Matthias Felix Gilgien

• Bruhin, Björn; Gander, Mara; Gilgien, Matthias & Romann, Michael (2026). Evaluation of inter- and intra-rater reliability of video analysis in ski and snowboard cross. Frontiers in Sports and Active Living. 8. doi: 10.3389/fspor.2026.1746697. Full text in Research Archive
• Monsonís, Oriol Bonell; Verhagen, Evert; Gouttebarge, Vincent; Alhammoud, Marine; Collins, Dave & Ellenberger, Lynn [Show all 15 contributors for this article] (2025). Risk management framework for competitive alpine skiing—co-developed with stakeholders. BMJ Open sport & exercise medicine. 11(3). doi: 10.1136/bmjsem-2025-002507. Full text in Research Archive Show summary

  Previous research has shown that stakeholders in the competitive alpine skiing communities consider risk management to be crucial in sports injury prevention. However, to date, there is a lack of a publicly available systematic and structured risk management approach for the competitive alpine skiing context. This work describes the codevelopment process of a risk management framework with stakeholders in the field of competitive alpine skiing. A panel of international experts invited through personal requests and with expertise in health protection and performance enhancement in competitive alpine skiing convened three times through online group meetings to co-develop a risk management framework through different activities. The underlying discussions focused on the fundamental questions of ‘why’, ‘what’, ‘who’, ‘how’ and ‘for whom’ and included the debate on specific examples from sports practice. The outcome after three meetings was a risk management framework. This framework includes a competitive alpine skiing-specific prevention wheel that integrates different stakeholder views relevant to different levels, their risk priorities, the main five domains and intervention areas identified from the literature, the graded and progressive timescale to intervene and the potential targets for risk management interventions. Moreover, the framework includes a decision-making tree, which operationalises the prevention wheel into a step-by-step sequence for risk management, including risk identification, risk assessment and risk mitigation. It should help stakeholders recognise their responsibilities and the potential actions they can take. Practical examples are provided to demonstrate how to apply the framework and to illustrate the complexity and dynamic interaction of the various factors in the competitive alpine skiing setting. The risk management framework developed lays a strong foundation for creating a safer environment for alpine skiers. It likewise contributes to providing overall awareness of the complexity and inter-relations of risks and prevention measures in the sport. By doing so, this framework has the potential to initiate further processes and on-field translation to sustainably and long-term improve athlete health and safety in competitive alpine skiing.

• Petrella, Davide; Ellenberger, Lynn & Gilgien, Matthias (2025). Accuracy evaluation of smartphone-based GNSS position and speed tracking for ski-slope and safety management. PLOS ONE. 20(8). doi: 10.1371/journal.pone.0327896. Full text in Research Archive Show summary

  Smartphones with integrated global navigation satellite system (GNSS) functionality are increasingly used in various apps beyond communication, including positioning, navigation, and tracking. This study explores the potential of smartphone GNSS data to improve ski slope safety through motion data analysis. Apps such as iSKI, Skitude, Slopes, and Strava measure speeds, distances, and altitude differences, generating valuable data on skiers’ movements. These data help ski resorts in planning and accident prevention by identifying high-risk areas based on movement patterns. We compared the accuracy of position and speed data from four apps across four smartphone models (two Android and two iOS) against a differential GNSS (dGNSS) reference system. Data were collected at two ski resorts during the winter of 2022/23, with smartphones recording at 1 Hz and dGNSS at 50 Hz. Analysis focused on downhill runs, excluding initial recording phases and vertical position data. Accuracy was assessed by calculating the Euclidean distance between the time-synchronized smartphone data and dGNSS reference data. High-end smartphones provided more accurate position data, with an average error of approximately 4 m, compared to 6 m for low-end models. Speed data were reliable across all devices, with an average error <1.9 km/h. However, accuracy diminished with increasing speeds and varied based on location-specific environmental factors. Thus, although smartphone position data can evaluate non-exact position-dependent parameters, such as slope utilization and user density, more precise systems, such as dGNSS, are necessary for exact position-dependent evaluations. Speed data derived from cleaned position data are reliable for estimating skier speeds, and data from different apps can be combined if consistent calculation methods are used. Future advances in smartphone technology are expected to enhance data accuracy. Recommendations include using smartphone data in open terrain for better accuracy and exercising caution when interpreting absolute position data for accident prevention or other context-specific analyses.

• Linløkken, Mai-Sissel; Meyer, Frederic; Högström, Sven Erik Claes; Jølstad, Petter Andre; Spieker, Helge & Guillaume, Sebastien [Show all 9 contributors for this article] (2025). Equivalent Fall Height and Aerial Maneuver Difficulty Both Influence Landing Stability on World Cup Slopestyle Rollover Jumps For Skiers and Snowboarders. Scandinavian Journal of Medicine & Science in Sports. ISSN 0905-7188. 35(4). doi: 10.1111/sms.70053. Full text in Research Archive Show summary

  This study investigates how landing stability on slopestyle jumps is affected by jump design and the athletes' aerial maneuvers, in World Cup skiers and snowboarders. The data were recorded on rollover jumps from a World Cup Slopestyle competition using a geodetic video method, allowing for a reconstruction of the athletes' center of mass trajectories in 3D-space and calculation of equivalent fall height (EFH). Aerial maneuvers and landing stability were assessed by human raters. A generalized estimating equations method with binary logistic regression was performed to investigate how aerial maneuvers and EFH impact landing stability (surrogate measure of potential injury risk). EFH increased the log odds for unstable landings for both skiers and snowboarders. Although five aerial maneuver factors affected landing stability for snowboarders (angular velocity, rotational axis, number of rotations, with interaction effects between multiaxial maneuvers and frontside rotation or switch landing), skiers landing stability was only affected by the number of rotations. This, along with the way skiers and snowboarders are attached to their equipment and their ability to compensate for instability in the landing, may explain why snowboarders show unstable landings more often than skiers. On this study's rollover jumps with generally low EFH, landing stability was regulated by both EFH and aerial maneuvers. As maneuver complexity and EFH have an influence on both performance and landing stability, it appears important that course builders emphasize the construction of safe jumps and athletes generate a good understanding of potential injury risk and performance reward when jumping.

• Spörri, Jörg; McGawley, Kerry; Alhammoud, Marine; Bahr, Roald; Dios, Caitlin & Engebretsen, Lars [Show all 27 contributors for this article] (2024). Snow sports-specific extension of the IOC consensus statement: methods for recording and reporting epidemiological data on injury and illness in sports. British Journal of Sports Medicine. ISSN 0306-3674. 59(1), p. 8–23. doi: 10.1136/bjsports-2024-108720. Full text in Research Archive Show summary

  The International Olympic Committee’s (IOC) consensus statement on ‘methods for recording and reporting of epidemiological data on injury and illness in sport’ recommended standardising methods to advance data collection and reporting consistency. However, additional aspects need to be considered when these methods are applied to specific sports settings. Therefore, we have developed a snow sports-specific extension of the IOC statement to promote the harmonisation of injury and illness registration methods among athletes of all levels and categories in the different disciplines governed by the International Ski and Snowboard Federation (FIS), which is also applicable to other related snow sports such as biathlon, ski mountaineering, and to some extent, para snow sports. The panel was selected with the aim of representing as many different areas of expertise/backgrounds, perspectives and diversity as possible, and all members were assigned to thematic subgroups based on their profiles. After panel formation, all members were provided with an initial draft of this extension, which was used as a basis for discussion of aspects specific to the discipline, application context, level and sex within their snow sports subgroup topic. The outcomes were then aligned with the IOC’s existing consensus recommendations and incorporated into a preliminary manuscript draft. The final version of this snow sports-specific extension was developed and approved in two iterative rounds of manuscript revisions by all consensus panel members and a final meeting to clarify open discussion points. This snow sports-specific extension of the IOC statement is intended to guide researchers, international and national sports governing bodies, and other entities recording and reporting epidemiological data in snow sports to help standardise data from different sources for comparison and future research.

• Luteberget, Live Steinnes; Jølstad, Petter Andre & Gilgien, Matthias (2023). Methods to assess validity of positioning systems in team sports: Can we do better? BMJ Open sport & exercise medicine. 9(1), p. 1–9. doi: 10.1136/bmjsem-2022-001496. Full text in Research Archive Show summary

  Objectives: There is previously reported a large variety of criterion measures and reference systems applied to validate position tracking systems in sports. This study aims to investigate the effect of different criterion measures and reference systems on the outcome of accuracy assessments of tracking systems in sports. Methods: Data from a commercially available standalone global navigation satellite system (GNSS) were compared with two different reference systems: a high-end differential GNSS and a tape measure. Differences in accuracy outcomes of position (static and dynamic), distance and speed (mean and instantaneous) were investigated in team sport imitation courses. Results: The mean horizontal position error was larger when athletes were in motion (dynamic position; 1.53±0.82 m) compared with static measurements (1.10±0.60 m). Measured distances of the courses were markedly different (+6% to −17%) between the two reference systems, causing differences in error. Differences in error were also found between mean speed and instantaneous speed (0.10 vs 0.28 m). Errors in mean speed were highly affected by the time over which speed was averaged. Conclusion: Choice of criterion measure and reference system has a substantial impact on the accuracy assessments of tracking systems. Specifically, assessing static position is not a substitute for dynamic position, and mean speed is not a substitute for instantaneous speed. Therefore, the outcomes of validation studies should always be interpreted in light of the reference methods that were used.

• Soligard, Torbjørn; Palmer, Debbie; Steffen, Kathrin; Lopes, Alexandre Dias; Grek, Natalia & He, Xuan [Show all 12 contributors for this article] (2023). Olympic Games during nationwide lockdown: Sports injuries and illnesses, including COVID-19, at the Beijing 2022 Winter Olympics. British Journal of Sports Medicine. ISSN 0306-3674. doi: 10.1136/bjsports-2023-107412. Full text in Research Archive Show summary

  Objective: The objective of this study is to describe the incidence of injuries and illnesses sustained during the Beijing Winter Olympic Games from 4 February 2022 to 20 February 2022. Methods: We recorded the daily number of athlete injuries and illnesses (1) through the reporting of all National Olympic Committee (NOC) medical teams and (2) in the polyclinic and medical venues by the Beijing 2022 medical staff. Results: In total, 2848 athletes (1276 women, 45%; 1572 men, 55%) from 91 NOCs were followed prospectively for the occurrence of injury and illness. NOC and Beijing 2022 medical staff reported 289 injuries and 109 illnesses, equalling 10.1 injuries and 3.8 illnesses per 100 athletes over the 17-day period. The injury incidence was highest in ski halfpipe (30%), ski big air (28%), snowboard slopestyle (23%) and ski slopestyle (22%), and lowest (1%–2%) in curling, alpine mixed team parallel slalom, Nordic combined and alpine super-G. The illness incidence was highest in ski aerials (10%), skeleton (8%), cross-country skiing (8%) and Nordic combined (7%). In the study period, COVID-19 affected 32 athletes, accounting for 29% of all illnesses affecting 1.1% of all athletes. Conclusion: Overall, 10% of the athletes incurred an injury and 4% an illness during the Beijing Winter Olympic Games. The incidence of illnesses overall, which was the lowest yet recorded in the Winter Olympic Games, and COVID-19 was mitigated through comprehensive countermeasures.

• Jølstad, Petter Andre; Gilgien, Matthias & Elfmark, Ola (2023). Investigation of individual strategies in the aerial phase in ski jumping. Scientific Reports. 13. doi: 10.1038/s41598-023-49683-0. Full text in Research Archive Show summary

  The purpose of this investigation was to examine the performance strategy of three ski jumpers during the steady glide phase and explain how different strategical solutions can lead to jumps of roughly the same length. In this study, a total of 24 jumps performed by two World Cup (WC) athletes and one Continental Cup (COC) athlete were measured with a differential Global Navigation Satellite System (dGNSS) on a large ski jumping hill. For each athlete, the continuous position data, velocity, aerodynamic forces and lift-to-drag ratio (LD-ratio) were averaged and compared for the steady glide phase to examine individual jump strategies. The dGNSS yielded accurate measurements of trajectory, velocity and aerodynamic forces, revealing clear differences between the athletes. The largest differences were found between the WC athletes and the COC athlete. The WC athletes focused on maximizing horizontal velocity while the COC athlete minimized vertical velocity. This difference may be explained by the different hill sizes the athletes normally compete on. One of the WC athletes consistently increased their horizontal velocity during the end of the steady glide phase by maintaining a high LD-ratio, which highlights the effect of aerodynamics on the resulting velocity, trajectory and jump length.

• Oğul, Burçin Buket; Gilgien, Matthias & Özdemir, Suat (2022). Ranking surgical skills using an attention-enhanced Siamese network with piecewise aggregated kinematic data. International Journal of Computer Assisted Radiology and Surgery. ISSN 1861-6410. 17(6), p. 1039–1048. doi: 10.1007/s11548-022-02581-8. Full text in Research Archive Show summary

  Purpose: Surgical skill assessment using computerized methods is considered to be a promising direction in objective performance evaluation and expert training. In a typical architecture for computerized skill assessment, a classification system is asked to assign a query action to a predefined category that determines the surgical skill level. Since such systems are still trained by manual, potentially inconsistent annotations, an attempt to categorize the skill level can be biased by potentially scarce or skew training data. Methods: We approach the skill assessment problem as a pairwise ranking task where we compare two input actions to identify better surgical performance. We propose a model that takes two kinematic motion data acquired from robot-assisted surgery sensors and report the probability of a query sample having a better skill than a reference one. The model is an attention-enhanced Siamese Long Short-Term Memory Network fed by piecewise aggregate approximation of kinematic data. Results: The proposed model can achieve higher accuracy than existing models for pairwise ranking in a common dataset. It can also outperform existing regression models when applied in their experimental setup. The model is further shown to be accurate in individual progress monitoring with a new dataset, which will serve as a strong baseline. Conclusion: This relative assessment approach may overcome the limitations of having consistent annotations to define skill levels and provide a more interpretable means for objective skill assessment. Moreover, the model allows monitoring the skill development of individuals by comparing two activities at different time points.

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• Linløkken, Mai-Sissel; Vigane, Sondre; Högström, Claes; Jølstad, Petter; Spieker, Helge & Hoholm, Sindre [Show all 7 contributors for this article] (2024). A Biomechanical Analysis of how Athlete Behavior and Equivalent Fall Height Affect Landing Stability for Skiers and Snowboarders in a World Cup Big Air Competition. Full text in Research Archive

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