Snow sports-specific extension of the IOC consensus statement: methods for recording and reporting epidemiological data on injury and illness in sports.

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.

Investigation of individual strategies in the aerial phase in ski jumping.

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.

Olympic Games during nationwide lockdown: sports injuries and illnesses, including COVID-19, at the Beijing 2022 Winter Olympics.

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.

Methods to assess validity of positioning systems in team sports: can we do better?

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.

Is there a contextual interference effect for sub-elite alpine ski racers learning complex skills?

Scientific understanding of the contextual interference effect stems mainly from studies on unskilled participants learning artificial laboratory tasks. Although one goal of such studies is to extrapolate the findings to include real-world learning situations such as sports, this generalization is not straightforward. This study tested the contextual interference effect with 66 sub-elite, competitive alpine ski racers who learned a new movement pattern-the pumping technique to increase velocity in slalom-by practicing this skill in three different slalom courses over a 3-day training period.

Assessment of the steady glide phase in ski jumping.

The purpose of this investigation was to compare how key variables of the steady glide phase relate to performance in the two hill sizes used in World Cup and Olympic competitions, i.e, normal and large hills. In this study, 38 and 33 jumps of elite ski jumpers were measured with a differential global navigation satellite system (dGNSS) on a normal (HS106) and large hill (HS140), respectively.

Ranking surgical skills using an attention-enhanced Siamese network with piecewise aggregated kinematic data.

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.

Kinematic Determination of the Aerial Phase in Ski Jumping.

The purpose of this study was to find a generic method to determine the aerial phase of ski jumping in which the athlete is in a steady gliding condition, commonly known as the 'stable flight' phase. The aerial phase of ski jumping was investigated from a physical point mass, rather than an athlete-action-centered perspective. An extensive data collection using a differential Global Navigation Satellite System (dGNSS) was carried out in four different hill sizes.

Performance Analysis in Ski Jumping with a Differential Global Navigation Satellite System and Video-Based Pose Estimation.

This study investigated the explanatory power of a sensor fusion of two complementary methods to explain performance and its underlying mechanisms in ski jumping. A differential Global Navigation Satellite System (dGNSS) and a markerless video-based pose estimation system (PosEst) were used to measure the kinematics and kinetics from the start of the in-run to the landing. The study had two aims; firstly, the agreement between the two methods was assessed using 16 jumps by athletes of national level from 5 m before the take-off to 20 m after, where the methods had spatial overlap.

Towards more valid simulations of slopestyle and big air jumps: Aerodynamics during in-run and flight phase.

Objectives: This study aimed to investigate air drag and lift during the in-run and flight phase of ski and snowboard slopestyle and big air, to allow more valid modeling of jumps and hence reduce injury risk.

Design: We present an experimental, multiple single athlete study based on wind tunnel measurements of 4 skiers and 3 snowboarders.

Methods: Measurements were carried out in a closed loop wind tunnel, measuring airflow speed and 3D forces acting on the athletes.

Classification of Cross-Country Ski Skating Sub-Technique Can Be Automated Using Carrier-Phase Differential GNSS Measurements of the Head's Position.

Position-time tracking of athletes during a race can provide useful information about tactics and performance. However, carrier-phase differential global navigation satellite system (dGNSS)-based tracking, which is accurate to about 5 cm, might also allow for the extraction of variables reflecting an athlete's technique. Such variables include cycle length, cycle frequency, and choice of sub-technique.

Injury prevention in Super-G alpine ski racing through course design.

In Super-G alpine ski racing mean speed is nearly as high as in Downhill. Hence, the energy dissipated in typical impact accidents is similar. However, unlike Downhill, on Super-G courses no training runs are performed.

Alpine Ski Motion Characteristics in Slalom.

Important insight into ski function, and ultimately skier technique and tactics, can be gained by studying how measured ski trajectories compare to predictions based on theoretical models of ski-snow interaction mechanics. The aim of this investigation was to use a 3D kinematic data set collected on highly-skilled skiers during slalom race simulations to quantify ski motion characteristics and to compare these measures with theoretical predictions based primarily on ski geometrical characteristics. For slalom turns on moderate steepness (19°), ski edging angles reached maximum values of 65.

Differences in pacing pattern and sub-technique selection between young and adult competitive cross-country skiers.

The present study describes differences in pacing patterns and sub-technique selection in young compared to adult competitive cross-country skiers. Eleven young male skiers (YOS) (14.4 ± 0.

Validation methods for global and local positioning-based athlete monitoring systems in team sports: a scoping review.

Background/objective: Global navigation satellite systems (GNSS) and local positioning systems (LPS) are to date common tools to measure external training load in athletes. The aim of this scoping review was to map out and critically appraise the methods used to validate different GNSS and LPS used in team sports.

Method: A total of 48 studies met the eligibility criteria and were included in the review.

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.

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.

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.

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).

Pole Length's Influence on Performance During Classic-Style Snow Skiing in Well-Trained Cross-Country Skiers.

Purpose: To investigate how self-selected pole length (PL) of ∼84% (PL84%) compared with ∼90% (PL90%) of body height influenced performance during a 700-m time trial with undulating terrain on snow.

Methods: Twenty-one cross-country skiers, 7 of whom were women, performed 4 trials at a maximal effort in a counterbalanced fashion with PL84% and PL90% separated by 20-minute breaks between trials. In trials I and II, only double poling was allowed, while in trials III and IV, skiers used self-selected classical subtechniques.

Oxygen Demand, Uptake, and Deficits in Elite Cross-Country Skiers during a 15-km Race.

Purpose: This study aimed to quantify the repeated oxygen deficits attained during intermittent endurance exercise by measuring oxygen consumption (V˙O2) and oxygen demand (V˙O2) throughout a simulated roller ski race.

Methods: Eight male elite cross-country skiers (V˙O2peak, 77.4 ± 4.

Propulsive Power in Cross-Country Skiing: Application and Limitations of a Novel Wearable Sensor-Based Method During Roller Skiing.

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 VO do not adequately reflect instantaneous metabolic power.

Tracking Performance in Endurance Racing Sports: Evaluation of the Accuracy Offered by Three Commercial GNSS Receivers Aimed at the Sports Market.

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).

A New Training Assessment Method for Alpine Ski Racing: Estimating Center of Mass Trajectory by Fusing Inertial Sensors With Periodically Available Position Anchor Points.

In this study we present and validate a method to correct velocity and position drift for inertial sensor-based measurements in the context of alpine ski racing. Magnets were placed at each gate and their position determined using a land surveying method. The time point of gate crossings of the athlete were detected with a magnetometer attached to the athlete's lower back.

Exercise Intensity During Cross-Country Skiing Described by Oxygen Demands in Flat and Uphill Terrain.

In this study wearable global navigation satellite system units were used on athletes to investigate pacing patterns by describing exercise intensities in flat and uphill terrain during a simulated cross-country ski race. Eight well-trained male skiers (age: 23.0 ± 4.

Validity of the Catapult ClearSky T6 Local Positioning System for Team Sports Specific Drills, in Indoor Conditions.

The aim of the present study was to determine the validity of position, distance traveled and instantaneous speed of team sport players as measured by a commercially available local positioning system (LPS) during indoor use. In addition, the study investigated how the placement of the field of play relative to the anchor nodes and walls of the building affected the validity of the system. The LPS (Catapult ClearSky T6, Catapult Sports, Australia) and the reference system [Qualisys Oqus, Qualisys AB, Sweden, (infra-red camera system)] were installed around the field of play to capture the athletes' motion.