Injury profile of competitive alpine skiers: a five-year cohort study

Jump performance and movement quality in 7- to 15-year-old competitive alpine skiers: a cross-sectional study

INTRODUCTION

Injury rates in competitive alpine skiing are high. With current methods, identifying people at risk is expensive and thus often not feasible at the youth level. The aims of this study were (1) to describe the jump performance and movement quality of youth competitive alpine skiers according to age and sex, (2) to compare the jump distance among skiers of different sexes and movement quality grades, and (3) to assess the inter-rater grading reliability of the qualitative visual movement quality classification of such jumps and the agreement between live and video-based post-exercise grading.

MATERIALS AND METHODS

This cross-sectional study is based on an anonymized dataset of 301 7- to 15-year-old competitive alpine skiers. The skiers performed two-legged forward triple jumps, whereby the jump distance was measured, and grades were assigned by experienced raters from the frontal and sagittal perspectives depending on the execution quality of the jumps. Furthermore, jumps were filmed and ultimately rated post-exercise. Differences in jump distance between various groups were assessed by multivariate analyses of variance (MANOVAs). Reliability was determined using Kendall's coefficient of concordance.

RESULTS

The jump distance was significantly greater in U16 skiers than in U11 skiers of both sexes and in skiers with good execution quality than in those with reduced or poor execution quality. Overall, jump distance in U16 skiers significantly differed between female (5.37 m with 95% CI [5.21, 5.53]) and male skiers (5.90 m with 95%CI [5.69, 6.10]). Slightly better inter-rater grading reliability was observed for video-based post-exercise (strong agreement) ratings than for live ratings (moderate agreement).

CONCLUSION

In competitive alpine skiers aged 7 to 15 years, jump performance increases with age, and around puberty, sex differences start to manifest. Our results highlight the importance of evaluating both jump distance and movement quality in youth skiers. To improve test-retest reliability, however, a video-based post-exercise evaluation is recommended.

Injury Profile in Youth Female Athletes: A Systematic Review and Meta-Analysis

BACKGROUND

An increasing number of epidemiological studies assessing the incidence, prevalence and severity of injury in youth female sport are available. However, no study has sought to synthesise the current evidence base across all youth female sport. As such, a systematic review and meta-analysis of injury in this cohort is necessary to understand the diversity of injury and its associated burden between sports in addition to identifying the density of research available.

OBJECTIVE

To conduct a systematic review and meta-analysis of epidemiological data of injuries in youth female athletes with particular attention to injury incidence, mean days lost and injury burden.

METHODS

Searches were performed in PubMed, EBSCO (SPORTDiscus with Full Text MEDLINE, APA PsycINFO, CINAHL, Academic Search Complete) and Cochrane databases. Studies were considered if they reported time-loss injury incidence or prevalence in youth female (≤ 19 years old) athletes. Study quality and risk of bias were assessed using STROBE-SIIS extension, Newcastle-Ottawa Scale, and funnel plots, respectively. Injury incidence and burden rate data were modelled using a mixed-effect Poisson regression model. Days lost data were modelled using a generalised linear mixed model.

RESULTS

Thirty-two studies were included. The overall incidence rate, mean days lost per injury, and burden rate were 4.4 injuries per 1000 h (95% CI 3.3-5.9), 10 days (95% CI 6-15), and 46 days per 1000 h (95% CI 23-92), respectively. Forty percent of athletes sustained at least one time-loss injury. Competitive level was a significant moderator of match and training injury incidence, with elite youth athletes presenting greater pooled injury incidence estimates than non-elite athletes (p = 0.0315 and p = 0.0047, respectively). The influence of moderators on days lost and injury burden could not be determined due to an insufficient number of studies for analysis.

CONCLUSION

Despite a broad inclusion criterion, there is limited injury surveillance research available across youth female sport. Outside of soccer, little research density is evidenced with single studies available in popular team sports such as Australian football and rugby union. Insufficient study numbers reporting mean days lost and injury burden data were available for analysis, and pooled days lost data could only be estimated for soccer. This highlights a need for future research to report days lost data alongside injury number and exposure so burden can be calculated and the full risk of injury to youth female athletes can be identified.

We know a lot about little and little about a lot: A contextualized scoping review on injury prevention in alpine ski racing

BACKGROUND

Our goal was to summarize and contextualize the available literature on alpine ski racing injury epidemiology, injury etiology, injury prevention measures, injury prevention context, and implementation issues.

MATERIALS AND METHODS

We searched four electronic databases using predetermined search terms. We included original studies that assessed injury, injury risk factors, and injury mechanisms, and assessed and reported the effect of an injury prevention measure in alpine ski racing. Two authors independently conducted title-abstract screening, and one performed the full-text review. For data synthesis and categorization, we used the Translating Research into the Injury Prevention Practice framework and a modified and adapted version of the Haddon matrix.

RESULTS

Of the 157 included studies, most corresponded to injury epidemiology and etiology, whereas few studies encompassed injury prevention measure development, implementation and evaluation. Preventive interventions targeting equipment, rules and regulations, course design and snow preparation were the most prevalent in the literature. Furthermore, various contextual factors in the current literature have been found, including gender, competition level, countries and federations, and time periods within a season.

CONCLUSIONS

We provided an in-depth and comprehensive overview of the current state-of-the-art in the alpine ski racing context. We know a lot about little and little about a lot across all the areas associated with injury prevention in such context. The limitations in the literature yield a road map for designing future injury prevention studies to address the key gaps identified. A more comprehensive context-driven approach throughout all stages of injury prevention would benefit the ultimate implementation of effective preventive strategies.

Comparison and analysis of skiing injuries at ski resorts in Chongli, China and Japan

PURPOSE

The rapid development of winter sports requires investigation on injuries in Chongli district, Zhangjiakou city, one of the ski sites of the 2022 Winter Olympics. Careful evaluation is required to observe which injuries are caused under what circumstances, and then we can make corresponding preventive measures and recommendations based on the results.

METHODS

In this retrospective study, the data of injury cases at ski resorts in China (Chongli district) and Japan were analyzed to provide a reference for the ongoing injury prevention at ski resorts. We collected data on injuries at Wanlong and Fulong ski resorts in Chongli district during the 2017-2018 and 2018-2019 ski seasons. We referred to the skiing injury report issued in February 2020 of a nationwide ski safety statistical service - Japan Ski Safety Association. The causes of injury and specific injured body parts were analyzed based on the data of Chinese and Japanese ski resorts. Statistical significance has been calculated using the Chi-square test.

RESULTS

During the 2019-2020 ski season in Japanese ski resorts, the number of reported injuries per 10,000 skiers was 0.93, of which 457 (17.3%) were over 50 years old, accounting for a large proportion of injuries, meanwhile in Chongli ski resort, the injury rate of skiers aged 50 and over was 7.1%. The knee joint (23.7% at Wanlong ski resort and 28.4% in Japanese ski resorts) was the most injured body part among Chongli and Japanese skiers. Among snowboarders, shoulder joint injury (17.7% in Japanese ski resorts) was the most common, and injury on hands and fingers (16.3% in Wanlong ski resorts) was the most common. Head injury rates are similar in Chongli, China and Japanese ski resorts (8.2% and 8.7%, respectively).

CONCLUSION

Our analysis demonstrated that injury data recorded among young skiers was higher in Chinese ski resorts (Chongli district) than that in Japanese ski resorts, and elderly skiers made up a larger proportion of skiing injuries in Japanese resorts. Thus, according to our research, the protection of knee joints, shoulder joints, and hands and fingers should be taken seriously. It should pay attention to the teaching of ski poles (for finger protection), and use protective devices such as knee pads, helmets, etc.

Relationship of Training Factors and Resilience with Injuries in Ski Mountaineers

Ski mountaineering is an increasingly popular sport with a relatively high risk of injury. Therefore, several studies have analyzed factors related to the likelihood of injury, including athlete characteristics, training, resilience and equipment. Thus, the aim of this study was to identify factors that may influence injury risk. A 15-minute online survey was sent to various ski mountaineering groups of different ages and levels. Both the Mann-Whitney U test and odds ratio analysis were performed in order to analyze the data. Results from 104 skiers showed that most injuries occurred in the lower extremities, especially in the knee (29.6%). The findings indicated that skiers who had suffered an injury performed in more competitions per year (p = 0.046), more ski mountaineering sessions per week (p = 0.022) and fewer core training sessions per week (0.029), although core training and competition were not statistically significant factors. Likewise, non-injured athletes had fewer pairs of skis (p = 0.019), which were also wider (p = 0.04). However, no difference was found for warm up and resilience between both groups (p = 0.275). In conclusion, it is important to implement preventive measures based on these factors, even if more research is needed.

Side-to-side differences in knee laxity and side hop test may predispose an anterior cruciate ligament reinjury in competitive adolescent alpine skiers

An anterior cruciate ligament (ACL) injury is a common, severe injury in alpine skiing, and anterior cruciate ligament reconstruction (ACLR) is frequently performed in competitive alpine skiers younger than 20 years old. To reduce the reinjury rate, both intrinsic and extrinsic risk factors should be examined. The aim of this study was to investigate possible intrinsic risk factors for an ACL reinjury in competitive alpine skiers. A cohort of 384 alpine skiers (191 males/193 females) from the Swedish ski high schools were prospectively followed during their high school years. The students were clinically examined and physically tested prior to each ski season. In addition, the RAND 36-Item health survey 1.0 (SF-36, Copyright 1994 Medical Outcome Trust, distributed by RAND Corporation) and injuries were prospectively registered. Thirty-one of the skiers (five males/26 females) had undergone an ACLR before entering the ski high school. This cohort was analyzed with respect to the occurrence of, and possible risk factors for an ACL reinjury (including ipsilateral and contralateral ACL injuries). Skiers who sustained an ACL reinjury were called the “ACL reinjury group,” and those who did not sustain an ACL reinjury were called the “ACL injury group.” Notably, 12 of the 31 students (39%), ten female and two male skiers, aged 16.5 (SD 0.5) years, sustained an ACL reinjury during the two first years at the ski high school. In addition, 10 of the 12 ACL reinjuries occurred within 10–23 months from the first injury [m 14.8 (SD4.7)] and two ACL reinjuries occurred at 29 and 47 months, respectively, from the first injury. It is noted that eight of the ACL reinjuries were to the ipsilateral knee and four to the contralateral knee. There were no differences between the groups with respect to muscle flexibility in the lower extremity, Beighton score, and one leg hop for distance or square hop test. Side-to-side differences were found with respect to knee joint laxity, >3 mm, measured with KT-1000 arthrometer (p = 0.02), and the side hop test (p = 0.04). RAND 36-Item health survey did not predict an ACL reinjury. In conclusion, a side-to-side difference in the side hop test and knee joint laxity (KT-1000) may predispose an ACL reinjury in competitive adolescent alpine skiers.

A screening instrument for side dominance in competitive adolescent alpine skiers

Previous research has shown that high school ski students injure their left anterior cruciate ligament (ACL) more often than their right ACL, and that a prevention program focusing on equal load to the right and left ski turns prevents ACL injuries. Whether the injuries were in the dominant or non-dominant side of ski students was not determined but may be important knowledge to ski coaches for future design of ski-specific training programs. There is no gold standard on how to investigate the dominant side of alpine skiers. Therefore, the aim of this study was to develop a screening instrument consisting of five questions for identifying side dominance and to evaluate side dominance in competitive adolescent alpine skiers. First, 121 competitive adolescent alpine skiers answered the questions on side dominance using a test-retest design. The questions were: which hand/arm (left/right) or foot/leg (left/right) one uses as the first choice when writing, throwing, kicking a ball, jumping over a fence and stair-climbing. A question about safer/better ski turn to the left or to the right was also added. Second, 274 skiers answered the questions at one occasion. A very good agreement was shown in writing and throwing and kicking a ball, and a fair agreement was shown in jumping over a fence and stair climbing. A total of 243 skiers reported right-sided dominance, and seven skiers reported left-sided dominance. One hundred and nineteen of the 121 skiers who took part in the test-retest design answered the question safer/better ski turn, and of those 70 (59%) reported that they had a safer/better ski turn to one side than to the other side. However, the side was not consistent between the two test occasions, and the question did not correlate with side dominance. A combination of the three questions “What hand/arm do you use as first choice when writing?” “What hand/arm do you use as first choice when throwing?” and “What foot/leg do you use as first choice when kicking a ball?”, may be used to decide side dominance in adolescent alpine skiers. Most adolescent alpine skiers reported right-sided dominance.

Prospective Study on Dynamic Postural Stability in Youth Competitive Alpine Skiers: Test-Retest Reliability and Reference Values as a Function of Sex, Age and Biological Maturation

This study aimed 1) to assess the test-retest reliability of dynamic postural stability index (DPSI) assessments using a ski-specific jump protocol that consists of single-leg landings on a three-dimensional force plate after forward-performed double-leg drop jumps from a box over a hurdle (DJSLLs), 2) to provide reference values for female and male youth competitive alpine skiers; 3) to explore their changes in DPSI over 3 years during adolescence; and 4) to investigate potential associations of DPSI with age and biological maturation. Using three-dimensional force plates, 16 healthy subjects were tested on the same day (test-retest reliability experiment; five test-retest assessments of right leg landings), and 76 youth skiers aged 13–15 years were tested 3 times within 2 years (main experiment; average of two trials per leg each time). The test-retest reliability experiment revealed an ICC(3,1) and 95% CI of 0.86 [0.74, 0.94] for absolute DPSI assessment. The within-subject SEM of absolute DPSI was 16.30 N [13.66 N, 20.65 N], and the standardized typical error was moderate (0.39 [0.33, 0.50]). Both absolute and relative DPSI values were comparable between male and female youth competitive alpine skiers. The mean absolute DPSI in year 1 (195.7 ± 40.9 N), year 2 (196.5 ± 38.9 N) and year 3 (211.5 ± 41.3 N) continuously increased (i.e., worsened) (p < 0.001). Mean relative, i.e. body weight force normalized, DPSI values significantly decreased, i.e., improved, from year 1 to 2 (0.42 ± 0.01 vs. 0.36 ± 0.004; p < 0.001) and year 1 to 3 (0.42 ± 0.01 vs. 0.36 ± 0.01; p < 0.001). Absolute DPSI correlated with age and biological maturation, while no such correlations were found for relative DPSI values. Our findings suggest that DPSI is a reliable and sensitive measure of dynamic postural control during DJSLLs and that relative DPSI improves annually in competitive youth skiers when accounting for body weight. Future work should consider biological maturation testing during the growth spurt, and normalizing to body weight force could be a possible solution.

The ISPA Int Injury Prevention Programme for Youth Competitive Alpine Skiers: A Controlled 12-Month Experimental Study in a Real-World Training Setting

Evidence-based injury prevention programmes for youth competitive alpine skiers are widely absent. The aims of this controlled 12-month experimental study were to introduce a novel injury prevention programme targeted to the injury patterns of youth skiers, called ISPA_Int, and to compare the differences in injury occurrence between an intervention group (IG) additionally performing the ISPA_Int programme and an independent, historical control group (CG) following their regular training routines. None of the skiers of the CG were part of the IG and vice versa. The study was directly conducted within the real-world youth development structures of skiers competing at the under 16 years (U16) level in Switzerland. Seventy-one skiers (aged 14.4 ± 0.3 years) assigned to the IG were compared to 58 age- and gender-matched controls. The IG was offered the ISPA_Int programme with the recommendation to perform it at least once per week. Skiers’ adherence to this recommendation was surveyed but not enforced. Injuries were recorded using the Oslo Sports Trauma Research Centre Questionnaire. Primary outcomes were the absolute injury rates (number of injuries/100 athletes per season) and epidemiological incidence proportion (number of injured athletes/100 athletes per season). The secondary outcome was the average 2-weekly prevalence of traumatic knee, knee overuse, and lower back overuse injuries. There were lower absolute rates of all traumatic injuries [rate/risk difference, RD: −57.1 (−98.1, −16.0); rate/risk ratio, RR: 0.665 (0.485, 0.884)] and overuse injuries [RD: −35.9 (−71.0, −0.7); RR: 0.699 (0.493, 0.989)] in the IG than in the CG. Likewise, the epidemiological incidence proportion for all overuse injuries was smaller in the IG [RD: −28.4 (−44.8, −12.0); RR: 0.598 (0.435, 0.822)], while the proportion of skiers suffering from traumatic injuries did not significantly differ between the groups. Notably, the IG particularity differed from the CG in the average 2-weekly prevalence of knee trauma, knee overuse, and lower back overuse complaints, three of the major injury-related hot spots in youth skiers. Based on these promising results, the ISPA_Int programme may have great potential to prevent injuries in youth competitive alpine skiers, and the underlying exercises should be considered complementary training content at the U16 level.

Incidence of injuries in professional snow sports: A systematic review and meta-analysis

PURPOSE

The study aimed to conduct a comprehensive systematic review and meta-analysis of injury incidence in professional skiers and snowboarders.

METHODS

We systematically searched PubMed, Web of Science, and MEDLINE for studies on injury incidence published from inception to April 2020. Injury data were extracted, alongside information on injury location, severity, type, cause, and sport discipline. Incidence of injuries was presented per 1000 athlete-days, with 95% confidence intervals (95%CIs).

RESULTS

The search identified 462 articles, and 22 were included in our review. The overall incidence of injuries among professional skiers and snowboarders was 3.49 per 1000 athlete-days (95%CI: 2.97-4.01). Lower extremity had the highest injury incidence (1.54 per 1000 athlete-days, 95%CI: 1.24-1.84). Incidence rates of slight, mild, moderate, and severe injuries were 0.26, 0.31, 0.57, and 0.59 per 1000 athlete-days, respectively. Contusion had the highest incidence rate (1.82 per 1000 athlete-days, 95%CI: 1.01-2.63). The most common cause of injury was contact trauma (3.20 per 1000 athlete-days, 95%CI: 1.32-5.08). Freestyle skiing had the highest incidence rate (6.83 per 1000 athlete-days, 95%CI: 4.00-9.66), and Nordic skiing had the lowest rate (2.70 per 1000 athlete-days, 95%CI: 1.94-3.46).

CONCLUSION

Professional skiers and snowboarders have a substantial risk of sustaining injuries. Our findings can be used to inform the planning and provision of healthcare for elite participants in different snow sports.

A Cross-Sectional Observation on Maximal Eccentric Hamstring Strength in 7- to 15-Year-Old Competitive Alpine Skiers

Simple Summary

Competitive alpine skiing is a sport with frequent occurrence of severe knee injuries, and it is well known that the hamstring muscles play an important role in preventing these injuries. The aim of this study was to assess the maximal strength capacity for braking, the downward movement during Nordic Hamstring Exercises, the so called maximal eccentric hamstring strength, in 7- to 15-year-old skiers. Absolute strength values were greater in skiers under 15 years old (U15) skiers than in those under 10 years old (U10), as well as in U15 males compared to their female counterparts. There were no sex differences in U10 skiers. Absolute strength values were generally dependent on age and biological developmental stage, but this dependence was considerably attenuated when body weight was considered. This should be kept in mind when testing athletes around the growth spurt.

Abstract

Severe knee injuries are common in alpine skiing and the hamstring muscles are known to counteract the anterior tibial displacement that typically accompanies major injury mechanisms. This study aimed to assess the Maximal Eccentric Hamstring Strength (MEHS) of youth competitive alpine skiers during Nordic Hamstring Exercise (NHE) in terms of dependence of sex, age and biological maturation. A total of 246 7- to 15-year-old skiers were tested with respect to their MEHS using an NHE-based measurement device (Vald Performance, Newstead, Australia). Significantly greater absolute MEHS was observed in skiers of the under 15 years (U15) category compared to skiers under 10 years old (U10) (227.9 ± 61.1 N vs. 142.6 ± 28.9 N; p < 0.001), also when grouped by sex. Absolute MEHS was revealed to be lower in U15 females compared to males (213.5 ± 49.0 N vs. 241.9 ± 68.4 N; p = 0.001); in U10 skiers there was no sex difference. For all age groups and sexes, absolute MEHS values were significantly correlated with age and biological maturation (p < 0.001). However, when normalized to body weight such associations disappeared, which is why this is strongly recommended when testing around their growth spurt. Overall, this study established sport-specific normative reference data that may be of interest to researchers and sport practitioners alike.

Perceptions of experts on key injury risk factors in alpine ski racing as a function of stakeholder role and associated level of competition

Objectives

(1) To update experts' priorities of perceived key injury risk factors in alpine ski racing based on a framework and list derived 10 years ago, (2) to identify additionally emerging risk factors since then and (3) to compile a list with countermeasure suggestions.

Methods

A sample of 532 expert stakeholders (athletes, coaches, team medical staff, Ski Racing Suppliers (SRS) and International Ski Federation (FIS) representatives) from the World Cup (WC), European Cup (EC) and FIS-race level participated in a cross-sectional online survey. Experts were asked to name those risk factors with the highest believed impact on injury risk and rank them according to their current priority from a predefined list. In addition, experts were encouraged to name additional (not listed) risk factors and to suggest countermeasures.

Results

Regardless of stakeholder role and competition level, snow-related factors appeared to have the highest perceived priority. However, WC athletes' and coaches' perceptions were also related to equipment, while at the EC and FIS-race level fatigue and physical fitness-related factors were considered important. Athletes' perceptions were largely in agreement with SRS (ie, snow-related and equipment-related factors). At the same time, while coaches, team medical staff and FIS representatives additionally emphasised fatigue and physical fitness-related factors.

Conclusion

Experts' perceptions on key injury risk factors in alpine ski racing depend on the stakeholder role and differ between the competition levels. Thus, to develop effective prevention measures and to successfully implement them, all relevant stakeholders should be given a voice, and prevention efforts should be targeted to the specific level.

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

PURPOSE

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.

METHODS

Over an entire season, all injuries occurring in 44 Swiss National 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.

RESULTS

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.

CONCLUSIONS

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.

LEVEL OF EVIDENCE

II.

Studying Force Patterns in an Alpine Ski Boot and Their Relation to Riding Styles and Falling Mechanisms

In skiing, performance and safety can depend on small details. Consequently, the measurement of forces within the ski boots, which represent the essential form-fitting and force transmitting interface during skiing, will lead to enhanced performance and more importantly safety. This study presents a methodology to measure force patterns (continuous data acquisition) under laboratory as well as realistic slope conditions. The force measurements will be analyzed to gain insights of the skiing style, skiing technique, specific falling mechanisms (i.e., boot induced anterior drawer, phantom foot, hyperextension of the knee joint, and valgus-external rotation). Furthermore, the locations of force sensors in a overlap designed ski boot are discussed in terms of practicability and applicability. These insights are of particular interest to derive release conditions for predictive binding systems and furthermore provide data to improve the style of skiing (e.g., turn release action or center of gravity behavior). For that purpose, a ski boot was instrumented with seven force (piezoresistive) sensors while the basic structure of the boot and the binding remained unchanged. Three sensors were placed on the insole to measure ground reaction forces as well as the contact forces between the skier's foot and the boot. The other four sensors were positioned at spoiler/shaft and toecap (front sole) regions of the ski boot. The locations of the force sensors within the ski-boot are defined with regard to the main body movement while skiing (body-related planes). In addition, a commercially available ski and body mount measuring system were utilized to correlate speed, inclination and body position with the force patterns occurring during skiing on the slope as well as simulating specific body positions on an inclined ramp under laboratory conditions. The measured force revealed that the toecap (upper) sensors provide insufficient even non-conclusive data to deduce significant patterns. However, the insole sensors (heel and front sole area) as well as the spoiler/shaft (back) sensors are more reliable and show characteristic patterns indicating forward or backward lean. These results will have an important impact to the development of predictiveelectro-mechanical bindings to prevent knee-related injuries, which, from a statistical point of view, concerns largely women and young athletes.

Training load characteristics and injury and illness risk identification in elite youth ski racing: A prospective study

PURPOSE

The study aimed to investigate the role of training load characteristics and injury and illness risk in youth ski racing.

METHODS

The training load characteristics as well as traumatic injuries, overuse injuries, and illnesses of 91 elite youth ski racers (age = 12.1 ± 1.3 years, mean ± SD) were prospectively recorded over a period of 1 season by using a sport-specific online database. Multiple linear regression analyses were performed to monitor the influence of training load on injuries and illnesses. Differences in mean training load characteristics between preseason, in-season, and post-season were calculated using multivariate analyses of variance.

RESULTS

Differences were discovered in the number of weekly training sessions (p = 0.005) between pre-season (4.97 ± 1.57) and post-season (3.24 ± 0.71), in the mean training volume (p = 0.022) between in-season (865.8 ± 197.8 min) and post-season (497.0 ± 225.5 min) and in the mean weekly training intensity (Index) (p = 0.012) between in-season (11.7 ± 1.8) and post-season (8.9 ± 1.7). A total of 185 medical problems were reported (41 traumatic injuries, 12 overuse injuries, and 132 illnesses). The weekly training volume and training intensity was not a significant risk factor for injuries (p > 0.05). Training intensity was found to be a significant risk factor for illnesses in the same week (β = 0.348; p = 0.044; R² = 0.121) and training volume represents a risk factor for illnesses in the following week (β = 0.397; p = 0.027; R² = 0.157).

CONCLUSION

A higher training intensity and volume were associated with increased illnesses, but not with a higher risk of injury. Monitoring training and ensuring appropriate progression of training load between weeks may decrease incidents of illness in-season.

Overuse injuries in the knee, back and hip of top elite female alpine skiers during the off-season preparation period: prevalence, severity and their association with traumatic preinjuries and training load

Objectives

To investigate knee, back and hip overuse injuries in top female elite alpine skiers during the off-season preparation, which has so far received little attention, and to assess their relationship with traumatic preinjuries and overall training load.

Methods

A cohort of 26 females of the Swiss Alpine Ski-Team were prospectively surveyed by the use of the Oslo Sports Trauma Research Centre questionnaire. Along with the surveys also total training loads were monitored. Data on preinjuries were assessed retrospectively by baseline questionnaires and were verified by team medical records.

Results

57.7% of the female skiers suffered from at least one severe traumatic knee injury during their preceding career. The average 2-weekly prevalence of overuse injuries was highest for the knee, followed by the back and hip. Technique specialists (major giant slalom and slalom) were more prone to back overuse injuries than speed specialists (major super-G and downhill). The occurrence of knee overuse complaints was directly associated to previous severe traumatic knee injuries and athletes' total training hours.

Conclusion

In top female elite alpine skiers, knee, back and hip overuse injuries are relatively frequent. Moreover, discipline preferences, previous traumatic injuries and the overall training load may play an important role for their manifestation.

Sex differences in the knee orthopaedic injury patterns among recreational alpine skiers

Background

Although studies have reported the sex differences in injury patterns among recreational skiers, the findings are still conflicting. This study aims to analyse the sex differences of orthopaedic knee injuries that occurred during alpine skiing.

Methods

A total of 306 recreational alpine skiers (125 females and 181 males) who sustained knee surgeries between June 2016 and December 2018 participated in this study. Age, height, weight, and physical activity level of the patients were recorded. The orthopaedic knee injury patterns were analysed based on the diagnosis given by the physicians.

Results

Male skiers (17.13%) had a higher proportion of multiple knee ligament injuries than females (6.40%). The combined anterior cruciate ligament (ACL) and medial collateral ligament injury were the most common injury types in both females and males, with ACL injury being more prevalent for females (79.20%) than that in males (56.35%). The proportion of female skiers (17.6%) with vigorous-intensity activity level was significantly lower than that of males (30.9%). Female skiers had lower body height, body weight, and body mass index than male skiers (P <  0.001).

Conclusions

ACL injury is the most common orthopaedic injury among both female and male knee-injured recreational skiers. The proportion of females with an ACL injury is higher than that of males, but the proportion of multiple knee ligament injuries is lower than that of males. More male recreational skiers have vigorous-intensity activity level habits in daily life than females.

Hip pain and its correlation with cam morphology in young skiers-a minimum of 5 years follow-up

BACKGROUND

There is conflicting evidence regarding the association between cam morphological changes and hip pain, and it remains unclear who with cam morphology will develop hip pain and who will not. This study aimed to investigate the correlation between cam morphology, hip pain, and activity level at a 5-year follow-up in young Alpine and Mogul skiers.

METHOD

All students (n = 76) at Åre Ski National Sports High School were invited and accepted participation in this prospective study at baseline. Magnetic resonance imaging (MRI) of both hips was conducted to evaluate the presence of cam morphology (α-angle ≥ 55°) and its size alongside the reporting of hip pain, type, and frequency of training by the Back and hip questionnaire, at baseline. After 5 years, the skiers were invited to complete a shortened version of the same questionnaire.

RESULTS

A total of 60 skiers (80%) completed the follow-up questionnaire, of which 53 had concomitant MRI data. Cam morphology was present in 25 skiers (47.2%, 39 hips). Hip pain at baseline and at follow-up was reported in 17 (28.3%) and 22 (36.7%) skiers, respectively. No correlations were found between the activity level, the frequency, and the size of cam morphology and hip pain, except for the right hip α-angle at 1 o'clock and hip pain in skiers with cam morphology at baseline (rs = 0.49; P = 0.03) and at follow-up (rs = 0.47; P = 0.04). A total of 73.3% skiers had retired, of which 48% reported this was due to injuries.

CONCLUSION

Hip pain was not shown to be correlated, or had a low correlation, with activity level and the presence and size of cam morphology in young skiers on a 5-year follow-up. Based on these results, cam morphology or activity level did not affect hip pain to develop during 5 years of follow-up in young skiers. Furthermore, this study highlights that almost 75% of young elite skiers had retired from their elite career with almost 50% reporting that this was due to injuries sustained from skiing.

Did injury incidence in alpine ski racing change after equipment regulations? An evaluation based on the injury surveillance system of the Austrian Ski Federation

OBJECTIVES

To assess the effects of alpine competition equipment regulations from 2003, 2007 and 2012 on severe injury incidence.

DESIGN

Case study METHOD: Data originated from records of the injury surveillance system of the Austrian Ski Federation. Injuries from the seasons 2001-2017 were divided in four periods between the equipment regulations. For comparison of consecutive periods, risk ratios (RR = later period / preceding period) with 95% CI were calculated. Total severe injury events, events with severe knee injuries, and events with severe ACL injuries were separately investigated.

RESULTS

A significant increase of total severe injury incidence was found after the equipment regulation in 2003 (RR1.52, 95% CI 1.00-2.31). None of the other comparisons revealed significance (p<0.05) or statistical trends (p<0.1). Only the minority (40%) of the RR showed a reduction in the injury incidence of the Austrian Ski Team (lowest RR 0.78). 60% of the RR increased after the regulations (highest RR 1.63).

CONCLUSIONS

Even though statistical uncertainties remain, our findings allow the conclusion, that the implemented equipment regulations did not cause a noticeable reduction of injuries. The three analysed equipment regulations were not appropriate or were counteracted by other factors.

Previous and current injury and not training and competition factors were associated with future injury prevalence across a season in adolescent elite athletes

INTRODUCTION

Understanding the factors associated with different injury prevalence profiles in young athletes is needed for the design of tailored injury prevention programs.

OBJECTIVES

To explore the factors associated with different levels of injury prevalence in adolescent elite athletes.

METHODS

A total of 389 adolescent elite athletes (age range 15-19 years), participating in 16 different sports, were monitored repeatedly over 52 weeks using the Oslo Sports Trauma Research Center Overuse Injury Questionnaire. The athletes were grouped in three injury categories: (1) "Low injury"; (2) "Medium injury"; and (3) "High injury," based on the proportion of times the athletes reported substantial injury over the season.

RESULTS

Logistic and multinomial regression identified substantial injury the first week (odds ratio (OR) 53.9, 95% confidence interval (CI) 7.1-407.7), and an interaction between sex and previous injury (OR 3.9, 95% CI 1.1-12.4) as significant factors that increased the odds of belonging in the High injury compared to the Low injury group. A female athlete with a previous injury the last 12 months had a higher probability of belonging in the High injury group compared to a male athlete.No significant (p > .05) difference in training, sleep, or competition exposure was found across the injury category.

CONCLUSION

Current substantial injury and previous injury were strongly associated with the most injured athletes. Coaches and medical team should consider limiting the injured athlete competition exposure.

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.

Subjective well-being is associated with injury risk in adolescent elite athletes

Objective: The purpose of this study was to explore the association of subjective well-being with injury and injury severity in adolescent elite athletes.Design: Prospective cohort study.Participants: Three hundred eighty-six adolescent elite athletes (age range 15-19), participating in seven different sports, were monitored repeatedly over 52 weeks using a valid questionnaire about injuries, substantial injuries, injury severity and subjective well-being (scale 0-100).Results: A linear mixed model showed that subjective well-being was significantly influenced by injury severity (p < .001, estimate -1.7, 95% CI -1.4 to -2.0) and sex (p = .019, estimate -3.6, 95% CI -6.0 to -0.2). Of all injury reports where the athletes reported a well-being score of less than or equal to 20, 54% reported substantial injury, whereas 9% of the injury reports where the athletes reported a well-being score above 80 reported substantial injuries. In addition, an increase in subjective well-being with a score of 10 decreased the odds of injury with 5.6% (p = .036, 95% CI 89.5 to 99.6) and injury severity with 0.4 points (p = .01, 95% CI -0.6 to -0.1).Conclusion: Medical personnel need to be aware that young athletes may face well-being challenges while injured and that a low subjective well-being increase the injury risk the subsequent week.

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.

Alpine Ski Racing Injuries

CONTEXT

This article reviews the epidemiology of alpine ski racing-related injuries, risk factors, mechanisms of injury, and injury prevention strategies.

EVIDENCE ACQUISITION

Pertinent literature from peer-reviewed publications from 1976 through 2018.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

The rate of injury in alpine ski racing is high. In general, knee injuries are the most common, with anterior cruciate ligament (ACL) disruptions being the most significant in terms of time loss from sport. Three specific mechanisms of ACL injury in alpine ski racers have recently been described (slip-catch, dynamic snowplow, and landing back-weighted). In contrast to other sports, female ski racers are not clearly at greater risk for ACL injury, especially at the highest level of competition. A high percentage of ski racers are able to return to their previous level of competition after ACL injury. Risk factors for injury and methods of injury prevention have been proposed; however, the rate of injury, particularly ACL injuries, has not decreased significantly.

CONCLUSION

Alpine ski racing has a high injury rate. ACL injuries in particular remain problematic. Further study is needed to identify modifiable risk factors and implementation of injury prevention strategies.

Challenges of talent development in alpine ski racing: a narrative review

Alpine ski racing is one of the most popular sports in many countries; nevertheless, selection disadvantages and severe injuries result in high dropout rates. In this review we summarize existing knowledge about the specific challenges associated with selection bias and injuries, and their effects on talent development in ski racing. The relative age effect (RAE) appears in all age categories of national Austrian and international alpine ski racing. Relatively younger athletes seem to only have a chance for selection if they are early maturing. Talent selection processes should consider both the biological maturity status as well as the relative age; additionally, a competition system based on a rotating cut-off date might contribute to a reduction of RAE. Youth and adolescent ski racers report lower injury rates compared to World Cup athletes. The knee was the most affected body part in relation to traumatic injuries. The most frequently reported overuse injuries were knee pain (youth) and low back pain (adolescent level). Athlete-related modifiable risk factors were core strength, neuromuscular control, leg extension strength and limb asymmetries. Based on these findings, prevention measures should be expanded to contribute to long-term injury prevention. In future research more multi-disciplinary, longitudinal studies should be performed.

Effect of wearing a knee brace or sleeve on the knee joint and anterior cruciate ligament force during drop jumps: A clinical intervention study

BACKGROUND

Knee braces are considered to be extremely useful tools in reducing the shear force of knee joints for non-contact anterior cruciate ligament (ACL) injury prevention. However, the effectiveness of sports knee braces and sleeves remains to be identified. Therefore, the purpose of this study was to evaluate the effectiveness of wearing commercialized sports knee braces and sleeves on knee kinematics, kinetics, and ACL force during drop jumps using musculoskeletal modeling analysis.

METHODS

Musculoskeletal modeling analysis was conducted on 19 male alpine skiers who performed drop jump motions from a 40-cm box under three conditions: without a brace/sleeve, with a brace, and while wearing a neoprene sleeve.

RESULTS

The physical performance (i.e., the center of mass of the jumping height) was not affected by the type of brace or sleeve. However, wearing a brace or sleeve during drop jump tasks reduced the knee joint's maximum flexion, abduction angles, and adduction moment. The knee joint shear force when wearing the brace or sleeve exhibited no statistical differences. Further, the ACL load estimated in this study did not exhibit any statistical differences in relation to wearing a brace or sleeve.

CONCLUSIONS

The knee braces and sleeves reduced flexion and abduction movement, and adduction moment but did not reduce the knee joint shear force, internal rotation moment, or the ACL force. Therefore, if a sports knee brace that controls the knee joint's shear force and internal rotation moment is developed, it may aid in preventing ACL injuries.

Limb symmetry index in competitive alpine ski racers: Reference values and injury risk identification according to age-related performance levels

PURPOSE

The aims of this study were to assess differences of limb symmetry index (LSI) in strength- and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers.

METHODS

The study (Study 1) included 285 high-level competitive ski racers (125 females, 160 males) of 3 age-related performance levels and based on the school system: 95 youth (10-14 years, secondary modern school), 107 adolescent (15-19 years, grammar school), and 83 elite athletes (20-34 years). To investigate the second aim (Study 2), 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests (strength related: one-leg counter movement jump (OL-CMJ) and one-leg isometric/isokinetic press strength test (OL-ILS); coordination related: one-leg stability test (OL-ST) and one-leg speedy jump test (OL-SJ)). The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted.

RESULTS

There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests: the OL-CMJ (χ²(2, 285) = 9.09; p = 0.01) and the OL-ILS (χ²(2, 285) = 14.79; p < 0.01). The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers (Wald = 7.08; p < 0.01). No significant risk factors were found for overuse injuries.

CONCLUSION

Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of <10% for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks (strength vs. coordination related) rather than on generalizations, and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.

A comparison of lower limb stiffness and mechanical muscle function in ACL-reconstructed, elite, and adolescent alpine ski racers/ski cross athletes

PURPOSE

The aim of this study was to compare mechanical muscle function in the eccentric/concentric phases of vertical bilateral jumping in anterior cruciate ligament-reconstructed (ACLR), elite (ELITE), and adolescent (ADOL) alpine ski racers and ski cross athletes.

METHODS

Alpine ski racers/ski crossers (ACLR: n = 12, age = 26.7 ± 3.8 years; ELITE: n = 12, age = 23.9 ± 3.0 years; ADOL: n = 12, age = 17.8 ± 0.7 years; females: n = 6 per group, males: n = 6 per group) performed 5 maximal countermovement jumps (CMJs) and 5 squat jumps. The ground reaction forces for each limb were analyzed using dual force plate recording to obtain body center of mass (BCM) velocity, displacement, and power. The eccentric deceleration (ECC) and concentric phases were determined from BCM velocity. CMJ net concentric and ECC impulses were calculated (body mass normalized) along with the peak and mean BCM power and maximal vertical jump height. CMJ lower limb stiffness (LLS) was determined by the slope of the ground reaction forces vs. the BCM displacement curve over the ECC phase. Concentric and ECC asymmetry indices were calculated for each leg, and the left vs. right LLS was compared. Outcome measures (reported as mean ± SD) calculated as a 5-jump mean were normalized to body mass and compared using an analysis of variance.

RESULTS

No between-group differences were found for peak and mean power or jump heights. There were no group differences for LLS or net concentric phase impulse, but the net ECC impulse was lower in the ADOL group compared with ELITE skiers (ADOL: 1.33 ± 0.32 Ns/kg; ELITE: 1.59 ± 0.16 Ns/kg; p < 0.05). Although no group differences were found for ECC asymmetry indices, a group × limb interaction was found for LLS (p < 0.01), which was systematically higher in the right vs. the left limb of ADOL skiers (right: 54.1 ± 17.9 N/m/kg; left: 48.7 ± 15.7 N/m/kg; p < 0.01).

CONCLUSION

ADOL skiers demonstrated decreased ECC impulse and systematic right limb dominance in LLS compared with ACLR and ELITE skiers. The implication of these findings for injury and performance are unknown, but further investigation into these potential relationships is warranted.

Effects of an 8-Week Body-Weight Neuromuscular Training on Dynamic Balance and Vertical Jump Performances in Elite Junior Skiing Athletes: A Randomized Controlled Trial

Vitale, JA, La Torre, A, Banfi, G, and Bonato, M. Effects of an 8-week body-weight neuromuscular training on dynamic balance and vertical jump performances in elite junior skiing athletes: a randomized controlled trial. J Strength Cond Res 32(4): 911-920, 2018-The aim of the present randomized controlled trial was to evaluate the effects of an 8-week neuromuscular training program focused on core stability, plyometric, and body-weight strengthening exercises on dynamic postural control and vertical jump performance in elite junior skiers. Twenty-four Italian elite junior male skiers were recruited and randomized to either an experimental group (EG), performing neuromuscular warm-up exercises, (EG; n = 12; age 18 ± 1 years; body mass 66 ± 21 kg; height 1.70 ± 0.1 m) or a control group (CG) involved in a standard warm-up (CG; n = 12; age 18 ± 1 years; body mass 62 ± 14 kg; height 1.73 ± 0.1 m). lower quarter Y-Balance Test (YBT), countermovement jump (CMJ), and drop jump (DJ) at baseline (PRE) and at the end (POST) of the experimental procedures were performed. No significant differences between EG and CG were observed at baseline. Results showed that EG achieved positive effects from PRE to POST measures in the anterior, posteromedial, posterolateral directions, and composite score of YBT for both lower limbs, whereas no significant differences were detected for CG. Furthermore, 2-way analysis of variance with Bonferroni's multiple comparisons test did not reveal any significant differences in CMJ and DJ for both EG and CG. The inclusion of an 8-week neuromuscular warm-up program led to positive effects in dynamic balance ability but not in vertical jump performance in elite junior skiers. Neuromuscular training may be an effective intervention to specifically increase lower limb joint awareness and postural control.

How to Prevent Injuries in Alpine Ski Racing: What Do We Know and Where Do We Go from Here?

Alpine ski racing is known to be a sport with a high risk of injury and a high proportion of time-loss injuries. In recent years, substantial research efforts with regard to injury epidemiology, injury etiology, potential prevention measures, and measures’ evaluation have been undertaken. Therefore, the aims of this review of the literature were (i) to provide a comprehensive overview of what is known about the aforementioned four steps of injury prevention research in the context of alpine ski racing; and (ii) to derive potential perspectives for future research. In total, 38 injury risk factors were previously reported in literature; however, a direct relation to injury risk was proven for only five factors: insufficient core strength/core strength imbalance, sex (depending on type of injury), high skill level, unfavorable genetic predisposition, and the combination of highly shaped, short and wide skis. Moreover, only one prevention measure (i.e. the combination of less-shaped and longer skis with reduced profile width) has demonstrated a positive impact on injury risk. Thus, current knowledge deficits are mainly related to verifying the evidence of widely discussed injury risk factors and assessing the effectiveness of reasonable prevention ideas. Nevertheless, the existing knowledge should be proactively communicated and systematically implemented by sport federations and sport practitioners.

Prevalence and Consequences of Injuries in Powerlifting: A Cross-sectional Study

Background:

Powerlifting consists of the squat, bench press, and dead lift, and extreme loads are lifted during training and competitions. Previous studies, which have defined an injury as an event that causes an interruption in training or competitions, have reported a relatively low frequency of powerlifting injuries (1.0-4.4 injuries/1000 hours of training). No previous study has investigated the prevalence of injuries, defined as a condition of pain or impairment of bodily function that affects powerlifters’ training, in a balanced sample of men and women, and no studies have established possible risk factors for an injury.

Purpose:

To investigate the prevalence, localization, and characterization of injuries among Swedish subelite classic powerlifters, with an emphasis on differences between men and women, and to investigate whether training and lifestyle factors are associated with an injury.

Study Design:

Cross-sectional study; Level of evidence, 3.

Methods:

A total of 53 female and 51 male Swedish subelite powerlifters answered an online questionnaire including questions about background characteristics, training habits, and lifestyle factors. The main part of the questionnaire included questions about injuries and their consequences. An injury was defined as a condition of pain or impairment of bodily function that affects powerlifters’ training.

Results:

Seventy percent (73/104) of participants were currently injured, and 87% (83/95) had experienced an injury within the past 12 months. The lumbopelvic region, shoulder, and hip were the most commonly injured areas for both sexes. Women experienced a significantly greater frequency of injuries in the neck and thoracic region than men. Injuries seemed to occur during training, although only 16% (11/70) of those currently injured had to completely refrain from training. Training frequency, greater personal best in the dead lift, injury onset during bench-press and dead-lift training, use of straps, alcohol consumption, and dietary issues were associated with current injuries.

Conclusion:

Injuries are very common in subelite powerlifters. Men and women report similar injury frequencies but different anatomic locations. These injuries do not prevent powerlifters from training and competing, but they may change the content of training sessions. Why powerlifters develop injuries is still unclear; however, it is likely that the management of training loads and optimization of the lifting technique during the squat, bench press, and dead lift are of importance.

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.

Young, talented and injured: Injury perceptions, experiences and consequences in adolescent elite athletes

Even though injury is common in elite sports, there is still a lack of knowledge of young athletes' injury perception both during and after injury. The aim of this mixed-method study was, therefore, to explore, in-depth, data on injury consequences and adolescent elite athletes' perceptions and experience of injury. Three hundred and forty adolescent elite athletes (age range 15-19), from 16 different sports, were bi-weekly monitored over 52 weeks using a valid questionnaire. Twenty athletes from the same cohort were interviewed in focus groups about injury experience and perceptions. The results show that the average bi-weekly prevalence of injury was 38.7% (95% CI 37.3-40.1), with 30.0% (n = 102) of the athletes injured for more than half of all reporting times. An overarching theme from the focus groups highlighted the risk among young athletes of a loss of identity while injured. The findings support several suggestions that may improve the rehabilitation process and enhance rehabilitation outcomes: (a) provide clear pathways to the medical team, (b) recognize the identity loss, (c) involve the injured athletes with the rest of the teammates and (d) educate athletes about how to interpret pain signals. Future research should explore and evaluate the effectiveness and generalization of such interventions.

High Injury Burden in Elite Adolescent Athletes: A 52-Week Prospective Study

CONTEXT

  Our understanding of the injury burden in elite adolescent athletes in most sports is limited or unknown because of the lack of prospective, long-term injury studies.

OBJECTIVE

  To describe injury patterns in terms of type, location, prevalence and incidence, recurrence, and severity grade; time to first injury; and prevalence of illness in elite adolescent athletes and to compare differences in injury data by sex and sport type.

DESIGN

  Cohort study.

SETTING

  Fifteen national sports high schools in Sweden.

PATIENTS OR OTHER PARTICIPANTS

  Participants were 284 elite adolescent athletes (boys = 147, girls = 137; median age = 17 years; 25th-75th percentile range = 16-18 years) competing at a high national level for their age in athletics (track and field), cross-country skiing, downhill skiing, freestyle skiing, handball, orienteering, or ski orienteering.

MAIN OUTCOME MEASURE(S)

  All athletes were monitored weekly over 52 weeks, using a validated online questionnaire to identify injury type, location, prevalence or incidence, and severity grade; time to first injury; and prevalence of illness.

RESULTS

  Among all athletes, 57.4% reported at least 1 new injury, whereas the 1-year injury prevalence was 91.6%. The overall injury incidence was 4.1/1000 hours of exposure to sport, and every week, on average, 3 of 10 (30.8%) elite adolescent athletes reported being injured. Of all injuries from which athletes recovered, 22.2% (n = 35) resulted in absence from normal training for at least 2 months. Female athletes reported higher ( P < .05) average weekly injury prevalence and substantial injury prevalence (injuries leading to a moderate or severe reduction in sport performance or participation or time loss) than male athletes.

CONCLUSIONS

  A considerable number of elite adolescent athletes were injured weekly, resulting in serious consequences for sport participation, training, or performance (or a combination of these). Appropriately designed interventions to prevent knee and foot injuries will target both the greatest number of injuries and the injuries with the most serious consequences in elite adolescent athletes.

Long-Term Athletic Development in Youth Alpine Ski Racing: The Effect of Physical Fitness, Ski Racing Technique, Anthropometrics and Biological Maturity Status on Injuries

Alpine ski racing is known to be a sport with a high risk of injuries. Because most studies have focused mainly on top-level athletes and on traumatic injuries, limited research exists about injury risk factors among youth ski racers. The aim of this study was to determine the intrinsic risk factors (anthropometrics, biological maturity, physical fitness, racing technique) for injury among youth alpine ski racers. Study participants were 81 youth ski racers attending a ski boarding school (50 males, 31 females; 9–14 years). A prospective longitudinal cohort design was used to monitor sports-related risk factors over two seasons and traumatic (TI) and overuse injuries (OI). At the beginning of the study, anthropometric characteristics (body height, body weight, sitting height, body mass index); biological maturity [status age at peak height velocity (APHV)]; physical performance parameters related to jump coordination, maximal leg and core strength, explosive and reactive strength, balance and endurance; and ski racing technique were assessed. Z score transformations normalized the age groups. Multivariate binary logistic regression (dependent variable: injury yes/no) and multivariate linear regression analyses (dependent variable: injury severity in total days of absence from training) were calculated. T-tests and multivariate analyses of variance were used to reveal differences between injured and non-injured athletes and between injury severity groups. The level of significance was set to p < 0.05. Relatively low rates of injuries were reported for both traumatic (0.63 TI/athlete) and overuse injuries (0.21 OI/athlete). Athletes with higher body weight, body height, and sitting height; lower APHV values; better core flexion strength; smaller core flexion:extension strength ratio; shorter drop jump contact time; and higher drop jump reactive strength index were at a lower injury risk or more vulnerable for fewer days of absence from training. However, significant differences between injured and non-injured athletes were only observed with respect to the drop jump reactive strength index. Regular documentation of anthropometric characteristics, biological maturity and physical fitness parameters is crucial to help to prevent injury in youth ski racing. The present findings suggest that neuromuscular training should be incorporated into the training regimen of youth ski racers to prevent injuries.

The Use of Body Worn Sensors for Detecting the Vibrations Acting on the Lower Back in Alpine Ski Racing

This study explored the use of body worn sensors to evaluate the vibrations that act on the human body in alpine ski racing from a general and a back overuse injury prevention perspective. In the course of a biomechanical field experiment, six male European Cup-level athletes each performed two runs on a typical giant slalom (GS) and slalom (SL) course, resulting in a total of 192 analyzed turns. Three-dimensional accelerations were measured by six inertial measurement units placed on the right and left shanks, right and left thighs, sacrum, and sternum. Based on these data, power spectral density (PSD; i.e., the signal's power distribution over frequency) was determined for all segments analyzed. Additionally, as a measure expressing the severity of vibration exposure, root-mean-square (RMS) acceleration acting on the lower back was calculated based on the inertial acceleration along the sacrum's longitudinal axis. In both GS and SL skiing, the PSD values of the vibrations acting at the shank were found to be largest for frequencies below 30 Hz. While being transmitted through the body, these vibrations were successively attenuated by the knee and hip joint. At the lower back (i.e., sacrum sensor), PSD values were especially pronounced for frequencies between 4 and 10 Hz, whereas a corresponding comparison between GS and SL revealed higher PSD values and larger RMS values for GS. Because vibrations in this particular range (i.e., 4 to 10 Hz) include the spine's resonant frequency and are known to increase the risk of structural deteriorations/abnormalities of the spine, they may be considered potential components of mechanisms leading to overuse injuries of the back in alpine ski racing. Accordingly, any measure to control and/or reduce such skiing-related vibrations to a minimum should be recognized and applied. In this connection, wearable sensor technologies might help to better monitor and manage the overall back overuse-relevant vibration exposure of athletes in regular training and or competition settings in the near future.

Injuries and illnesses in a cohort of elite youth alpine ski racers and the influence of biological maturity and relative age: a two-season prospective study

BACKGROUND

Studies on injuries and illnesses involving youth ski racers younger than 15 years are lacking in the literature. The aim of this study was prospectively to assess the incidence, prevalence, and severity of traumatic and overuse injuries, as well as illnesses of elite youth ski racers with regard to sex, biological maturity status, and relative age.

SUBJECTS AND METHODS

A prospective, longitudinal cohort design was used to monitor the anthropometrics, training characteristics, traumatic and overuse injuries, and illnesses of 82 elite youth ski racers (51 males, 31 females, age 9-14 years) over 2 consecutive years. The exact training exposure (skiing and athletic) was recorded. Relative age and estimated biological maturity status were assessed.

RESULTS

Relatively low injury incidence or prevalence (traumatic, 0.86/1,000 hours of training; overuse, 0.28/1,000 hours) and comparably high illness prevalence (2.4/athlete) were reported. The knee was the most commonly affected body part (traumatic injuries 36.5%, overuse injuries 82%). A high number of bone fractures were revealed (46%), while no stress fractures occurred; 66% of the illnesses were respiratory tract infections. No differences were found between males and females, the differing maturity groups, or relative age quartiles. Early-maturing athletes had comparably low traumatic and overuse-injury rates. Relatively younger athletes had low traumatic injury rates.

CONCLUSION

The injury-prevention measures implemented in the training process of youth ski racers seem to contribute to a low incidence of injury. Biological maturity status should be considered in the training process to prevent injuries in late-maturing athletes.

Anterior cruciate ligament injury/reinjury in alpine ski racing: a narrative review

The purpose of the present review was to: 1) provide an overview of the current understanding on the epidemiology, etiology, risk factors, and prevention methods for anterior cruciate ligament (ACL) injury in alpine ski racing; and 2) provide an overview of what is known pertaining to ACL reinjury and return to sport after ACL injury in alpine ski racing. Given that most of the scientific studies on ACL injuries in alpine ski racing have been descriptive, and that very few studies contributed higher level scientific evidence, a nonsystematic narrative review was employed. Three scholarly databases were searched for articles on ACL injury or knee injury in alpine ski racing. Studies were classified according to their relevance in relation to epidemiology, etiology, risk factors, and return to sport/reinjury prevention. Alpine ski racers (skiers) were found to be at high risk for knee injuries, and ACL tears were the most frequent diagnosis. Three primary ACL injury mechanism were identified that involved tibial internal rotation and anteriorly directed shear forces from ski equipment and the environment. While trunk muscle strength imbalance and genetics were found to be predictive of ACL injuries in development-level skiers, there was limited scientific data on ACL injury risk factors among elite skiers. Based on expert opinion, research on injury risk factors should focus on equipment design, course settings/speed, and athlete factors (eg, fitness). While skiers seem to make a successful recovery following ACL injury, there may be persistent neuromuscular deficits. Future research efforts should be directed toward prospective studies on ACL injury/reinjury prevention in both male and female skiers and toward the effects of knee injury on long-term health outcomes, such as the early development of osteoarthritis. International collaborations may be necessary to generate sufficient statistical power for ACL injury/reinjury prevention research in alpine ski racing.

Sports injuries and illnesses during the Granada Winter Universiade 2015

Objective

To analyse the incidence of diseases and injuries suffered by athletes participating in the 27th Winter Sports Universiade held in Granada, Spain.

Methods

The daily occurrence of injuries and diseases was registered at the point of first aid (Borreguiles, 2665 metres above sea level (masl)) and in the clinic of Pradollano (2017 masl), both in Sierra Nevada, as well as in medical services provided by the organising committee of Granada 2015 Universiade and located in sport pavilions in which indoor competitions are held.

Results

A total of 1109 athletes (650 men, 58.61%; 459 women, 41.39%). Nine diseases and 68 injuries were recorded. In total, the rate of injury was 6.13% (7.07% for men and 4.79% for women). The percentage of injury was highest in alpine skiing (10.34%) followed by freestyle skiing (8.62%). In relation to the time of exposure, freestyle skiing showed the shortest time of exposure (0.31 hours) before suffering an injury. Short track speed skating showed the longest exposure (9.80 hours), before suffering an injury. The most common anatomical areas of injury were the head, shoulder and knee (13.23%). Only nine diseases were suffered (four women and five men) of which six were infections, one was a friction burn, one was a lipothymy and one a cluster headache due to height.

Conclusion

In general, 6.13% of the athletes sustained at least one injury and 0.81% a disease, which is a much lower percentage than that recorded in similar events. The incidence of injuries and diseases varied among sport specialities.

Injuries among weightlifters and powerlifters: a systematic review

BACKGROUND

Olympic weightlifting and powerlifting are two sports that expose the body to great forces. Injury characteristics have not been systematically reviewed for these two growing sports.

OBJECTIVE

The purpose of this study was to systematically review the literature regarding various definitions of injuries used, injury localisation, the prevalence and incidence of injuries and the associated risk factors for injuries in weightlifting and powerlifting.

DESIGN

Systematic review.

DATA SOURCES

Five databases, PubMed, MEDLINE, SPORTDiscus, Scopus and Web of Science, were searched between 9 March and 6 April 2015.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies assessing injury incidence and prevalence in Olympic weightlifting and powerlifting were included. The Quality assessment tool for observational cohort and cross-sectional studies was used to assess methodological quality.

RESULTS

9 studies were included in the review. Injury was defined fairly consistently across studies. Most studies were of low methodological quality. The spine, shoulder and the knee were the most common injury localisations in both sports. The injury incidence in weightlifting was 2.4-3.3 injuries/1000 hours of training and 1.0-4.4 injuries/1000 hours of training in powerlifting. Only one retrospective study had analysed possible risk factors.

SUMMARY/CONCLUSIONS

The risk of injury in both sports were similar to other non-contact sports also requiring strength/power, but low compared to contact sports. The severity of injuries differed in the included studies. Since little has been studied regarding possible risk factors to injuries, further research is therefore warranted to explain why athletes get injured and how to prevent injuries.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42015014805.

Sidecut radius and the mechanics of turning-equipment designed to reduce risk of severe traumatic knee injuries in alpine giant slalom ski racing

BACKGROUND

There is limited empirical knowledge about the effect of ski geometry, particularly in the context of injury prevention in alpine ski racing. We investigated the effect of sidecut radius on biomechanical variables related to the mechanics of turning.

METHODS

During a field experiment, six European Cup level athletes skied on three different pairs of giant slalom (GS) skis varying in sidecut radii (30 m, 35 m and 40 m). Using a video-based three-dimensional (3D) kinematic system, a 22-point body segment model of the athletes was reconstructed in 3D, and the variables ground reaction force, centre of mass (COM) speed, COM turn radius, ski turn radius, edge angle, fore/aft position and skid angle were calculated.

RESULTS

While steering out of the fall line after gate passage, ground reaction force significantly differed between the 30 m and 40 m skis and between the 35 m and 40 m skis. These differences were mainly explainable by larger COM turn radii when skiing on the 40 m ski. During the same turn phase, significant differences in ski turn radius also were found, but there were no differences in edge angle, fore/aft position and skid angle.

SUMMARY

The sidecut-induced reduction in ground reaction force and the sidecut-induced increase in centre of mass and ski turn radius observed in this study provides indirect evidence of reduced self-steering of the ski. Self-steering plays a central role in the mechanism of anterior cruciate ligament rupture in alpine ski racing.

Back pain and MRI changes in the thoraco-lumbar spine of young elite Mogul skiers

Athletes have a higher prevalence of LBP and spinal abnormalities on Magnetic Resonance Imaging (MRI) compared to non-athletes. The objective of this study was to investigate the amount of spinal MRI abnormalities and the lifetime prevalence of low back pain (LBP) in 16 young elite Mogul skiers compared to 28 non-athletes in the corresponding age in a cross-sectional design. LBP was assessed by a questionnaire consisting of a part regarding previous or present back pain, the Oswestry disability index, and the EuroQol questionnaire. MRI examinations from Th5 to sacrum were conducted to evaluate spinal pathologies. The Mogul skiers had significantly more MRI abnormalities (like disc degeneration) in mean (7.25 vs 3.78, P < 0.023) compared to the controls. No significant difference was seen regarding the lifetime LBP prevalence between the groups (50% vs 42%, P = 0.555). No correlation could be found between disc degeneration and back pain in this study. Young elite Mogul skiers, compared to an age-matched control group of non-athletes, have an increased risk of developing spinal abnormalities potentially due to the different high loads that they are subjected to in their sport. Future relationship between the MRI abnormalities and LBP cannot be verified by this study design.

Injuries in Swedish floorball: a cost analysis

The epidemiology of sport injuries is well documented. However, the costs are rarely discussed. Previous studies have presented such costs in specific sports or localization. No study has investigated the costs related to injuries in elite floorball. Thus, the aim of this study was to estimate cost of injuries in Swedish elite floorball players. During 1 year, 346 floorball players were prospectively followed. All time-loss injures were recorded. The injured players were asked to complete a questionnaire regarding their costs tied to the injury. Mean costs were calculated by multiplying the total resource use with the collected unit costs and dividing these total costs with the number of injuries as well as players. The results showed that the average cost per injury increased with the level of severity and ranged from 332 to 2358 Euros. The mild and moderate overuse injuries were costlier than the corresponding traumatic injuries. However, the severe traumatic injuries were associated with higher costs than overuse injuries. Knee injuries were the costliest. Our results indicate that there are costs to be saved, if floorball injuries can be avoided. They should be of interest to decision makers deciding whether to invest in preventive interventions.