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## Über dieses Buch

This book constitutes thoroughly revised and selected papers from the Second International Congress on Sports Science Research and Technology Support, icSPORTS 2014, held in Rome, Italy, in October 2014.

The 8 thoroughly revised and extended papers presented in this volume were carefully reviewed and selected from originally 131 submissions.

## Inhaltsverzeichnis

### Development of Skill Scoring System for Ski and Snowboard

Abstract
Observation of dynamic posture during sports activity is one of the most important factors to give absolute evaluation to the player’s performance. The sports like the figure skating and the skiing have difficulty in evaluation of skill because the evaluation depends mostly on the observation from the third person. The training method for such sports inevitably needs feedback comments from the experts. However, it is hard for all players of the sports to receive such expensive feedbacks at any time when they need. In order to overcome the inconvenience to perform self-training without the third experts, this paper focuses on development of a training system using smartphone device that gives a clear guide for body balance control in the skier and the snowboarder. The system gives scores and comments for the ski’s parallel turn. The system automatically scores skill for body balance control regarding three aspects: the tempo at turns of body balance movements between the right and the left in the skiing, the distribution of body balance, and the angle between the snow slope and the body of the skier. This paper also performs a preliminary evaluation of the system in the case of snowboard. The system brings a new method to know the skills of body balance control in skiing and snowboarding from the absolute data measured by sensor devices.
Shinichi Yamagiwa, Hiroyuki Ohshima, Kazuki Shirakawa

### Monocular Tracking of Human Motion in Evaluation of Hurdle Clearance

Abstract
In this paper, markerless method of human motion tracking for measurement of hurdle clearance kinematic parameters was presented. The analysis involved 5 hurdlers at various training levels. Acquisition of video sequences was carried out under simulated starting conditions of a 110 m hurdle race. Kinematic parameters were determined based on the analysis of images recorded with a 100 Hz monocular camera. The accuracy of determined hurdle clearance parameters was verified by comparison of estimated poses with the ground truth poses. As the quality criterion, the mean absolute error was adopted. The level of computed errors showed that the presented method can be used for estimation of hurdle clearance kinematic parameters.
Tomasz Krzeszowski, Krzysztof Przednowek, Janusz Iskra, Krzysztof Wiktorowicz

### Prediction of the Results in 400-Metres Hurdles in Two Different Time Intervals Using Statistical Learning Methods

Abstract
This research presents the selected statistical learning methods in predicting the results of 400 m hurdles in two different time intervals. The calculated models predict results in selected training period and in annual training cycle. In the study, detailed training programs of 21 Polish hurdlers were analyzed. Building of the predictive models was conducted by means of regression shrinkage and artificial neural networks. To evaluate calculated models the leave-one-out cross validation was used. The outcome of the studies shows that the best method in both analysed time intervals was LASSO regression. The prediction error for a training period was at the level of 0.67 s, whereas for the annual training cycle was at the level of 0.39 s. Additionally, for both time intervals the optimal set of predictors was calculated. In terms of training periods, the LASSO model eliminated 8 variables, whereas in terms of the annual training cycle 12 variables were eliminated.
Krzysztof Przednowek, Janusz Iskra, Karolina H. Przednowek

### Sampling Rates and Sensor Requirements for Kinematic Assessment During Running Using Foot Mounted IMUs

Abstract
Inertial sensors have the potential to enable in-situ monitoring of athletic performance. They may offer applications in injury prevention and rehabilitation as well as in technique assessment for improved performance. This paper investigates the use of foot worn inertial sensors in order to assess running kinematics. Footwear provides a potential platform for continuous and in-situ monitoring that does not require additional components to be worn by the athlete since inertial sensors are now small enough to be integrated into footwear. These sensors are also inexpensive enough to be accessible to consumers, opening up the possibility of biomechanical assessment not only to elite athletes but also recreational runners. To facilitate widespread adoption by athletes of all types, sensor systems must be as cheap as possible. To achieve this, sensor systems must be engineered with sampling rates that are not unnecessarily high and components that are not over specified. At the same time accuracy requirements must be met. We investigate multiple sensor parameters (sampling rate, acceleration range) and the effects these have on the accuracy of kinematic assessment using foot worn inertial sensors. We find that Extended Kalman Filter based trajectory recovery seems to be little affected by sampling rate until lower than 250 Hz. We investigate impact accelerations using an inertial measurement unit attached to the foot and find that, at 250 Hz, the acceleration signal peaks at up to 70g around heel strike. We also show that the addition of a high range accelerometer improves accuracy of two example metrics that may be useful in gait assessment, maximum foot clearance (FC) and mean step velocity (SV). The 95 % limits of agreement for FC using a ($$\pm$$ 16g) accelerometer were -4.4 cm to 5.4 cm, this was improved using a high range ($$\pm$$ 200g) accelerometer. The limits of agreement for FC using the improved system where -2.6 cm to 2.6 cm.
G. P. Bailey, R. K. Harle

### A Real-Time Simulator of Foiling Catamarans

Abstract
The new trends in the design of race catamarans has introduced new innovations as huge vertical wings instead of main soft sails, and foiling underwater wings. The scope of the paper is the development of a mathematical model of these new features to be implemented in a simulator designed for training purpose. The paper describes the principal assumptions, the simplifications, and the modeling strategies that were adopted in order to obtain a real time simulation. The mathematical model is implemented in an already existing SIMULINK simulator developed at the University of Southampton and exploits its graphical interfaces. The main new feature is the “flying” simulation. The simulator is designed to interact with the in-training team and to feedback the crewmen with realistic cues. Beside training purpose, the simulator could also be a useful tool in comparing different race strategies in order to select the most promising one.
Paolo Conti, Filippo Rocchini

### Guiding System for Visually Impaired Running on a Track

Abstract
Sighted people can enjoy many social activities that the visually impaired are denied. Our project has the major goal to develop a guidance system: A real-time locating system (RTLS) based on radio signals guides runners with the highest level of safety by estimating the angle of arrival (AoA) and round-trip time (RTT). First results show the position accuracy of the proposed locating system with real-world data with a deviation of less than one metre. Thus we provide an enormous freedom for the visually impaired runners compared to the other solutions: Blind and sighted runners will have the opportunity to do sport together without another person’s assistance.
Ferdinand Kemeth, Sven Hafenecker, Ágnes Jakab, Máté Varga, Tamás Csielka, Sylvie Couronné

### Hydrodynamic Resistance Prediction of an Olympic Class Sailing Dinghy Using CFD and Towing Tank Testing

Abstract
The study presented in this paper aims at investigating, from a hydrodynamic point of view, the most favourable attitude of a sailing dinghy. The procedure includes both an experimental and a numerical approach. Of interest is if these two methods gives analogous results in terms of resistant force and optimal attitude. The numerical study extends to investigating the effects of adding appendages and leeway to the computational model. As this addition strongly affects the computational effort it is also of interest for future reference to see is the same attitude can be predicted this way and thus be discarded from future studies of this kind.
The included verification and validation study reveals that the resistance is greatly under predicted by the numerical method. Furthermore a complete set of results from the numerical predictions was not obtained which makes the goals of the study unfulfilled. This paper also suggest future work on the topic of sailing.
Rickard Lindstrand Levin, Christian Finnsgård, Jeremy Peter

### Do We Need Goal Line Technology in Soccer or Could Video Proof Be a More Suitable Choice: A Cost-Benefit-Analysis of Goal Line Technology in Soccer and Thoughts About an Introduction of Video Proof

Abstract
The aim of this study was to investigate the necessity of goal line technology for top level soccer and compare it to video proof. 1167 games of the 1st and 2nd German Bundesliga were screened for critical goal line decisions as well as other critical goal decisions including penalty calls. 16.8 critical goal line decisions were found per season, of which 76.6 % could directly be resolved by tv-review. On average, 5.0 and 2.8 cases were found respectively in the 1st and 2nd Bundesliga that could justify goal line technology. Furthermore, just 5.0 % of all critical calls concerned goal-line decisions, while 84.3 % involve offside, representing the main reason for critical goal calls. Based on these findings, in terms of a cost-benefit-relation, a video proof could be more suitable than goal line technology. Consequently, we discuss the obstacles and preconditions for the introduction of a video proof in soccer.