Competitive Alpine Skiers Research Articles

Lower Back Complaints in Adolescent Competitive Alpine Skiers: A Cross-Sectional Study

Background: Little is known about lower back complaints in adolescent competitive alpine skiers. This study assessed their prevalence and severity (i.e., intensity and disability) with respect to sex, category, discipline preference, and training attributes. Methods: 188 competitive skiers aged 15 to 18 years volunteered in this study. Data collection included (i) questions on participants’ demographics, sports exposure, discipline preferences, and other sports-related practices; (ii) the Nordic Musculoskeletal Questionnaire on lower back complaints; and (iii) the Graded Chronic Pain Scale. Results: As many as 80.3% and 50.0% of all skiers suffered from lower back complaints during the last 12 months and 7 days, respectively. A total of 50.7% reported their complaints to be attributable to slalom skiing, and 26% to giant slalom. The majority of complaints were classified as low intensity/low disability (Grade I, 57.4%) and high intensity/low disability complaints (Grade II, 21.8%). The Characteristic Pain Intensity was found to be significantly related to the skiers’ years of sports participation, number of competitions/season, and number of skiing days/season. Conclusion: This study further supports the relatively high magnitudes of lower back-related pain in adolescent competitive alpine skiers, with a considerable amount of high intensity (but low disability) complaints, and training attributes being a key driver.

Panoramic ultrasound vs. MRI for the assessment of hamstrings cross-sectional area and volume in a large athletic cohort

We investigated the validity of panoramic ultrasound (US) compared to magnetic resonance imaging (MRI) for the assessment of hamstrings cross-sectional area (CSA) and volume. Hamstrings CSA were acquired with US (by an expert operator) at four different sites of femur length (FL) in 85 youth competitive alpine skiers (14.8 ± 0.5 years), and successively compared to corresponding scans obtained by MRI, analyzed by a trained vs. a novice rater. The agreement between techniques was assessed by Bland–Altman analyses. Statistical analysis was carried out using Pearson’s product moment correlation coefficient (r). US-derived CSA showed a very good agreement compared to MRI-based ones. The best sites were 40% FL (0 = mid patellar point) for biceps femoris long head (r = 0.9), 50% for semitendinosus (r = 0.9), and 30% for semimembranosus (r = 0.86) and biceps femoris short head (BFsh, r = 0.8). US-based vs. MRI-based hamstrings volume showed an r of 0.96. Poorer r values were observed for the novice compared to the trained rater, with the biggest difference observed for BFsh at 50% (r = 0.001 vs. r = 0.50, respectively) and semimembranosus at 60% (r = 0.23 vs. r = 0.42, respectively). Panoramic US provides valid CSA values and volume estimations compared to MRI. To ensure optimal US-vs.-MRI agreement, raters should preferably possess previous experience in imaging-based analyses.

Biomechanical quantification of deadbug bridging performance in competitive alpine skiers: Reliability, reference values, and associations with skiing performance and back overuse complaints

Objectives(1) To study the reliability of quantifying rear-chain stabilization capacity during deadbug bridging (DBB), (2) to provide reference values for competitive alpine skiers, and (3) to study associations with age, anthropometrics, maturation, skiing performance and back overuse complaints. DesignCross-sectional. SettingBiomechanical field experiment including questionnaires. Participants12 healthy subjects (reliability experiment); 133 skiers of the U16 category and 38 of the elite category (main experiment). Main outcome measuresDBB performance was quantified using 3D motion capture as the maximum amplitude of the relative vertical displacement of two pelvis markers (DBBdisplacement). Additionally, in U16 skiers, age, anthropometrics, maturation, skiing performance, and back overuse complaints were assessed. ResultsThe reliability experiment revealed an ICC(3,1) and 95% CI of 0.81 [0.61, 0.93]. Within-subject SEM was 3.89 mm [3.16 mm, 5.12 mm]. Depending on sex and category, medians of DBBdisplacement in skiers ranged between 29 mm and 45 mm. DBBdisplacement differed between elite and U16 skiers (p < 0.001), but not between sexes. In U16 skiers, DBBdisplacement was independent of age, anthropometrics, and biological maturation, however, associated with skiing performance and back overuse complaints (p < 0.05). ConclusionThe proposed approach may be considered an adequate method to quantify athletes’ rear-chain stabilization capacity.

Health problems in youth competitive alpine skiing: A 12-month observation of 155 athletes around the growth spurt.

Alpine ski racing is known as a high-risk sport; however, little is known on the health problems occurring at youth level. The purpose of this study was to investigate the prevalence of health problems in youth competitive alpine skiers with respect to sex, age, and season differences, to describe their severity and location and to assess the influence of biological maturation. Over a 12-month period, 155 youth competitive alpine skiers around the growth spurt were prospectively monitored for health problems using the Oslo Sports Trauma Research Centre (OSTRC) questionnaire. These data were verified by supplemental interviews at the end. Biological maturation was estimated by a non-invasive, anthropometric-based assessment method. During competition season, 42.2% of the skiers suffered from health problems and 19.8% reported their problem being substantial. Females had significantly higher rates of acute and overuse injuries compared to males, while there was no sex difference in duration, severity, and time loss. Skiers of the category U15 showed higher prevalence of acute and overuse injuries than U14 skiers. During preparation season, health problem prevalence was substantially lower. The knee was found to be the most affected body part for both acute and overuse injuries. There was a direct association between the offset to the age at peak height velocity (APHV) and the occurrence and severity of acute injuries. In conclusion, youth competitive alpine skiers suffer from a large number of health problems. Since sex, age, and biological maturation are important, effective injury prevention should already start before reaching the APHV.

Distal Femoral Cortical Irregularity at Knee MRI: Increased Prevalence in Youth Competitive Alpine Skiers.

Background Tumor-like cortical irregularities at the posterior distal femur are common incidental findings in adolescents, but the origin of these irregularities is debated. Purpose To compare the prevalence of distal femoral cortical irregularities (DFCIs) at different tendon attachment sites in youth competitive alpine skiers with that in young adults. Materials and Methods In this secondary analysis of a prospective trial, unenhanced 3-T knee MRI scans obtained in youth competitive alpine skiers were compared with images in control participants of the same age from 2014 to 2019 (Cantonal Ethics Committee Zurich registry number: KEK-ZH-2017-01395) for presence of DFCIs at the femoral attachment of the medial head of the gastrocnemius muscle (MHG) and/or lateral head of the gastrocnemius muscle (LHG) and adductor magnus tendon by two radiologists. DFCI size and tendon attachment position were measured. Tendon attachment position and associated MRI findings (meniscus, cartilage, bone marrow edema, joint effusion, ligaments, tendons) were examined for an association with DFCI. Pearson χ2, Student t test, logistic regression, and κ statistics were applied. Results Unilateral knee MRI scans obtained in 105 skiers (mean age, 14.8 years ± 0.6 [standard deviation]; 66 boys) and in 105 control participants (mean age, 14.6 years ± 0.5; 59 boys) were evaluated. DFCIs were found in 61 of 105 skiers (58%; 95% confidence interval [CI]: 48.5%, 67.2%) compared with 28 of 105 control participants (27%; 95% CI: 18.9%, 35.7%) (P < .001). Two skiers had more than one DFCI. Distribution of DFCIs for skiers and control participants was 60 of 63 (95.2%) and 26 of 28 (92.8%) at the MHG, three of 63 (4.8%) and one of 28 (3.6%) at the LHG, and zero of 63 (0%) and one of 28 (3.6%) at the adductor magnus attachment site, respectively. Interreader agreement was almost perfect (κ = 0.87; 95% CI: 0.80, 0.93). The mean size of MHG-related DFCIs in skiers (3.7 mm) was not different compared to the size of those in control participants (3.4 mm) (P = .32), nor was a difference found for the MHG tendon attachment position in knees with DFCI (63.9 mm vs 63.0 mm, P = .83) or without DFCI (63.6 mm vs 62.8 mm, P = .86). Regarding associated MRI findings, increased signal intensity of the MHG tendon showed a significant association with MHG-related DFCI in both groups (P = .01 for both). Conclusion A distal femoral cortical irregularity at the attachment sites of tendons was a frequent incidental finding on knee MRI scans, with an increased prevalence in youth competitive alpine skiers. © RSNA, 2020 Online supplemental material is available for this article.

Injury risks among elite competitive alpine skiers are underestimated if not registered prospectively, over the entire season and regardless of whether requiring medical attention.

Prospective studies assessing the injuries occurring in elite competitive alpine skiers are lacking, and a full picture of all injuries, including those not requiring medical attention, is absent. Likewise, little is known about the sex-specific injury risks and patterns of elite skiers throughout an entire season (i.e. an off-season preparation period and a competition period). Accordingly, this study investigated the injuries of a national team cohort with respect to season period and sex. Over an entire season, all injuries occurring in 44 SwissNational Ski Team members (25 females and 19 males) were registered, regardless of whether they required medical attention. Skiers were prospectively monitored by the Oslo Sports Trauma Research Centre (OSTRC) questionnaire and by continuously updated team medical records. Finally, these data were used as a reference for supplemental interviews, in which the correctness and completeness of the prospective data were verified. The risk of suffering at least one injury during an entire season was 75.0% with a 95% confidence interval (73.1%, 76.9%) for traumatic injuries, and 52.3% (50.0%, 54.5%) for overuse injuries. Traumatic injuries concerned the head, lower leg and knee, while overuse injuries affected the lumbar spine, knee and hip. During the competition period, skiers were more prone to traumatic injuries, while during the off-season preparation period, skiers' risk was higher for overuse injuries. Over an entire season, there were no sex differences. However, females were more vulnerable to traumatic injuries during the preparation period and overuse injuries during the competition period, while males had a higher risk for overuse injuries during the preparation period. When prospectively registering injuries among elite competitive alpine skiers over an entire season, regardless of whether the injuries required medical attention, the injury risks were alarmingly high and substantially larger than those previously reported. Moreover, since injury risks and patterns are season period and sex dependent, it is strongly recommended that (1) injury registration focuses on both the off-season preparation period and the competition period and (2) prevention efforts are specifically tailored to the sex of the athletes. II.

High Rates of Overuse-Related Structural Abnormalities in the Lumbar Spine of Youth Competitive Alpine Skiers: A Cross-sectional MRI Study in 108 Athletes.

Background:Alpine ski racing is known as a sport with unfavorable spinal loads and high rates of back overuse injuries at the elite level. However, little is known about overuse-related structural abnormalities occurring in the spine of youth athletes.Purpose:To describe the prevalence of abnormal magnetic resonance imaging (MRI) findings in the lumbar spine of youth competitive alpine skiers within the U16 category (under 16 years) with respect to sex, height growth, multifidus size, increasing age, and clinical relevance.Study Design:Cross-sectional study; Level of evidence, 3.Methods:A total of 108 youth competitive alpine skiers aged 13 to 15 years underwent MRI examination of the lumbar spine and measurement of the multifidus cross-sectional area on a 3-T Magnetom Prisma scanner. Complementary assessments included the determination of anthropometrics and biological maturation. Athletes were classified as symptomatic when, pursuant to the Oslo Sports Trauma Research Center questionnaire on health problems, at least 1 substantial back overuse–related health problem episode had been registered during the 12 months before the MRI examination.Results:Of the analyzed youth skiers, 37.0% presented with ≥1 abnormal MRI finding in the lumbar spine. The most prevalent findings in both sexes were disc degeneration (23.1%), Schmorl nodes (19.4%), end plate changes (10.2%), and pars interarticularis anomalies (10.2%); the pars interarticularis anomalies occurred exclusively in males. A smaller relative lumbar multifidus cross-sectional area was related to more frequent occurrence of disc protrusions (P = .018; R2 = 0.116) and end plate changes (P = .024; R2 = 0.096). Overall, the occurrence of abnormal MRI findings in the lumbar spine increased with age (P = .034; R2 = 0.054). Disc degeneration (particularly disc dehydration and disc protrusion) were significantly more prevalent in symptomatic versus asymptomatic athletes (P < .05 for all).Conclusion:As early as age 15 years or younger, competitive alpine skiers demonstrated distinct overuse-related structural abnormalities in the lumbar spine, with some of them being clinically relevant and restrictive of sports participation. As sex, height growth, multifidus size, and increasing age seem to play an important role for the occurrence of such abnormalities, considering these factors might be essential for prevention.

Remarkably high prevalence of overuse-related knee complaints and MRI abnormalities in youth competitive alpine skiers: a descriptive investigation in 108 athletes aged 13–15 years

Background/aimCompetitive alpine skiing is known to be associated with a high risk of traumatic knee injuries. However, little is known about the exact prevalence of knee overuse injuries and their...

Dynamic knee valgus in competitive alpine skiers: Observation from youth to elite and influence of biological maturation.

Numerous studies investigated the association between dynamic knee valgus and injury risk in post-pubertal and elite athletes; however, normative reference scores for competitive alpine skiers and observations on the development process throughout and beyond athletes' growth spurt are lacking. Thus, the aim of this study was to describe the dynamic knee valgus of competitive alpine skiers during drop jump landings (DJ) and single-leg squats (SLS) with respect to sex, sportive level, and biological maturation. Thirty-seven elite and 104 youth competitive alpine skiers around the growth spurt (U15) were examined for their maximal medial knee displacement (MKD) during DJ and SLS by a marker-based 3D motion analysis evaluating dynamic knee valgus. Additionally, skiers' age, anthropometry and biological maturation were assessed. MKD of youth and elite alpine skiers during DJ was comparable and did not improve with increasing training age. Female U15 skiers (on average further matured) had significantly larger MKD values during DJ than male U15 skiers (less matured) (P<.01). Moreover, MKD during DJ was directly associated with the athlete's individual biological maturation status. MKD values obtained from DJ significantly differed from those obtained during SLS (P<.01). The gender-specific difference in MKD values during DJ and their relationship with maturity offset highlight the fundamental changes to the neuromuscular control system during the growth spurt. Thus, biological maturation needs to be considered as a confounding factor for knee valgus screening. Caution is required when evaluating MKD by using high- and low-dynamic tasks, as corresponding information can differ.

Prevention of Anterior Cruciate Ligament Injuries in Competitive Adolescent Alpine Skiers.

Anterior cruciate ligament (ACL) injury is one of the most serious injuries among Swedish alpine ski high school students. An ACL injury forces the skier to stop skiing for several months, and some skiers even have to give up their skiing career. Therefore, an ACL injury prevention program might play an important role for alpine skiers. In the present study ski high school students have been followed in terms of ACL injuries during 1–2 ski seasons between 2006/2007 and 2012/2013. Alpine skiers studying at the Swedish ski high schools during the ski seasons 2011/2012 and 2012/2013 received a specific ACL injury prevention program (n = 305), while alpine skiers who attended a Swedish ski high school between the ski seasons 2006/2007 and 2010/2011 served as controls (n = 431). The prevention program was based on earlier studies and included indoor and outdoor exercises on snow focusing on core stability and neuromuscular control. Alpine skiing is an equilateral sport. Therefore, the goal of the prevention was to encourage the skiers to practice these exercises in order to perform equally good on both legs. The outcome measure consisted of the number and incidence of ACL injuries. The 2 years of prevention resulted in 12 ACL injuries (3.9%) compared with 35 ACL injuries during the control period (8.1%). The absolute risk rate showed a decreased incidence rate of −0.216 [CI −0.001–(−0.432)]/100 months attending a ski high school in favor of the intervention group. A prevention program focusing on the skier's ability to perform neuromuscular exercises equally good on both legs led to a reduction of ACL injuries.

Are Existing Monocular Computer Vision-Based 3D Motion Capture Approaches Ready for Deployment? A Methodological Study on the Example of Alpine Skiing.

In this study, we compared a monocular computer vision (MCV)-based approach with the golden standard for collecting kinematic data on ski tracks (i.e., video-based stereophotogrammetry) and assessed its deployment readiness for answering applied research questions in the context of alpine skiing. The investigated MCV-based approach predicted the three-dimensional human pose and ski orientation based on the image data from a single camera. The data set used for training and testing the underlying deep nets originated from a field experiment with six competitive alpine skiers. The normalized mean per joint position error of the MVC-based approach was found to be 0.08 ± 0.01 m. Knee flexion showed an accuracy and precision (in parenthesis) of 0.4 ± 7.1° (7.2 ± 1.5°) for the outside leg, and −0.2 ± 5.0° (6.7 ± 1.1°) for the inside leg. For hip flexion, the corresponding values were −0.4 ± 6.1° (4.4° ± 1.5°) and −0.7 ± 4.7° (3.7 ± 1.0°), respectively. The accuracy and precision of skiing-related metrics were revealed to be 0.03 ± 0.01 m (0.01 ± 0.00 m) for relative center of mass position, −0.1 ± 3.8° (3.4 ± 0.9) for lean angle, 0.01 ± 0.03 m (0.02 ± 0.01 m) for center of mass to outside ankle distance, 0.01 ± 0.05 m (0.03 ± 0.01 m) for fore/aft position, and 0.00 ± 0.01 m2 (0.01 ± 0.00 m2) for drag area. Such magnitudes can be considered acceptable for detecting relevant differences in the context of alpine skiing.

Fitness- and Health-related Effects of a Sports Injury Prevention Program in Competitive Alpine Skiers

Fitness- and Health-related Effects of a Sports Injury Prevention Program in Competitive Alpine Skiers

Maximal Eccentric Hamstrings Strength in Competitive Alpine Skiers: Cross-Sectional Observations From Youth to Elite Level.

Competitive alpine skiers are subject to substantial risks of injury, especially concerning the anterior cruciate ligament (ACL). During “landing back weighted” episodes, hamstrings may partially counteract the anterior shear force acting on the tibia by eccentrically resisting the boot-induced drawer of the tibia relative to the femur. The aim of the present study was to provide novel descriptive data and sport-specific reference values on maximal eccentric hamstrings strength (MEHS) in competitive alpine skiers from youth to elite level, and to explore potential relationships with sex, age and biological maturation. 170 competitive alpine skiers were investigated: 139 youth athletes (51 females, 88 males; age: 13.8 ± 0.59 years) and 31 elite athletes (19 females, 12 males; age: 21.7 ± 2.8 years). MEHS was assessed by the (Vald Performance, Newstead, Australia). U15 female skiers presented lower MEHS compared to female elite skiers for both limbs (R = 210 ± 44 N vs. 340 ± 48 N, respectively, p < 0.001, and L = 207 ± 46 N vs. 303 ± 35 N, respectively, p < 0.001). Similarly, lower MEHS was observed in U15 male skiers compared to male elite skiers for both limbs (R = 259 ± 51 N vs. 486 ± 62 N, respectively, p < 0.001, and L = 258 ± 57 N vs. 427 ± 54 N, respectively, p < 0.001). Correlations between MEHS and chronological age were modestly significant only for the U15 group (r = 0.37 and p < 0.001). When the correlations for the U15 group were performed between MHES and maturity offset (obtained from the calculation of biological age, i.e., age at peak height velocity), statistical significance was reached by all the correlations run for 3 variables (Males < 0: r = 0.59, p < 0.0001; Males > 0: r = 0.70, p < 0.0001; and Females > 0: r = 0.46, p < 0.0001, start of maturity offset = 0). This cross-sectional description of MEHS in alpine skiers from youth to elite level highlights the importance of biological maturation for MEHS values in youth athletes and presents novel data that may offer insights into new approaches for injury prevention.

The Influence of Directional Compression Tights onMuscle Activity and Performance in Recreational Alpine Skiers

INTRODUCTION Recent studies reported reduced muscle activity in competitive alpine skiers using directional compression (DC). It is not known whether the effects of DC are limited to competitive skiers, or if similar changes would be observed in recreational skiers. The purpose of this study was to examine changes in hip and leg muscle EMG patterns in recreational alpine skiers when skiing with and without a lower body DC garment. METHODS 11 intermediate and expert skiers volunteered for this study. Subjects skied 2 days, 2 weeks apart, with DC and non-compressive (TNC) base layer in a randomized order. EMG of the gluteus medius (GMED), rectus femoris (RF), and adductor longus (ADL) were recorded using surface EMG during measurement runs. Two measurement runs with standardized turns were taken on each visit. Subjects free skied for 1.75 hrs between measurement runs. This sequence of ski runs was replicated on the second testing day. Standardized turns were normalized to 100% turn duration and averaged together for each trial in each condition. A 2x2 ANOVA with repeated measures was used to compare turn time, edge angle, RMS, and MF within trials. Paired t-tests were used to compare percent change (%Δ) RMS, MF and self-paced skiing between trials. RESULTS Subjects skied more runs (8.0 ± 1.5 vs. 5.6 ± 1.8; p<0.05) and vertical (1969 ± 489 m vs. 1382 ± 304 m; p<0.05) during free skiing with DC than TNC. No differences were observed between trials for turn duration or edge angle. Although no statistical differences in %Δ RMS or MF were found, there was a trend towards smaller magnitude %Δ MF with DC (Table 1). CONCLUSIONS Although there were no differences in muscle activity between trials in either condition, subjects improved their self-paced skiing performance in the DC condition. There was also a trend towards smaller %Δ MF the DC condition. Further research should investigate the biomechanical influence of DC on skiing performance.Table: No title available.

Risk Factors for Anterior Cruciate Ligament Injury in Competitive Adolescent Alpine Skiers.

Background:There is a high risk for anterior cruciate ligament (ACL) injuries in alpine skiers. To reduce or try to prevent these injuries, intrinsic and extrinsic risk factors need to be identified.Purpose:To identify possible intrinsic and extrinsic ACL injury risk factors among competitive adolescent alpine skiers.Study Design:Case-control study; Level of evidence, 3.Methods:Between 2006 and 2009, a cohort of 339 alpine ski students (176 male, 163 female) from Swedish ski high schools were prospectively observed in terms of ACL injuries. First-time ACL injuries were recorded. In September, prior to each ski season, the skiers were clinically examined according to a specific knee protocol.Results:Overall, 11 male and 14 female skiers sustained a total of 25 first-episode ACL injuries. The majority of injuries occurred in the left knee (P < .05). Skiers who had participated in alpine skiing for >13 years (hazard ratio, 0.83; 95% CI, 0.68-1.00; P < .05) had a reduced risk of sustaining an ACL injury. Eighteen ACL injuries occurred during training, 12 in the technical discipline of giant slalom, and 8 in slalom. Fourteen skiers reported not to be fatigued at all at the time of injury, and 8 skiers reported that they were somewhat fatigued.Conclusion:ACL injuries occurred more often in the left knee than the right. This should be taken into consideration in the design of ACL injury prevention programs. Those who reported a higher number of active years in alpine skiing showed a reduced risk of sustaining an ACL injury. No other factor among those studied could be identified as an independent risk factor for ACL injury.

Relative Age Effect in Young Swiss Alpine Skiers From 2004 to 2011.

To verify whether relative age effects (RAEs) occur among young male and female Swiss Alpine skiers of different age groups and performance levels. In addition, the efficacy of normalizing performance in physical tests to height and body mass to attenuate RAEs eventually present was tested. The Swiss Ski Power Test consists of anthropometric measures and physical tests for coordination and speed, endurance, and strength and has been used since 2004 to evaluate 11- to 19-y-old Swiss competitive Alpine skiers. The authors analyzed the distribution of 6996 tests performed by 1438 male and 1031 female Alpine skiers between 2004 and 2011 according to the athletes' respective relative age quartiles. Differences in anthropometric measures and performance in physical tests according to quartile were assessed, and the possibility of attenuating eventual RAEs on performance by normalization of results to height and body mass was tested. RAEs were found among all female and male age groups, with no differences between age groups. While performance level did not affect RAE for male skiers, it influenced RAE among female skiers. RAEs also influenced results in all physical tests except upper-limb strength. Normalization of results to body mass attenuated most RAEs identified. Small RAEs are present among young Swiss competitive Alpine skiers and should be taken into account in training and selection settings to prevent the waste of possible future talents. When ranking junior athletes according to their performance in physical tests, normalization of results to body mass decreases the bias caused by RAEs.

Potential Mechanisms Leading to Overuse Injuries of the Back in Alpine Ski Racing

Background: Overuse injuries of the back are a common complaint among top athletes and of competitive alpine skiers in particular. However, there is limited understanding about the sport-specific causes of these injuries that is essential for their prevention. Purpose/Hypothesis: This study was undertaken to describe the sport-specific, overall trunk kinematics and skiers’ loading during giant slalom turns and to assess the plausibility of the hypothesis that a combination of frontal bending, lateral bending, and/or torsion in the loaded trunk might be a potential mechanism leading to overuse injuries of the back in alpine ski racing. Study Design: Descriptive laboratory study. Methods: Eight European Cup–level athletes performed giant slalom runs with 2 different pairs of skis (varying in length, width, and sidecut). They were analyzed with respect to selected kinematic variables related to spinal disc loading. The overall trunk movement components (frontal bending, lateral bending, and torsion) were measured using 2 inertial measurement units fixed on the sacrum and sternum. Total ground-reaction forces were measured by pressure insoles. Results: During the turn phase in which the total ground-reaction forces were the greatest (up to 2.89 times the body weight), the highest average values of frontal bending (38.7°), lateral bending (14.7°), and torsion (7.7°) in the trunk occurred. Similar magnitudes were observed when skiing on longer, giant slalom skis with less width and sidecut. Conclusion: The typical loading patterns of the back in alpine ski racing include a combined occurrence of frontal bending, lateral bending, and torsion in the loaded trunk. Because these factors are known to be related to high spinal disc loading, they may be considered important components of mechanisms leading to overuse injuries of the back in alpine ski racing. Clinical Relevance: Prevention measures should aim to control and/or reduce the magnitude of frontal bending, lateral bending, and torsion in the trunk, as well as the peak loads, while skiing.

Les facteurs de risque de rupture du ligament croisé antérieur chez le skieur alpin en équipe de France

IntroductionThe aim of this study was to analyze risk factors of anterior crucial ligament (ACL) injury in competitive alpine skiers. Material and methodWe included the French team's skiers who suffered from an ACL total rupture between April 2002 and April 2010. It was a retrospective study about 8 seasons of ski and including 2 Olympiads. We sent by mail to each concerned skier a questionnaire. They had to answer to one questionnaire by rupture in the considered period. ResultsForty-two answers (24 from girls, 18 from men) were collected. Fifty-five percent of injuries occurred by sunny weather and 22% by overcast weather, 52% on compact snow and 24% on ice-cold snow, 60% on well-prepared ski run. Downhill and Giant Slalom were responsible for 74% of injuries. Athletes especially injured themselves on December and January (52.5%). The warm-up was globally well done (83%), the skiers not tired and well concentrated. The injuries occurred mostly during a period with many travels and races, lot of stress. It is necessary to hold 27 cases of non-release of bindings while international standard were respected. DiscussionThe evolution of alpine skiing equipment clearly increased the number of ACL injuries, increasing forces on the knee. ConclusionFrom now on, environmental and intrinsic factors seem to be well controlled. We can wonder if it exists a delay of adjustment of skiers face to a constantly evolving equipment which becomes more and more successful.

The correlation between anterior cruciate ligament injury in elite alpine skiers and their parents.

The aim of this study was to investigate whether a familiar correlation with anterior cruciate ligament (ACL) injury exists between competitive alpine skiers and their parents. All 593 (293 males, 300 females) elite alpine skiers who have studied at a Swedish alpine Ski High School during 2006 and 2012 answered a questionnaire whether they or their parents had suffered an ACL injury. A total of 418 skiers (70%) answered the questionnaire. Twenty-nine per cent (n = 19) out of the 65 ACL-injured skiers reported that they had a parent (mother or father) who have had an ACL injury. In skiers without an ACL injury (n = 353), the result was 18% (n = 64). An odds ratio of 1.95 (95% confidence interval 1.04-3.65) was found to suffer an ACL injury if you have a parent who has had an ACL injury compared with if you have a parent without any ACL injury. The findings of the current study demonstrated a family history to tear the ACL between alpine skiers who had studied at a Swedish Ski High School and ACL injuries of their parents. III.

The relationship between ACL injuries and physical fitness in young competitive ski racers: a 10-year longitudinal study

BackgroundEpidemiological studies have shown a high incidence of anterior cruciate ligament (ACL) injuries among competitive alpine skiers. Little is known regarding modifiable risk factors in young skiers. There are still...