Giant Slalom Research Articles

Fatigue-induced alterations in force production, trajectory and performance in alpine skiing

ABSTRACT In giant slalom, the ability to apply a high amount of force in the radial direction is essential for performance. A race is characterized by repeated turns performed at high velocity, potentially inducing fatigue. Therefore, this study aimed to assess the effect of fatigue on performance, trajectory characteristics, and force production capacities onto the snow. Twelve skiers ran a 4-turn section with (FATIGUE) and without pre-induced fatigue (CONTROL). Knee extensor maximal voluntary contraction (MVC) was performed before the experiment and after both conditions. Section time, energy dissipation, path length, total force output, force application effectiveness, and EMG activity of the main lower-limb muscles were compared between conditions. Multiple linear regressions were used to understand whether interindividual variability in the kinematic, kinetic and EMG between conditions explains variability in performance changes with fatigue. MVC was lower after FATIGUE (−19.1 ± 6.4%, p < 0.001) but did not change after CONTROL. FATIGUE was associated with longer section times (+0.21 ± 0.11 s, p < 0.001), energy dissipation (−0.78 ± 1.05 J.s.kg.m−1, p = 0.026), path length (+1.1 ± 1.6 m, p = 0.033) and lower force application effectiveness (−0.1 ± 0.1, p = 0.017). This study experimentally demonstrates that fatigue in giant slalom results in lower force application effectiveness, inducing over-dissipation of mechanical energy and longer path length, leading to lower performance.

3D Motion Analysis of Alpine Skiing on Steep Slope Gate in Men’s Giant Slalom

This study aimed to determine the characteristics of the elite skiers and the techniques required to improve their performance in the men’s giant slalom alpine skiing competition by conducting a three-dimensional (3D) motion analysis. The top nine skiers were compared with the next nine skiers using 3D motion analysis in a single-gate section with an average slope of 25.6°. The results revealed the following characteristics of superior skiing techniques. (1) The skiers started the turn from a high position relative to the gate and obtained high velocity by skiing in a gentle arc using potential energy. (2) By quickly rotating and edging the skis, the skiers were able to gain centripetal force early, enter the gate, ski in the direction of the fall line, and change skiing direction timely. (3) The skiers had quick inward leaning of the body and early lowering of the pelvis on the outside ski to form an angulation posture to resist the large external forces acting on the body during the turn.

Endoscopic Treatment of Proximal Vastus Lateralis Myo-Aponeurosis Rupture in a Professional Skier: A Case Report.

We present the case of a 33-year-old World Cup giant slalom skier treated by endoscopically assisted proximal vastus lateralis (VL) release for persistent lateral thigh pain, due to a VL proximal myo-aponeurosis rupture. At the completion of rehabilitation, he was able to return to Olympic-level competition following surgery and was still symptom free at the 3-year follow-up. The unusual location of this injury and the symptoms and physical examination are of interest. The endoscopic release of the VL proximal insertion allowed a rapid and lasting result with a return to competitive skiing at an elite level.

Are the Positions in the Word Ranking of Competitive Alpine Skiers Explainable by Prominent Polymorphisms in Regulatory Genes of Mechanical and Metabolic Muscle Functioning?

ABSTRACT Background: The success of competitive alpine skiers with respective to their world ranking (WR) positions might be associated with prominent gene polymorphisms. Methods: Twenty-six competitive alpine skiers were followed from 2015 to 2019 for their WR positions (FIS-ranking). Using PCR, the genotypes of ACE-I/D, TNC, ACTN3, and PTK2 were identified. The correlations between the discipline-specific WR position (slalom—SL, giant slalom—GS, super G—SG, downhill—DH, and alpine combined—AC) and gene polymorphisms were analyzed concerning an influence with multivariate regression models. Results: The WR position and the ACE gene as well as the copy number of the ACE I-allele exhibited reciprocal relationships for speed specialists (SG and DH) but not for technical specialists (SL and GS). Similarly, the gene polymorphisms ACTN3 and (partly) PTK2 were associated with the WR position in disciplines characterized by a high number of turns (technical specialists—SL and GS) and speed (speed-specialists—SG and DH), respectively. Conclusions: Our findings emphasize the contributions of aerobic and cardiovascular metabolism in fueling muscle work and recovering from muscle fatigue for competitive success in slalom-driven skiing disciplines and highlight the contributions of sequence variants in the genes ACE, TNC, and ACTN3.

Angiogenic Regulators during Alpine Skiing Training

Purpose: The present study evaluates angiogenesis response through the determination of acute changes in hypoxia inducible factor 1 alpha, vascular endothelial growth factor, erythropoietin and endostatin levels measured after both slalom and giant slalom trainings. Material and Methods: A total of 20 volunteer male athletes over the age of 18 years with no health problems, and with international alpine skiing competition experience were included in the study. At the outset, the height, body weight and VO2max values of the volunteers was measured, and a giant slalom training lasting 2.5 hours was performed after a week on a giant slalom course. The volunteers were then asked not to exercise for a week, and slalom training was performed lasting 2.5 hours on a slalom course. The endostatin, erythropoietin, hypoxia inducible factor 1 alpha, and vascular endothelial growth factor levels of the volunteers were examined from 5 ml venous blood samples drawn into biochemistry tubes 20 minutes before and as soon as trainings over both the giant slalom and slalom trainings. Results: A significant increase was determined in the hypoxia inducible factor 1 alpha, vascular endothelial growth factor, erythropoietin and endostatin levels after both the giant slalom and slalom trainings (p &lt; 0.05). Conclusion: These increases observed in the angiogenesis markers suggests that a single unit giant slalom and slalom trainings induces angiogenesis responses.

Difference in Injury Risk between Male and Female Alpine Skiers: Review of the Literature

Alpine skiing is popular at varying levels of competitiveness with many skiers participating recreationally and elite skiers competing in downhill, super-G, giant slalom, slalom, and combined events in the World Cup and in the Winter Olympic Games. The rate of injury in alpine skiing is high both recreationally and competitively and methods to reduce injury rates are needed. Additionally, it is well-established in other sports that the risk of injury for an athlete varies based on gender. The purpose of this review is to determine how injury risk differs for each gender of alpine skier. Injury rates vary throughout the literature but point towards males being at a higher risk for overall injury and upper body injuries while females are at a higher risk for knee injuries. Even the specific knee injuries for which each gender is at risk varies with medial collateral ligament (MCL) injuries more common in males and anterior cruciate ligament (ACL) injuries more common in females. More studies are needed to confirm the differences in injury risks and how these risks may differ across levels of competition, thus allowing regulations and injury prevention methods that may be tailored specifically to the injuries an alpine skier is most susceptible to.

The Analysis of the Effects of Interval Training Program on Aerobic and Anaerobic Performance in Slalom and Giant Slalom Athletes

The purpose of this study is to analyze the effects of interval training on the aerobic and anaerobic performance of elite-level athletes in slalom and giant slalom disciplines. The study consisted of thirteen male athletes in the alpine skiing discipline (slalom-giant slalom). The heights of the athletes were measured with a stadiometer with a precision of ±1mm (Holtain, UK). Weight measurements were conducted using a Tanita brand body composition analyzer (BC, 418 Tanita, Japan) with a precision of 100 grams. For aerobic power and capacity testing, a breath-by-breath measurement method was employed using the Cosmed K5 portable gas analysis system (Italy). The MaxVO2 protocol was performed on a cycle ergometer, and the anaerobic power and capacity test were conducted using the Wingate method. Aerobic/anaerobic power values of athletes were measured twice, before and after a 4-week interval training program. An Independent Samples T-Test was used to identify differences between pre-test and post-test values of athletes. Significant relationships were found between pre-test and post-test values of MaxVO2, peak power, average power, and power drop percentage for slalom and giant slalom athletes subjected to interval training (p0.05). In conclusion, interval training was observed to increase body muscle mass, reduce body fat percentage, and enhance aerobic and anaerobic capacity in slalom and giant slalom athletes. Including interval training in the content of athletes' training programs when creating annual training plans is considered to positively influence aerobic and anaerobic performance using the interval training method.

Modeling and analysis of Alpine skiing downhill based on the DPAS model considering four-way inhomogeneous environmental winds with digital twins at downhill course of the Beijing Olympic Winter Games

In Alpine skiing, the influence of the environment wind on the athlete is crucial. To accurately analyze the coupling effect of environment wind speed, wind direction, and the athlete’s skiing process, this paper establishes the kinematic equations of the athlete based on Newtonian classical mechanics and computational fluid dynamics (CFD) and proposes a discretization method for the course. Simulation results were obtained by using CFD to obtain digital twins for the course and its surroundings. The simulation results were also used as input to the wind parameters to analyze the athletes’ sliding performance. The Downhill Process in Alpine Skiing (DPAS) model was constructed to validate the actual downhill course in the Beijing Olympic Winter Games. An analytical framework for downhill skiing with way inhomogeneous winds was demonstrated to be a good simulation and validation of our analytical framework, proving its good simulatability and reliability. The downhill process is also subdivided into four phases: start-up acceleration phase, core acceleration phase, intermittent acceleration phase, and endurance sprint phase, based on the velocity-time curve derived from the actual course simulation. Tactical skiing strategies for skiers to improve their performance are proposed for the different stages of the process. We believe that the DPAS model can also be applied to other parts of Alpine skiing such as slalom, giant slalom, and super-G, and that the results can be used to suggest tactical strategies to improve performance.

Expectations, gender, and choking under pressure: Evidence from alpine skiing

In alpine skiing competitions, one of the coaches of the participating countries sets the course. This may provide an advantage, but it may also exert higher pressure on the racers. We analyze 45,467 men’s and 41,221 women’s performances from all competitions in alpine skiing’s Slalom, Giant Slalom, and Super Giant disciplines that took place in the World Cups, World Championships, and Olympic Games between the 2001/2002 and 2019/2020 seasons. We compare the performance of racers when competing on a course that was set by their compatriot to the performance of the same racers in the same season when the course was set by a coach from another country. Having a compatriot course setter only has an effect in the second (and decisive) run of the most technical discipline Slalom. We find that men fail significantly more often to complete their run when their compatriots set the course, whereas women fail significantly less in the same situation. The most likely drivers of our results relate to gender differences in response to expectations and choking under pressure in skill-based tasks.

Retracted: Computer-Assisted Quantitative Analysis of Skeletal Muscles of Snowboarding Parallel Giant Slalom Athletes after Exercise Based on Artificial Intelligence and Complex Networks.

[This retracts the article DOI: 10.1155/2022/9755658.].

The "velocity barrier" in giant slalom skiing: An experimental proof of concept.

Alpine skiing involves the conversion of potential energy into kinetic energy, with the "velocity barrier" (VB) at each moment corresponding to the maximal velocity at which the athlete can ski while staying within the boundaries of the gates and maintaining control. Nevertheless, this concept has never been proven by evidence. The aim of this study was to experimentally test the existence of the VB and clarify its relationship with skier's force production/application capacities. Fourteen skiers were equipped with ski-mounted force plates and a positional device and ran a 2-turn Giant Slalom section starting from eight different heights on the slope. Three conditions were selected for further analysis: minimal entrance velocity (vmin ); entrance velocity allowing the better section time (VB); maximal entrance velocity (vmax ). Entrance velocity, section time, mean force output, ratio of force application effectiveness, velocity normalized energy dissipation, and path length were compared between the three conditions. Moreover, skier's mechanical energy and velocity curves were compared all along the section between the three conditions using SPM analysis. The section time was reduced in VB compared to vmin (p < 0.001) and vmax (p = 0.002). Skiers presented an incapacity to increase force output beyond the VB (p = 0.441) associated with a lower force application effectiveness (p = 0.005). Maximal entrance velocity was associated to higher energy dissipation (p < 0.001) and path length (p = 0.005). The present study experimentally supports the existence of the VB. The force production/application capacities seem to limit the skiing effectiveness beyond the VB, associated to increased energy dissipations and path length.

Constituent Year Effects and Performance in Alpine Skiing Junior World Championships.

This study examines constituent year effect (CYE) and race performance among junior alpine skiers in the World Championships. In various junior age cohorts competing together, variation in skiing performance can be expected not only due to practice load and experience but also due to inter-individual differences in physical and psychological maturation. Within a one-year cohort, this effect has been referred to as the birth month effect or the relative age effect (RAE). In cohorts with multiple age bands, the effect is termed the constituent year effect (CYE). The CYE works in principle as the RAE but can function as a magnifying lens of the development within a larger multi-year cohort. The results of the current study indicate that CYEs are present among junior alpine skier performance in the junior World Championships. The magnitude of the constituent year effect is greater in speed events (i.e., downhill and super-G) than in technical events (i.e., slalom and giant slalom), and greater among male skiers compared to female skiers. The findings are discussed in relation to previous research on relative age effects more generally and within the sport context specifically.

Classification in Para skiing: do better performing skiers have better visual functions?

Currently, Paralympic skiers with vision impairment are allocated to classes based only on their better eye static visual acuity and visual field diameter. These studies were conducted to investigate whether a broad range of visual functions were different among groups of skiers with different levels of skiing performance. Static and dynamic visual acuities, contrast sensitivity, light and glare sensitivity, glare recovery, motion perception, and visual field were assessed binocularly in elite Para nordic (n = 26) and Para alpine skiers (n = 15) at 3 international Paralympic events. Skiing performances were calculated using modified skiing points systems based on skiers' raw race times. Clusters of skiers with similar performances were identified in each sport, and their vision and non-vision variables were compared. Skiers in the best performing Para nordic clusters (1 and 2) had better static visual acuities (p = 0.041) and larger visual fields (p = 0.004) compared to cluster 3. In Para alpine slalom (p = 0.019), giant slalom (p = 0.019), and Super-G (p = 0.039) the average static visual acuities among the better performing clusters were significantly better compared to the worst performing cluster. In slalom, the cluster with better performance also had a significantly larger visual field (p = 0.038). In downhill, the better performance cluster demonstrated better dynamic visual acuity (p = 0.029). Clusters with better performing skiers appear to have better visual function in both sports. The results of this study would suggest that Para nordic and Para alpine skiers with light perception or no light perception vision should be in one class and that the skiers with quantifiable static VA should be in a different class.

Mass point versus whole-body modeling of skiers for performance evaluation in alpine skiing.

The altitude differential of the specific mechanical energy, , is used to evaluate skiing performance. It is defined as the negative differential between the skier's total specific mechanical energy ( ) and the altitude of the skier's center of mass (COM). Till now, was obtained upon a mass-point (MP) model of the skier's COM, which neither considered the segmental energies of their relative movements to the COM, nor their rotational kinetic energies. The aims of the study were therefore: (a) to examine the deviations in between the MP and a more complex linked segment (LS) skier model consisting of 15 rigid bodies, which encountered the aforementioned defectiveness, (b) to compare the energy fluctuations of the two skier models, and (c) to investigate the influence of the gate setup on (a) and (b) in giant slalom. Three-dimensional whole-body kinematics of nine skiers was measured using a global navigation satellite system and an inertial motion capture system while skiing on a predefined course divided into a turny and open gate setup. Mechanical energies including their altitude differentials were calculated for the LS and MP models. There were no significant differences in and ski turn averages, as in individual data points, between both skier models for both analyzed gate setups. The energies additionally considered by the LS model presented a negligible part regardless of the gate setup. In conclusion, the MP skier model is sufficiently accurate for the evaluation of the skiing performance with .

Coefficient of Difficulty in Running a Sports Course in Alpine Skiing

In alpine ski disciplines, it is common for competitors to record incomplete runs. In some instances, up to 40% of competitors have failed to complete a course. Possible reasons include incorrect preparation of skiers (lack of adequate motor preparation) and poor tactical approaches. However, there are also some errors in the setting of gates on a course. The aim of this paper is to determine the objective difficulty coefficient of alpine skiing competition courses, based on course geometry and the kinematic parameters of the run. This research monitored alpine skiers during the FIS World Cup. All four alpine skiing disciplines (i.e., downhill, super giant, giant slalom, and slalom) were considered. The average value of the coefficient of difficulty (W.tr) was the highest for the downhill style runs and amounted to 1.20, the super giant and the giant had comparable values of 1.13–1.14, and for the slalom, the W.tr value was the lowest at 0.97. Based on the determined coefficients of route difficulty, it is possible to derive a quantifiable metric to estimate the degree of risk associated with different sections of a course.

Effects of six weeks of sub-plateau cold environment training on physical functioning and athletic ability in elite parallel giant slalom snowboard athletes.

Hypoxic and cold environments have been shown to improve the function and performance of athletes. However, it is unclear whether the combination of subalpine conditions and cold temperatures may have a greater effect. The present study aims to investigate the effects of 6 weeks of training in a sub-plateau cold environment on the physical function and athletic ability of elite parallel giant slalom snowboard athletes. Nine elite athletes (four males and five females) participated in the study. The athletes underwent 6 weeks of high intensity ski-specific technical training (150 min/session, six times/week) and medium-intensity physical training (120 min/session, six times/week) prior to the Beijing 2021 Winter Olympic Games test competition. The physiological and biochemical parameters were collected from elbow venous blood samples after each 2-week session to assess the athletes' physical functional status. The athletes' athletic ability was evaluated by measuring their maximal oxygen uptake, Wingate 30 s anaerobic capacity, 30 m sprint run, and race performance. Measurements were taken before and after participating in the training program for six weeks. The repeated measure ANOVA was used to test the overall differences of blood physiological and biochemical indicators. For indicators with significant time main effects, post-hoc tests were conducted using the least significant difference (LSD) method. The paired-samples t-test was used to analyze changes in athletic ability indicators before and after training. (1) There was a significant overall time effect for red blood cells (RBC) and white blood cells (WBC) in males; there was also a significant effect on the percentage of lymphocytes (LY%), serum testosterone (T), and testosterone to cortisol ratio (T/C) in females (p<0.001-0.015, ). In addition, a significant time effect was also found for blood urea(BU), serum creatine kinase (CK), and serum cortisol levels in both male and female athletes (p=0.001-0.029, ). (2) BU and CK levels in males and LY% in females were all significantly higher at week 6 (p=0.001-0.038), while WBC in males was significantly lower (p=0.030). T and T/C were significantly lower in females at week 2 compared to pre-training (p=0.007, 0.008, respectively), while cortisol (C) was significantly higher in males and females at weeks 2 and 4 (p (male)=0.015, 0.004, respectively; p (female)=0.024, 0.030, respectively). (3) There was a noticeable increase in relative maximal oxygen uptake, Wingate 30 s relative average anaerobic power, 30 m sprint run performance, and race performance in comparison to the pre-training measurements (p<0.001-0.027). Six weeks of sub-plateau cold environment training may improve physical functioning and promote aerobic and anaerobic capacity for parallel giant slalom snowboard athletes. Furthermore, male athletes had a greater improvement of physical functioning and athletic ability when trained in sub-plateau cold environments.

The Influence of Trunk Impairment Level on the Kinematic Characteristics of Alpine Sit-Skiing: A Case Study of Paralympic Medalists

This study aimed to examine the relationship between the trunk impairment level and the trunk kinematic characteristics during alpine sit-skiing from a classification perspective. Three Paralympic medalists in sitting classes (LW10-2, LW11, and LW12-2) participated in the present study. To simulate the racing conditions, giant slalom gates were set. To measure the kinematics of the skier and sit-ski during skiing, a motion capture method with inertial measurement units was used. The muscle activities of the trunk muscles were evaluated using electromyography. Chest lateral flexion, chest flexion, and hip flexion/extension angle during sit-skiing were reduced due to impairment. Additionally, the insufficient lateral flexion (angulation) caused a decrease in edging angle, and that the insufficient chest and hip flexion/extension caused a lower loading in the latter half of the turn through smaller vertical movement. Since edging angle and loading are key factors in ski control, the three joint motions could be measures of sport-specific activity limitation in sit-skiing classification. Between the LW10-2 and LW11 skiers, no distinct differences in trunk kinematics were found. Assuming the scaling factor of race time as a measure of skiing performance, one possible reason is that the difference in skiing performance the LW10-2 and LW11 skiers is considerably smaller relative to differences between the LW11 and LW12-2 skiers. There were no distinct differences among classes in the results of muscle activity, and therefore, this information appears to play a minimal role for classification.

Repeated practice runs during on-snow training do not generate any measurable neuromuscular alterations in elite alpine skiers.

BackgroundAlpine skiers typically train using repeated practice runs requiring high bursts of muscle activity but there is little field-based evidence characterizing neuromuscular function across successive runs.PurposeTo examine the impact of repeated ski runs on electromyographic activity (EMG) of the knee extensors and flexors in elite alpine skiers.MethodsNineteen national team alpine skiers were tested during regular ski training [Slalom (SL), Giant Slalom (GS), Super Giant Slalom and Downhill (Speed)] for a total of 39 training sessions. The surface EMG of the vastus lateralis (VL), rectus femoris (RF), vastus medialis (VM), biceps femoris (BF) and semimembranosus/semitendinosus (SMST) muscles was continuously recorded along with right knee and hip angles. The EMG root mean square signal was normalized to a maximal voluntary contraction (%MVC). The first and fourth runs of the training session were compared.ResultsThere was no meaningful main effect of run on EMG relative activation time or mean power frequency beyond the skier's intrinsic variability. However, EMG activity of the vastii increased from the first to the fourth run in SL [VM, ~+3%MVC for IL and outside leg (OL), p = 0.035)], speed (VL, IL:+6%/OL:+11%, p = 0.015), and GS (VM, IL:0/OL:+7%, p < 0.001); the later with an interaction with leg (p < 0.001) due to a localized increase on the OL. The run time and turn time did not change from the first to the fourth run. There were no meaningful changes in angular velocities, amplitude of movement, or maximal and minimal angles.ConclusionNeuromuscular activity remains highly stable in elite skiers with low variability across four runs.

How Does the Starting Order in the First and Second Run Affect the Final Rank in the FIS World Cup Giant Slalom?

The aim of this study was to determine the impact of runs 1 and 2 on overall rank in Giant Slalom. Data from 15 seasons (2005/2006–2019/2020) including and unique starts for women (n = 2,294) and men (n = 2,328) were analyzed. Skiers were grouped based on final ranks 1–3 (G3), 4–10 (G10), and 11–20 (G20) and separately analyzed for women and men. A Wilcoxon-signed rank test was used for comparisons between runs 1 and 2, while a multi-nominal logistic regression was used to identify odds ratios (OR) associated with group rank. Women had similar run times for runs 1 and 2 (p = 0.734), while men had faster times on run 2 (p < 0.001). The strongest association to G3 was during run 1 for run time (men: OR 1.06–1.12; women: OR 1.06–1.11, all p < 0.01) and gate-to-gate times (men: OR 33–475; women: OR 81–2,301, all p < 0.001). Overall, this study demonstrates the importance of a fast first run for improving the final ranking group and the need to increase the tempo going from the first to the second run for men.

Computer-Assisted Quantitative Analysis of Skeletal Muscles of Snowboarding Parallel Giant Slalom Athletes after Exercise Based on Artificial Intelligence and Complex Networks.

The snowboarding project has the characteristics of high risk and high technical level. The current publicity level is not high, and the number of participants is also very limited. Another potential advantage medal breakthrough project that is expected to be achieved in the Winter Olympics has received a lot of attention, creating favorable opportunities for the promotion and development of this project in China. The event requires good special physical support, skeletal muscle contraction is the body to produce motor function, and special physical training and recovery are key factors for athletes to obtain excellent results in the competition. This article is aimed at performing ultrasonic quantitative analysis on the skeletal muscles of skiers after exercise based on artificial intelligence and complex networks and at studying the skeletal muscle conditions of snowboarders after exercise, so as to provide a certain theoretical basis for coaches in future scientific training. Based on a large amount of literature, this paper uses variational optical flow calculation and split Bregman method to solve the typical HS model, L1-L2 model, and L1-high-order model, respectively, and uses the motion estimation method to describe the movement of muscles. An experiment was designed to collect ultrasound images of the gastrocnemius and quadriceps muscles during contraction. In addition, a motion target positioning algorithm was used to obtain some motion parameters, which provided direct help for athletes in rationally arranging training load and scientific training. The experimental results in this paper show that the muscle motion features extracted from the ultrasound sequence images can quantitatively express a lot of important information about the skeletal muscle motion form and function and have potential practical application value. And the different invariants of each type of ski trajectory vary greatly, floating between 1.5429 and 7.6759.