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Bonell Monsonís O, Spörri J, Warsen M, Bolling C, Gouttebarge V, Verhagen E. We know a lot about little and little about a lot: A contextualized scoping review on injury prevention in alpine ski racing. Scand J Med Sci Sports 2024; 34:e14533. [PMID: 37955281 DOI: 10.1111/sms.14533] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/19/2023] [Accepted: 10/25/2023] [Indexed: 11/14/2023]
Abstract
BACKGROUND Our goal was to summarize and contextualize the available literature on alpine ski racing injury epidemiology, injury etiology, injury prevention measures, injury prevention context, and implementation issues. MATERIALS AND METHODS We searched four electronic databases using predetermined search terms. We included original studies that assessed injury, injury risk factors, and injury mechanisms, and assessed and reported the effect of an injury prevention measure in alpine ski racing. Two authors independently conducted title-abstract screening, and one performed the full-text review. For data synthesis and categorization, we used the Translating Research into the Injury Prevention Practice framework and a modified and adapted version of the Haddon matrix. RESULTS Of the 157 included studies, most corresponded to injury epidemiology and etiology, whereas few studies encompassed injury prevention measure development, implementation and evaluation. Preventive interventions targeting equipment, rules and regulations, course design and snow preparation were the most prevalent in the literature. Furthermore, various contextual factors in the current literature have been found, including gender, competition level, countries and federations, and time periods within a season. CONCLUSIONS We provided an in-depth and comprehensive overview of the current state-of-the-art in the alpine ski racing context. We know a lot about little and little about a lot across all the areas associated with injury prevention in such context. The limitations in the literature yield a road map for designing future injury prevention studies to address the key gaps identified. A more comprehensive context-driven approach throughout all stages of injury prevention would benefit the ultimate implementation of effective preventive strategies.
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Affiliation(s)
- Oriol Bonell Monsonís
- Amsterdam Collaboration on Health and Safety in Sports, Department of Public and Occupational Health, Amsterdam Movement Sciences, Amsterdam UMC, University Medical Centers - Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Amsterdam Movement Sciences, Musculoskeletal Health and Sports, Amsterdam, The Netherlands
| | - Jörg Spörri
- Sports Medical Research Group, Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- University Centre for Prevention and Sports Medicine, Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marit Warsen
- Amsterdam Collaboration on Health and Safety in Sports, Department of Public and Occupational Health, Amsterdam Movement Sciences, Amsterdam UMC, University Medical Centers - Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Caroline Bolling
- Amsterdam Collaboration on Health and Safety in Sports, Department of Public and Occupational Health, Amsterdam Movement Sciences, Amsterdam UMC, University Medical Centers - Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Amsterdam UMC Location University of Amsterdam, Orthopedic Surgery and Sports Medicine, Amsterdam, The Netherlands
| | - Vincent Gouttebarge
- Amsterdam Movement Sciences, Musculoskeletal Health and Sports, Amsterdam, The Netherlands
- Amsterdam UMC Location University of Amsterdam, Orthopedic Surgery and Sports Medicine, Amsterdam, The Netherlands
- Section Sports Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Evert Verhagen
- Amsterdam Collaboration on Health and Safety in Sports, Department of Public and Occupational Health, Amsterdam Movement Sciences, Amsterdam UMC, University Medical Centers - Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Amsterdam Movement Sciences, Musculoskeletal Health and Sports, Amsterdam, The Netherlands
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2
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Meinke A, Spörri J, Brogli L, Schwab P, Karlen W. Addressing the unresolved challenge of quantifying skiing exposure-A proof of concept using smartphone sensors. Front Sports Act Living 2023; 5:1157987. [PMID: 37229363 PMCID: PMC10203200 DOI: 10.3389/fspor.2023.1157987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/21/2023] [Indexed: 05/27/2023] Open
Abstract
In epidemiological studies related to winter sports, especially alpine skiing, an unresolved methodological challenge is the quantification of actual on-snow activity exposure. Such information would be relevant for reporting meaningful measures of injury incidence, which refers to the number of new injuries that occur in a given population and time period. Accordingly, accurate determination of the denominator, i.e., actual "activity exposure time", is critical for injury surveillance and reporting. In this perspective article, we explore the question of whether wearable sensors in combination with mHealth applications are suitable tools to accurately quantify the periods in a ski day when the skier is physically skiing and not resting or using a mechanical means of transport. As a first proof of concept, we present exemplary data from a youth competitive alpine skier who wore his smartphone with embedded sensors on his body on several ski days during one winter season. We compared these data to self-reported estimates of ski exposure, as used in athletes' training diaries. In summary, quantifying on-snow activity exposure in alpine skiing using sensor data from smartphones is technically feasible. For example, the sensors could be used to track ski training sessions, estimate the actual time spent skiing, and even quantify the number of runs and turns made as long as the smartphone is worn. Such data could be very useful in determining actual exposure time in the context of injury surveillance and could prove valuable for effective stress management and injury prevention in athletes.
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Affiliation(s)
- Anita Meinke
- Mobile Health Systems Lab, Institute of Robotics and Intelligent Systems, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Jörg Spörri
- Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- University Centre for Prevention and Sports Medicine, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Luzius Brogli
- Mobile Health Systems Lab, Institute of Robotics and Intelligent Systems, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Patrick Schwab
- Mobile Health Systems Lab, Institute of Robotics and Intelligent Systems, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
| | - Walter Karlen
- Mobile Health Systems Lab, Institute of Robotics and Intelligent Systems, Department of Health Sciences and Technology, ETH Zurich, Zurich, Switzerland
- Institute of Biomedical Engineering, University of Ulm, Ulm, Germany
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3
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Ruedl G, Posch M, Tecklenburg K, Schranz A, Faulhaber M, Burtscher M. Skill-Specific Differences in Equipment-Related Risk Factors for ACL Injury in Male and Female Recreational Skiers. Orthop J Sports Med 2023; 11:23259671231155841. [PMID: 36896096 PMCID: PMC9989403 DOI: 10.1177/23259671231155841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 11/08/2022] [Indexed: 03/11/2023] Open
Abstract
Background In recreational alpine skiing, the anterior cruciate ligament (ACL) is affected in approximately 50% of serious knee injuries. There are established sex-based and skill-based differences in ACL injury risk, but the potential impact of equipment used (eg, skis, bindings, and boots) has not been evaluated. Purpose To evaluate individual and equipment-related risk factors for an ACL injury depending on sex and skill level. Study Design Case-control study; Level of evidence, 3. Methods This was a retrospective questionnaire-based, case-control study of female and male skiers with and without ACL injuries during 6 winter seasons (from 2014-2015 to 2019-2020). Demographic data, skill level, equipment specifications, risk-taking behavior, and ownership of ski equipment were recorded. Ski geometry (ski length; sidecut radius; and widths of the tip, waist, and tail) was taken from each participant's ski. The standing heights of the front and back part of the ski binding were measured using a digital sliding caliper, and the standing height ratio was calculated. Abrasion of the ski boot sole was also measured at the toe and heel. Participants were divided by sex into less and more skilled skiers. Results A total of 1817 recreational skiers participated in this study, of whom 392 (21.6%) sustained an ACL injury. A greater standing height ratio and more abrasion at the toe of the boot sole were associated with increased ACL injury risk in both sexes, independent of the skill level. Riskier behavior increased the injury risk only in male skiers, independent of the skill level, and longer skis increased the injury risk only in less skilled female skiers. Older age, the use of rented/borrowed skis, and more abrasion at the heel of the boot sole were independent risk factors for ACL injury in the more skilled skiers of both sexes. Conclusion Individual and equipment-related risk factors for an ACL injury partly differed according to skill level and sex. Consideration of the demonstrated equipment-related factors should be implemented in order to reduce ACL injuries in recreational skiers.
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Affiliation(s)
- Gerhard Ruedl
- Department of Sport Science, Universität Innsbruck, Innsbruck, Austria
| | - Markus Posch
- Department of Sport Science, Universität Innsbruck, Innsbruck, Austria
| | | | | | - Martin Faulhaber
- Department of Sport Science, Universität Innsbruck, Innsbruck, Austria
| | - Martin Burtscher
- Department of Sport Science, Universität Innsbruck, Innsbruck, Austria
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Zullo G, Cibin P, Bortolan L, Botteon M, Petrone N. An Innovative Compact System to Measure Skiing Ground Reaction Forces and Flexural Angles of Alpine and Touring Ski Boots. SENSORS (BASEL, SWITZERLAND) 2023; 23:836. [PMID: 36679634 PMCID: PMC9867497 DOI: 10.3390/s23020836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/28/2022] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Skiing is a popular winter activity spanning various subdisciplines. Key hardware are ski boots, bindings, and skis, which are designed to withstand loads generated during skiing. Obtaining service forces and moments has always been challenging to researchers in the past. The goal of the present study is to develop and test a lightweight and compact measurement system to obtain the Ground Reaction Forces and the kinematics for ski touring and alpine ski. To do so, we adapted two six-axis load cells to fit into ski touring and alpine skis adding 20 mm height and 500 g weight to the original ski. To measure kinematics, we created custom angular sensors from rotary potentiometers. The system was tested indoors using a force platform and motion capture system before a first set of field tests in which the sensors were used to measure ski touring and alpine skis kinetics and kinematics. Validation trials showed maximum errors of 10% for kinetics and 5% for kinematics. Field tests showed data in agreement with previous findings on the topic. The results of this study show the possibility of using our system to study biomechanics and equipment performances for ski touring, alpine skiing, and possibly other disciplines.
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Affiliation(s)
- Giuseppe Zullo
- Department of Industrial Engineering, University of Padua, Via Venezia 1, 35131 Padova, Italy
| | - Pierluigi Cibin
- Department of Industrial Engineering, University of Padua, Via Venezia 1, 35131 Padova, Italy
| | - Lorenzo Bortolan
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, 38068 Rovereto, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37124 Verona, Italy
| | | | - Nicola Petrone
- Department of Industrial Engineering, University of Padua, Via Venezia 1, 35131 Padova, Italy
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5
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Xu Y, Yang C, Yang Y, Zhang X, Zhang S, Zhang M, Liu L, Fu W. A Narrative Review of Injury Incidence, Location, and Injury Factor of Elite Athletes in Snowsport Events. Front Physiol 2021; 11:589983. [PMID: 33488394 PMCID: PMC7820716 DOI: 10.3389/fphys.2020.589983] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 12/10/2020] [Indexed: 11/13/2022] Open
Abstract
Snowsport athletes face a high injury risk both during training and in competitions. Reducing injury incidence is crucial for athletes to achieve breakthroughs. This narrative review aimed to summarize and analyze injury data of elite athletes in snowsports and provide references for injury prevention and health security for these athletes and their coaches. A total of 39 studies that investigated snowsport injury were analyzed in the present study. On the basis of injury data of elite athletes in snowsports events, this narrative review focused on four aspects, namely, injury incidence, severity, location and causes. The findings of this review were as follows. (1) The highest injury incidence was recorded in freestyle skiing, followed by alpine skiing and snowboarding, the majority of which were moderate and severe injuries. (2) The proportion of injury in competitions and during training was similar. However, more injuries occurred in official training during the Winter Olympic Games; by contrast, injury proportion was higher in competitions during World Cup/World Championships. (3) The most commonly and severely injured body parts were the knees (29.9%), head and face (12.1%), shoulders and clavicula (10.5%), and lower back (8.9%). The most common injury types were joint and ligament injury (41.5%), fracture and bone stress (24.4%), concussion (11.1%), and muscle/tendon injury (10.7%). (4) The main causes of snowsport injury were collisions, falls, and non-contact injuries. Snowsport injury was also influenced by the skill level of the athletes, gender, course setup and equipment. Future studies should further explore the influence of event characteristics and intrinsic and extrinsic risk factors on snowsport injury. An injury or trauma reconstruction may be developed to predict athletic injuries and provide effective prevention strategies.
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Affiliation(s)
- Yongxin Xu
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Chenhao Yang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Yang Yang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Xini Zhang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Shen Zhang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Mingwen Zhang
- Beijing Institute of Fashion Technology, Beijing, China.,Institute for Frontier Materials, Deakin University, Geelong, VIC, Australia
| | - Li Liu
- Beijing Institute of Fashion Technology, Beijing, China
| | - Weijie Fu
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
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6
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Petrone N, Vanzetto D, Marcolin G, Bruhin B, Gilgien M. The effect of foot setting on kinematic and kinetic skiing parameters during giant slalom: A single subject study on a Paralympic gold medalist sit skier. J Sci Med Sport 2020; 24:1049-1054. [PMID: 32998849 DOI: 10.1016/j.jsams.2020.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 04/04/2020] [Accepted: 08/26/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Aim was to study the effect of monoski foot adjustment on kinematic and kinetic skiing parameters expressing sit skier's technique. DESIGN Independent variable was skier position with respect to bindings, acting on position of monoski foot sole clamp. Front (F), Mid (M) and Rear (R) settings changed with intervals of 20mm. Course time, skiing speed, Ground Reaction Forces (GRFs) magnitude and point of application and damper stroke were dependent variables. METHOD A Paralympic monoski was equipped with a dynamometric binding plate measuring GRFs, roll and pitch moments. A Paralympic gold medalist (LW10-1) was involved. Skier trajectory and gates location were measured by a differential global navigation satellite system (GNSS) in steep and medium steep slope portions. The athlete performed two giant slalom runs for each foot setting the same day. RESULTS GRFs, center of pressure (COP) and variations with foot settings were measured. Peaks values up to 3.36 times the total weight and damper speed of 675mm/s in compression were found. Fastest runs, highest peak loads and best subjective ratings were recorded with F setting. COP mean values were influenced by foot adjustments. GRFs in left turns were 54% larger than in the right turns with F setting on steep slope. CONCLUSIONS The monoski foot adjustment influenced kinematic and kinetic skiing, with F setting showing best results. A skier asymmetric behavior between right and left turning was discovered. Findings can support the design of monoskis for a wider dissemination of Paralympic alpine sit skiing.
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Affiliation(s)
- Nicola Petrone
- Department of Industrial Engineering, University of Padova, Italy.
| | - Dario Vanzetto
- Department of Industrial Engineering, University of Padova, Italy
| | | | - Björn Bruhin
- Swiss-Ski, Switzerland; Section for Elite Sport, Swiss Federal Institute of Sport Magglingen, Switzerland
| | - Matthias Gilgien
- Department of Physical Performance, Norwegian School of Sport Sciences, Norway; Center of Alpine Sports Biomechanics, Engadin Health and Innovation Foundation, Switzerland
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7
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Gilgien M, Crivelli P, Kröll J, Luteberget LS, Müller E, Spörri J. Preventing injuries in alpine skiing giant slalom by shortening the vertical distance between the gates rather than increasing the horizontal gate offset to control speed. Br J Sports Med 2020; 54:1042-1046. [PMID: 32341022 DOI: 10.1136/bjsports-2019-101692] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2020] [Indexed: 11/04/2022]
Abstract
BACKGROUND/AIM To set a safe giant slalom course, speed needs to be controlled in certain sections. Speed may be reduced by adjusting how the gates are set on a course. We studied the effect of elements of course-setting, entrance speed and terrain incline on the mechanics of turning (ie, turn speed, turn radius, and ground reaction force and impulse). METHODS During seven World Cup alpine giant slalom competitions, the course and terrain characteristics of the official racetracks and the mechanics of a professional-level athlete skiing the course immediately prior to competition were analysed with differential global navigation satellite system technology. Data were analysed using a linear mixed-effects model. RESULTS Course-setting geometry (vertical gate distance and horizontal gate offset), entrance speed and terrain incline modulated the injury-relevant factor turn speed. Depending on the terrain, the speed throughout a turn can be reduced by 0.5 m/s either by shortening the vertical gate distance by 4.9-6.9 m (from -20% to -29%) or by increasing the horizontal gate offset by 2.8-3.2 m (from +33% to +55%). However, increasing the horizontal gate offset causes the skier to turn with a smaller minimal turn radius, increase maximal ground reaction force and also increase impulse. DISCUSSION To reduce speed, we recommend decreasing the vertical gate distance rather than increasing the horizontal gate offset. Increasing horizontal gate offset would require the skiers to sharpen and prolong their turns (reducing turn radius), and this increases the acting ground reaction force and impulse and thus the athlete's fatigue.
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Affiliation(s)
- Matthias Gilgien
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway .,Center of Alpine Sports Biomechanics, St Moritz Health and Innovation Foundation, Samedan, Switzerland
| | - Philip Crivelli
- Group for Snowsports, WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
| | - Josef Kröll
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein-Rif, Austria
| | - Live S Luteberget
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Erich Müller
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein-Rif, Austria
| | - Jörg Spörri
- Sports Medical Research Group, Department of Orthopaedics, Balgrist Balgrist University Hospital, University of Zurich, Zurich, Switzerland.,Center for Prevention and Sports Medicine, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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8
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Alhammoud M, Racinais S, Rousseaux‐Blanchi M, Bouscaren N. Recording injuries only during winter competitive season underestimates injury incidence in elite alpine skiers. Scand J Med Sci Sports 2020; 30:1177-1187. [PMID: 32141109 DOI: 10.1111/sms.13648] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 12/31/2019] [Accepted: 02/28/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Marine Alhammoud
- High‐Level Sport Medicine Centre Hospital of Albertville‐Moûtiers Albertville France
- French Ski Federation Annecy France
- Aspetar Orthopaedic and Sports Medicine Hospital Doha Qatar
| | - Sébastien Racinais
- Aspetar Orthopaedic and Sports Medicine Hospital Doha Qatar
- Laboratory Sport, Expertise and Performance French Institute of Sport (INSEP) Paris France
| | - Marie‐Philippe Rousseaux‐Blanchi
- High‐Level Sport Medicine Centre Hospital of Albertville‐Moûtiers Albertville France
- French Ski Federation Annecy France
- International Ski Federation Oberhofen am Thunersee Switzerland
| | - Nicolas Bouscaren
- French Ski Federation Annecy France
- Inserm CIC1410 CHU Réunion Saint Pierre France
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9
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Supej M, Spörri J, Holmberg HC. Methodological and Practical Considerations Associated With Assessment of Alpine Skiing Performance Using Global Navigation Satellite Systems. Front Sports Act Living 2020; 1:74. [PMID: 33344996 PMCID: PMC7739811 DOI: 10.3389/fspor.2019.00074] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/24/2019] [Indexed: 12/20/2022] Open
Abstract
Reliable assessment of the performance of alpine skiers is essential. Previous studies have highlighted the potential of Global Navigation Satellite Systems (GNSS) for evaluating this performance. Accordingly, the present perspective summarizes published research concerning methodological and practical aspects of the assessment of alpine skiing performance by GNSS. Methodologically, in connection with trajectory analysis, a resolution of 1-10 cm, which can be achieved with the most advanced GNSS systems, has proven to provide acceptable accuracy. The antenna should be positioned to follow the trajectory of the skier's center-of-mass (CoM) as closely as possible and estimation of this trajectory can be further improved by applying advanced modeling and/or other computerized approaches. From a practical point of view, effective assessment requires consideration of numerous parameters related to performance, including gate-to-gate times, trajectory, speed, and energy dissipation. For an analysis that is both more comprehensive and more easily accessible to coaches/athletes, video filming should be synchronized with the GNSS data. In summary, recent advances in GNSS technology already allow, at least to some extent, precise biomechanical analysis of performance over an entire alpine skiing race course in real-time. Such feedback has both facilitated and improved the work of coaches. Thus, athletes and coaches are becoming more and more aware of the advantages of analyzing alpine skiing performance by GNSS in combination with advanced computer software, paving the way for the digital revolution in both the applied research on and practice of this sport.
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Affiliation(s)
- Matej Supej
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
| | - Jörg Spörri
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Hans-Christer Holmberg
- Swedish Winter Sports Research Center, Mid Sweden University, Östersund, Sweden.,China Institute of Sport and Health Science, Beijing Sport University, Beijing, China
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10
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Fasel B, Spörri J, Kröll J, Müller E, Aminian K. A Magnet-Based Timing Tystem to Detect Gate Crossings in Alpine Ski Racing. SENSORS 2019; 19:s19040940. [PMID: 30813371 PMCID: PMC6412682 DOI: 10.3390/s19040940] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/20/2019] [Accepted: 02/20/2019] [Indexed: 11/16/2022]
Abstract
In alpine skiing, intermediate times are usually measured with photocells. However, for practical reasons, the number of intermediate cells is limited to three⁻four, making a detailed timing analysis difficult. In this paper, we propose and validate a magnet-based timing system allowing for the measurement of intermediate times at each gate. Specially designed magnets were placed at each gate and the athletes wore small magnetometers on their lower back to measure the instantaneous magnetic field. The athlete's gate crossings caused peaks in the measured signal which could then be related to the precise instants of gate crossings. The system was validated against photocells placed at four gates of a slalom skiing course. Eight athletes skied the course twice and one run per athlete was included in the validation study. The 95% error intervals for gate-to-gate timing and section times were below 0.025 s. Each athlete's gate-to-gate times were compared to the group's average gate-to-gate times, revealing small performance differences that would otherwise be difficult to measure with a traditional photocell-based system. The system could be used to identify the effect of tactical choices and athlete specific skiing skills on performance and could allow a more efficient and athlete-specific performance analysis and feedback.
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Affiliation(s)
- Benedikt Fasel
- Archinisis GmbH, 1700 Fribourg, Switzerland.
- Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
| | - Jörg Spörri
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, 8008 Zurich, Switzerland.
- Department of Sport Science and Kinesiology, University of Salzburg, 5400 Hallein-Rif, Austria.
| | - Josef Kröll
- Department of Sport Science and Kinesiology, University of Salzburg, 5400 Hallein-Rif, Austria.
| | - Erich Müller
- Department of Sport Science and Kinesiology, University of Salzburg, 5400 Hallein-Rif, Austria.
| | - Kamiar Aminian
- Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
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11
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Supej M, Holmberg HC. Recent Kinematic and Kinetic Advances in Olympic Alpine Skiing: Pyeongchang and Beyond. Front Physiol 2019; 10:111. [PMID: 30842740 PMCID: PMC6391578 DOI: 10.3389/fphys.2019.00111] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 01/30/2019] [Indexed: 11/13/2022] Open
Abstract
Alpine skiing has been an Olympic event since the first Winter Games in 1936. Nowadays, skiers compete in four main events: slalom, giant slalom, super-G and downhill. Here, we present an update on the biomechanics of alpine ski racers and their equipment. The technical and tactical ability of today’s world-class skiers have adapted substantially to changes in equipment, snow conditions and courses. The wide variety of terrain, slopes, gate setups and snow conditions involved in alpine skiing requires skiers to continuously adapt, alternating between the carving and skidding turning techniques. The technical complexity places a premium on minimizing energy dissipation, employing strategies and ski equipment that minimize ski-snow friction and aerodynamic drag. Access to multiple split times along the racing course, in combination with analysis of the trajectory and speed provide information that can be utilized to enhance performance. Peak ground reaction forces, which can be as high as five times body weight, serve as a measure of the external load on the skier and equipment. Although the biomechanics of alpine skiing have significantly improved, several questions concerning optimization of skiers’ performance remain to be investigated. Recent advances in sensor technology that allow kinematics and kinetics to be monitored can provide detailed information about the biomechanical factors related to success in competitions. Moreover, collection of data during training and actual competitions will enhance the quality of guidelines for training future Olympic champions. At the same time, the need to individualize training and skiing equipment for each unique skier will motivate innovative scientific research for years to come.
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Affiliation(s)
- Matej Supej
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
| | - H-C Holmberg
- The Swedish Winter Sports Research Centre, Mid Sweden University, Östersund, Sweden.,School of Sport Sciences, UiT The Arctic University of Norway, Tromsø, Norway
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12
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Tarka MC, Davey A, Lonza GC, O'Brien CM, Delaney JP, Endres NK. Alpine Ski Racing Injuries. Sports Health 2019; 11:265-271. [PMID: 30689522 DOI: 10.1177/1941738119825842] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
CONTEXT This article reviews the epidemiology of alpine ski racing-related injuries, risk factors, mechanisms of injury, and injury prevention strategies. EVIDENCE ACQUISITION Pertinent literature from peer-reviewed publications from 1976 through 2018. STUDY DESIGN Clinical review. LEVEL OF EVIDENCE Level 5. RESULTS The rate of injury in alpine ski racing is high. In general, knee injuries are the most common, with anterior cruciate ligament (ACL) disruptions being the most significant in terms of time loss from sport. Three specific mechanisms of ACL injury in alpine ski racers have recently been described (slip-catch, dynamic snowplow, and landing back-weighted). In contrast to other sports, female ski racers are not clearly at greater risk for ACL injury, especially at the highest level of competition. A high percentage of ski racers are able to return to their previous level of competition after ACL injury. Risk factors for injury and methods of injury prevention have been proposed; however, the rate of injury, particularly ACL injuries, has not decreased significantly. CONCLUSION Alpine ski racing has a high injury rate. ACL injuries in particular remain problematic. Further study is needed to identify modifiable risk factors and implementation of injury prevention strategies.
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Affiliation(s)
- Mitchell C Tarka
- Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont
| | - Annabelle Davey
- Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Geordie C Lonza
- Larner College of Medicine, University of Vermont, Burlington, Vermont
| | - Casey M O'Brien
- Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts
| | - John P Delaney
- Cleveland Clinic Orthopaedic and Rheumatologic Institute, Cleveland, Ohio
| | - Nathan K Endres
- Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont
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13
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Gløersen Ø, Losnegard T, Malthe-Sørenssen A, Dysthe DK, Gilgien M. Propulsive Power in Cross-Country Skiing: Application and Limitations of a Novel Wearable Sensor-Based Method During Roller Skiing. Front Physiol 2018; 9:1631. [PMID: 30524298 PMCID: PMC6256136 DOI: 10.3389/fphys.2018.01631] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/29/2018] [Indexed: 11/24/2022] Open
Abstract
Cross-country skiing is an endurance sport that requires extremely high maximal aerobic power. Due to downhill sections where the athletes can recover, skiers must also have the ability to perform repeated efforts where metabolic power substantially exceeds maximal aerobic power. Since the duration of these supra-aerobic efforts is often in the order of seconds, heart rate, and pulmonary VO2 do not adequately reflect instantaneous metabolic power. Propulsive power (P prop) is an alternative parameter that can be used to estimate metabolic power, but the validity of such calculations during cross-country skiing has rarely been addressed. The aim of this study was therefore twofold: to develop a procedure using small non-intrusive sensors attached to the athlete for estimating P prop during roller-skiing and to evaluate its limits; and (2) to utilize this procedure to determine the P prop generated by high-level skiers during a simulated distance race. Eight elite male cross-country skiers simulated a 15 km individual distance race on roller skis using ski skating techniques on a course (13.5 km) similar to World Cup skiing courses. P prop was calculated using a combination of standalone and differential GNSS measurements and inertial measurement units. The method's measurement error was assessed using a Monte Carlo simulation, sampling from the most relevant sources of error. P prop decreased approximately linearly with skiing speed and acceleration, and was approximated by the equationP prop ( v , v ˙ ) = -0.54·v -0.71 · v ˙ + 7.26 W·kg-1. P prop was typically zero for skiing speeds >9 m·s-1, because the athletes transitioned to the tuck position. Peak P prop was 8.35 ± 0.63 W·kg-1 and was typically attained during the final lap in the last major ascent, while average P prop throughout the race was 3.35 ± 0.23 W·kg-1. The measurement error of P prop increased with skiing speed, from 0.09 W·kg-1 at 2.0 m·s-1 to 0.58 W·kg-1 at 9.0 m·s-1. In summary, this study is the first to provide continuous measurements of P prop for distance skiing, as well as the first to quantify the measurement error during roller skiing using the power balance principle. Therefore, these results provide novel insight into the pacing strategies employed by high-level skiers.
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Affiliation(s)
- Øyvind Gløersen
- Condensed Matter Physics, Department of Physics, University of Oslo, Oslo, Norway
- Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
| | - Thomas Losnegard
- Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
| | - Anders Malthe-Sørenssen
- Condensed Matter Physics, Department of Physics, University of Oslo, Oslo, Norway
- Department of Physics, Center for Computing in Science Education, University of Oslo, Oslo, Norway
| | - Dag Kristian Dysthe
- Condensed Matter Physics, Department of Physics, University of Oslo, Oslo, Norway
| | - Matthias Gilgien
- Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway
- Department of Sport Science, Alpine Skiing, Norwegian Ski Federation, Oslo, Norway
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14
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Gløersen Ø, Kocbach J, Gilgien M. Tracking Performance in Endurance Racing Sports: Evaluation of the Accuracy Offered by Three Commercial GNSS Receivers Aimed at the Sports Market. Front Physiol 2018; 9:1425. [PMID: 30356794 PMCID: PMC6189485 DOI: 10.3389/fphys.2018.01425] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 09/19/2018] [Indexed: 11/23/2022] Open
Abstract
Advances in global navigation satellite system (GNSS) technology have resulted in smaller and more accurate GNSS receivers, which have become increasingly suitable for calculating instantaneous performance parameters during sports competitions, for example by providing the difference in time between athletes at any location along a course. This study investigated the accuracy of three commercially available GNSS receivers directed at the sports market and evaluated their applicability for time analysis in endurance racing sports. The receivers evaluated were a 1 Hz wrist-worn standalone receiver (Garmin Forerunner 920XT, Gar-920XT), a 10 Hz standalone receiver (Catapult Optimeye S5, Cat-S5), and a 10 Hz differential receiver (ZXY-Go). They were validated against a geodetic, multi-frequency receiver providing differential position solutions (accuracy < 5 cm). Six volunteers skied four laps on a 3.05 km track prepared for cross-country skiing, with all four GNSS receivers measuring simultaneously. Deviations in position (horizontal plane, vertical, direction of travel) and speed (horizontal plane and direction of travel) were calculated. In addition, the positions of all receivers were mapped onto a mapping trajectory along the ski track, and a time analysis of all 276 possible pairs of laps was performed. Specifically, the time difference between any two skiers for each integer meter along the track was calculated. ZXY-Go, CAT-S5, and GAR-920XT had horizontal plane position errors of 2.09, 1.04, and 5.29 m (third quartile, Q3), and vertical precision 2.71, 3.89, and 13.35 m (interquartile range, IQR), respectively. The precision in the horizontal plane speed was 0.038, 0.072, and 0.66 m s-1 (IQR) and the time analysis precision was 0.30, 0.13, and 0.68 s (IQR) for ZXY-Go, Cat-S5, and Gar-920XT, respectively. However, the error was inversely related to skiing speed, implying that for the low speeds typically attained during uphill skiing, substantially larger errors can occur. Specifically, at 2.0 m s-1 the Q3 was 0.96, 0.36, and 1.90 s for ZXY-Go, Cat-S5, and Gar-920XT, respectively. In summary, the differential (ZXY-Go) and 10 Hz standalone (Cat-S5) receivers performed substantially better than the wrist-worn receiver (Gar-920XT) in terms of horizontal position and horizontal speed calculations. However, all receivers produced sub-second accuracy in the time analysis, except at very low skiing speeds.
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Affiliation(s)
- Øyvind Gløersen
- Condensed Matter Physics, Department of Physics, University of Oslo, Oslo, Norway.,Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Jan Kocbach
- Centre for Elite Sports Research, Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Matthias Gilgien
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.,Norwegian Ski Federation, Alpine Skiing, Oslo, Norway
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15
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Abstract
Alpine ski racing is known to be a sport with a high risk of injury and a high proportion of time-loss injuries. In recent years, substantial research efforts with regard to injury epidemiology, injury etiology, potential prevention measures, and measures’ evaluation have been undertaken. Therefore, the aims of this review of the literature were (i) to provide a comprehensive overview of what is known about the aforementioned four steps of injury prevention research in the context of alpine ski racing; and (ii) to derive potential perspectives for future research. In total, 38 injury risk factors were previously reported in literature; however, a direct relation to injury risk was proven for only five factors: insufficient core strength/core strength imbalance, sex (depending on type of injury), high skill level, unfavorable genetic predisposition, and the combination of highly shaped, short and wide skis. Moreover, only one prevention measure (i.e. the combination of less-shaped and longer skis with reduced profile width) has demonstrated a positive impact on injury risk. Thus, current knowledge deficits are mainly related to verifying the evidence of widely discussed injury risk factors and assessing the effectiveness of reasonable prevention ideas. Nevertheless, the existing knowledge should be proactively communicated and systematically implemented by sport federations and sport practitioners.
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16
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Gilgien M, Kröll J, Spörri J, Crivelli P, Müller E. Application of dGNSS in Alpine Ski Racing: Basis for Evaluating Physical Demands and Safety. Front Physiol 2018; 9:145. [PMID: 29559918 PMCID: PMC5845727 DOI: 10.3389/fphys.2018.00145] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 02/13/2018] [Indexed: 12/05/2022] Open
Abstract
External forces, such as ground reaction force or air drag acting on athletes' bodies in sports, determine the sport-specific demands on athletes' physical fitness. In order to establish appropriate physical conditioning regimes, which adequately prepare athletes for the loads and physical demands occurring in their sports and help reduce the risk of injury, sport-and/or discipline-specific knowledge of the external forces is needed. However, due to methodological shortcomings in biomechanical research, data comprehensively describing the external forces that occur in alpine super-G (SG) and downhill (DH) are so far lacking. Therefore, this study applied new and accurate wearable sensor-based technology to determine the external forces acting on skiers during World Cup (WC) alpine skiing competitions in the disciplines of SG and DH and to compare these with those occurring in giant slalom (GS), for which previous research knowledge exists. External forces were determined using WC forerunners carrying a differential global navigation satellite system (dGNSS). Combining the dGNSS data with a digital terrain model of the snow surface and an air drag model, the magnitudes of ground reaction forces were computed. It was found that the applied methodology may not only be used to track physical demands and loads on athletes, but also to simultaneously investigate safety aspects, such as the effectiveness of speed control through increased air drag and ski-snow friction forces in the respective disciplines. Therefore, the component of the ground reaction force in the direction of travel (ski-snow friction) and air drag force were computed. This study showed that (1) the validity of high-end dGNSS systems allows meaningful investigations such as characterization of physical demands and effectiveness of safety measures in highly dynamic sports; (2) physical demands were substantially different between GS, SG, and DH; and (3) safety-related reduction of skiing speed might be most effectively achieved by increasing the ski-snow friction force in GS and SG. For DH an increase in the ski-snow friction force might be equally as effective as an increase in air drag force.
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Affiliation(s)
- Matthias Gilgien
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
- St. Moritz Health and Innovation Foundation, Center of Alpine Sports Biomechanics, St. Moritz, Switzerland
| | - Josef Kröll
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein, Austria
| | - Jörg Spörri
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein, Austria
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Philip Crivelli
- Group for Snowsports, WSL - Institute for Snow and Avalanche Research SLF, Davos, Switzerland
| | - Erich Müller
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein, Austria
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17
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Fasel B, Spörri J, Schütz P, Lorenzetti S, Aminian K. An Inertial Sensor-Based Method for Estimating the Athlete's Relative Joint Center Positions and Center of Mass Kinematics in Alpine Ski Racing. Front Physiol 2017; 8:850. [PMID: 29163196 PMCID: PMC5672088 DOI: 10.3389/fphys.2017.00850] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 10/12/2017] [Indexed: 11/13/2022] Open
Abstract
For the purpose of gaining a deeper understanding of the relationship between external training load and health in competitive alpine skiing, an accurate and precise estimation of the athlete's kinematics is an essential methodological prerequisite. This study proposes an inertial sensor-based method to estimate the athlete's relative joint center positions and center of mass (CoM) kinematics in alpine skiing. Eleven inertial sensors were fixed to the lower and upper limbs, trunk, and head. The relative positions of the ankle, knee, hip, shoulder, elbow, and wrist joint centers, as well as the athlete's CoM kinematics were validated against a marker-based optoelectronic motion capture system during indoor carpet skiing. For all joints centers analyzed, position accuracy (mean error) was below 110 mm and precision (error standard deviation) was below 30 mm. CoM position accuracy and precision were 25.7 and 6.7 mm, respectively. Both the accuracy and precision of the system to estimate the distance between the ankle of the outside leg and CoM (measure quantifying the skier's overall vertical motion) were found to be below 11 mm. Some poorer accuracy and precision values (below 77 mm) were observed for the athlete's fore-aft position (i.e., the projection of the outer ankle-CoM vector onto the line corresponding to the projection of ski's longitudinal axis on the snow surface). In addition, the system was found to be sensitive enough to distinguish between different types of turns (wide/narrow). Thus, the method proposed in this paper may also provide a useful, pervasive way to monitor and control adverse external loading patterns that occur during regular on-snow training. Moreover, as demonstrated earlier, such an approach might have a certain potential to quantify competition time, movement repetitions and/or the accelerations acting on the different segments of the human body. However, prior to getting feasible for applications in daily training, future studies should primarily focus on a simplification of the sensor setup, as well as a fusion with global navigation satellite systems (i.e., the estimation of the absolute joint and CoM positions).
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Affiliation(s)
- Benedikt Fasel
- Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jörg Spörri
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein-Rif, Austria.,Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Pascal Schütz
- Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Silvio Lorenzetti
- Department of Health Sciences and Technology, ETH Zürich, Zürich, Switzerland
| | - Kamiar Aminian
- Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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18
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Müller E, Spörri J, Kröll J, Hörterer H. Equipment designed to reduce risk of severe traumatic injuries in alpine ski racing: constructive collaboration between the International Ski Federation, industry and science. Br J Sports Med 2016; 50:1-2. [PMID: 26702012 DOI: 10.1136/bjsports-2015-095689] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Erich Müller
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein-Rif, Austria
| | - Jörg Spörri
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein-Rif, Austria
| | - Josef Kröll
- Department of Sport Science and Kinesiology, University of Salzburg, Hallein-Rif, Austria
| | - Hubert Hörterer
- Medical Committee, International Ski Federation (FIS), Oberhofen, Switzerland
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19
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Three-Dimensional Body and Centre of Mass Kinematics in Alpine Ski Racing Using Differential GNSS and Inertial Sensors. REMOTE SENSING 2016. [DOI: 10.3390/rs8080671] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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