CortexVR: Immersive analysis and training of cognitive executive functions of soccer players using virtual reality and machine learning.

Goal: This paper presents an immersive Virtual Reality (VR) system to analyze and train Executive Functions (EFs) of soccer players. EFs are important cognitive functions for athletes. They are a relevant quality that distinguishes amateurs from professionals. Method: The system is based on immersive technology, hence, the user interacts naturally and experiences a training session in a virtual world. The proposed system has a modular design supporting the extension of various so-called game modes. Game modes combine selected game mechanics with specific simulation content to target particular training aspects. The system architecture decouples selection/parameterization and analysis of training sessions via a coaching app from an Unity3D-based VR simulation core. Monitoring of user performance and progress is recorded by a database that sends the necessary feedback to the coaching app for analysis. Results: The system is tested for VR-critical performance criteria to reveal the usefulness of a new interaction paradigm in the cognitive training and analysis of EFs. Subjective ratings for overall usability show that the design as VR application enhances the user experience compared to a traditional desktop app; whereas the new, unfamiliar interaction paradigm does not negatively impact the effort for using the application. Conclusion: The system can provide immersive training of EF in a fully virtual environment, eliminating potential distraction. It further provides an easy-to-use analyzes tool to compare user but also an automatic, adaptive training mode.

Are Measurement Instruments Responsive to Assess Acute Responses to Load in High-Level Youth Soccer Players?

Purpose: The aim of this study was to assess the short-term responsiveness of measurement instruments aiming at quantifying the acute psycho-physiological response to load in high-level adolescent soccer players. Methods: Data were collected from 16 high-level male youth soccer players from the Under 15 age group. Players were assessed on two occasions during the week: after 2 days of load accumulation ("high load") and after at least 48 h of rest. Measurements consisted of the Short Recovery and Stress Scale (SRSS), a countermovement jump (CMJ) and a sub-maximal run to assess exercise heart-rate (HRex) and heart-rate recovery (HRR60s). Training load was quantified using total distance and high-speed running distance to express external and sRPE training load to express internal load. It was expected that good instruments can distinguish reliably between high load and rest. Results: Odd ratios (0.74-1.73) of rating one unit higher or lower were very low for athlete-reported ratings of stress and recovery of the SRSS. Standardized mean high load vs. rest differences for CMJ parameters were trivial to small (-0.31 to 0.34). The degree of evidence against the null hypothesis that changes are interchangeable ranged from p = 0.04 to p = 0.83. Moderate changes were observed for HRex (-0.62; 90% Cl -0.78 to -0.47; p = 3.24 × 10-9), while small changes were evident for HRR60s (0.45; 90% Cl 0.08-0.80; p = 0.04). Only small to moderate repeated-measures correlations were found between the accumulation of load and acute responses across all measurement instruments. The strongest relationships were observed between HRex and total distance (rm-r = -0.48; 90% Cl -0.76 to -0.25). Conclusion: Results suggest that most of the investigated measurement instruments to assess acute psycho-physiological responses in adolescent soccer players have limited short-term responsiveness. This questions their potential usefulness to detect meaningful changes and manage subsequent training load and program adequate recovery.

The Development of Executive Functions in High-Level Female Soccer Players.

Executive functions (EFs) are higher-level cognitive functions that help keep an individual's goal-oriented thoughts and actions aligned. While many studies have shown the importance of EFs in sport, a limitation in this literature is that female participants have been underrepresented. In this mixed-longitudinal study, we examined the development of EFs in a cohort of high performing female athletes. We collected data over five seasons in a large sample of 175 female soccer players (aged 12-29 years old) from the U14 - senior age groups of a professional German soccer club. Players undertook a large battery of cognitive tasks aimed at measuring higher-level cognitive functioning: a sustained attention task, a stop-signal task, a Go-No-go test, an N-Back Test, and both a 180°- and 360°-multiple-object tracking task. We used linear and non-linear mixed effect regressions to examine the relationship between age and EFs. Second order polynomial curves explained many of these relationships between age and EFs compared to their linear relationships. Negatively accelerated curves reveal that these players' cognitive abilities mainly developed before players reached early adulthood, with a performance plateau evident at around 21 years of age. Age explained low to moderate proportions of the variance in EFs (<1-50%), while cognitive development across playing positions was not a strong contributor to this variance (M = 2.1, SD = 2.1%). We concluded that age has a negatively accelerated relationship with EFs in female soccer players that does not differ between playing positions. These data support the idea that athletes require only a reasonable level of EF ability to perform at the highest level of their sport. Our research raises new questions regarding the validity of current EF measurement methods for inferring information about in-game use of these cognitive abilities.

Poor Reliability of Measurement Instruments to Assess Acute Responses to Load in Soccer Players Irrespective of Biological Maturity Status.

PURPOSE: To assess the short-term reliability of measurement instruments to quantify the acute psychophysiological response to load in adolescent soccer players in relation to biological maturity. METHODS: Data were collected from 108 U12 to U17 soccer players on 2 consecutive weeks (pre, n = 32; at, n = 34; and post, n = 42 estimated peak height velocity). Measurements consisted of the Short Recovery and Stress Scale, a countermovement jump, assessment of leg stiffness, and a submaximal run to assess exercise heart rate and heart rate recovery. Test-retest reliability was assessed with the coefficient of variation (CV) and intraclass correlation coefficient (ICC). RESULTS: Items of the Short Recovery and Stress Scale showed poor reliability across maturity groups (CV = 7.0%-53.5%; ICC = .28 to .79). Only few countermovement jump variables (jump height, concentric impulse, and concentric velocity) possessed good reliability. For most variables of the countermovement jump, reliability was better for the post peak height velocity group followed by at-peak height velocity and prepeak height velocity. Very high levels of reliability across maturity groups were observed for exercise heart rate (CV < 1.8%; ICC > .94), while heart rate recovery was more variable (CV < 16.5%; ICC > .48). CONCLUSION: Results suggest that the majority of investigated variables have poor reliability, questioning their ability to detect small, yet meaningful changes in acute responses to load in adolescent soccer players.

Ethical issues with testing and treatment for Krabbe disease.

Early-infantile Krabbe disease (EIKD) is an autosomal recessive, progressive, neurodegenerative disorder that usually leads to death in infancy. A study published in 2005 indicated that hematopoietic stem-cell transplantation (HSCT) was effective in the treatment for EIKD when used before the onset of symptoms. This finding suggested that newborn screening for EIKD, which would allow earlier diagnosis, might lead to earlier treatment and better outcomes. In 2006, New York was the first state to implement newborn screening for Krabbe disease; however, the results were not as good as proponents had hoped. In this paper, we present the history of efforts to diagnose and treat EIKD. Based on our findings, we question the efficacy of newborn screening for Krabbe disease. We present two arguments. First, testing itself is too imprecise. Even with the most rigorous testing standards, such as those used in New York, many of the children who are identified as being 'at risk' for EIKD remain asymptomatic. It is unclear if they will remain asymptomatic forever and, thus, whether the tests should be considered 'false positives', or whether they will eventually develop the disease. Second, we question the efficacy of early HSCT. We recommend placing a moratorium on mandatory newborn screening for EIKD. WHAT THIS PAPER ADDS: Current tests to identify which children are likely to develop Krabbe diseased are inadequate. Many children identified as being 'at risk' for early infantile Krabbe disease remain asymptomatic. Psychosine appears to be more specific than low galactosylceramidase levels for diagnosing early infantile Krabbe disease.