Impact of environmental factors on knee injuries in male and female recreational skiers

In alpine skiing, the knee represents the dominant injury location with marked gender differences. Snow, slope and weather conditions as well as altitude and low temperatures are thought to influence the prevalence of knee injuries. Therefore, ski patrol injury reports were used to compare gender-specific prevalence of knee injuries with regard to several environmental factors including the actual air temperatures. A total of 1039 non-contact knee injuries were reported with a corresponding prevalence of knee injuries of 44.4% (males: 30.1%; females: 57.4%). Temperature quartiles of all recorded injuries were calculated to compare gender-specific prevalence of knee injury with regard to temperatures. Comparing the first quartile (mean temperature -11°C) with the fourth quartile (mean temperature +3°C), the prevalence of knee injury in female skiers was higher at low ambient temperatures (61% vs 50%, odds ratio: 1.60, 95% confidence interval: 1.16-2.22; P=0.005) while no such association was found for male skiers. Additionally, knee-injured females showed a twofold prevalence when skiing during snowfall compared with females with other injuries (15.4% vs 8.6%; P=0.001). No other environmental factor showed a significant association with the gender-specific prevalence of knee injury. In conclusion, low ambient temperature and snowfall are important environmental risk factors for knee injuries in female skiers.     

ACL injury mechanisms and related factors in male and female carving skiers: a retrospective study

In recreational alpine skiing, ACL injury risk is 3 times greater in females. However, since the introduction of carving skis ACL injury risk seems to have decreased. No study has yet investigated the distribution of ACL injury mechanisms in male and female carving skiers. Therefore, the aim of the study was to investigate potential gender specific differences of ACL injury mechanisms and related factors among carving skiers. In total, 220 recreational carving skiers (59 males and 161 females) suffering from an ACL injury volunteered for this study. Demographic data, skiing ability, equipment related and environmental factors, circumstances and causes for the fall, and type of fall (injury mechanisms) were collected by questionnaire. The forward twisting fall is the most reported ACL injury mechanism in both gender (p=0.672) accounting for 54% of all injuries, although male and female skiers differed significantly with regard to circumstances of fall (p=0.001) and actions when ACL injury occurred (p=0.04). Bindings not releasing at the time point of accident occurred 2.6 times more with females than with males (p=0.005). The forward twisting fall seems to have become the dominant ACL injury mechanism both in male and female recreational skiers since the introduction of carving skis.     

The intrinsic risk factors for ACL ruptures: an evidence-based review

This article aims to assess the evidence related to the intrinsic risk factors for anterior cruciate ligament (ACL) ruptures. The level of evidence (according to evidence-based guidelines) for each study and the level of certainty for each risk factor were determined. After a review of the evidence, femoral notch geometry was the only risk factor that was found to be associated with risk of ACL rupture with high certainty. This review concludes that more research, particularly high-quality, prospective studies, are required to provide accurate measures of risk. These data should be used to establish multifactorial risk factor models designed to identify individuals at high risk of sustaining an ACL injury.     

Exercise-related leg pain in female collegiate athletes: the influence of intrinsic and extrinsic factors

BACKGROUND: Exercise-related leg pain is a common complaint among athletes, but there is little evidence regarding risk factors for this condition in female collegiate athletes. PURPOSE: To examine prospectively the effect of selected extrinsic and intrinsic factors on the development of exercise-related leg pain in female collegiate athletes. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Subjects were 76 female collegiate athletes participating in fall season sports, including cross-country running, field hockey, soccer, and volleyball. Athletes were seen for a pre-season examination that included measures of height, weight, foot pronation, and calf muscle length as well as a questionnaire for disordered eating behaviors. Body mass index was calculated from height and weight (kg/m(2)). Those athletes who developed exercise-related leg pain during the season were seen for follow-up. All athletes who developed the condition and a matched group without such leg pain underwent bone mineral density and body composition testing. Statistical analyses of differences and relationships were conducted. RESULTS: Of the 76 athletes, 58 (76%) reported a history of exercise-related leg pain, and 20 (26%) reported occurrence of exercise-related leg pain during the season. A history of this condition was strongly associated with its occurrence during the season (odds ratio, 13.2). Exercise-related leg pain was most common among field hockey and cross-country athletes and least common among soccer players. There were no differences between athletes with and without such leg pain regarding age, muscle length, self-reported eating behaviors, body mass index, menstrual function, or bone mineral density. Athletes with exercise-related leg pain had significantly (P < .05) greater navicular drop compared with those without. CONCLUSION: Exercise-related leg pain was common among this group of female athletes. The results suggest that there are certain factors, including foot pronation, sport, and a history of this condition, that are associated with an increased risk of exercise-related leg pain.     

Kinetic risk factors of running‐related injuries in female recreational runners

Our objective was to prospectively investigate the association of kinetic variables with running‐related injury (RRI ) risk. Seventy‐four healthy female recreational runners ran on an instrumented treadmill while 3D kinetic and kinematic data were collected. Kinetic outcomes were vertical impact transient, average vertical loading rate, instantaneous vertical loading rate, active peak, vertical impulse, and peak braking force (PBF ). Participants followed a 15‐week half‐marathon training program. Exposure time (hours of running) was calculated from start of program until onset of injury, loss to follow‐up, or end of program. After converting kinetic variables from continuous to ordinal variables based on tertiles, Cox proportional hazard models with competing risks were fit for each variable independently, before analysis in a forward stepwise multivariable model. Sixty‐five participants were included in the final analysis, with a 33.8% injury rate. PBF was the only kinetic variable that was a significant predictor of RRI . Runners in the highest tertile (PBF  < −0.27 BW ) were injured at 5.08 times the rate of those in the middle tertile and 7.98 times the rate of those in the lowest tertile. When analyzed in the multivariable model, no kinetic variables made a significant contribution to predicting injury beyond what had already been accounted for by PBF alone. Findings from this study suggest PBF is associated with a significantly higher injury hazard ratio in female recreational runners and should be considered as a target for gait retraining interventions.     

Prospective analysis of intrinsic and extrinsic risk factors on the development of Achilles tendon pain in runners

There are currently no generally accepted, consistent results that clearly characterize factors causing Achilles tendon pain (AT) in runners. Therefore, we carried out a prospective study to evaluate the multifactorial influence of clinical, biomechanical (isometric strength measurements and three‐dimensional kinematics) and training‐related risk factors on the development of AT. Two hundred sixty‐nine uninjured runners were recruited and underwent an initial examination. One hundred forty‐two subjects completed their participation by submitting training information on a weekly basis over a maximal period of 1 year. Forty‐five subjects developed an overuse injury, with 10 runners suffering from AT. In an uninjured state, AT runners already demonstrated decreased knee flexor strength and abnormal lower leg kinematics (sagittal knee and ankle joint) compared with a matched control group. A relationship between years of running experience or previous overuse injuries and the development of new symptoms could not be established. The interrelationship of biomechanical and training‐specific variables on the generation of AT is evident. A combination of alterations in lower leg kinematics and higher impacts caused by fast training sessions might lead to excessive stress on the Achilles tendon during weight bearing and thus to AT in recreational runners.     

Personal risk factors associated with injury among female recreational ice hockey players.

INTRODUCTION: Women's ice hockey is a rapidly growing sport, however little is known about the injuries sustained by this group of athletes. PURPOSE: The objective of this research was to identify risk factors associated with injury among female recreational ice hockey players. METHODS: This prospective study followed players from two women's ice hockey leagues in Edmonton, Canada during the 1997-98 hockey season. The occurrence of injuries was monitored during the season through standardized telephone follow-up. Risk factors were determined using multiple logistic regression. RESULTS: The initial study sample consisted of 314 players, however as the season progressed 19 (6%) were lost to follow-up. The results of the study are based on 295 (94%) participants. A total of 125 injuries were reported; the injury rate was 7.5 injuries/1,000 player-exposures. Risk factors found to be significantly related to the occurrence of injury were: injury in the past year (OR= 1.57), more than 5 years of hockey experience (OR=1.49), and high exposure level (OR=1.41). CONCLUSION: This research is the first to quantify personal risk factors associated with injury among female recreational ice hockey players. A sports injury in the previous 12 months appears to be highly associated with injury and further research is required to more fully understand this relationship. The importance of controlling for level of exposure when investigating risk factors for sports injury was demonstrated.     

Distribution of injury mechanisms and related factors in ACL-injured female carving skiers

While ACL injury mechanisms in skiers using traditional skis are well studied, no study has yet investigated the distribution of injury mechanisms in carving skiers. In traditional skiers, the backward twisting fall seems to be the dominant injury mechanism, especially in female skiers. Female recreational skiers have a threefold higher risk to sustain an ACL injury than male skiers; therefore, it is important to determine if carving skis influence the distribution of injury mechanisms and the related frequencies of ACL injuries in female skiers. We investigated the frequencies of injury mechanisms and related factors in 65 ACL-injured female carving skiers by questionnaire. The forward twisting fall was the most reported ACL injury mechanism with about 51%, followed by the backward twisting fall within 29% of cases. Catching an edge of the ski (59 vs. 24%, P = 0.03) when executing turns (69 vs. 41%, P = 0.053) was a more frequent cause for forward twisting falls than for the other types of falling. While 29% of bindings released during a forward twisting fall, only 3.1% released during the remaining mechanisms. In contrast to traditional skiers, the forward twisting fall was the dominant injury mechanism in female carving skiers with ACL injury.     

Interaction of foot and hip factors identifies Achilles tendinopathy occurrence in recreational runners

ObjectivesTo investigate the interaction of ankle-foot complex and hip joint factors with Achilles Tendinopathy (AT) occurrence in recreational runners.DesignCross-sectional.SettingResearch Laboratory.Participants51 runners, 26 healthy and 25 with AT.Main outcomes measuresShank-forefoot alignment (SFA), weight bearing lunge test (WBLT), passive hip internal rotation (IR) range of motion (ROM), hip external rotators (ER) and ankle plantar flexors (PF) isometric strength. CART analyses were performed to assess interactions that could distinguish those with AT.ResultsPassive hip IR ROM, ankle PF torque, SFA, and hip ER isometric torque were associated AT occurrence. The model correctly classified 92% of individuals without AT and 72% of those with AT. The area under the receiver operating characteristic curve was 0.88. Interaction factors revealed in nodes 3 and 10 were statistically significant. In node 3, runners with more than 29.33° of passive hip IR ROM had a 130% increased likelihood (PR = 2.30) of AT. Node 10 showed that individuals with higher PF torque, SFA varus, ER torque, but reduced passive hip IR ROM had an 87% increased likelihood (PR = 1.87) of AT.ConclusionInteractions between hip and foot factors could accurately classify recreational runners with and without AT.     

Intrinsic and extrinsic risk factors for muscle strains in Australian football

Muscle strains are common injuries in Australian football and other sports involving sprinting. Between 1992 and 1999, 83,503 player-matches in the Australian Football League were analyzed for risk of muscle strain injuries using logistic regression analysis. There were 672 hamstring, 163 quadriceps, and 140 calf muscle strain injuries. All three types of muscle strains were associated with significant risk factors. For all injuries, the strongest risk factor was a recent history of that same injury and the next strongest risk factor was a past history of the same injury. History of one type of muscle strain increased the risk for certain types of other muscle strains. Age was a risk factor for hamstring and calf muscle strains (even when adjusted for injury history) but was not a risk factor for quadriceps muscle strains. Quadriceps muscle injuries were more common in shorter players and were more likely when there had been less rainfall at the match venue in the previous week. Quadriceps muscle injuries were significantly more common in the dominant kicking leg, whereas hamstring and calf muscle injuries showed no difference in frequency between the dominant and nondominant legs.     

Parachute ankle brace and extrinsic injury risk factors during parachuting

INTRODUCTION: This study examined the injury prevention effectiveness of the parachute ankle brace (PAB) while controlling for known extrinsic risk factors. METHODS: Injuries among airborne students who wore the PAB during parachute descents were compared with injuries among those who did not. Injury risk factors from administrative records included wind speed, combat loads, and time of day (day/night). Injuries were collected in the drop zone. RESULTS: A total of 596 injuries occurred in 102,784 parachute descents. In univariate analysis, students not wearing the PAB (Controls) were 2.00 [95% confidence interval (95% CI) = 1.32-3.02] times more likely to experience an ankle sprain, 1.83 (95% CI = 1.04-3.24) times more likely to experience an ankle fracture, and 1.92 (95% CI = 1.38-2.67) times more likely to experience an ankle injury of any type. PAB wearers and Controls had a similar incidence of lower body injuries exclusive of the ankle [risk ratio (Control/PAB) = 0.92, 95% CI = 0.65-1.30]. After accounting for known extrinsic injury risk factors, Controls were 1.90 (95% CI = 1.24-2.90) times more likely than PAB wearers to experience an ankle sprain, 1.47 (95% CI = 0.82- 2.63) times more likely to experience an ankle fracture, and 1.75 (95% CI = 1.25-2.48) times more likely to experience an ankle injury of any type. The incidence of parachute entanglements that persisted until the jumpers reached the ground were similar among PAB wearers and Controls IRR (Control/PAB) = 1.17, 95% CI = 0.61-2.29]. CONCLUSION: After controlling for known injury risk factors, the PAB protected against ankle injuries, and especially ankle sprains, while not influencing parachute entanglements or lower body injuries exclusive of the ankle.     

Comparison of some intrinsic risk factors of shoulder injury in three phases of menstrual cycle in collegiate female athletes

Objectivespresent study aims to investigate the changes in the shoulder joint stability factors during the menstrual cycle.Designcross-sectional study;Settinglaboratory.Participants15 healthy collegiate female athletes with normal menstrual cycles.Main outcome measuresshoulder strength, proprioception, laxity and functional stability were the primary outcomes. Participants were assessed in three phases (mense, ovulation, midluteal (day 21) by 4 different categories of tests, each designed for a different factor. Shapiro-Wilk Test was used to determine normality of data, ANOVA and Friedman Test were used to compare results. Significance level and alpha were considered 95 percent and ≥0.05, respectively. Data shown a relation between proprioception, strength and menstrual cycle.Resultsshoulder strength was significantly increased in ovulation phase compared to other phases (p < 0.5) (effect size >0.14). Proprioception was significantly decreased in luteal phase than in mense and ovulation phases (p < 0.5) (effect size >0.14). Finally, ligament laxity and functional stability showed no change in all phases (p < 0.5).ConclusionMenstrual cycle and sexual hormones affect muscle strength and proprioception of shoulder joint, but have no effect on ligament laxity and functional stability.