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Volume 18 (2019): Issue 2 (September 2019)
Special Issue: Selected papers presented at the 12th Symposium of the Section Computer Science in Sport of the German Association of Sport Science (September 4.-7., 2018)

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Journal Details
Format
Journal
eISSN
1684-4769
First Published
16 Apr 2016
Publication timeframe
2 times per year
Languages
English

Search

Volume 18 (2019): Issue 2 (September 2019)
Special Issue: Selected papers presented at the 12th Symposium of the Section Computer Science in Sport of the German Association of Sport Science (September 4.-7., 2018)

Journal Details
Format
Journal
eISSN
1684-4769
First Published
16 Apr 2016
Publication timeframe
2 times per year
Languages
English

Search

5 Articles
Open Access

Data Mining in Elite Beach Volleyball – Detecting Tactical Patterns Using Market Basket Analysis

Published Online: 16 Sep 2019
Page range: 1 - 19

Abstract

Abstract

Sports coaches today have access to a growing amount of information that describes the performance of their players. Methods such as data mining have become increasingly useful tools to deal with the analytical demands of these high volumes of data. In this paper, we present a sports data mining approach using a combination of sequential association rule mining and clustering to extract useful information from a database of more than 400 high level beach volleyball games gathered at FIVB events in the years from 2013 to 2016 for both men and women. We regard each rally as a sequence of transactions including the tactical behaviours of the players. Use cases of our approach are shown by its application on the aggregated data for both genders and by analyzing the sequential patterns of a single player. Results indicate that sequential rule mining in conjunction with clustering can be a useful tool to reveal interesting patterns in beach volleyball performance data.

Keywords

  • data mining
  • beach volleyball
  • association rules
  • performance analysis
Open Access

Possibilities to Use a Virtual Opponent for Enhancements of Reactions and Perception of Young Karate Athletes

Published Online: 16 Sep 2019
Page range: 20 - 33

Abstract

Abstract

We conducted a virtual reality (VR) training with ten sessions, performed by fifteen young karate athletes, who responded to attacks of a virtual opponent to improve their response behavior and their decision-making. The control groups continued with their normal training. Results of the Friedman tests with subsequent Dunn-Bonferroni post-hoc-tests and estimation of effect sizes showed that the karate specific response behavior (measured by a movement analysis) improved significantly due to the training. The parameters time for response (as the time for the attack initiation) and response quality improved with large effect sizes for the intervention groups, whereas the control groups demonstrated improvements with only small effect sizes. The unspecific response behavior (analyzed by two forms of the reaction test of the Vienna test system) did not show any significant changes. Paired t-tests revealed an improvement in attack recognition. While in the pretests, the intervention groups responded to late movement stages of the attack (execution of the main phase), they responded to early movement stages (reduction of distance and preparing steps) in the posttests. Furthermore, Friedman-tests and bivariate correlation analysis showed that the intervention groups were highly motivated to perform the VR training because of the new and safe learning conditions.

Keywords

  • virtual reality
  • VR training
  • response behavior
  • attack recognition
  • anticipation
Open Access

Gait Training in Orthopedic Rehabilitation after Joint Replacement - Back to Normal Gait with Sonification?

Published Online: 16 Sep 2019
Page range: 34 - 48

Abstract

Abstract

Even several years after total hip (THR) and total knee replacement (TKR) surgery patients frequently show deficient gait patterns leading to overloads and relieving postures on the contralateral side or in the spine. Gait training is, in these cases, an essential part of rehabilitation. The aim of this study was to compare different feedback methods during gait training after THR and TKR focusing, in particular, on auditory feedback via sonification. A total of 240 patients after THR and TKR were tested in a pre-post-test design during a 3-week rehabilitation period. Even though sonification did not show, statistically, a clear advantage over other feedback methods, it was well accepted by the patients and seemed to significantly change gait pattern during training. A sudden absence of sonification during training led to a rapid relapse into previous movement patterns, which highlights its effectiveness in breaking highly automated gait patterns. A frequent use of sonification during and after rehabilitation could, hence, reduce overloading after THR and TKR. This may soon be viable, since new technologies, such as inertial measurement units, allow for wearable joint angle measurement devices. Back to normal gait with sonification seems possible.

Keywords

  • sonification
  • gait training
  • sequelae
  • automatisms
  • relearning
Open Access

Validation of Sensor-Based Game Analysis Tools in Tennis

Published Online: 16 Sep 2019
Page range: 49 - 59

Abstract

Abstract

Three inertial measurement unit (IMU) based tennis sensor systems from BABOLAT (PURE DRIVE PLAY, POP) and HEAD (Tennis Sensor) and a camera-based system (PlaySight) were tested with respect to the question whether the information about the number of strokes by swing type and spin type in training exercises and/or matches and the average as well as the maximum speed of the service per session are reliable. Subsequently, the question whether the mechanical properties of the BABOLAT PURE DRIVE PLAY racket are the same as the mechanical properties of the BABOLAT PURE DRIVE racket without IMU was addressed.

For swing types in standard exercises the results are acceptable for forehand groundstrokes, backhand groundstrokes and services but not for volleys. In a match environment we find inacceptably high errors (>10%) for the number of strokes for forehand and completely inacceptable levels for volley. The wrist-based IMU of BABOLAT POP has not reached an acceptable accuracy at all. For spin types the results are acceptable. The large variances in service speed assessment between devices make it doubtful whether any of them may be used for the control of training processes aiming at increasing the average service speed The mechanical properties of the BABOLAT rackets with and without IMU are quite the same.

Keywords

  • tennis
  • sensor
  • IMU
  • validation
  • gold standard
Open Access

Energy Cost of Running Under Hypogravity in Well-Trained Runners and Triathletes: A Biomechanical Perspective

Published Online: 16 Sep 2019
Page range: 60 - 80

Abstract

Abstract

Hypogravity treadmills have become a popular training tool in distance running and triathlon. Counter-intuitively, tibial acceleration load is not attenuated by hypogravity unloading during running, while, equally surprisingly, leaps become flatter instead of higher. To explain these effects from a biomechanical perspective, Polet, Schroeder, and Bertram (2017) recently developed an energetic model for hypogravity running and validated it with recreational athletes at a constant jogging speed. The present study was conducted to refine that model for competitive athletes at relevant running speeds of 12–22 km h−1 and gravity levels of 100 %, 80 % and 60 %. Based on new experimental data on 15 well-trained runners in treadmill tests until volitional exhaustion, the enhanced semi-empirical model well describes energy expenditure and the observed biomechanical effects of hypogravity running. Remarkably, anaerobic contributions led to an increase in energy cost per meter for speeds above 16–18 km h−1 (p < 0.001), irrespective of hypogravity unloading. Moreover, some converging trends were observed that might reflect general adaptations in running motor control for optimization of efficiency. In essence, the outcome of this research might help sports scientists and practitioners to design running programs for specific training stimuli, e.g. conditioning of anaerobic energy metabolism.

Keywords

  • alterg
  • aerobic and anaerobic energy metabolism
  • oxygen consumption and lactate accumulation
  • tibial accelerations
  • inertial measurement unit
5 Articles
Open Access

Data Mining in Elite Beach Volleyball – Detecting Tactical Patterns Using Market Basket Analysis

Published Online: 16 Sep 2019
Page range: 1 - 19

Abstract

Abstract

Sports coaches today have access to a growing amount of information that describes the performance of their players. Methods such as data mining have become increasingly useful tools to deal with the analytical demands of these high volumes of data. In this paper, we present a sports data mining approach using a combination of sequential association rule mining and clustering to extract useful information from a database of more than 400 high level beach volleyball games gathered at FIVB events in the years from 2013 to 2016 for both men and women. We regard each rally as a sequence of transactions including the tactical behaviours of the players. Use cases of our approach are shown by its application on the aggregated data for both genders and by analyzing the sequential patterns of a single player. Results indicate that sequential rule mining in conjunction with clustering can be a useful tool to reveal interesting patterns in beach volleyball performance data.

Keywords

  • data mining
  • beach volleyball
  • association rules
  • performance analysis
Open Access

Possibilities to Use a Virtual Opponent for Enhancements of Reactions and Perception of Young Karate Athletes

Published Online: 16 Sep 2019
Page range: 20 - 33

Abstract

Abstract

We conducted a virtual reality (VR) training with ten sessions, performed by fifteen young karate athletes, who responded to attacks of a virtual opponent to improve their response behavior and their decision-making. The control groups continued with their normal training. Results of the Friedman tests with subsequent Dunn-Bonferroni post-hoc-tests and estimation of effect sizes showed that the karate specific response behavior (measured by a movement analysis) improved significantly due to the training. The parameters time for response (as the time for the attack initiation) and response quality improved with large effect sizes for the intervention groups, whereas the control groups demonstrated improvements with only small effect sizes. The unspecific response behavior (analyzed by two forms of the reaction test of the Vienna test system) did not show any significant changes. Paired t-tests revealed an improvement in attack recognition. While in the pretests, the intervention groups responded to late movement stages of the attack (execution of the main phase), they responded to early movement stages (reduction of distance and preparing steps) in the posttests. Furthermore, Friedman-tests and bivariate correlation analysis showed that the intervention groups were highly motivated to perform the VR training because of the new and safe learning conditions.

Keywords

  • virtual reality
  • VR training
  • response behavior
  • attack recognition
  • anticipation
Open Access

Gait Training in Orthopedic Rehabilitation after Joint Replacement - Back to Normal Gait with Sonification?

Published Online: 16 Sep 2019
Page range: 34 - 48

Abstract

Abstract

Even several years after total hip (THR) and total knee replacement (TKR) surgery patients frequently show deficient gait patterns leading to overloads and relieving postures on the contralateral side or in the spine. Gait training is, in these cases, an essential part of rehabilitation. The aim of this study was to compare different feedback methods during gait training after THR and TKR focusing, in particular, on auditory feedback via sonification. A total of 240 patients after THR and TKR were tested in a pre-post-test design during a 3-week rehabilitation period. Even though sonification did not show, statistically, a clear advantage over other feedback methods, it was well accepted by the patients and seemed to significantly change gait pattern during training. A sudden absence of sonification during training led to a rapid relapse into previous movement patterns, which highlights its effectiveness in breaking highly automated gait patterns. A frequent use of sonification during and after rehabilitation could, hence, reduce overloading after THR and TKR. This may soon be viable, since new technologies, such as inertial measurement units, allow for wearable joint angle measurement devices. Back to normal gait with sonification seems possible.

Keywords

  • sonification
  • gait training
  • sequelae
  • automatisms
  • relearning
Open Access

Validation of Sensor-Based Game Analysis Tools in Tennis

Published Online: 16 Sep 2019
Page range: 49 - 59

Abstract

Abstract

Three inertial measurement unit (IMU) based tennis sensor systems from BABOLAT (PURE DRIVE PLAY, POP) and HEAD (Tennis Sensor) and a camera-based system (PlaySight) were tested with respect to the question whether the information about the number of strokes by swing type and spin type in training exercises and/or matches and the average as well as the maximum speed of the service per session are reliable. Subsequently, the question whether the mechanical properties of the BABOLAT PURE DRIVE PLAY racket are the same as the mechanical properties of the BABOLAT PURE DRIVE racket without IMU was addressed.

For swing types in standard exercises the results are acceptable for forehand groundstrokes, backhand groundstrokes and services but not for volleys. In a match environment we find inacceptably high errors (>10%) for the number of strokes for forehand and completely inacceptable levels for volley. The wrist-based IMU of BABOLAT POP has not reached an acceptable accuracy at all. For spin types the results are acceptable. The large variances in service speed assessment between devices make it doubtful whether any of them may be used for the control of training processes aiming at increasing the average service speed The mechanical properties of the BABOLAT rackets with and without IMU are quite the same.

Keywords

  • tennis
  • sensor
  • IMU
  • validation
  • gold standard
Open Access

Energy Cost of Running Under Hypogravity in Well-Trained Runners and Triathletes: A Biomechanical Perspective

Published Online: 16 Sep 2019
Page range: 60 - 80

Abstract

Abstract

Hypogravity treadmills have become a popular training tool in distance running and triathlon. Counter-intuitively, tibial acceleration load is not attenuated by hypogravity unloading during running, while, equally surprisingly, leaps become flatter instead of higher. To explain these effects from a biomechanical perspective, Polet, Schroeder, and Bertram (2017) recently developed an energetic model for hypogravity running and validated it with recreational athletes at a constant jogging speed. The present study was conducted to refine that model for competitive athletes at relevant running speeds of 12–22 km h−1 and gravity levels of 100 %, 80 % and 60 %. Based on new experimental data on 15 well-trained runners in treadmill tests until volitional exhaustion, the enhanced semi-empirical model well describes energy expenditure and the observed biomechanical effects of hypogravity running. Remarkably, anaerobic contributions led to an increase in energy cost per meter for speeds above 16–18 km h−1 (p < 0.001), irrespective of hypogravity unloading. Moreover, some converging trends were observed that might reflect general adaptations in running motor control for optimization of efficiency. In essence, the outcome of this research might help sports scientists and practitioners to design running programs for specific training stimuli, e.g. conditioning of anaerobic energy metabolism.

Keywords

  • alterg
  • aerobic and anaerobic energy metabolism
  • oxygen consumption and lactate accumulation
  • tibial accelerations
  • inertial measurement unit

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