmet performance criteria and design

Investasi Reksa Dana Dengan Sistem Mudharabah Oleh Pt.bank Syariah Mandiri Pekalongan

Mutual Fund is an organization that works for the small investor to take part in the investment world. Mutual Funds Sharia comes to meet the needs of investors to income derived from the investment of funds could be accounted for religious. Implementation of Shariah Fund has similarities to conventional mutual fund. The basic thing that distinguishes them among other application-contract agreement (engagement) Islam in its operational mechanism. Arrangements regarding the application of the agreement set forth in Sharia Fund DSN-MUI Fatwa No.20/DSNMUI/IV/2001. Under the decree, agreement occurring in Mutual Funds Sharia al-wakalah (representative) and mudaraba (profit sharing). Based on the description, the authors are interested in conducting a study entitled "Mutual Fund Investing System With PT Bank Syariah Mandiri Mudaraba By Pekalongan branch". The formulation of the problem studied, namely: how the application of the Mutual Fund mudaraba PT. Bank Syariah Mandiri branch Pekalongan?, How ahambatan that arise in the application of the principle of mudaraba by PT Bank Syariah Mandiri branch Pekalonagan? This study uses empirical juridical approach is a method research approach to solve the problem denagan conduct research on primary data that exist in the field. On the implementation of Sharia Fund was still bias on a particular understanding of mudaraba system many people are still unfamiliar to the mutual fund products Syariah.hal This has become an important task for the PT. Bank Syariah Mandiri branch Pekalongan to promote products and Shariah Investment Fund meningkatkanya growth based Islamic investment in Indonesia, especially in Islamic Fund

Fahrlinie und Belastungsverlauf bei Torlauf und Riesentorlauf : eine biokinematische und biodynamische Analyse der Schitechnik von Schirennfahrern

eingereicht von: Werner NachbauerInnsbruck, Univ., Diss., 1986(VLID)220181