Injury risk factors among telemark skiers

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.

Injuries in World Cup telemark skiing: a 5-year cohort study

BACKGROUND

There are limited data on injuries in World Cup (WC) telemark skiing.

OBJECTIVE

To describe the injury incidence and injury pattern seen among WC telemark skiers during the competitive season.

METHODS

We interviewed all WC athletes (or their coach, if the athlete was not present) at the end of five winter seasons from 2008 until 2013. All acute injuries occurring in the competitive season that required the attention of medical personnel were registered. Exposure was calculated based on the official International Ski Federation (FIS) results database.

RESULTS

149 acute injuries were registered during 565 WC skier seasons. The absolute injury incidence was 26.4 injuries per 100 athletes per season (95% CI 22.1 to 30.6), higher for females than males (risk ratio (RR) 1.49, 95% CI 1.07 to 2.08). During the FIS WC competitions, 69 injuries were registered, corresponding to a relative incidence of 8.2 injuries per 1000 runs (95% CI 6.3 to 10.1). The most frequently injured body part was the knee (21%) followed by the hand-finger-thumb (20%), ankle (13%) and shoulder/clavicle (13%). The absolute risk of knee and shoulder/clavicle injuries was higher for females versus males (RR for knee injuries 2.72, 95% CI 1.35 to 5.51; RR for shoulder/clavicle injuries 2.55, 95% CI 1.06 to 6.14). No differences were detected in the injury incidence between disciplines.

CONCLUSIONS

Female telemark skiers are at 1.5 times greater risk of injury than male skiers. The most commonly injured body part was the knee. The risk of knee and shoulder/clavicle injuries was higher for female athletes than for male athletes.

Military exercises, knee and ankle joint position sense, and injury in male conscripts: a pilot study

CONTEXT

The high incidence of lower limb injuries associated with physical exercises in military conscripts suggests that fatigue may be a risk factor for injuries. Researchers have hypothesized that lower limb injuries may be related to altered ankle and knee joint position sense (JPS) due to fatigue.

OBJECTIVE

To evaluate if military exercises could alter JPS and to examine the possible relation of JPS to future lower extremity injuries in military service.

DESIGN

Cohort study.

SETTING

Laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 50 male conscripts (age = 21.4 ± 2.3 years, height = 174.5 ± 6.4 cm, mass = 73.1 ± 6.3 kg) from a unique military base were recruited randomly. main outcome measure(s): Participants performed 8 weeks of physical activities at the beginning of a military course. In the first part of the study, we instructed participants to recognize predetermined positions before and after military exercises so we could examine the effects of military exercise on JPS. The averages of the absolute error and the variable error of 3 trials were recorded. We collected data on the frequency of lower extremity injuries over 8 weeks. Next, the participants were divided into 2 groups: injured and uninjured. Separate 2 × 2 × 2 (group-by-time-by-joint) mixed-model analyses of variance were used to determine main effects and interactions of these factors for each JPS measure. In the second part of the study, we examined whether the effects of fatigue on JPS were related to the development of injury during an 8-week training program. We calculated Hedges effect sizes for JPS changes postexercise in each group and compared change scores between groups.

RESULTS

We found group-by-time interactions for all JPS variables (F range = 2.86-4.05, P < .01). All participants showed increases in JPS errors postexercise (P < .01), but the injured group had greater changes for all the variables (P < .01).

CONCLUSIONS

Military conscripts who sustained lower extremity injuries during an 8-week military exercise program had greater loss of JPS acuity than conscripts who did not sustain injuries. The changes in JPS found after 1 bout of exercise may have predictive ability for future musculoskeletal injuries.

Self-estimation of ability among skiers and snowboarders in alpine skiing resorts

Skiing ability is thought to be an important risk factor for injuries, but the best method to classify skiing ability is not known. The objective of this study was to validate five different questions designed to self-report skiing ability for ski injury surveillance. To this end 512 alpine skiers, Telemark skiers, snowboarders and skiboarders were asked to selfestimate their skiing ability using five different questions based on skiing skill, piste difficulty, turning technique, skiing experience and falling frequency, each with four categories. The participants then made a test run to test their skiing ability. Observed and self-reported skiing ability were compared using kappa statistics. The correlation between observed and self-reported skiing ability was low to fair, with kappa values of 0.34 for skiing skill), 0.33 for piste difficulty, 0.38 for turning technique, 0.26 for experience and 0.16 for falling frequency. However, the sensitivity and specificity for each of the questionnaires in discriminating between individuals in the poorest skiing ability category on the test and the rest of the group was relatively good (skiing skill: sensitivity 75%, specificity 91%; piste difficulty 68, 96%; turning technique 75, 91%; experience 75, 90%; falling frequency 61, 97%). The results show that the capacity to self-assess skiing ability is limited, but estimation based upon turning technique or skiing skill seem to be best methods for epidemiological studies on injuries in snow sports.

The effects of ankle bracing on motion of the knee and the hip joint during trunk rotation tasks

BACKGROUND

The use of prophylactic ankle braces is common during athletic activities since the ankle is one of the most commonly injured joints. Past studies have focused on the effects of ankle braces on ankle movement restriction, preventing injuries, proprioception, balance and athletic performance. However, the influence of ankle restriction on other joints has not been studied. The constraint of ankle movement may lead to an increased loading on the knee joint, which could be a potential risk of knee injuries during athletic activities. The primary goal of the current study was to determine quantitatively the effect of an ankle brace on the knee axial rotation during two different trunk turning tasks.

METHODS

Ten healthy subjects performed trunk turning movements while standing on one leg: turning sideways to catch a ball and turning sideways to touch a target with the shoulder. The tasks were performed with and without an ankle brace worn on the supporting leg. The trunk axial rotation in reference to the floor and three dimensional joint angular motions of the ankle, knee and hip were determined.

FINDINGS

The use of an ankle brace resulted in reduced trunk axial rotation during the ball catching tasks, and increased knee axial rotation during the target touching tasks.

INTERPRETATION

The results of this study showed that the effect of the ankle brace on the knee axial rotation depended on the context of the tasks performed. Under situations that required forceful trunk turning movement while standing on a single leg, the ankle braces may cause an increase in the knee axial rotation indicating higher risk of knee injury.

Development of a new activity score for the evaluation of ankle instability

BACKGROUND

Tegner and Lysholm described their generally acknowledged activity score in 1985. It was originally tested for knee ligament injuries, but for the past 17 years it has been used for other joint evaluations as well. The development of already existing and new kinds of sports, differences between knee and ankle loading, and different injury rates provided reasons for developing an ankle-specific activity score.

HYPOTHESIS

The new score should have a higher reliability, validity, and sensitivity than the Tegner score when evaluating ankle-related activity changes.

STUDY DESIGN

Methodological study.

METHODS

Fifty-three sports, 3 working activities, and 4 general activities were inserted into a 0-to-10 category system based on the rankings of a 7 x 2-point pre-evaluation system, followed by a direct comparison with the Tegner score and reliability, validity, and sensitivity testing on 2 different patient populations.

RESULTS

In direct comparison, there is a strong overall correlation of the 2 activity-scoring systems (r = 0.7565), but the ankle activity score proved to be different from the Tegner score in the higher categories, especially in the top 4 ankle score categories (r = 0.1450). Further tests demonstrated the high reliability (1.00) of the new score. Analysis of variance proved that activity changes measured by the ankle score correspond well to the difference between the patients' subjective results and their Karlsson functional scores (P =.0119). This is not the case when we measure ankle activity changes using the knee-specific Tegner score (P =.0987). Furthermore, ankle score differences spread over a wider range (-1.18 +/- 2.12) than did Tegner score differences (-0.68 +/- 1.29), which demonstrates the higher sensitivity of the new score.

CONCLUSIONS

Based on these results, the new ankle activity score could be a better complement in the complex evaluation of ankle instability.

The effect of local and general fatigue on knee proprioception

PURPOSE

The purpose of this study was to compare the effects of local and general fatigue loads on knee proprioception.

TYPE OF STUDY

Experimental controlled study.

METHODS

Proprioception of the knee joint was evaluated by measuring absolute angular error (AAE) at matching defined index angles before and after 2 different types of fatigue protocols (local load and general load) in 27 healthy male volunteers. Local load was provided with maximum isokinetic knee flexion-extension on the isokinetic dynamometer, and general load was 5 minutes running on a treadmill.

RESULTS

After local load, a significant decrease in peak torque of knee flexors and extensors was found, but no significant change in AAE was seen. In contrast, after general load, a significant increase of AAE was noted without significant muscle weakness.

CONCLUSIONS

The different results in previous studies evaluating the effect of fatigue on knee proprioception may have been affected by the difference of fatigue protocols, whether local or general load. Although local load was intended to produce local fatigue of the knee, which may cause dysfunction of muscle mechanoreceptors, general load may have produced general fatigue and affected other mechanisms in the proprioceptional pathway. The results of the present study suggest that decreased reproduction ability after general load is not due to the loss of peripheral afferent signals, but to other factors, especially deficiency of central processing of proprioceptive signals.

CLINICAL RELEVANCE

To prevent knee injury caused by fatigue-induced proprioceptional decline, muscle endurance training alone is not enough, and neuromuscular training, including central motor programming, is essential.

Snow sports injuries in Scotland: a case-control study

OBJECTIVES

To examine the incidence and patterns of snow sports injuries at the three largest commercial ski areas in Scotland and to identify factors associated with injury risk.

METHODS

A prospective case-control study of all injured people at Cairngorm, Glenshee, and Nevis Range ski areas during the 1999-2000 winter season. Personal details, snow sports related variables, diagnosis, and treatment were recorded. Control data were collected at random from uninjured people at all three areas. Random counts were performed to analyse the composition of the on slope population.

RESULTS

A total of 732 injuries were recorded in 674 people. Control data were collected from 336 people. The injury rate for the study was 3.7 injuries per 1000 skier days. Alpine skiers comprised 67% of the on slope population, snowboarders 26%, skiboarders 4%, and telemark skiers 2%. Lower limb injuries and sprains were the commonest injuries in alpine skiers and skiboarders. Snowboarders sustained more injuries to the upper limb and axial areas. Skiboarders and snowboarders had a higher incidence of fractures. After adjustment for other variables, three factors were all independently associated with injury: snowboarding (odds ratio (OR) 4.07, 95% confidence interval (CI) 1.65 to 10.08), alpine skiing (OR 3.82, CI 1.6 to 9.13), and age <16 years (OR 1.9, CI 1.14 to 3.17). More than five days of experience in the current season and at least one week of experience in total had a protective effect against injury.

CONCLUSIONS

Despite a change in the composition of the alpine population at Scottish ski areas, the overall rate and pattern of injury are similar to those reported previously in comparable studies. Several factors are associated with an increased risk of injury and should be targeted in future injury prevention campaigns.