Knee Injuries in Downhill Skiers: A 6-Year Survey Study

An Innovative Compact System to Measure Skiing Ground Reaction Forces and Flexural Angles of Alpine and Touring Ski Boots

Skiing is a popular winter activity spanning various subdisciplines. Key hardware are ski boots, bindings, and skis, which are designed to withstand loads generated during skiing. Obtaining service forces and moments has always been challenging to researchers in the past. The goal of the present study is to develop and test a lightweight and compact measurement system to obtain the Ground Reaction Forces and the kinematics for ski touring and alpine ski. To do so, we adapted two six-axis load cells to fit into ski touring and alpine skis adding 20 mm height and 500 g weight to the original ski. To measure kinematics, we created custom angular sensors from rotary potentiometers. The system was tested indoors using a force platform and motion capture system before a first set of field tests in which the sensors were used to measure ski touring and alpine skis kinetics and kinematics. Validation trials showed maximum errors of 10% for kinetics and 5% for kinematics. Field tests showed data in agreement with previous findings on the topic. The results of this study show the possibility of using our system to study biomechanics and equipment performances for ski touring, alpine skiing, and possibly other disciplines.

A biomechanical analysis of skiing-related anterior cruciate ligament injuries based on biomedical imaging technology

Alpine skiing is an attractive but highly risky sport, and the anterior cruciate ligament (ACL) tear is one of the most common diagnoses of skiing-related injuries. To better prevent such injuries among athletes and recreational skiers, we developed a facile and reliable biomechanical method to analyze the differences between "right" and "wrong" movements during skiing and their impacts on ACL stress loading. Unlike those conventional methods that are very difficult to implement and time-consuming, our method was developed based on inverse dynamics analyses and video capture, which were much easier to implement in the real-world setting. It is shown that, with a harmful skiing action, the knee joint's maximum reaction force significantly increases compared to nonharmful skiing actions. The peak front-and-rear force increased from 1242 N to 3105 N, and the peak axial force increased from 1023 N to 3443 N, which significantly exceeded the maximum tensile loading (2000 N) in the ACL. Our results are proven to be reliable and consistent with findings obtained with other methods. This method may substitute current complex analytical methods and be easier to apply in sports-related injury-prevention applications.

[Winter sports nation Germany-injuries in alpine ski racing and mass sports : Statistics and injury mechanisms in winter sports and current trends in sports science]

BACKGROUND

In Germany, winter sports are very popular. About 7 million people go skiing at least 6 days per season. The German national winter teams won about 50% of the Olympic medals for the last several Olympic games. The downside of winter sports is the everlasting high number of injuries. This affects both professionals and the large number of amateur skiers.

TREND

The ASU institute of German insurances and skiing association find a decreasing number of injuries overall and a decreasing number of inpatient stays in hospitals. Still, the knee is the most injured region of the body. There is an increasing number of ACL ruptures within the knee lesions. The numbers in professional teams have been monitored with the FIS surveillance system since 2006. The highest rates of knee injuries (41.3%) are found with the ski world cup teams all over the world. The most common injury mechanism is the slip-catch mechanism. In current sports science examinations of the German skiing association there are extremely high forces of more than three times the body weight found on the body during skiing. Slalom skiing is especially affected. To understand the popular carving ski technology, you must know about the waist and the edge angle of the ski. There can be enormous forces coming along with the skis that can hardly be controlled by the skier.

[Knee injuries in winter sports]

Winter sports represent a relevant entity for knee injuries due to their great popularity. In alpine skiing and snowboarding, knee joint injuries are the most common affected body regions, while in ice hockey they are in third place. Various accident mechanisms lead to different injury types and severities. In addition to medial collateral ligament injuries, anterior cruciate ligament injuries are of particular importance. In professional sports, severe combination injuries are more common. Therapy is exemplified using the anterior cruciate ligament rupture. The gold standard is replacement ligament surgery. The return-to-sport rate of 80% for skiing and snowboarding is comparable to summer sports such as football, basketball or baseball. For ice hockey, it is even better. Prevention is possible by targeted training programs, but also by optimizing the equipment and its adjustment.

A Comparison of ACL Injury Risk, Ski Geometry and Standing Height Parameters between Skiers with Rented and with Owned Skis

to evaluate if ACL injuries are associated with recreational skiers using rented skis and whether individual factors, ski geometry parameters and standing heights differ between skiers who rented or owned skis. A retrospective questionnaire-based, case-control study of ACL-injured and uninjured recreational skiers was conducted during six winter seasons. Age, sex, body height, body weight, nationality, ownership of skis, skill level, risk-taking behavior, ski length, side-cut radius, widths of the tip, waist, and tail, and the standing heights at the front and rear components of the ski binding were assessed. Additionally, ratios between ski widths and a standing height ratio were calculated. Altogether, 1780 skiers (48.9% females) with a mean age of 39.2 ± 13.0 years participated, of whom 22.0% sustained an ACL injury and 32.3% rented skis. ACL injury risk was significantly associated with rented skis (OR 3.2, 95% CI 2.5-4.0). Compared to skiers using own skis, participants who rented skis were more likely female, smaller and lighter, tourists, less skilled and more cautious. In comparison to owned skis, rented skis showed significantly lower mean values in ski length, side-cut radius, ski widths, and for the three ski widths ratios. Additionally, standing heights were significantly lower while standing height ratio was higher for rented skis. Beside individual factors, equipment-related factors should be considered when renting skis in order to reduce ACL injury risk.

Ski-geometric parameters do not differ between ACL injury mechanisms in recreational alpine skiing

PURPOSE

It is not known so far if ski-equipment-related factors differ between the ACL injury mechanisms, potentially influencing the circumstances and causes of falling, finally resulting in ACL injury. More specifically focusing on the injury mechanisms will provide a deeper understanding of injury causation. The aim of the study was to evaluate whether ACL injury mechanisms in recreational alpine skiing differ with regard to ski-geometric parameters, self-reported circumstances and causes of accident and injury severity.

METHODS

Among a cohort of 392 ACL-injured (57.9% females) skiers, age, sex, height, weight, skill level, risk-taking behavior, circumstances and causes of accident, and ACL injury severity were collected by questionnaire. Additionally, patients had to recall their type of fall (ACL injury mechanism) by classifying forward and backward falls with and without body rotation. Ski length, side cut radius and widths of the tip, waist and tail were directly notated from the ski.

RESULTS

The forward fall with body rotation was the most common reported ACL injury mechanism (63%). A riskier behavior was associated with forward falls without body rotation. Ski-geometric parameters did not significantly influence the type of ACL injury mechanism. Regarding accident characteristics, catching an edge of the ski was more frequent (p < 0.001) the cause for forward falls (75% and 67%) when compared to the backward falls (46 and 15%) and executing a turn was the most frequent action in all falls (39-68%). A complete rupture of the ACL (66-70%) was more commonly reported than a partial tear (30-34%) among all four non-contact ACL injury mechanisms (n.s.).

CONCLUSION

In contrast to risk-taking behavior and accident characteristics, ski-geometric parameters and injury severity do not significantly differ between ACL injury mechanisms in recreational skiing. Thus, an individual skiing style seems to have more impact on ACL injury mechanisms than ski equipment. Future studies should evaluate potential effects of ski geometry on the incidence of ACL injury.

LEVEL OF EVIDENCE

III.

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.

Method to Investigate Multi-Axis Release Action of Ski Safety Bindings: A New Approach for Testing in Research and Development

The authors developed and elaborated on a new method to release ski bindings by utilizing an industrial robot to simulate release movement showing a spatial repeatability of ± 0.06 mm. The parametric programming of the release parameters gave free control while executing repeatable release tests. A series of different motion patterns were performed, on the one hand, to test the applicability of the setup to the simulation of motion patterns and, on the other, to check for the impact of the ski deformations like ski deflections within the range of −5 mm to −85 mm, on the safety bindings' release forces. As certain falling mechanisms are related to knee injury, which is the most common severe injury in alpine skiing, this testing method can be used to develop related displacement movements in future. This movements do not necessarily accord with the directional release mechanics of safety ski bindings. The authors specify the developed testing apparatus as device for force measurements in 3D with an accuracy of ± 0.5% in boot-sole-plane. The intention behind this development is to enable faster, more versatile and adaptive testing procedures in R&D.

In recreational alpine skiing, the ACL is predominantly injured in all knee injuries needing hospitalisation

PURPOSE

The knee joint still represents the most frequent anatomical injury location accounting for about one-third of all injuries in recreational alpine skiers. However, comprehensive information on current knee injury patterns in this populations is sparse.

METHODS

During the winter seasons 2016/17 and 2019/20, this retrospective questionnaire-based study was conducted in an Austrian sportclinic situated in a large ski area. Among a cohort of 282 recreational skiers (51.8% females), all injuries were diagnosed by the use of magnetic resonance imaging. Additionally, data were recorded on anthropometric characteristics, the perceived speed at the moment of injury, type of fall, physical fitness, self-reported skill level and risk-taking behaviour.

RESULTS

The anterior cruciate ligament (ACL) was injured in all knee injuries recorded. Of the total study sample, 64.5% (n = 182) were ACL injuries with concomitant injuries and about 35.5% (n = 100) were isolated ACL injuries, not involving any other structures of the knee joint. In general, most common concomitant injury diagnoses among ACL-injured recreational alpine skiers were injuries of the medial collateral ligament (MCL) (n = 92, 50.5%), medial meniscus (MM) (n = 73, 40.1%) and lateral collateral ligament (LCL) (n = 41, 22.5%). No significant differences regarding additionally recorded characteristics were found between ACL-injured individuals with concomitant injuries and those with isolated ACL injury.

CONCLUSIONS

Whereas, before the introduction of carving skis, the MCL was reported being the most common injured part of the knee, currently, the majority of knee injuries are ACL injuries accompanied by injury of other knee joint structures, i.e. the MCL, MM and LCL.

LEVEL OF EVIDENCE

Level III.

Wide Skis As a Potential Knee Injury Risk Factor in Alpine Skiing

Alpine skis with wider waist widths have recently become more popular. With such skis, the contact point of the ground reaction force during ski turns is displaced more medially from beneath the sole of the outer ski, which may present an increased risk of injury. The aim of this study was to investigate knee joint kinetics, kinematics, and lower limb muscle activation as a function of changes of the ski waist width in a laboratory setting. A custom skiing simulator was constructed to enable simulation of different ski waist widths in a quasi-static ski turn position. An optical system was used for capturing knee joint kinematics of the outer leg, whereas a force plate was used to determine the ground reaction force vector. The combination of both systems enabled values for external torques acting on the knee joint to be calculated, whereas electromyographic measurements enabled an analysis of knee flexor muscle activation. With respect to the outer ski, the knee joint external torques were independent of ski waist width, whereas knee joint external rotation and biceps femoris activation increased significantly with the increase of the ski waist width. Skier muscle and kinematics adaptation most probably took place to diminish the external knee joint torque changes when the waist width of the ski was increased. The laboratory results suggest that using skis with large waist widths on hard, frozen surfaces may change the load of knee joint surfaces. However, future research is needed to clarify if this may result in the increased risk of knee injury.

Mechanisms of Acute Knee Injuries in Bouldering and Rock Climbing Athletes

BACKGROUND

There is limited insight into the mechanisms of knee injuries in rock climbing and bouldering in noncompetitive and competitive athletes.

PURPOSE

To examine the traumatic mechanisms of injury, demographics, distribution, and severity of knee injuries in affected athletes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

During a 4-year period, we performed a retrospective multicenter analysis of acute knee injuries in competitive and noncompetitive climbing athletes. Traumatic mechanisms were inquired and severity levels, therapies, and outcomes recorded with visual analog scale, Tegner, Lysholm, and climbing-specific outcome scores.

RESULTS

Within the observation period, 71 patients (35% competitive athletes, 65% noncompetitive athletes) with 77 independent acute knee injuries were recorded. Four trauma mechanisms were identified: high step (20.8%), drop knee (16.9%), heel hook (40.3%), and (ground) fall (22.1%). The leading structural damage was a medial meniscal tear (28.6%), found significantly more often in the noncompetitive group. A specific climbing injury is iliotibial band strain during the heel hook position. Most injuries resulted from indoor bouldering (46.8%). Surgical procedures were predominantly necessary in noncompetitive climbers. One year after the injury, the Tegner score was 5.9 ± 0.8 (mean ± SD; range, 3-7); the Lysholm score was 97 ± 4.8 (range, 74-100); and the climbing-specific outcome score was 4.8 ± 0.6 (range, 2-5).

CONCLUSION

Increased attention should be placed on the climber's knee, especially given the worldwide rise of indoor bouldering. Sport-specific awareness and training programs for noncompetitive and competitive climbing athletes to reduce knee injuries should be developed, and sports medical supervision is mandatory.

A Prospective Injury Surveillance Study on Ski Touring

Background:

Ski touring is an outdoor sport with growing popularity in alpine countries. Information about injuries in ski touring is limited.

Purpose:

To determine injury rates, mechanisms, causes, and risk factors in ski touring.

Study Design:

Descriptive epidemiology study.

Methods:

Between November 2015 and May 2016, a total of 191 participants from the Alps region were prospectively tracked via personalized online questionnaires. Injury rates were calculated per 1000 hours of sports exposure. Risk factors were assessed per multivariate logistic regression analysis.

Results:

A total of 3900 ski tours were performed, with 10,955 hours and 4,108,503 m in height ascension (uphill) recorded. The overall injury rate was 2.5 injuries per 1000 hours of ski touring. A total of 27 injury-events were reported, of which 18 (67%) were classified as mild, 7 (26%) as moderate, and 2 (7%) as severe. Hands (28%) and knees (16%) were the most commonly involved anatomic regions. Most injuries were limited to the soft tissue, such as bruises (31%) and abrasions (18%). Significantly more injuries happened during the descent (n = 17; 63%) than during the ascent (n = 6; 22%) (odds ratio, 5.96; P = .004), while poor weather conditions, icy surface, and inattentiveness were the most often reported reasons for injury. Sidecountry ski touring was identified as the only significant independent risk factor for injury (P < .001).

Conclusion:

In this prospective injury surveillance study, the majority of ski touring injuries were mild and limited to the soft tissue. Ski touring injuries were more likely to happen during the descent of a tour, and sidecountry ski touring was the only significant independent risk factor for injury. Bad weather, icy surface, and inattentiveness were found to be the leading causes for an injury-event in this study.

Are Risk-Taking and Ski Helmet Use Associated with an ACL Injury in Recreational Alpine Skiing?

According to the risk compensation hypothesis, the use of a ski helmet might provide a false sense of security, resulting in a riskier behavior by skiing faster or more aggressively, which might lead to an increased injury risk. Injury of the anterior cruciate ligament (ACL) is a common diagnosis in downhill skiers. Thus, the aim of the study was to evaluate the potential impact of risk-taking and ski helmet use on ACL injury risk in recreational skiing. Eighty-two ACL injured and 446 uninjured skiers with a mean age of 37.3 ± 11.9 years (52% females) were surveyed during the winter season 2018/19 about age, sex, self-reported risk-taking behavior, self-reported skill level, perceived speed, and ski helmet use. Multiple regression analysis revealed that older age (OR: 1.3, 95% CI: 1.2–1.4), riskier behavior (OR: 5.4, 95% CI: 2.8–10.5), and lower skill level (OR: 6.7, 95% CI: 3.4–13.3) were found to be factors associated with ACL injury, while ski helmet use was not. In conclusion, no support for the risk compensation hypothesis was found with regard to ACL injuries. Therefore, we doubt that ski helmet use increases the risk for ACL injury and recommend wearing a ski helmet due to reported protective effects.

Alpine Skiing Injuries

Context:

Alpine skiing is a popular sport worldwide but has significant risk for injury. The epidemiology of skiing-related injuries has been described, which has led to the identification of risk factors for specific types of injuries.

Evidence Acquisition:

Pertinent literature from peer-reviewed publications was reviewed.

Study Design:

Clinical review.

Level of Evidence:

Level 5.

Results:

The adoption of international standards for ski-boot-binding systems has changed the profile of skiing-related injuries over time, as has the widespread use of helmets. An understanding of mechanisms of injury, risk factors, and preventative measures may decrease the incidence of skiing-related injuries.

Conclusion:

Advances in standards for skiing equipment have been effective at decreasing both the frequency and severity of skiing-related injuries, but additional efforts are required to improve the safety of the sport.

Effects of 8-Week Complex Balance Training in Young Alpine Skiers: A Pilot Study

Objectives

The purpose of this study was to determine the effects of an 8-week complex balance training program on dynamic balance in skiers according to the new balance training protocol.

Design

Intervention study, comprising 8 weeks of core stability, plyometric, balance, and stretching exercises.

Participants

Ten young skiers volunteered to take part in this study (average age, height, and body mass were 16,44 +/- 1,07 years, 172,76+/-8,84 cm, and 67,4 11,44 kg, respectively (mean +/- SD)).

Main Outcome Measures

Subjects' dynamic balance performance was assessed and retested after training completion with the use of dynamic balance measurement within the Optojump Next System.

Results

The results of 8-week complex balance training showed significant improvements for jump height (H) and flight time (FT) for the left leg and jumping area in both legs.

Conclusion

The complex balance training program improved parameters of dynamic stability in young skiers and led to decreased asymmetry between lower extremities.

Hyperextension injuries of the knee: do patterns of bone bruising predict soft tissue injury?

OBJECTIVE

To establish whether patterns of soft tissue injury following knee hyperextension are associated with post-traumatic 'bone bruise' distribution.

MATERIALS AND METHODS

Patients with a knee MRI within one year of hyperextension injury were identified at our institution over a 7 year period. MRIs, plain radiographs and clinical details of these patients were reviewed.

RESULTS

Twenty-five patients were identified (median time from injury to MRI = 24 days). The most common sites of bone bruising were the anteromedial tibial plateau (48%) and anterolateral tibial plateau (44%). There were high rates of injury to the posterior capsule (52%), ACL (40%) and PCL (40%) but lower rates of injury to the menisci (20%), medial and lateral collateral ligaments (16%) and posterolateral corner (16%). Anterior tibial plateau oedema and rupture of the posterior capsule predicted cruciate ligament injury [OR = 10.5 (p = 0.02) and 24.0 (p = 0.001) respectively]. Whilst anterolateral tibial plateau oedema strongly predicted PCL injury [OR = 26.0, p = 0.003], ACL injury was associated with a variable pattern of bone bruising. Meniscal injury was unrelated to the extent or pattern of bone bruising. 5 out of 8 patients with a 'double sulcus' on the lateral radiograph had ACL injury. The presence of a double sulcus showed significant association with anteromedial kissing contusions (OR = 7.8, p = 0.03).

CONCLUSIONS

Following knee hyperextension, bone bruising patterns may be associated with cruciate ligament injury. Other structures are injured less frequently and have weaker associations with bone bruise distribution. The double sulcus sign is a radiographic marker that confers a high probability of ACL injury.

Comprehensive Review of Skiing and Snowboarding Injuries

Skiing and snowboarding have increased in popularity since the 1960s. Both sports are responsible for a substantial number of musculoskeletal injuries treated annually by orthopaedic surgeons. Specific injury patterns and mechanisms associated with skiing and snowboarding have been identified. No anatomic location is exempt from injury, including the head, spine, pelvis, and upper and lower extremities. In these sports, characteristic injury mechanisms often are related to the position of the limbs during injury, the athlete's expertise level, and equipment design. Controversy exists about the effectiveness of knee bracing and wrist guards in reducing the incidence of these injuries. Understanding these injury patterns, proper training, and the use of injury prevention measures, such as protective equipment, may reduce the overall incidence of these potentially debilitating injuries.

What Makes a Successful Survey? A Systematic Review of Surveys Used in Anterior Cruciate Ligament Reconstruction

PURPOSE

To characterize and assess the methodological quality of patient and physician surveys related to anterior cruciate ligament reconstruction, and to analyze the factors influencing response rate.

METHODS

The databases MEDLINE, Embase, and PubMed were searched from database inception to search date and screened in duplicate for relevant studies. Data regarding survey characteristics, response rates, and distribution methods were extracted. A previously published list of recommendations for high-quality surveys in orthopaedics was used as a scale to assess survey quality (12 items scored 0, 1, or 2; maximum score = 24).

RESULTS

Of the initial 1,276 studies, 53 studies published between 1986 and 2016 met the inclusion criteria. Sixty-four percent of studies were distributed to physicians, compared with 32% distributed to patients and less than 4% to coaches. The median number of items in each survey was 10.5, and the average response rate was 73% (range: 18% to 100%). In-person distribution was the most common method (40%), followed by web-based methods (28%) and mail (25%). Response rates were highest for surveys targeted at patients (77%, P < .0001) and those delivered in-person (94%, P < .0001). The median quality score was 12/24 (range = 8.5/24 to 21/24). There was high inter-rater agreement using the quality scale (intraclass correlation coefficient = 0.92), but there was no correlation with the response rate (Rho = -0.01, P = .97).

CONCLUSIONS

Response rates vary based on target audience and distribution methods, with patients responding at a significantly higher rate than physicians and in-person distribution yielding significantly higher response rates than web or mail surveys.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV studies.

Factors associated with self-reported failure of binding release among ACL injured male and female recreational skiers: a catalyst to change ISO binding standards?

BACKGROUND

Female recreational skiers have twice the rate of knee injuries and three time the rate of ACL injuries compared with their male counterparts. Female skiers suffering from a knee injury reported a significantly higher proportion of failure of binding release than knee injured male skiers.

PURPOSE

To evaluate factors associated with failure of binding release among ACL injured male and female recreational skiers.

STUDY DESIGN

Cohort study.

METHODS

Among a cohort of 498 recreational skiers (68% females) suffering from an ACL injury (complete rupture or partial rupture), age, sex, height, weight, self-reported skill level and self-reported risk taking behaviour, gear origin, ski length, date of last binding adjustment, perceived speed at the moment of injury, type of fall, and failure of binding release of the ski of the injured knee, were collected by questionnaire.

RESULTS

Failure of binding release was reported within 78% of cases and was significantly higher for females compared to males (83 vs 66%, p<0.001) with an adjusted OR of 2.7 (95% CI 1.7 to 4.4). A higher perceived speed at the moment of injury was significantly associated with a decreasing proportion of failure of binding release. A slow perceived speed was independently associated with failure of binding release (adjusted OR 2.0; 95% CI 1.2 to 3.5). There was a significantly higher proportion of failure of binding release during backward falling compared to forward falling (87 vs 72%, p=0.002); similarly, a higher proportion of failure of binding release occurred in cases of complete rupture compared with a partial tear of the ACL (81 vs 64%, p=0.001), respectively.

CONCLUSIONS

Among this cohort of ACL-injured skiers, failure of binding release was significantly associated with female sex, a slow perceived speed at the moment of injury and complete rupture of the ACL.

The Waist Width of Skis Influences the Kinematics of the Knee Joint in Alpine Skiing

Recently alpine skis with a wider waist width, which medially shifts the contact between the ski edge and the snow while turning, have appeared on the market. The aim of this study was to determine the knee joint kinematics during turning while using skis of different waist widths (65mm, 88mm, 110mm). Six highly skilled skiers performed ten turns on a predefined course (similar to a giant slalom course). The relation of femur and tibia in the sagital, frontal and coronal planes was captured by using an inertial motion capture suit, and Global Navigation Satellite System was used to determine the skiers' trajectories. With respect of the outer ski the knee joint flexion, internal rotation and abduction significantly decreased with the increase of the ski waist width for the greatest part of the ski turn. The greatest abduction with the narrow ski and the greatest external rotation (lowest internal rotation) with the wide ski are probably the reflection of two different strategies of coping the biomechanical requirements in the ski turn. These changes in knee kinematics were most probably due to an active adaptation of the skier to the changed biomechanical conditions using wider skis. The results indicated that using skis with large waist widths on hard, frozen surfaces could bring the knee joint unfavorably closer to the end of the range of motion in transversal and frontal planes as well as potentially increasing the risk of degenerative knee injuries. Key pointsThe change in the skis' waist width caused a change in the knee joint movement strategies, which had a tendency to adapt the skier to different biomechanical conditions.The use of wider skis or, in particular, skis with a large waist width, on a hard or frozen surface, could unfavourably bring the knee joint closer to the end of range of motion in transversal and frontal planes as well as may potentially increase the risk of degenerative knee injuries.The overall results of the abduction and internal rotation in respect to turn radii and ground reaction forces indicated that the knee joint movements are likely one of the key points in alpine skiing techniques. However, the skiing equipment used can still significantly influence the movement strategy.