Reduction of injuries in downhill skiing by use of an instructional ski-video: a prospective randomised intervention study

Despite various attempts at prevention, injury in downhill skiing continues to be a worrisome recreational problem. The purpose of this study was to test the effect of an instructional ski video on the behaviour and injuries of 763 downhill skiers. They were enrolled in two study groups, based on whether or not an instructional video had been shown in their bus on the way to a skiing resort. The video focussed on information regarding how to get started in downhill skiing and injury prevention. The outcome parameters, behaviour (binding test and adjustment), injury risk, type and consequence, were registered on the return trip 8 days later by a questionnaire. In the intervention group all outcome parameters changed significantly. The binding test was performed by 86% in the intervention group and by only 59% in the control group (P < 0.05). Adjustment of the bindings was done by 22% in the intervention group vs 14% in the control group. Regarding injury risk, 205 injuries were seen in 158 persons (20.7%) which is 26 injured skiers per 1000 skier-days and 33.6 injuries per 1000 skier-days. In the intervention group 16% of all skiers were injured vs 23% in the control group, yielding a reduction in injury risk of 30% (P < 0.05). Injuries caused by falls were seen in 12.6% in the intervention group vs 16.2% in the control group (P < 0.05). Injuries caused by collision were seen in 6% of the intervention group vs 12% in the control group (P < 0.05). The overall mean injury risk was 16 injuries per 1000 falls. Knee injuries made up 32.6% of the total. For inexperienced skiers the knee injury risk was significantly lower if the bindings had been tested (P < 0.05). Therefore, an instructional ski video can change the behaviour of downhill skiers and reduce the injury risk and consequences significantly. Received: 26 March 1997 Accepted: 20 December 1997     

Personal and environmental factors in relation to injury risk in downhill skiing

A case-control study was conducted among Dutch downhill skiers. This article presents data on the circumstances of the accident leading to injury and on personal and environmental risk factors for both cases (n = 572) and controls (n = 576). Most accidents (84%) happened on the pistes and ski lifts were involved in about 6% of them. Bad condition of the ski run (30%) and lost balance (24%) were the direct causes most frequently mentioned. Risk seemed to be constant for particular days and moments of the day. Injury risk for the individual appeared to rise with increasing duration of exposure, although very small durations had an elevated risk as well. A relatively low risk was observed for skiers who reported to be only moderately rested (OR = 0.4) and for those who admitted a certain fear of having a ski accident (OR = 0.6). A relatively high risk was observed for the presence of icy spots (OR = 1.4), while poor visibility (OR = 0.4), the presence of clouds (OR = 0.5), and perceived coldness (OR = 0.5) were associated with a relatively low injury risk. No recommendations for prevention can be based on these results. Most factors mentioned are not open to manipulation and further quantification should involve prospective study designs and independent measurements of these factors.     

Soccer injuries and their mechanisms: a prospective study

In order to study the incidence and mechanisms of injury in soccer and to recommend prophylactic measures, 180 players in a senior male soccer division were followed prospectively for 1 yr. Attendance records for games and practice sessions were kept, and all injuries were examined and treated by the same orthopaedic surgeon. One hundred twenty-four players incurred 256 injuries, mostly sprains and strains of the lower extremities. Of these, 62% were considered minor with ankle sprains being the most common (17%), while 11% were considered major with knee ligament sprains being the most frequent (32%). Overuse injuries were most frequent in the preseason training period. Traumatic leg injuries involved players with inadequate or no shin guards. Of the traumatic knee injuries, 11 of 18 (61%) occurred during a collision; non-contact knee injuries were frequently seen in those players with a history of knee injury and existing instability. Study of injury sequence disclosed that a minor injury was often followed within two months by a major one. In addition, with severe injuries incurred during fouls, the individual causing the penalty was injured. This prospective study suggested that those with knee instability and those allowed to resume play with poorly rehabilitated or clinically unhealed injuries are more apt to sustain further injury. Some injuries can be avoided by using better equipment and by observance of the rules.     

Relationship between jump landing kinematics and peak ACL force during a jump in downhill skiing: A simulation study

Recent data highlight that competitive skiers face a high risk of injuries especially during off‐balance jump landing maneuvers in downhill skiing. The purpose of the present study was to develop a musculo‐skeletal modeling and simulation approach to investigate the cause‐and‐effect relationship between a perturbed landing position, i.e., joint angles and trunk orientation, and the peak force in the anterior cruciate ligament (ACL) during jump landing. A two‐dimensional musculo‐skeletal model was developed and a baseline simulation was obtained reproducing measurement data of a reference landing movement. Based on the baseline simulation, a series of perturbed landing simulations (n = 1000) was generated. Multiple linear regression was performed to determine a relationship between peak ACL force and the perturbed landing posture. Increased backward lean, hip flexion, knee extension, and ankle dorsiflexion as well as an asymmetric position were related to higher peak ACL forces during jump landing. The orientation of the trunk of the skier was identified as the most important predictor accounting for 60% of the variance of the peak ACL force in the simulations. Teaching of tactical decisions and the inclusion of exercise regimens in ACL injury prevention programs to improve trunk control during landing motions in downhill skiing was concluded.     

Salzburg Skiing for the Elderly Study: study design and intervention--health benefit of alpine skiing for elderly

The aim of this study was to monitor the long-term effects of skiing on the health-related parameters of older individuals. This paper describes the overall study design and the intervention phase. The study utilized a randomized control group design consisting of an intervention group (n=27; age: 67.5 ± 2.8 years) and a control group (n=20; age: 67.3 ± 4.4 years). Parameters of interest were measured during pre-, post- and retention-test sessions. The intervention phase lasted for 12 weeks, with an average of 28.5 days of guided skiing. Daily heart rate (HR) profiles and global positioning system data throughout the ski day were recorded. Perceived exertion levels as well as mood status of the subjects were recorded regularly. The intervention group completed an average of 4885 vertical meters of downhill skiing, with a total skiing distance of 40.5 km/day. In the skiing phase, the average physiological load was 72.4 ± 8.9% of HR(max) . The dimension "positive mood" referred to skiing (on scale of 0-10), with an average value of 7.6 ± 1.7 after skiing. The dimension of "negative mood" was much less pronounced, having a mean of 1.1 ± 1.5 after skiing. Two subjects suffered injuries while falling during skiing. The effects of the 12-week skiing intervention on the tested parameters will be reported in the following papers of this supplementum.     

Back injuries to fast bowlers in cricket: a prospective study.

Eighty-two high performance young male fast bowlers (mean age 16.8 years) were tested immediately prior to the season for selected kinanthropometric and physiological data. Subjects were also filmed both laterally (200 Hz) and from above (100 Hz) while bowling so that their front foot impacted a force platform during the delivery stride. The players then completed a log book over the ensuing season that detailed their training and playing programmes. All cricket related injuries over this season were assessed by a sports physician who used computerized tomography to assist in the diagnosis of spinal injuries. At the completion of this season the players were grouped according to their injury status (Group 1--bony injury to a vertebra; Group 2--soft tissue injury to the back that caused the player to miss at least one game, and Group 3--no injuries). A one-way analysis of variance was used to identify if any variables were significantly (P less than 0.05) different between the three groups, and a Scheffe post hoc comparison was used to determine which groups were significantly different. Eleven per cent of the players sustained a stress fracture to a vertebra(e) (L4 to S1), while 27 per cent sustained a soft tissue injury to the back. Bowlers with a low longitudinal foot arch were more likely to develop a stress fracture than those with a high arch. Shoulder depression and horizontal flexion strength for the preferred limb and quadriceps power in the non-preferred limb were also significantly related to back injuries. Results suggest that bowlers with the above physical characteristics, who bowl with these biomechanical techniques for extended periods, are predisposed to back injuries.     

Sports injuries in floorball: a prospective one-year follow-up study

Two hundred and ninety-five licensed floorball players from Finnish premier to fifth division were observed prospectively for one season to study the incidence, nature, causes and severity of floorball injuries. During the study period, 100 out of the 295 (34 %) players sustained 120 injuries. Thirty-seven percent (73/199) of the male players and 28 % (27/96) of the females suffered from an injury. The injury rate was 1.0 per 1000 practice hours for both sexes. The injury rates per 1000 game hours were 23.7 for men and 15.9 for women. One hundred injuries (83 %) were acute and the remaining 20 (17 %) were overuse injuries. Sprain was the most common type of injury in men while overuse injuries were the most frequent injury type in women. The lower extremity was involved in 62 %, spine or trunk in 19 % and upper extremity in 10 % of the injuries. The most commonly injured sites were the knee and ankle (22 % and 20 % of all injuries), followed by head and neck (8 %). In both sexes the majority of injuries were minor, level II, injuries. Ten of the knee injuries (38 %) were serious, level IV injuries, of which seven were ACL ruptures. In conclusion, the individual risk of injury in floorball is relatively low in game practice while rather high during the game itself. Before initiation of clinical trials on prevention of floorball injuries, an exact knowledge of the risk factors and mechanisms of floorball injuries are needed.     

Volleyball injuries presenting in casualty: a prospective study.

During 1986, all sports injuries (n = 5222) were prospectively recorded at the two casualty departments in Arhus, Denmark. Volleyball injuries (n = 278) accounted for 5.3% of all sports injuries. An evaluation of the rehabilitation period and the consequences of the injuries was undertaken by questionnaire three years after the injury. The injury incidence was 1.9 injuries/1000 inhabitants/year. Hand, finger, and ankle sprains were the most frequent injuries. Female players had significantly more hand/finger injuries than male players, who incurred more ankle/foot injuries. Knee (6%) and ankle injuries (31%) were responsible for the longest duration of absence from sports participation. There were relatively few chronic injuries. The study suggests the need to enhance prophylactic measures with regard to blocking and overhand pass techniques, in order to reduce the number and extent of ankle and hand/finger injuries.     

Musculoskeletal injuries in the Norwegian National Ballet: a prospective cohort study

The purpose of the present study was to determine the incidence of musculoskeletal injuries among professional ballet dancers in the Norwegian National Ballet. A 19 weeks prospective study with registration and clinical assessment of dancers with injuries was conducted. Medical staff working for the National Ballet registered incidence of injuries. In addition the dancers filled out a questionnaire about previous injuries, their work situation, and factors they believed increased the risk of injuries. Of the 41 dancers (80% response rate), 31 dancers experienced one injury or more. The majority of injuries involved foot and ankle. Twenty-two per cent of the injuries were acute injuries. Seventy-five per cent of the injuries were soft tissue injuries. Most injuries were of mild to moderate severity. Sixteen per cent of the injuries resulted in absence from work. Factors, the dancers believed were associated with risk of injuries were related to training, organizational factors and environmental factors. Seventy-eight per cent of the dancers experienced "negative" stress at work. Sixty-four per cent experienced that they had little influence on their work conditions. This study showed, however, no significant association between these psychological factors and musculoskeletal injuries. It is concluded that there is a high incidence of musculoskeletal injuries in the Norwegian National Ballet.     

The effect of foot setting on kinematic and kinetic skiing parameters during giant slalom: A single subject study on a Paralympic gold medalist sit skier

ObjectivesAim was to study the effect of monoski foot adjustment on kinematic and kinetic skiing parameters expressing sit skier’s technique.DesignIndependent variable was skier position with respect to bindings, acting on position of monoski foot sole clamp. Front (F), Mid (M) and Rear (R) settings changed with intervals of 20 mm. Course time, skiing speed, Ground Reaction Forces (GRFs) magnitude and point of application and damper stroke were dependent variables.MethodA Paralympic monoski was equipped with a dynamometric binding plate measuring GRFs, roll and pitch moments. A Paralympic gold medalist (LW10-1) was involved. Skier trajectory and gates location were measured by a differential global navigation satellite system (GNSS) in steep and medium steep slope portions. The athlete performed two giant slalom runs for each foot setting the same day.ResultsGRFs, center of pressure (COP) and variations with foot settings were measured. Peaks values up to 3.36 times the total weight and damper speed of 675 mm/s in compression were found. Fastest runs, highest peak loads and best subjective ratings were recorded with F setting. COP mean values were influenced by foot adjustments. GRFs in left turns were 54% larger than in the right turns with F setting on steep slope.ConclusionsThe monoski foot adjustment influenced kinematic and kinetic skiing, with F setting showing best results. A skier asymmetric behavior between right and left turning was discovered. Findings can support the design of monoskis for a wider dissemination of Paralympic alpine sit skiing.     

Skiing and snowboarding injuries: a review with a focus on mechanism of injury

Skiing and snowboarding are ever increasing in popularity, with participation across a wide patient demographic. This article focuses on common skiing and snowboarding injuries, with an emphasis on unique mechanisms of injury and discusses the contribution of equipment design to evolving patterns of injury. Knowledge of mechanisms of injury and injury patterns allows a targeted approach to the interpretation of imaging modalities in this patient population.     

Epidemiology and traumatology of injuries in elite soccer: a prospective study in Finland

A prospective study of male soccer injuries among 12 teams playing at the highest competition level was carried out in Finland in 1993. Overall, two out of three players were injured during the whole season. The injury incidence per 1000 playing hours among injured players and all players during games was higher than during practice, 14.2 vs. 11.3 and 2.3 vs. 1.8, respectively. The lower extremity was involved in 76% of the injuries. Thigh injuries were most frequent (22%), whereas overuse injuries were scarce (6%). Eighteen per cent of the injured players needed surgery and in most cases (58%) the reason for surgery was a knee injury. Sixteen per cent of all injured players were absent from soccer for more than 1 month after the injury. The mean absence time was 17 days for all and 84 days for operatively treated players.     

Spinal injuries in professional rugby union: a prospective cohort study.

OBJECTIVES: To determine the incidence, severity, nature, and causes of cervical, thoracic, and lumbar spine injuries sustained during competition and training in professional rugby union. DESIGN: A 2 season prospective cohort design. SETTING: Twelve English Premiership rugby union clubs. PARTICIPANTS: Five hundred and forty-six male rugby union players of whom 296 were involved in both seasons. MAIN OUTCOME MEASURES: Location, diagnosis, severity (number of days unavailable for training and matches), and cause of injury: incidence of match and training injuries (injuries/1000 player-hours). RISK FACTORS: Player age, body mass, stature, playing position, use of headgear, and activity and period of season. RESULTS: The incidences of spinal injuries were 10.90 (9.43 to 12.60) per 1000 player match-hours and 0.37 (0.29 to 0.47) per 1000 player training-hours. No player sustained a catastrophic spinal injury, but 3 players sustained career-ending injuries. Overall, players were more likely to sustain a cervical injury during matches and a lumbar injury during training. Forwards were significantly more likely to sustain a spinal injury than backs during both matches (P < 0.01) and training (P = 0.02). During matches, injuries to the cervical (average: 13 days; P < 0.01) and lumbar (13 days; P < 0.01) spine were more severe than injuries to the thoracic (5 days) spine; during training, injuries to the lumbar spine (26 days) were more severe than injuries to the cervical (13 days; P = 0.10) or thoracic (12 days; P = 0.06) spine. A total of 4037 days were lost to competition and training through spinal injuries with lumbar disc injuries sustained during training accounting for 926 days (23%) and cervical nerve root injuries sustained during matches for 621 days (15%). During matches, more injuries were caused by tackles (37%), and during training more injuries were caused by weight-training (33%). CONCLUSIONS: The results showed that rugby union players were exposed to a high risk of noncatastrophic spinal injury during tackling, scrummaging, and weight-training activities; injury prevention strategies, therefore, should be focused on these activities.     

Prevention of soccer injuries: a prospective intervention study in youth amateur players

BACKGROUND: Risk factors for soccer injuries and possibilities for prevention have been discussed by several authors, but only a few have investigated the effectiveness of preventive interventions. PURPOSE: The aim of the present study was to evaluate the effects of a prevention program on the incidence of soccer injuries in male youth amateur players. STUDY DESIGN: Prospective controlled intervention study. METHODS: Seven soccer teams took part in a prevention program that focused on education and supervision of coaches and players, while seven other teams were instructed to train and play soccer as usual. Over 1 year all injuries were documented weekly by physicians. Complete weekly injury reports were available for 194 players. RESULTS: The incidence of injury per 1000 hours of training and playing soccer was 6.7 in the intervention group and 8.5 in the control group, which equates to 21% fewer injuries in the intervention group. The greatest effects were observed for mild injuries, overuse injuries, and injuries incurred during training. The prevention program had greater effects in low-skill than in high-skill teams. CONCLUSIONS: The incidence of soccer injuries can be reduced by preventive interventions, especially in low skill level youth teams. Coaches and players need better education regarding injury prevention strategies and should include such interventions as part of their regular training.     

The significance of peroneus tertius muscle in ankle injuries: a prospective study

BACKGROUND: The peroneus tertius is absent in 5% to 17% of the human white population. The function of the peroneus tertius is eversion and dorsiflexion of the foot. These 2 strength parameters have been identified as important parameters in the development of ankle ligament injuries. HYPOTHESIS: Subjects without the peroneus tertius are at higher risk for ankle ligament injuries. STUDY DESIGN: Cohort study (Prevalence); Level of evidence, 1. METHODS: One hundred physical education students were palpated for the presence of peroneus tertius before the start of their education; they were also isokinetically measured for eversion and dorsiflexion strength. All ankle injuries were registered during 2 years, and exposure to sport was recorded. RESULTS: The peroneus tertius was absent in 37 of the 200 subjects (18.5%). In the group with peroneus tertius (n = 163), 21 ankle sprains (12.9%) were observed during the 2-year follow-up. In the group without peroneus tertius (n = 37), 7 ankle sprains (18.9%) were noted. Statistical analysis (Cox regression) showed no significant difference between both groups in the incidence of ankle sprains (P = .335). Comparisons between the group of subjects with peroneus tertius and the group without peroneus tertius concerning the concentric and eccentric isokinetic eversion and the concentric dorsiflexion strength did not attain significance at any tested velocity (P > .05). CONCLUSION: This study shows that subjects without peroneus tertius are not at higher risk for an ankle ligament injury. In addition, subjects without peroneus tertius do not exhibit decreased eversion or dorsiflexion strength. CLINICAL RELEVANCE: This study is the first to clarify the exact contribution of the peroneus tertius within the muscular system around the ankle. As a result, the clinical importance of the peroneus tertius concerning prevention and treatment of ankle ligament injuries is low.     

High school football injuries: a prospective study and pitfalls of data collection

A 4 year prospective study (1982 to 1985) of high school varsity football injuries from the four Peoria high school football teams was undertaken. Two hundred fifty-one injuries were recorded among a player population of 598, resulting in an injury rate of 42.1% per 100 players. All of the players followed a prescribed preseason summer conditioning program that was endorsed by the Illinois High School Athletic Association. The injuries were recorded on an athletic injury profile and entered into a computer for data analysis and retrieval. The injury distribution by player position showed that halfbacks, tackles, linebackers, and guards had a higher risk of injury than other positions. The knee was the body part injured most frequently (20.3%). A matrix of injuries to halfbacks was set up to examine the relationship of body part injured to type of play, time of injury, and activity during injury. An anthropometric study using the Quetelet index did not reveal any correlation between injury and body size when the injured players were compared with the non-injured players. Experience since 1969 has taught us many of the errors and pitfalls involved in injury surveillance. Strict adherence to recording of data will ensure an accurate and useful injury surveillance program.     

Energy exchange in downhill and uphill walking: a calorimetric study

Energy balance can be written as 1) M = sigma Q +/- W +/- S, expressed as power (W), where M is the rate of metabolic energy transformation, sigma Q the rate of heat loss, W the work rate, and S the rate of body heat storage. When submaximal treadmill exercise continues long enough, body temperature stops changing, S becomes zero, and the heat storage term is dropped from equation 1. For uphill walking the equation becomes 2) M = sigma Q + Wvert, and for downhill walking it becomes 3) M = sigma Q - Wvert. This study tested the energy balance equations with direct measurements of heat exchange using a suit calorimeter and M from standard measurements of respiratory gas exchange. Ten healthy men walked on a motor driven treadmill at 1.5 m.s-1 at grades of 0, 5, 10, -5, and -10% for 70-90 min to ensure a thermal steady state. As expected, +Wvert was identified as a power output, whereas -Wvert was accounted for as a power input, totally transformed to heat in the downhill walking subject. There also appeared to be a quantity of non-thermal energy, Wwalk, needed to satisfy the energy balance equation. This was significant at 0, 5, and 10% grades (P less than 0.01) but not significant at -5 and -10% grades (P greater than 0.05). The data confirm previous results for level walking and extend them to include uphill walking. While it had been suggested that Wwalk represents an externalization of energy at the foot, the present data suggest an alternative explanation.(ABSTRACT TRUNCATED AT 250 WORDS)