2019-08, Artiga Gonzalez, Alexander, Bertschinger, Raphael, Brosda, Fabian, Dahmen, Thorsten, Thumm, Patrick, Saupe, Dietmar

Measurements of oxygen uptake are central to methods for the assessment of physical fitness and endurance capabilities in athletes. Two important parameters extracted from such data of incremental exercise tests are the maximal oxygen uptake and the critical power. A commonly accepted model of the dynamics of oxygen uptake during exercise at a constant work rate comprises a constant baseline oxygen uptake, an exponential fast component, and another exponential slow component for heavy and severe work rates. We have generalized this model to variable load protocols with differential equations that naturally correspond to the standard model for a constant work rate. This provides the means for predicting the oxygen uptake response to variable load profiles including phases of recovery. The model parameters have been fitted for individual subjects from a cycle ergometer test, including the maximal oxygen uptake and critical power. The model predictions have been validated by data collected in separate tests. Our findings indicate that the oxygen kinetics for a variable exercise load can be predicted using the generalized mathematical standard model. Such models can be applied in the field where the constant work rate assumption generally is not valid.

2015, Artiga Gonzalez, Alexander, Bertschinger, Raphael, Brosda, Fabian, Dahmen, Thorsten, Thumm, Patrick, Saupe, Dietmar

Measurements of oxygen uptake and blood lactate content are central to methods for assessment of physical fitness and endurance capabilities in athletes. Two important parameters extracted from such data of incremental exercise tests are the maximal oxygen uptake and the critical power. A commonly accepted model of the dynamics of oxygen uptake during exercise at constant work rate comprises a constant baseline oxygen uptake, an exponential fast component, and another exponential slow component for heavy and severe work rates. We generalized this model to variable load protocols by differential equations that naturally correspond to the standard model for constant work rate. This provides the means for prediction of oxygen uptake response to variable load profiles including phases of recovery. The model parameters were fitted for individual subjects from a cycle ergometer test. The model predictions were validated by data collected in separate tests. Our findings indicate that oxygen kinetics for variable exercise load can be predicted using the generalized mathematical standard model, however, with an overestimation of the slow component. Such models allow for applications in the field where the constant work rate assumption generally is not valid.

2013, Quintana, Juan Carlos, Dahmen, Thorsten, Saupe, Dietmar

Pedal forces in cycling are of interest for several applications: correction of asymmetry between left and right leg motion, training for an even distribution of pedal force during the pedaling cycle, etc. Direct measurement of pedal forces along a full pedaling cycle requires sophisticated sensor technology. We propose to derive pedal force variation from pedal motion that can be acquired in the lab using motion capturing or optical motion tracking.

2012, Byshko, Roman, Dahmen, Thorsten, Gratkowski, Maciej, Gruber, Markus, Quintana, Juan, Saupe, Dietmar, Vieten, Manfred, Woll, Alexander

Das 9. Symposium der Sektion Sportinformatik der Deutschen Vereinigung für Sportwissenschaft (dvs) fand an der Universität Konstanz vom 12.-14. September 2012 statt. In vier eingeladenen Hauptvorträgen und den eingereichten Beiträgen wurden die aktuellen Entwicklungen in den Gegenstandsbereichen der Sportinformatik und deren Anwendungen in der Sportwissenschaft präsentiert und diskutiert. Dieser Band enthält die Abstracts der 32 Beiträge der neun Arbeitskreise: Datenanalyse, Visualisierung und e-Learning, Künstliche Intelligenz, Modellierung und Simulation, Serious Games, Sportgeräte-Entwicklung, mobile Systeme, Wahrnehmung und Kognition, Sensorik. Die vollständigen Beiträge werden in einem weiteren Tagungsband erscheinen.

2016, Artiga Gonzalez, Alexander, Dahmen, Thorsten, Widmann, Claudia, Baiker, Ingrid, Gratkowski, Maciej, Wolf, Stefan, Bertschinger, Raphael, Saupe, Dietmar

This book contains the proceedings of the Workshop Modelling in Endurance Sports, which has taken place in Konstanz (Germany) from 11 to 13 September 2016. The workshop was supported by the German Research Foundation (DFG) and the University of Konstanz and coorganized by the University of Konstanz and the German Society of Sport Science (dvs). In 15 oral presentations, current research topics with focus on modelling in endurance sports like cycling, running and speed skating were discussed. They were organized in four sessions: “Performance Modelling”, “Physiology: VO2, HR, and Lactate”, “Parameter Estimation”, and “Training: Monitoring and Modelling”.

2015, Quintana Duque, Juan Carlos, Dahmen, Thorsten, Saupe, Dietmar

In cycling, the pedalling technique is determined mostly by variations in the torque applied to the pedals during crank rotation. We developed and validated a method to compute these variations from the pedalling motion using an ergometer. The torque at the pedal is the sum of the torques needed to overcome all resistive forces and the torque required for any changes of angular momentum of the ergometer flywheel. This last torque is proportional to the angular acceleration of the crank. For an ergometer with almost constant brake torque, we may assume that variations in the pedal force can be extracted from the pedal motion alone. The key problem is to reliably estimate the angular pedal acceleration from noisy 3D motion capture (MoCap) or 2D video data. We projected the positional data onto a least squares fitting circle, then filtered the resulting angular time sequence by local polynomial regression. Finally, we solved the torque equilibrium equation for the pedal torque. For validation of the method, we used direct pedal torque measurement. In our experiments, pedal brake forces ranged between 100 and 250 N, and cadences of 60, 80, and 100 rpm were used. The pedal torque results from MoCap were better than from video. The results from video were close to MoCap results when a correction of the marker position was applied.

2013, Saupe, Dietmar, Dahmen, Thorsten

2015, Dahmen, Thorsten, Saupe, Dietmar

Normalized power and xPower have become standard measures for metabolic demand with road cycling. In contrast to average power these quantities account for the additional exertion resulting from time-variations of the pedaling power. In this contribution, we develop a method to use a modified xPower to generate pacing strategies for road cycling time trials, where determining the optimal variations of the pedaling power is the ultimate goal. We tackle severe numerical issues related to singular arcs in optimal control, derive the necessary condition and use the Chebfun software system with its essential and unique capability to compute with Fr'echet derivatives automatically.

2014, Dahmen, Thorsten, Saupe, Dietmar

For optimal pacing strategies in the case of two or more competing or cooperating cyclists only few approaches take slipstreaming into account. However, by incorporating the slipstream effect in the model of a race of two runners on a flat course , it has been shown, how the trailing runner can position himself at striking distance behind the other and when he should start the final sprint. (Pitcher, 2009: Optimal strategies for a two - runner model of middle - distance running. SIAM Journal on Applied Mathematics, 70(4), 1032 – 1046)

2012, Byshko, Roman, Dahmen, Thorsten, Gratkowski, Maciej, Gruber, Markus, Quintana, Juan, Saupe, Dietmar, Vieten, Manfred, Woll, Alexander

Das 9. Symposium der Sektion Sportinformatik der Deutschen Vereinigung für Sportwissenschaft (dvs) fand an der Universität Konstanz vom 12.-14. September 2012 statt. In vier eingeladenen Hauptvorträgen und den eingereichten Beiträgen wurden die aktuellen Entwicklungen in den Gegenstandsbereichen der Sportinformatik und deren Anwendungen in der Sportwissenschaft präsentiert und diskutiert. Nach der Tagung haben die meisten der Autoren der angenommenen Einreichungen ihre Abstracts zu vollen Beiträgen ausgearbeitet, die in diesem Band zusammengefasst sind.