Neuromechanics of the lower limb: Implications for ACL injury prevention.

This research identified the muscle activation patterns that can contribute to increased anterior cruciate ligament (ACL) injury risk in female athletes during high-risk landing tasks, and how these change with training. Appropriate methods for identifying athletes at-risk of ACL injury in both elite and community-level sport were also explored.

Non-contact ACL injuries : association with clegg soil impact test values for sports fields, soil moisture and prevailing weather

Introduction: There is a recognised relationship between dry weather conditions and increased risk of anterior cruciate ligament (ACL) injury. Previous studies have identified 28 day evaporation as an important weather-based predictor of non-contact ACL injuries in professional Australian Football League matches. The mechanism of non-contact injury to the ACL is believed to increased traction and impact forces between footwear and playing surface. Ground hardness and the amount and quality of grass are factors that would most likely influence this and are inturn, related to the soil moisture content and prevailing weather conditions. This paper explores the relationship between soil moisture content, preceding weather conditions and the Clegg Soil Impact Test (CSIT) which is an internationally recognised standard measure of ground hardness for sports fields. Methodology: The 2.25 kg Clegg Soil Impact Test and a pair of 12 cm soil moisture probes were used to measure ground hardness and percentage moisture content. Five football fields were surveyed at 13 prescribed sites just before seven football matches from October 2008 to January 2009 (an FC Women’s WLeague team). Weather conditions recorded at the nearest weather station were obtained from the Bureau of Meteorology website and total rainfall less evaporation was calculated for 7 and 28 days prior to each match. All non-contact injuries occurring during match play and their location on the field were recorded. Results/conclusions: Ground hardness varied between CSIT 5 and 17 (x10G) (8 is considered a good value for sports fields). Variations within fields were typically greatest in the centre and goal areas. Soil moisture ranged from 3 to 40% with some fields requiring twice the moisture content of others to maintain similar CSIT values. There was a non-linear, negative relationship for ground hardness versus moisture content and a linear relationship with weather (R2, of 0.30 and 0.34, respectively). Three non-contact ACL injuries occurred during the season. Two of these were associated with hard and variable ground conditions.

The Sports Overload Injuries of the Lower Extremities from the Biomechanical Point of View

This work studies the major sports overload injuries of the lower extremities from the biomechanical point of view. At the same time, the main paradigms of podiatric biomechanics and the application of new biomechanical theories in the study of these lesions are reviewed. With current legislation, clinical gait biomechanical studies should be carried out in health centres and the only health professionals who can perform them are podiatrists and doctors (because they both can diagnose). Graduates in physical education can carry out studies in the field or in the sports court for the sole purpose of improving athletic performance, but never intended to treat a pathology overload.

Spinal and pelvic injuries in airborne sports: a retrospective analysis from a major Swiss trauma centre

Adrenalin-seeking airborne sports like BASE-jumping, paragliding, parachuting, delta-gliding, speedflying, and skysurfing are now firmly with us as outdoor lifestyle activities and are associated with a high frequency of severe injuries, especially to the spine.

INJURIES RELATED TO COMPETITIVE AND NONCOMPETITIVE SPORTS IN ELDERLY MEN

Objective: To verify the sociodemographic profile and the frequency of musculoskeletal injuries in elderly people who practice competitive and noncompetitive sports activities in the city of Pelotas, RS. Methods: Descriptive study, including 29 male subjects, aged 65 years or older, who practiced sports modalities in a competitive and noncompetitive way, in the city of Pelotas, in 2015. Data collection was performed through the application of a questionnaire with questions addressing economic, sociodemographic, nutritional and behavioral issues, and injuries sustained in sports activities. Statistical analysis was performed by calculating measures of central tendency for continuous variables and proportions for categorical variables. Results: The current practice of competitive sports was described by 58.6% (n=17) of the subjects, and the most practiced sports were 7-a-side football (53.0%, n=9), tennis (23.5%, n=4) and swimming (23.5%, n=4). Noncompetitive sports were practiced by 44.8% (n=13), and tennis was the most popular sport played (92.3%, n=12). The frequency of injuries among individuals practicing competitive and noncompetitive sports was, respectively, 35.3% (n=6), and 38.5% (n=5). The most frequent injuries were epicondylitis (50.0%, n=3) and meniscus injuries (60.0%, n=3), and the most affected body regions were knee (27.3%, n=3), elbow (27.3%, n=3), and shoulder (18.2%, n=2). The injuries occurred during the sports activities, and the dominant side was the one affected in 63.6% (n=7). Conclusion: This study verified that the occurrence of injuries in elderly individuals who practice sports is relevant, even among those who practice them noncompetitively, with epicondylitis as the most frequent among them, whereas meniscus injuries are the most frequent among those who practice competitive sports.

Modelling of inflatable rescue boats (IRBs) in surf conditions to reduce injuries

The Inflatable Rescue Boat (IRB) is arguably the most effective rescue tool used by the Australian surf lifesavers. The exceptional features of high mobility and rapid response have enabled it to become an icon on Australia's popular beaches. However, the IRB's extensive use within an environment that is as rugged as it is spectacular, has led it to become a danger to those who risk their lives to save others. Epidemiological research revealed lower limb injuries to be predominant, particularly the right leg. The common types of injuries were fractures and dislocations, as well as muscle or ligament strains and tears. The concern expressed by Surf Life Saving Queensland (SLSQ) and Surf Life Saving Australia (SLSA) led to a biomechanical investigation into this unique and relatively unresearched field. The aim of the research was to identify the causes of injury and propose processes that may reduce the instances and severity of injury to surf lifesavers during IRB operation. Following a review of related research, a design analysis of the craft was undertaken as an introduction to the craft, its design and uses. The mechanical characteristics of the vessel were then evaluated and the accelerations applied to the crew in the IRB were established through field tests. The data were then combined and modelled in the 3-D mathematical modelling and simulation package, MADYMO. A tool was created to compare various scenarios of boat design and methods of operation to determine possible mechanisms to reduce injuries. The results of this study showed that under simulated wave loading the boats flex around a pivot point determined by the position of the hinge in the floorboard. It was also found that the accelerations experienced by the crew exhibited similar characteristics to road vehicle accidents. Staged simulations indicated the attributes of an optimum foam in terms of thickness and density. Likewise, modelling of the boat and crew produced simulations that predicted realistic crew response to tested variables. Unfortunately, the observed lack of adherence to the SLSA footstrap Standard has impeded successful epidemiological and modelling outcomes. If uniformity of boat setup can be assured then epidemiological studies will be able to highlight the influence of implementing changes to the boat design. In conclusion, the research provided a tool to successfully link the epidemiology and injury diagnosis to the mechanical engineering design through the use of biomechanics. This was a novel application of the mathematical modelling software MADYMO. Other craft can also be investigated in this manner to provide solutions to the problem identified and therefore reduce risk of injury for the operators.

Injuries across adolescence : an investigation using the Extended Adolescent Injury Checklist (E-AIC)

Injury is the leading cause of death among adolescents, and in many countries, accounts for more deaths than all other causes combined. Rates of death due to injury also increase dramatically across adolescence. The Australian Institute of Health and Welfare reported that, in 2005, there were 954 deaths of young Australians due to injury, which is a rate of 26 deaths per 100,000 young people. Of these deaths, 4% were adolescents aged 12-14, 17% were aged 15-17, and 80% were aged 18-24 years. Issues addressed: Injuries are the leading cause of death among adolescents. The current research examined a measure of adolescent injury in terms of whether it encompasses the diverse injury experiences of Australian adolescents, including high-risk and normative adolescents, and thus determine its utility as a tool for health promotion research. Grade 9 students from two Brisbane high schools (n=202, aged 13-14 years) and adolescents recruited from the Emergency Department waiting rooms of four Brisbane hospitals (n=98, aged 16-18 years) completed the Extended Adolescent Injury Checklist (E-AIC). The most common cause of injury among adolescents was a sports activity, followed by fights for all participants except schoolbased males, who experienced more bicycle injuries. Alcohol use was most frequently reported in association with interpersonal violence injuries. A broad variety of injuries, occurring in context of multiple risk as well as normative behaviours, were reported by adolescents in both school and ED settings, and were captured by the E-AIC. Findings suggest that the E-AIC is a useful measure that captures the injury experiences of adolescents in different contexts. The high occurrence of injuries that do not result in formal medical treatment also indicates scope for interventions to be based around lessons in first aid, while also incorporating injury prevention components.

Hamstring strain injuries : factors that lead to injury and re-injury

Hamstring strain injuries (HSIs) are common in a number of sports and incidence rates have not declined in recent times. Additionally, the high rate of recurrent injuries suggests that our current understanding of HSI and re-injury risk is incomplete. Whilst the multifactoral nature of HSIs is agreed upon by many, often individual risk factors and/or causes of injury are examined in isolation. This review aims to bring together the causes, risk factors and interventions associated with HSIs to better understand why HSIs are so prevalent. Running is often identified as the primary activity type for HSIs and given the high eccentric forces and moderate muscle strain placed on the hamstrings during running these factors are considered to be part of the aetiology of HSIs. However, the exact causes of HSIs remain unknown and whilst eccentric contraction and muscle strain purportedly play a role, accumulated muscle damage and/or a single injurious event may also contribute. Potentially, all of these factors interact to varying degrees depending on the injurious activity type (i.e. running, kicking). Furthermore, anatomical factors, such as the biarticular organization, the dual innervations of biceps femoris (BF), fibre type distribution, muscle architecture and the degree of anterior pelvic tilt, have all been implicated. Each of these variables impact upon HSI risk via a number of different mechanisms that include increasing hamstring muscle strain and altering the susceptibility of the hamstrings to muscle damage. Reported risk factors for HSIs include age, previous injury, ethnicity, strength imbalances, flexibility and fatigue. Of these, little is known, definitively, about why previous injury increases the risk of future HSIs. Nevertheless, interventions put in place to reduce the incidence of HSIs by addressing modifiable risk factors have focused primarily on increasing eccentric strength, correcting strength imbalances and improving flexibility. The response to these intervention programmes has been mixed with varied levels of success reported. A conceptual framework is presented suggesting that neuromuscular inhibition following HSIs may impede the rehabilitation process and subsequently lead to maladaptation of hamstring muscle structure and function, including preferentially eccentric weakness, atrophy of the previously injured muscles and alterations in the angle of peak knee flexor torque. This remains an area for future research and practitioners need to remain aware of the multifactoral nature of HSIs if injury rates are to decline.

Suspected mechanisms in the cause of overuse running injuries : A clinical review

Context: Various epidemiological studies have estimated that up to 70% of runners sustain an overuse running injury each year. Although few overuse running injuries have an established cause, more than 80% of running-related injuries occur at or below the knee, which suggests that some common mechanisms may be at work. The question then becomes, are there common mechanisms related to overuse running injuries? Evidence Acquisition: Research studies were identified via the following electronic databases: MEDLINE, EMBASE PsycInfo, and CINAHL (1980–July 2008). Inclusion was based on evaluation of risk factors for overuse running injuries. Results: A majority of the risk factors that have been researched over the past few years can be generally categorized into 2 groups: atypical foot pronation mechanics and inadequate hip muscle stabilization. Conclusion: Based on the review of literature, there is no definitive link between atypical foot mechanics and running injury mechanisms. The lack of normative data and a definition of typical foot structure has hampered progress. In contrast, a large and growing body of literature suggests that weakness of hip-stabilizing muscles leads to atypical lower extremity mechanics and increased forces within the lower extremity while running.

The financial cost of hamstring strain injuries in the Australian Football League

Background/Aim Hamstring strain injuries (HSIs) have remained the most prevalent injury in the Australian football league (AFL) over the past 21 regular seasons. The impact of HSIs in sport is often expressed as regular season games missed due to injury. However the financial cost of athletes missing games due to injury has not been investigated. The aim of this report is to estimate the financial cost of games missed due to HSIs in the AFL. Method Data was collected using publically available information from the AFL’s injury report and the official AFL annual report for the past 10 competitive AFL seasons. Average athlete salary and injury epidemiology data was used to determine the average yearly financial cost of HSIs for AFL clubs and the average financial cost of a single HSI over this time period. Results Across the observed period, average yearly financial cost of HSIs per club increased by 71% compared to a 43% increase in average yearly athlete salary. Over the same time period the average financial cost of a single HSI increased by 56% from $25,603 in 2003 to $40,021 in 2012, despite little change in HSI rates during the period. Conclusion The observed increased financial cost of HSIs was ultimately explained by the failure of teams to decrease HSI rates, but coupled with increases in athlete salaries over the past 10 season. The information presented in this report will highlight the financial cost of HSIs and other sporting injuries, raising greater awareness and the need for further funding for research into injury prevention strategies to maximise economical return for investment in athletes.

The effect of previous hamstring strain injuries on the change in eccentric hamstring strength during preseason training in elite Australian footballers

Background Hamstring strain injuries (HSIs) are the most common injury type in Australian football and the rate of recurrence has been consistently high for a number of years. Long lasting neuromuscular inhibition has been noted in previously injured athletes but it is not known if this influences athletes adaptive response to training. Purpose To determine if elite Australian footballers with a prior unilateral HSI (previously injured group) display lesser improvements in eccentric hamstring strength during pre-season training compared to athletes without a history of HSI (control group). Study design Prospective cohort study. Methods Ninety-nine elite Australian footballers participated (17 with a history of unilateral HSI in the previous 12 month period). Eccentric hamstring strength was assessed at the start and end of pre-season training using an instrumented Nordic hamstring device. Change in eccentric strength across preseason was determine in absolute terms and normalised to start of preseason strength. Start of preseason strength was used as a covariate to control for differences in starting strength. Results The left and right limbs in the control group showed no difference in absolute or relative change (left limb absolute change, 60.7±72.9N; relative change, 1.28±0.34; right limb absolute change, 48.6±83.8N; relative change, 1.24±0.43) . Similarly, the injured and uninjured limbs from the previously injured group showed no difference for either absolute or relative measures of change (injured limb absolute change, 13.1±57.7N; relative change, 1.07±0.18; uninjured limb absolute change, 14.7±54.0N; relative change, 1.07±0.22N). The previously injured group displayed a significantly lesser increase in eccentric hamstring strength across the preseason (absolute change, 13.9±55.0; relative change, 1.07±0.20) compared to the control group (absolute change, 54.6±78.5; relative change, 1.26±0.39) for both absolute and relative measures (p < 0.001), even after controlling for differences in start of pre-season eccentric hamstring strength, which had a significant effect on strength improvement. Conclusion Elite Australian footballers with a unilateral HSI history displayed lesser improvements in eccentric hamstring strength across preseason training. The smaller improvements were not restricted to the previously injured limb as the contralateral limb also displayed similarly small improvements in eccentric strength. Whether this is the cause of or the result of injury remains to be seen, but it has the potential to contribute to the risk of hamstring strain re-injury.

Acute injuries in track and field athletes: A 3-year observational study at the Penn Relays Carnival with epidemiology and medical coverage implications

Background Few studies have examined acute injuries in track and field in both elite and sub-elite athletes. Purpose To observe the absolute and relative rates of injury in track and field athletes across a wide range of competition levels and ages during three years of the Penn Relays Carnival to assist with future medical coverage planning and injury prevention strategies. Study design: Descriptive epidemiology study. Methods Over a 3-year period all injuries treated by the medical staff were recorded on a standardised injury report form. Absolute injury rates (absolute number of injuries) and relative injury rates (number of injuries per 1000 participants) were determined and odds ratios (OR) of injury rates were calculated between sexes, competition levels and events. Injuries were also broken down into major or minor medical or orthopedic injuries. Results Throughout the study period 48,473 competing athletes participated in the Penn Relays Carnival, and 436 injuries were sustained. For medical coverage purposes, the relative rate of injury subtypes was greatest for minor orthopedic injuries (5.71 injuries per 1000 participants), followed by minor medical injuries (3.42 injuries per 1000 participants), major medical injuries (0.69 injuries per 1000 participants) and major orthopedic injuries (0.18 injuries per 1000 participants). College/elite level athletes displayed the lowest relative injury rate (7.99 injuries per 1000 participants), which was significantly less than high school (9.87 injuries per 1000 participants) and masters level athletes (16.33 injuries per 1000 participants). Males displayed a greater likelihood of suffering a minor orthopedic injury compared to females (OR = 1.36, 95% CI = 1.06 to 1.75; χ2 = 5.73, p = 0.017) but were less likely to sustain a major medical injury (OR = 0.33, 95% CI = 0.15 to 0.75; χ2 = 7.75, p = 0.005). Of the three most heavily participated in events, the 4 x 400m relay displayed the greatest relative injury rate (13.6 injuries per 1000 participants) compared to the 4 x 100 and 4 x 200m relay. Conclusions Medical coverage teams for future large scale track and field events need to plan for at least two major orthopedic and seven major medical injuries per 1000 participants. Male track and field athletes, particularly masters level male athletes, are at greater risk of injury compared to other genders and competition levels.

Eccentric knee-flexor strength and risk of hamstring injuries in Rugby Union: A prospective study

BACKGROUND Hamstring strain injuries (HSIs) represent the most common cause of lost playing time in rugby union. Eccentric knee-flexor weakness and between-limb imbalance in eccentric knee-flexor strength are associated with a heightened risk of hamstring injury in other sports; however these variables have not been explored in rugby union. PURPOSE To determine if lower levels of eccentric knee-flexor strength or greater between-limb imbalance in this parameter during the Nordic hamstring exercise are risk-factors for hamstring strain injury in rugby union. STUDY DESIGN Cohort study; level of evidence, 3. METHODS This prospective study was conducted over the 2014 Super Rugby and Queensland Rugby Union seasons. In total, 178 rugby union players (age, 22.6 ± 3.8 years; height, 185 ± 6.8 cm; mass, 96.5 ± 13.1 kg) had their eccentric knee-flexor strength assessed using a custom-made device during the pre-season. Reports of previous hamstring, quadriceps, groin, calf and anterior cruciate ligament injury were also obtained. The main outcome measure was prospective occurrence of hamstring strain injury. RESULTS Twenty players suffered at least one hamstring strain during the study period. Players with a history of hamstring strain injury had 4.1 fold (RR = 4.1, 95% CI = 1.9 to 8.9, p = 0.001) greater risk of subsequent hamstring injury than players without such history. Between-limb imbalance in eccentric knee-flexor strength of ≥ 15% and ≥ 20% increased the risk of hamstring strain injury 2.4 fold (RR = 2.4, 95% CI = 1.1 to 5.5, p = 0.033) and 3.4 fold (RR = 3.4, 95% CI = 1.5 to 7.6, p = 0.003), respectively. Lower eccentric knee flexor strength and other prior injuries were not associated with increased risk of future hamstring strain. Multivariate logistic regression revealed that the risk of re-injury was augmented in players with strength imbalances. CONCLUSION Previous hamstring strain injury and between-limb imbalance in eccentric knee-flexor strength were associated with an increased risk of future hamstring strain injury in rugby union. These results support the rationale for reducing imbalance, particularly in players who have suffered a prior hamstring injury, to mitigate the risk of future injury.