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Validation of temporal parameters within the skating sub-techniques when roller skiing on a treadmill, using inertial measurement units. PLoS One 2022; 17:e0270331. [PMID: 35981009 PMCID: PMC9387861 DOI: 10.1371/journal.pone.0270331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 06/09/2022] [Indexed: 11/27/2022] Open
Abstract
The aim of this study was to develop and validate a method using inertial measurements units (IMUs) to determine inner-cycle parameters (e.g., cycle, poles and skis contact, and swing time) and the main sub-techniques (i.e., G2, G3 and G4) in cross-country roller ski skating on a treadmill. The developed method is based on the detection of poles and skis initial and final contacts with the ground during the cyclic movements. Thirteen well-trained athletes skied at different combinations of speed (6–24 km∙h-1) and incline (2–14%) on a treadmill using the three different sub-techniques. They were equipped with IMUs attached to their wrists and skis. Their movements were tracked using reflective markers and a multiple camera infrared system. The IMU-based method was able to detect more than 99% of the temporal events. It calculated the inner-cycle temporal parameters with a precision ranging from 19 to 66 ms, corresponding to 3.0% to 7.8% of the corresponding inner-cycle duration. The obtained precision would likely allow differentiation of skiers on different performance levels and detection of technique changes due to fatigue. Overall, this laboratory validation provides interesting possibilities also for outdoor applications.
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Kayser B, Mariani B. Exceptional Performance in Competitive Ski Mountaineering: An Inertial Sensor Case Study. Front Sports Act Living 2022; 4:854614. [PMID: 35469245 PMCID: PMC9033938 DOI: 10.3389/fspor.2022.854614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 03/07/2022] [Indexed: 11/13/2022] Open
Abstract
Organized biannually in the Swiss Alps since 1984, the “Patrouille des Glaciers” (PDG) is one of the most challenging long-distance ski mountaineering (skimo) team competitions in the world. The race begins in Zermatt (1,616 m) and ends in Verbier (1,520 m), covering a total distance of 53 km with a cumulated 4,386 m of ascent and 4,482 m of descent. About 4,800 athletes take part in this competition, in teams of three. We hereby present the performance analysis of the uphill parts of this race of a member (#1) of the winning team in 2018, setting a new race record at 5 h and 35 min, in comparison with two amateur athletes. The athletes were equipped with the Global Navigation Satellite System (GNSS) antenna, a heart rate monitor, and a dedicated multisensor inertial measurement unit (IMU) attached to a ski, which recorded spatial-temporal gait parameters and transition events. The athletes' GNSS and heart rate data were synchronized with the IMU data. Athlete #1 had a baseline VO2 max of 80 ml/min/kg, a maximum heart rate of 205 bpm, weighed 69 kg, and had a body mass index (BMI) of 21.3 kg/m2. During the race, he carried 6 kg of gear and kept his heart rate constant around 85% of max. Spatiotemporal parameters analysis highlighted his ability to sustain higher power, higher pace, and, thus, higher vertical velocity than the other athletes. He made longer steps by gliding longer at each step and performed less kick turns in a shorter time. He spent only a cumulative 5 min and 30 s during skins on and off transitions. Skimo performance, thus, requires a high aerobic power of which a high fraction can be maintained for a prolonged time. Our results further confirm earlier observations that speed of ascent during endurance skimo competitions is a function of body weight and race gear and vertical energy cost of locomotion, with the latter function of climbing gradient. It is also the first study to provide some reference benchmarks for spatiotemporal parameters of elite and amateur skimo athletes during climbing using real-world data.
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Affiliation(s)
- Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
- *Correspondence: Bengt Kayser ; orcid.org/0000-0002-9776-7501
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Bortolan L, Savoldelli A, Pellegrini B, Modena R, Sacchi M, Holmberg HC, Supej M. Ski Mountaineering: Perspectives on a Novel Sport to Be Introduced at the 2026 Winter Olympic Games. Front Physiol 2021; 12:737249. [PMID: 34744777 PMCID: PMC8566874 DOI: 10.3389/fphys.2021.737249] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/20/2021] [Indexed: 11/13/2022] Open
Abstract
Ski mountaineering is a rapidly growing winter sport that involves alternately climbing and descending slopes and various racing formats that differ in length and total vertical gain, as well as their distribution of downhill and uphill sections. In recent years, both participation in and media coverage of this sport have increased dramatically, contributing, at least in part, to its inclusion in the 2026 Winter Olympics in Milano-Cortina. Here, our aim has been to briefly describe the major characteristics of ski mountaineering, its physiological and biomechanical demands, equipment, and training/testing, as well as to provide some future perspectives. Despite its popularity, research on this discipline is scarce, but some general characteristics are already emerging. Pronounced aerobic capacity is an important requirement for success, as demonstrated by positive correlations between racing time and maximal oxygen uptake and oxygen uptake at the second ventilatory threshold. Moreover, due to the considerable mechanical work against gravity on demanding uphill terrain, the combined weight of the athlete and equipment is inversely correlated with performance, prompting the development of both lighter and better equipment in recent decades. In ski mountaineering, velocity uphill is achieved primarily by more frequent (rather than longer) strides due primarily to high resistive forces. The use of wearable technologies, designed specifically for analysis in the field (including at elevated altitudes and cold temperatures) and more extensive collaboration between researchers, industrial actors, and coaches/athletes, could further improve the development of this sport.
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Affiliation(s)
- Lorenzo Bortolan
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.,CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
| | - Aldo Savoldelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.,CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
| | - Barbara Pellegrini
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.,CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
| | - Roberto Modena
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.,CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
| | | | | | - Matej Supej
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
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Development and Evaluation of a Low-Drift Inertial Sensor-Based System for Analysis of Alpine Skiing Performance. SENSORS 2021; 21:s21072480. [PMID: 33918498 PMCID: PMC8038258 DOI: 10.3390/s21072480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 11/20/2022]
Abstract
In skiing it is important to know how the skier accelerates and inclines the skis during the turn to avoid injuries and improve technique. The purpose of this pilot study with three participants was to develop and evaluate a compact, wireless, and low-cost system for detecting the inclination and acceleration of skis in the field based on inertial measurement units (IMU). To that end, a commercial IMU board was placed on each ski behind the skier boot. With the use of an attitude and heading reference system algorithm included in the sensor board, the orientation and attitude data of the skis were obtained (roll, pitch, and yaw) by IMU sensor data fusion. Results demonstrate that the proposed IMU-based system can provide reliable low-drifted data up to 11 min of continuous usage in the worst case. Inertial angle data from the IMU-based system were compared with the data collected by a video-based 3D-kinematic reference system to evaluate its operation in terms of data correlation and system performance. Correlation coefficients between 0.889 (roll) and 0.991 (yaw) were obtained. Mean biases from −1.13° (roll) to 0.44° (yaw) and 95% limits of agreements from 2.87° (yaw) to 6.27° (roll) were calculated for the 1-min trials. Although low mean biases were achieved, some limitations arose in the system precision for pitch and roll estimations that could be due to the low sampling rate allowed by the sensor data fusion algorithm and the initial zeroing of the gyroscope.
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Ski Position during the Flight and Landing Preparation Phases in Ski Jumping Detected with Inertial Sensors. SENSORS 2019; 19:s19112575. [PMID: 31174278 PMCID: PMC6603655 DOI: 10.3390/s19112575] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 05/24/2019] [Accepted: 06/04/2019] [Indexed: 01/23/2023]
Abstract
Ski movement plays an important role during landing preparation, as well as in the whole ski jumping performance. Good landing preparation timing and correct ski position increase the jump length and reduce the impact forces. Inertial motion units (IMUs) placed on the skis could constitute a promising technology for analyzing the ski movements during training. During regular summer trainings, 10 elite athletes (17 ± 1 years) performed jumps while wearing IMUs and wireless force insoles. This set-up enabled the analysis of a possible correlation between ski movements and ground reaction force (GRF) during landing impact. The results showed that the pitch during the landing preparation is the most influential movement on the impact kinetic variables since it is related to the angle of attack, which affects the aerodynamics. The ski position at 0.16 s before landing did not influence the kinetics because the athlete was too close to the ground. During the impact, the roll angle did not correlate with GRF. Moreover, each athlete showed a different movement pattern during the flight phase. Concluding, the combination of IMUs and force insoles is a promising set-up to analyze ski jumping performance thanks to the fast placement, low weight, and high reliability.
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Degache F, Bonjour A, Michaud D, Mondada L, Newman CJ. The effects of tandem skiing on posture and heart rate in children with profound intellectual and multiple disabilities. Dev Neurorehabil 2019; 22:234-239. [PMID: 29658801 DOI: 10.1080/17518423.2018.1462268] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
PURPOSE The objective of study was to determine the effect of tandem ski (TS) activity on postural control and cardiac activity in children with profound intellectual and multiple disabilities (PIMDs). METHOD Twenty children with PIMD and 20 age-matched controls (typically developed (TD) children) participated. Body segment movements were measured with inertial sensors (Physilog®) placed on the head, C7, trunk (including ECG) and pelvis with a seat reference. Each participant was measured during a 12-turn slalom pattern. RESULTS In each group, significant differences were observed between the head vs. trunk and head vs. pelvis angular speeds (p<0.001). In both groups, heart rate differed significantly during rest (PIMD 99 bpm, TD 97 bpm), exercise (PIMD 140 bpm, TD 139 bpm; rest vs. exercise p<0.001) and recovery (PIMD 101 bpm, TD 107 bpm; exercise vs. recovery p<0.001). CONCLUSIONS In children with PIMD, TS elicits active postural control associated with cardiac activities similar to that of the controls.
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Affiliation(s)
- F Degache
- a University of Health Sciences , University of Applied Sciences and Arts Western , Lausanne , Switzerland.,b Institute of Sport Sciences University of Lausanne (ISSUL) , University of Lausanne , Lausanne , Switzerland
| | - A Bonjour
- a University of Health Sciences , University of Applied Sciences and Arts Western , Lausanne , Switzerland.,b Institute of Sport Sciences University of Lausanne (ISSUL) , University of Lausanne , Lausanne , Switzerland
| | - D Michaud
- a University of Health Sciences , University of Applied Sciences and Arts Western , Lausanne , Switzerland.,b Institute of Sport Sciences University of Lausanne (ISSUL) , University of Lausanne , Lausanne , Switzerland
| | - L Mondada
- b Institute of Sport Sciences University of Lausanne (ISSUL) , University of Lausanne , Lausanne , Switzerland
| | - C J Newman
- c Pediatric Neurology and Neurorehabilitation Unit , Lausanne University Hospital , Lausanne , Switzerland
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Gellaerts J, Bogdanov E, Dadashi F, Mariani B. In-Field Validation of an Inertial Sensor-Based System for Movement Analysis and Classification in Ski Mountaineering. SENSORS 2018; 18:s18030885. [PMID: 29547554 PMCID: PMC5876535 DOI: 10.3390/s18030885] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/07/2018] [Accepted: 03/14/2018] [Indexed: 11/21/2022]
Abstract
Ski Mountaineering (SkiMo) is a fast growing sport requiring both endurance and technical skills. It involves different types of locomotion with and without the skis. The aim of this study is to develop and validate in the snowfield a novel inertial-based system for analysing cycle parameters and classifying movement in SkiMo in real-time. The study was divided into two parts, one focused on real-time parameters estimation (cadence, distance from strides, stride duration, stride length, number of strides, slope gradient, and power) and, second, on transition detection (kickturns, skin on, skin off, ski on and off backpack) in order to classify between the different types of locomotion. Experimental protocol involved 16 experienced subjects who performed different SkiMo trials with their own equipment instrumented with a ski-mounted inertial sensor. The results obtained by the algorithm showed precise results with a relative error near 5% on all parameters. The developed system can, therefore, be used by skiers to obtain quantitative training data analysis and real-time feedback in the field. Nevertheless, a deeper validation of this algorithm might be necessary in order to confirm the accuracy on a wider population of subjects with various skill levels.
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Affiliation(s)
- Jules Gellaerts
- UFR Sciences & Montagne (SceM), Département STAPS, Université Savoie Mont-Blanc, Campus Scientifique Technolac, 73376 Le Bourget du Lac, France.
| | - Evgeny Bogdanov
- Gait Up SA, EPFL Innovation Park, CH-1015 Lausanne, Switzerland.
| | - Farzin Dadashi
- Gait Up SA, EPFL Innovation Park, CH-1015 Lausanne, Switzerland.
| | - Benoit Mariani
- Gait Up SA, EPFL Innovation Park, CH-1015 Lausanne, Switzerland.
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Trends Supporting the In-Field Use of Wearable Inertial Sensors for Sport Performance Evaluation: A Systematic Review. SENSORS 2018; 18:s18030873. [PMID: 29543747 PMCID: PMC5877384 DOI: 10.3390/s18030873] [Citation(s) in RCA: 215] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 03/09/2018] [Accepted: 03/11/2018] [Indexed: 01/19/2023]
Abstract
Recent technological developments have led to the production of inexpensive, non-invasive, miniature magneto-inertial sensors, ideal for obtaining sport performance measures during training or competition. This systematic review evaluates current evidence and the future potential of their use in sport performance evaluation. Articles published in English (April 2017) were searched in Web-of-Science, Scopus, Pubmed, and Sport-Discus databases. A keyword search of titles, abstracts and keywords which included studies using accelerometers, gyroscopes and/or magnetometers to analyse sport motor-tasks performed by athletes (excluding risk of injury, physical activity, and energy expenditure) resulted in 2040 papers. Papers and reference list screening led to the selection of 286 studies and 23 reviews. Information on sport, motor-tasks, participants, device characteristics, sensor position and fixing, experimental setting and performance indicators was extracted. The selected papers dealt with motor capacity assessment (51 papers), technique analysis (163), activity classification (19), and physical demands assessment (61). Focus was placed mainly on elite and sub-elite athletes (59%) performing their sport in-field during training (62%) and competition (7%). Measuring movement outdoors created opportunities in winter sports (8%), water sports (16%), team sports (25%), and other outdoor activities (27%). Indications on the reliability of sensor-based performance indicators are provided, together with critical considerations and future trends.
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Praz C, Fasel B, Vuistiner P, Aminian K, Kayser B. Optimal slopes and speeds in uphill ski mountaineering: a field study. Eur J Appl Physiol 2016; 116:2017-24. [PMID: 27534770 DOI: 10.1007/s00421-016-3455-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 08/11/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE The aim of this study is to describe the effects of speed and gradient during uphill ski mountaineering on energy expenditure, to relate any changes to changes in stride characteristics, and to determine an optimal gradient and speed allowing minimization of energy expenditure. METHODS 11 subjects were tested on snowy trails using their mountaineering skis (fitted with skins), boots and poles, at three gradients (7, 11 and 33 %) at 80 % of maximum heart rate (HRmax), and at 11 % also at 90 and 100 % of HRmax. Energy expenditure was calculated by indirect calorimetry to derive energy cost of locomotion (EC), vertical energy cost (ECvert) and mechanical efficiency, while stride length, stride frequency, relative and absolute thrust phase duration, and slope gradient were measured with an inertial sensor-based system. RESULTS At 11 % there was no change with speed in EC, ECvert and mechanical efficiency, while stride length and frequency increased and absolute thrust phase duration decreased. There was an effect of gradient on EC, ECvert and mechanical efficiency, while speed, stride length and stride frequency decreased and absolute and relative thrust phase duration increased. The most economical gradient (lowest ECvert) was the steepest one. CONCLUSION During ski mountaineering uphill at shallow gradient (11 %), EC, ECvert and mechanical efficiency do not vary with speed, while at steeper gradient (33 %) economy is improved. It follows that to minimize energy expenditure and optimize performance to reach a place located at a higher altitude, an athlete should choose a steep gradient, if he/she is able to maintain a sufficient speed.
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Affiliation(s)
- Caroline Praz
- Institute of Sports Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Géopolis, Campus Dorigny, Lausanne, 1015, Switzerland.,Institute for Research in Rehabilitation, SuvaCare Rehabilitation Clinic, Sion, Switzerland
| | - Benedikt Fasel
- Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Philippe Vuistiner
- Institute for Research in Rehabilitation, SuvaCare Rehabilitation Clinic, Sion, Switzerland.,Institute of Social and Preventive Medicine (IUMSP), University Hospital of Lausanne (CHUV), Lausanne, Switzerland
| | - Kamiar Aminian
- Laboratory of Movement Analysis and Measurement, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sports Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Géopolis, Campus Dorigny, Lausanne, 1015, Switzerland.
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