Professional Skiers Research Articles

Knee ligament injuries in alpine skiing - the mechanism of injury and the possibilities of using modern knowledge and technology to prevent injuries in skiing

Introduction: Over the years, advances in alpine ski equipment such as helmets, bindings, skis and boots have resulted in risk reduction, remodelling of injury patterns and mechanisms. Skiers’ injuries are currently about 1 to 5 per 1000 days spent in the snow per athlete. The most common area of the injury is the knee, especially ACL and MCL. Purpose of the work: The purpose of the work is analysis of literature on mechanism of knee ligaments injury and potential prevention intervention in alpine skiing. Methods and materials: The present study was based on available data collected in the PubMed and Google Scholar database. The study was conducted by reviewing keywords such as: “alpine skiing”, “ski bindings”, “alpine skiing injuries”, “ACL”. Results: Taking into consideration less advanced skiers, we can distinguish three types of injury mechanism: valgus-external rotation sequence, boot-induced anterior drawer mechanism and phantom-foot mechanism. Three mechanisms have been described for professional skiers: slip-catch, landing back-weighted and dynamic snowplow. Female skiers have a higher risk of ACl injury than male skiers. Conclusion: Most of the described injury mechanisms are linked with no releasing of bindings. The future injury prevention should concentrate on injury mechanisms using electronic sensors placed at skiers equipment. New micro-electronic technologies can help create mechatronic ski bindings.

Description of Telemark Skiing Technique Using Full Body Inertial Measurement Unit.

Researchers involved in skiing investigations postulate Telemark skiing as an alternative technique to Alpine skiing, which may be associated with lower injury risk. A free heel of the boot, and a boot that enables flexion of the toe, are characteristic features. The aim of this research was to compare three types of turns on Telemark skis, through a biomechanical description of each skiing technique. Seven professional skiers were investigated. Two cameras and the MyoMotion Research Pro system were utilized. Eighteen wireless IMU sensors were mounted on each skier's body. For every skier, five runs were recorded for each of the three turning techniques. Velocity of run, range of movement, angular velocity in joints, time sequences, and order of initialization of movement were obtained. A higher velocity of skiing was obtained during the parallel (14.2 m/s) and rotational turns (14.9 m/s), compared to a low-high turn (8.9 m/s). A comparison of knee angles, revealed similar minimum (18 and 16 degrees) and maximum (143 and 147 degrees) values achieved during the parallel and rotational techniques, which differed considerably from the low-high technique (27 and 121 degrees, respectively). There were no significant differences in trunk rotation angles. A detailed analysis of the Telemark skiing technique revealed novel information on how turns are executed by well-trained skiers and the impact of different approaches.

Single-Sided Jacquard Knit Fabric Development and Seamless Ski Underwear Zoning Design based on Body Mapping Sportswear

Abstract In order to meet the functional requirements of professional skiers for ski underwear, such as warmth, breathability, moisture absorption, sweat drainage, and stretch elasticity, six single-sided jacquard knit fabric structures were designed and then knitted with polyester and DRYARN. Then, 12 fabrics were acquired and ranked comprehensively by the one-way analysis of variance and grey correlative analysis based on entropy. According to the fabric properties and sweat distribution on the human skin surface, the professional ski underwear was zoning designed and the wearing experiment and evaluation were carried out on the “Newton” sweated manikin system. The analysis results show that the fabric with DRYARN® material has better air permeability and moisture permeability. Thermal resistance, Clo value, and permeability play important roles in comprehensive evaluation. The results of wearing experiment show that the seamless professional ski underwear woven based on body mapping sportswear has superior function and reasonable design, which can provide technical support for the design of professional seamless ski underwear.

Flow Experience Study for Outdoor Recreation: Ilgaz Ski Area Case Study

Outdoor recreation is considered within the nature tourism potential of destinations. The study aims to measure the effect of the psychological levels of the ski athletes skiing in Ilgaz Mountain in the context of the flow experience dimensions on their perceived value for their activity and their behavioral intentions towards the destination. In addition, measuring the effect of the perceived value of the activity on the behavioral intention towards the destination is also within the scope of the other purpose. The study population consists of ski athletes coming to Ilgaz National Park. The Flow Experience Scale, developed by Jackson and Marsh (1996), was used in the study. The questionnaire method – a face-to-face interview technique, was preferred as a data collection tool. The collected data were analyzed with SPSS and AMOS package programs. As a result of the regression analysis, it was determined that the flow experience had a positive effect on the perceived value and behavioral intention. In addition, it was concluded that perceived value positively affected behavioral intention. The perceived value of amateur and professional skiers coming to the Ilgaz ski area is important for the destination. Athletes' enjoyment in the context of their flow experiences influences their goal-directed behavioral intentions. Local government support is needed to develop the potential of destinations where winter tourism and recreation activities are carried out. This study is important for promoting and sustaining eco-tourism activities and outdoor recreation.

Expertise and injury experience in professional skiers modulate the ability to predict the outcome of observed ski-related actions

Professional athletes, compared to beginners, can better predict the outcome of sport-related observed movements, via mirror motor-system modulations (motor resonance). Furthermore, motor-system inhibition occurs when observing other people experiencing pain (pain resonance). Here we investigated whether observing sport-related actions, whose outcome can lead or not to a painful experience, results into different prediction performances depending on expertise and history of injury. Experiment 1 revealed that professional skiers, relative to beginners, show greater prediction accuracy but slower reaction times. Experiment 2 revealed that, among professional skiers, those previously injured, compared to uninjured ones, are slower in predicting the outcome of the observed action when it actually leads to an injury. We hypothesize that such results could be explained by an automatic activation of both motor and pain resonance mechanisms in the onlooker, inducing a sort of experience-dependant freezing response while observing actions likely leading to an injury.

Kinesiophobia in Skiers with Knee Injuries

Abstract Introduction. Alpine skiing is one of the most dangerous winter sports that entails a high number of injuries, most commonly affecting the knee. Kinesiophobia is a condition in which an individual experiences fear of physical movement and activity as a result of feeling susceptible to injuries or recurrent injuries. The objective was to examine the level of kinesiophobia in skiers who have sustained knee injuries. Material and methods. The sample consisted of 22 female and 11 male professional skiers, with the average age of 24 ± 7.391 years. For the purpose of the assessment, the Tampa scale for kinesiophobia (TSK) was employed. Results. The number of knee injuries in skiers totals at least 1 and 11 at most, on average 2.45, most commonly involving the anterior cruciate ligament and meniscus. There were no significant differences between the left and the right knee or bilateral injuries. The average score in the TSK totals 36 points, which is close to the critical threshold of 37 points. 36% of the participants possess a high level of kinesiophobia. With respect to the general level of kinesiophobia, no significant differences were found in relation to gender, with regard to the number of surgeries or whether one or both knees were affected by injuries. Older skiers have also been found to have significantly lower fear of recurrent injuries. Conclusions. The number of knee injuries in skiing is high and aggravating, in such a way that almost one third of skiers that have sustained knee injuries experience a critical level of kinesiophobia, and that requires intervention. During rehabilitation, psychological support should also be provided to athletes in order to prevent or reduce kinesiophobia and thus prevent recurrent or new injuries.

Nitric Oxide Production in Professional Skiers During Physical Activity at Maximum Load.

The purpose of this study is to assess the production of nitric oxide in professional cross-country skiers with normotensive and hypertensive responses to physical activity at maximum load. The observation group included professional cross-country skiers (22.2 ± 7.1 years, = 107) who were current members of the national team of the Komi Republic. All the examined athletes performed the exercise test on a cycle ergometer “until exhaustion.” The following parameters were determined for each participant while they were sitting at rest, while at their anaerobic threshold level, during peak load, and during the recovery period (5th min): systolic blood pressure, diastolic blood pressure, heart rate, and the level of stable nitric oxide metabolites (nitrites, nitrates) in capillary blood samples. According to the blood pressure results, the cross-country skiers were divided into two groups. Group I included athletes with a normotensive response to stress. Group II was composed of individuals with a hypertensive response to stress. During the performance of the test “until exhaustion,” a significant (p < 0.05) increase in the amount of stable metabolites of nitric oxide was observed in the group of athletes with a normotensive response to the load compared with the group with a hypertensive response to the load. In athletes with a normotensive reaction to the load during exercise at maximum load and in the early recovery period, nitrate was prioritized in the regulation of vascular tone. The exercise test on a cycle ergometer “until exhaustion,” combined with the assessment of the levels of stable nitric oxide metabolites in plasma, can be considered a test for the early diagnosis of endothelial dysfunction in professional athletes.

Anaerobic Power Assessment in Athletes: Are Cycling and Vertical Jump Tests Interchangeable?

Regularly assessing anaerobic power is important for athletes from sports with an explosive strength component. Understanding the differences and overlap between different assessment methods might help coaches or smaller-scale testing facilities maximize financial and temporal resources. Therefore, this study investigated the degree to which cycling sprint and vertical jump tests are interchangeable for determining peak mechanical leg power output in strength-trained athletes. Professional skiers (n = 19) performed unloaded squat jumps (SJ) and other jump forms on a force plate and a six-second cycling sprint (6sCS) test on an ergometer on six occasions over two years. Along with cross-sectional correlations between cycling and jumping power, correlations between longitudinal percent changes and agreement between magnitude-based inferences about individual changes were assessed. Among the tested jump forms, SJ reflected 6sCS best. However, despite extremely large cross-sectional correlation coefficients (0.92) between 6sCS and SJ, and moderate (Pearson’s r = 0.32 for 6sCS with SJ over one-year time spans) to large (r = 0.68 over shorter time spans) correlation coefficients on percent changes, magnitude-based inferences agreed in only around 50% of cases. Thus, for making qualitative assessments about the development of anaerobic power over time in athletes, cycling sprint and squat jump tests are not interchangeable. Rather, we recommend employing the test form that best reflects athletes’ strength and conditioning training.

Исследование индивидуальных особенностей дыхательной системы спортсменов-лыжников в зависимости от физического состояния

Objective: to identify skiers individual respiratory system characteristics depending on their physical condition. Materials and methods: the study involved 20 professional skiers (10 men and 10 women, aged 23.2±0.9) who performed a long-term aerobic test (treadmill and bicycle ergometer) and a short-term anaerobic physical test (Wingate test on a bicycle ergometer). The gender and age specifi c data was processed and analyzed with generally accepted statistical methods. Before and after exercise, each subject underwent the individual respiratory system frequency characteristics and lung vital and forced vital capacity measurement to evaluate the physical activity effect on the respiratory system volume and frequency characteristics. The mean values in the reference groups and their standard deviations were calculated. Results: an analysis of the respiratory system frequency characteristics after physical exercise revealed a signifi cant change in resonance in men only in the exhalation phase after the “to failure” bicycle ergometric test, and in women only in the inhalation phase after treadmill test, all other frequency characteristics changes were insignifi cant. The maximum change in lung vital and forced vital capacity was found in men after treadmill stress test. The minimum change in lung vital and forced vital capacity was found in the male athletes after the “to failure” bicycle ergometer test. A signifi cant change in the resonant frequencies was found in the group of men only at the exhalation phase after “to failure” bicycle ergometer test., in women – only at the inhalation phase after the treadmill test. Conclusions: thus, the study revealed that both prolonged aerobic exercise and short anaerobic exercise do not result in signifi cant changes in the athletes’ respiratory system frequency characteristics suggesting the great potential of respiratory system bio-acoustic stimulation in sports medicine, since it can be performed at any period of the competitive training process at the time convenient for an athlete.

Оценка оксидативно-антиоксидантного статуса и аэробной работоспособности элитных лыжников-гонщиков в динамике тренировок в условиях естественного среднегорья

Adaptation to hypoxia is an integral part of elite athletes training at various stages of the training and competition season. One of the key issues in the use of additional hypoxic stimulation methods is the potential risk of oxidative stress development and dangerous shifts in oxidative-antioxidant status (OAS). Objective: to identify the impact of altitude training and the subsequent period of reacclimatization on exercise performance, aerobic efficiency and oxidative-antioxidant balance of elite skiers-racers. Materials and Methods: The study involved 10 highly qualified athletes who underwent a comprehensive examination three times at different stages of training camps: initially, after 3-week camps in the natural midlands and after a 2-week camp on the plain. Each comprehensive examination included exercise treadmill testing under normoxia and in moderate hypoxia with determination of spiroergometric indicators, measurement of hemoglobin, hematocrit, total hemoglobin mass, as well as OAS parameters. Results: Endurance training at moderate altitude led to significant increase in the total hemoglobin mass and with the delay of 16-18 days of reacclimatization – in performance indicators (VO 2 max and VO 2 /AT), tested both in normoxia and hypoxia. No significant average group changes in the oxidativeantioxidant status in the dynamics of professional skiers' 3 weeks acclimatization period were revealed. In the analysis of individual indices dynamics it was noted that in the majority of athletes the values of oxidative stress indicator (d-ROM) did not exceed the limits of normative data, and the index of total antioxidant blood potential were in the zone of slightly increased values at all stages of testing. As a result, the values of the OAS integral index of athletes were in the border zone, with several elevated values. At the same time, the level of overall activation of the pro-antioxidant system correlated with the increase in aerobic capacity of athletes. Conclusions: The OSA parameters tested using the FRAS-4 method make it possible to evaluate the dynamics of OSA in athletes training for endurance at moderate altitude.

A Unified Deep-Learning Model for Classifying the Cross-Country Skiing Techniques Using Wearable Gyroscope Sensors.

The automatic classification of cross-country (XC) skiing techniques using data from wearable sensors has the potential to provide insights for optimizing the performance of professional skiers. In this paper, we propose a unified deep learning model for classifying eight techniques used in classical and skating styles XC-skiing and optimize this model for the number of gyroscope sensors by analyzing the results for five different configurations of sensors. We collected data of four professional skiers on outdoor flat and natural courses. The model is first trained over the flat course data of two skiers and tested over the flat and natural course data of a third skier in a leave-one-out fashion, resulting in a mean accuracy of ~80% over three combinations. Secondly, the model is trained over the flat course data of three skiers and tested over flat course and natural course data of one new skier, resulting in a mean accuracy of 87.2% and 95.1% respectively, using the optimal sensor configuration (five gyroscope sensors: both hands, both feet, and the pelvis). High classification accuracy obtained using both approaches indicates that this deep learning model has the potential to be deployed for real-time classification of skiing techniques by professional skiers and coaches.

Fitness, knee function and competition performance in professional alpine skiers after ACL injury

ObjectivesTo assess the fitness of elite alpine skiers during recovery from anterior cruciate ligament (ACL) reconstruction and changes in performance level after return to competition. DesignRetrospective cohort study. MethodsThe database of a specialized sports clinic was screened for professional alpine skiers with a history of ACL rupture and reconstruction. Strength and further functional tests as well as questionnaire data reflecting the athletes’ subjective perception of pain, function in activities of daily living and physical activity levels were extracted. The website of the International Ski Federation (FIS) was used to obtain FIS points reflecting the competition performance level prior to injury, after return to competition as well as one year later. ResultsQuestionnaire data revealed the highest patient satisfaction. Measurements performed 161.5±24.2days after surgery showed persistent muscle strength and power deficits, which primarily affected the knee extensor muscles and were more pronounced following reconstruction using quadriceps as compared to hamstring tendon grafts. FIS points increased immediately after return to competition (364.3±142.5days post-reconstruction) but dropped below pre-injury levels within the first year. ConclusionsACL injuries sustained by professional skiers entail muscle strength and power deficits that persist for more than five months after surgery. The rate of recovery of knee extensor muscle function may be slower following ACL reconstruction using quadriceps tendon grafts. On average, athletes returned to competition within one year after surgery and succeeded in surpassing their baseline performance level within the first year after return to competition.

Smart sport equipment: SmartSki prototype for biofeedback applications in skiing

Miniature sensors are already integrated into various sport equipment. A combination of body-attached sensor devices and sensors integrated into the sport equipment, together with an adequate sensor fusion algorithms, can help with developing better sport's gear, speed up the learning process, and improve the skill level and performance. The paper presents our SmartSki system including SmartSki prototype, measuring equipment, and several SmartSki applications. The SmartSki system was functionally tested and verified by a group of alpine skiing experts through several snow tests during the period of 1 year. The snow test results were used to improve the prototype and extract several important skiing parameters that are used in various feedback applications, for example, in a trainer feedback system or in a real-time biofeedback system for the skier. We are confident that the SmartSki can offer many benefits to recreational skiers, ski equipment manufacturers, ski schools, coaches, and even professional skiers.

ОСОБЕННОСТИ ИЗМЕНЕНИЯ ДИАМЕТРА ЭРИТРОЦИТОВ В КРОВИ СПОРТСМЕНОВ В УСЛОВИЯХ ФИЗИЧЕСКОЙ НАГРУЗКИ

Цель. Изучить характер распределения эритроцитов по диаметру в циркулирующей крови лыжников-гонщиков в период достижения порога анаэробного обмена (ПАНО).Материалы и методы. Обследованы лыжники-гонщики (юноши и мужчины, девушки и женщины) в условиях физической нагрузки на велоэргометре в возрасте 17–37 лет (n=33) с квалификацией КМС и МС. Исследование проведено согласно протоколу, утвержденному локальным комитетом по биоэтике при Институте физиологии Коми научного центра Уральского отделения Российской академии наук. Пробы крови брали из локтевой вены натощак, затем из капилляров пальца до, – на пороге анаэробного обмена, после выполнения нагрузки «до отказа» и через 5 мин восстановления.На окрашенных мазках крови измеряли диаметр 50 эритроцитов (Лабораторные …, 1987). Результаты обрабатывали статистически с использованием пакета прикладных программ Windows (Basic, 2011).Результаты. На этапе ПАНО у 36% спортсменов определили увеличение среднего диаметра эритроцитов с 7,46±0,06 до 7,68±0,08 мкм (р&lt;0,05), без изменений у 12% (7,45±0,04 – 7,43±0,05 мкм) и уменьшение размера клеток у 52% с 7,51±0,04 до 7,35±0,05 мкм (р&lt;0,05). В условиях максимальной нагрузки (337,1±12,4 Вт у мужчин и 246,7±10,8 Вт у женщин) и на 5-й мин восстановления диаметр эритроцитов в крови спортсменов возвращался к исходному значению.Заключение. Таким образом, индивидуальный характер изменения среднего диаметра эритроцитов у спортсменов проявляется во время достижения ПАНО и, вероятно, соответствует избирательной элиминации преимущественно макро- или микроцитов.

Potential of IMU Sensors in Performance Analysis of Professional Alpine Skiers.

In this paper, we present an analysis to identify a sensor location for an inertial measurement unit (IMU) on the body of a skier and propose the best location to capture turn motions for training. We also validate the manner in which the data from the IMU sensor on the proposed location can characterize ski turns and performance with a series of statistical analyses, including a comparison with data collected from foot pressure sensors. The goal of the study is to logically identify the ideal location on the skier’s body to attach the IMU sensor and the best use of the data collected for the skier. The statistical analyses and the hierarchical clustering method indicate that the pelvis is the best location for attachment of an IMU, and numerical validation shows that the data collected from this location can effectively estimate the performance and characteristics of the skier. Moreover, placement of the sensor at this location does not distract the skier’s motion, and the sensor can be easily attached and detached. The findings of this study can be used for the development of a wearable device for the routine training of professional skiers.

Кардиореспираторные предикторы завершения теста с максимальной нагрузкой у высококвалифицированных лыжников-гонщиков

Кардиореспираторные предикторы завершения теста с максимальной нагрузкой у высококвалифицированных лыжников-гонщиков

Age-specific features in renal response to food intakes and training loads in young professional skiers

The age-specific features of renal functions have been studied in older adolescents and young adults training in ski racing before and after their water and food intake and training loads. Baseline renal functions in the morning demonstrated higher glomerular filtration rate (GFR) and more mature development of the osmoregulatory mechanisms (higher excretion of osmotically active substances, osmotic concentration index, and reabsorption of solute-free liquid) in young adults, compared with adolescents. After food intake, the osmoregulatory mechanisms provided in young adults an adequate renal response—increased excretion of ions in exchange for urea, which preserves osmolality. At the same time, increased excretion of osmotically active substances synchronously with growth in the rate of urine output, higher GFR and reabsorption of solute-free liquid was marked in adolescents, which points to less mature development of the osmoregulatory system. The similar trend of renal homeostatic responses after physical training indicated the activation of volume regulatory mechanisms which did not differ between age groups. Our conclusion is that the definitive volume regulation develops ahead of osmoregulation.

The effect of the use of coenzyme Q10 on lactic acid and total antioxidant capacity in professional skiers

The effect of the use of coenzyme Q10 on lactic acid and total antioxidant capacity in professional skiers

Common Mechanisms of Hip Injury and Associated Hip Pathology in Professional Skiers and Snowboarders

Abstract Hip injuries are common among athletes. Recent studies have analyzed hip pathology in many athletic populations; however, little research has been done on hip injuries and pathology among skiers and snowboarders. The purpose of this study is to review common mechanisms of hip injury and associated hip pathology in professional skiers and snowboarders. This study was institutional review board-approved. A retrospective database review was performed on all professional skiers and snowboarders who were evaluated by the senior author and underwent hip arthroscopy between 2005 and 2010 for debilitating hip pain. Professional skiers and snowboarders included athletes who compete at the professional level and instructors. Thirty-six painful hips were identified in 29 professionals (7 with bilateral involvement). Pathology and intra-operative findings were identified at time of index procedure. Subjective mechanism of injury was recorded. All data were prospectively collected and retrospectively reviewed. Twenty alpine skiers (4 bilateral), three Nordic skiers (2 bilateral), four snowboarders, and two aerialists (1 bilateral) were identified. A high-speed ski crash resulting in hip pain was the most common mechanism of injury (n = 14 hips), with all of those injuries occurring in racers and aerialists. All Nordic skiers (n = 5 hips) reported a gradual onset of hip pain with no specific injury. Three hip dislocations were reported by two alpine ski instructors and one alpine ski racer. All hips were found to have labral pathology and femoroacetabular impingement (FAI) at the time of index procedure. An Outerbridge grade IV chondral defect was treated with arthroscopic microfracture technique in five hips (14%). Seventeen hips (47%) were treated with capsular plication for hip instability. High-speed crashes are common mechanisms of hip injury. Labral pathology, FAI, and hip instability are frequent pathological arthroscopic findings in professional skiers and snowboarders.

Growth hormone response to the strenuous training in professional skiers has longer recovery time than expected

According to literature, 20–30 minutes recovery period is considered sufficient to normalize growth hormone (GH) levels after exercise stimulation. Aim of our study was to analyze GH response in elite athletes after strenuous training and after 2 hours recovery. We used longitudinal (different years, repeated measures) GH secretion data of 15 skiers (altogether 78 measurements) after very intensive training. Training lasted 3.5 hours with following structure: 0…1 h Lactate (La) &lt;2.5; 1…2h La &lt;3; 2&amp;#8230;2:45 La&lt;4; 2:45…3:30 La&lt;8. Exercise induced very high increase in GH level. Mean basal level of GH was 0.9 mU/L (range 11.2 ), after exercise GH level was 22.1 mU/L (range 103.7). After 2 h recovery, GH level was 3.1 mU/L (range 18.7, p &lt; 005 compared to the basal level). Our results show that depending on intensity and individual variability, GH responses to exercise in elite athletes can be much higher than described in the literature.ConclusionGH level after strenuous training in professional skiers remain still significantly higher after 2‐hour recovery period compared to the pre‐exercise level. The European Regional Development Fund together with the Archimedes Foundation supported this study.