Propensity For Injury Research Articles

Hormonal Fluctuation and Ankle Instability in Women – Is There a Correlation?

Category: Ankle; Basic Sciences/Biologics Introduction/Purpose: Lateral ankle sprains are one of the most common injuries to occur in the lower extremity, especially amongst female athletes. With higher incidences of ankle sprains and chronic ankle instability in women, it has been postulated that hormonal modulation and ligamentous laxity influences injury propensity. The role of estrogen in muscle mass and laxity has been demonstrated as collagen synthesis is inhibited by estrogen, resulting in increased elasticity and decreased muscle tone and synthesis. During ovulation and luteal phases, when estrogen is highest, greatest laxity is observed. The purpose of this study is to investigate the impact of hormonal fluctuation on ankle stability and ligamentous laxity and whether these variations can contribute to injury propensity. Methods: In November 2023, a systematic review of the MEDLINE, ProQuest, and Cochrane Library databases was performed between 2000 and 2023 based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The following search terms were used: “(sex or gender) AND (ankle stability)” and “(hormone) AND (ankle)”. Articles were included if they evaluated outcomes related to the impact of hormones on ankle stability in healthy patients, included menstrual tracking, were peer-reviewed, had a minimum of 5 patients per cohort, were written in English, were human patients, and were published after the year 2000. Studies with a male control group were included and evaluated, though this was not a requirement for inclusion. Articles were excluded if they evaluated patients that were injured or experiencing other associated pathological processes impacting ankle function or stability. Results: Fourteen articles were included, composed of 2 clinical trials, 5 cohort studies, 5 case series, and 2 cross-sectional studies. There were 253 (76.4%) females at a weighted mean age for females was 21.9 ± 2.0 years (range, 20.0-25.9). Five studies evaluated postural sway and balance properties noting greater sway rates during ovulation when compared with the follicular phase. Greater muscle tone (p < 0.001) and elasticity (p < 0.05) was observed in the follicular phase compared with ovulation for the tibialis anterior, peroneus longus, and lateral gastrocnemius. Significantly higher ankle joint laxity was observed in ovulation (p=0.016) compared to follicular and luteal phases. Conclusion: The findings in this study demonstrate that postural stability, balance, ligamentous laxity, and tendon properties fluctuate throughout the menstrual cycle. The ovulation phase, a state when estrogen levels peak, demonstrated impaired balance with higher postural sway rates, significantly greater ankle joint laxity, and decreased muscle and ligamentous tone and stiffness – an indicator of laxity. These results demonstrate an underlying etiology for the increased propensity to ankle instability in the female athlete. Additionally, syncing an athlete’s workout type and intensity around menstrual cycle phase may be an advantageous strategy for injury prevention.

A comparison of three methods for establishing an ACL reference length in vivo

As anterior cruciate ligament (ACL) injuries are highly prevalent among active individuals, it is vital to better understand the loading conditions which lead to injury. One method for doing so is through measurement of dynamic, in vivo ACL strain. To measure strain, it is necessary to normalize elongation of the ACL to a ‘reference length’ which corresponds to the point at which the ligament transitions from being unloaded to carrying tension. The purpose of this study was to compare the length of the ACL in three different positions to evaluate their utility for establishing a reference (or zero-strain) length of the ACL.ACL reference length was determined using three different methods for each of ten healthy participants. Using magnetic resonance and biplanar radiographic imaging techniques, we measured the length of the ACL during supine resting, quiet standing, and anterior/posterior (AP) drawer testing. During the AP drawer testing, the slack-taut transition point was defined as the inflection point of the AP translation vs ACL elongation curve.There was good consistency between the three ACL length measurements (ICC=0.80). Differences in mean ACL length between the three methods were within 1 mm.While determining the precise zero-strain length of the ACL in vivo remains a challenge, the reference positions utilized in this study produce consistent measurements of ACL length. These findings are important because reliable measurements of in vivo ACL strain have the potential to serve as indicators of propensity for injury.

Injury rates and mechanisms of starting and replacement players

ABSTRACT To examine injury rates, injury mechanisms and injury inciting tackle characteristics of both starting and replacement players. A prospective, cohort study of four male professional Welsh Rugby Union (WRU) teams. Injury surveillance and Global Positioning System (GPS) data were collected from league matches between the 1st of July 2017 to the 31st of August 2020. Video analysis included league matches from the 1st of July 2017 to the 31st of March 2021. Player-specific GPS exposure was used to calculate injury incidence. Generalised linear mixed models were used to analyse the effect of replacement players on injuries. Tackle injury propensity (injuries/100 tackle events) and descriptive characteristics for the tackle event were reported. A total of 290 injuries were sustained by 105 players. Starting players had a higher injury incidence than replacement players (80.8 vs 57.2 injuries/1000 match hours; rate ratio: 1.41 (95% CI 1.00 – 1.98)). For every replacement used there was a 12% increase in the number of injuries (p = 0.037). However, there was no increase in the number of injuries accounting for the replacement time-in-game (p = 0.099). The injury propensity was highest for starting versus opposition replacement players (RR: 4.08, 95% CI: 2.28 – 7.29). Injury inciting tackles for starting players showed higher body positions, whereas replacement players maintained a lower body position. Match injuries were influenced by the number of replacement players, but this was mitigated when accounting for the replacement player time-in-game. Starting and replacement players have differing injury inciting tackle characteristics, suggesting that injury risk mitigation associated with the tackle should be incorporated at a player-specific level.

An investigation of an athlete injury likelihood monitoring system using the random forest algorithm and DWT.

The main goal of sports science is to monitor sports injuries. Nevertheless, the existing sports injury monitoring projects have many expensive instruments and excessively extended monitoring periods, which makes it difficult to expand sports injury monitoring on a large scale. The advancement of machine learning algorithms opens up new avenues for the tracking of sports injuries. A training set of sports injuries was created using the Discrete Wavelet Transform (DWT) and Random Forest algorithms. Next, a basic analytic framework was created based on the lower-body movement of runners, and an athlete's injury likelihood monitoring system was established. First off, the wearable gyroscope device can efficiently plot the motion displacement curve and monitor the three-dimensional mechanics of the athlete's hips, thighs, and calves. Secondly, the system has a higher computational efficiency and an advantage over other classifier-based systems in terms of testing and training times. The suggested system framework identifies athletes' injury propensity, providing preventive recommendations based on displacement curves, and offering a low total cost and high testing accuracy, making it easy to implement and cost-effective. All things considered, the sports injury monitoring device is very accurate and reasonably priced, making it appropriate for widespread use.

Comparative Analysis of Clinical Severity and Outcomes in Penetrating Versus Blunt Traumatic Brain Injury Propensity Matched Cohorts.

Traumatic brain injury (TBI) is a global health challenge; however, penetrating brain injury (PBI) remains under-represented in evidence-based knowledge and research efforts. This study utilized data from the Trauma Quality Improvement Program (TQIP) of the National Trauma Data Bank (NTDB) to investigate outcomes of PBI as compared with clinical-severity-matched non-penetrating or blunt TBI. A total of 1765 patients with PBI were 1:1 propensity score-matched for clinical severity with blunt TBI patients. The intent of PBI was self-inflicted in 34.1% of the cases, and the mechanism was firearm-inflicted in 89.1%. Mortality was found to be significantly more common in PBI than in the severity- matched TBI cohort (33.9% vs. 14.3 %, p < 0.001) as was unfavorable outcome. Mortality was mediated by withdrawal of life-sustaining therapies (WOLST) 30% of the time, and WOLST occurred earlier (median 3 days vs. 6 days, p < 0.001) in PBI. Increased rate of mortality was observed with a Glasgow Coma Scale (GCS) of <11 in PBI as compared with <7 in blunt TBI. In conclusion, PBI patients exhibited higher mortality rates and unfavorable outcomes; one third of excess mortality was mediated by WOLST. The study also brings into question the applicability of the conventional TBI classification, based on GCS, in PBI. We emphasize the need to address the observed disparities and better understand the distinctive characteristics and mechanisms underlying PBI outcomes to improve patient care and reduce mortality.

Video analysis of heading and risk of head injury situations in elite international men's football: Does the frequency of headers increase with the level of play?

AbstractFootball is the only sport in which the ball can be played with the head. Therefore, compared to other ball team sports, head injuries are quite common. Headers and head injuries are dreaded to cause severe neurological impairments in long‐term, but there is still a lack of data on how often headers are performed in different levels and how often head injuries occur. In a prospective cohort study, all heading situations as well as incidents with a propensity of injury (critical incidents) of 45 elite‐level international matches were analyzed using a standardized video analysis protocol and compared to existing data from German professional leagues. A total of 3670 headers were recorded in 4050 match minutes (0.9 headers/minute). A mean of 81.5 headers per game (SD = 18.4) and 3.7 headers per player and match (SD = 0.8) was found. Compared to a cohort group of the German Bundesliga and 2nd Bundesliga, a significant reduction of −33.8 headers per game (p &lt; 0.01) and 1.7 per player and match was found. A total of 18 risk of injury situations were recorded giving a rate per match of 0.4 (SD = 0.6). In comparison to the German league data, this also displayed a reduction. The incidence rate was 266 risk of injury situations per 1000 h match exposure, which was far below the rates of German national data (314/1000 h) and correlated with the frequency of headers performed.

Incidence rate of injury and injury sites in European and Swiss karate competitions: a prospective epidemiological study of 2404 fights

ObjectivesTo compare the rates and injury sites among competitors in European and Swiss karate tournaments and to identify differences in these incidence rates by sex and age.MethodsThis prospective cohort study...

Distal Tibial Bone Properties and Bone Stress Injury Risk in Young Men Undergoing Arduous Physical Training

Trabecular microarchitecture contributes to bone strength, but its role in bone stress injury (BSI) risk in young healthy adults is unclear. Tibial volumetric BMD (vBMD), geometry, and microarchitecture, whole-body areal BMD, lean and fat mass, biochemical markers of bone metabolism, aerobic fitness, and muscle strength and power were measured in 201 British Army male infantry recruits (age 20.7 [4.3] years, BMI 24.0 ± 2.7 kg·m2) in week one of basic training. Tibial scans were performed at the ultra-distal site, 22.5 mm from the distal endplate of the non-dominant leg using High Resolution Peripheral Quantitative Computed Tomography (XtremeCT, Scanco Medical AG, Switzerland). Binary logistic regression analysis was performed to identify associations with lower body BSI confirmed by MRI. 20 recruits (10.0%) were diagnosed with a lower body BSI. Pre-injured participants had lower cortical area, stiffness and estimated failure load (p = 0.029, 0.012 and 0.011 respectively) but tibial vBMD, geometry, and microarchitecture were not associated with BSI incidence when controlling for age, total body mass, lean body mass, height, total 25(OH)D, 2.4-km run time, peak power output and maximum dynamic lift strength. Infantry Regiment (OR 9.3 [95%CI, 2.6, 33.4]) Parachute versus Line Infantry, (p ≤ 0.001) and 2.4-km best effort run time (1.06 [95%CI, 1.02, 1.10], p < 0.033) were significant predictors. Intrinsic risk factors, including ultradistal tibial density, geometry, and microarchitecture, were not associated with lower body BSI during arduous infantry training. The ninefold increased risk of BSI in the Parachute Regiment compared with Line Infantry suggests that injury propensity is primarily a function of training load and risk factors are population-specific.

A literature review study on kabaddi injuries

Kabaddi is Indian origin and combat game. This is aggressive in nature in this holding, pushing, catching, and jumping in fractions of second which directly increase the chances of injuries. This Research study gives a review on kabaddi game injuries.Using the information partners Google Scholar, The Web of Science, PubMed, SPORT Discus, MEDLINE, and Science immediate, a regressive review was conducted on kabaddi injuries using the following key-phrases in combination: Kabaddi, ACl, Sports Injury, kabaddi injury causes, prevention of injuries, combact sport, etc. Sports injuries in kabaddi led to the selection of 13 papers for regressive review. The most recent evidence suggested that Kabaddi is a game with a strong propensity for injuries. Injuries to the lower leg were considered to be more common in Kabaddi players after those to the knee. It was noted that mouth-guards do a fantastic job of preventing injuries, and playing techniques have improved. In the Indian context of this game, epidemiology studies and anticipatory techniques are absent. Therefore, injury prevention technique should be carried out for the betterment of kabaddi game.

Are rugby league players involved in more tackles than normal, prior to an injury sustained during a tackle event?

ABSTRACT Rugby league has a relatively high injury risk, with the tackle having the greatest injury propensity. The number of tackles players engage in, prior to injurious tackles may influence injury risk, which has yet to be investigated. Therefore, this study investigated if rugby league players are involved in more tackles (as either tackler or ball carrier) (i) in the 10 minutes, or (ii) 1-min periods prior to an injurious tackle-event, (iii) differences for ball carriers vs. tacklers, and (iv) forwards vs. backs. Video analysis was utilised to quantify the number and rate of tackles in the 10-min periods prior to 61 tackle-related injuries. One thousand two hundred and eighty 10-min periods where players were not injured, were used as matched-controls. Generalized mixed linear models were used to analyse mean total and rate for tackles. Injured players were involved in significantly fewer tackles during the 10-min period, yet significantly more tackles during the final minute prior to the injurious tackle-event, compared to non-injured players. There were no differences between ball carriers vs. tacklers during the 10-min period. Both injured position groups were involved in significantly more tackles in the final minute. Additional match data sources are needed to further inform injury preventive strategies of tackle events.

Video analysis of 100 matches in male semi-professional football reveals a heading rate of 5.7 headings per field player and match

IntroductionHeading is an integral part of football and frequent media reports and previous studies about potential danger of heading and head trauma in football fuelled discussions. Epidemiological data and video analyses regarding headings situation and associated head injuries are still missing in male adult professional football.MethodsIn a prospective cohort study in the male fourth German football league, 100 official matches of the 2015–2016 season were assessed by video analysis and a standardized protocol. Heading situations and concomitant circumstances as well as incidents with a propensity of injury (critical incidents) were analyzed. Critical incidents (CI) and seasonal reported head injuries were cross-referenced.ResultsOverall, 11,514 headings were analysed in detail. Video analysis yielded a mean of 5.7 headings per player and match (SD: 1.2; range 0–15). Heading was predominantly performed with the frontal part of the head (76.8%), and nearly two thirds of all headings occurred during defending (65.8%). 71.0% of all headings occured during tacklings, of which 71.9% involved body contact with the opponent player. Video analysis yielded 31 CI on the head due to heading (incidence: 1.02 per 1000 h match exposure and player). 29 CI occurred during heading duels (odds ratio: 5.91), 30 CI with body contact (odds ratio: 28.8) and 6 CI with elbow contact (odds ratio: 6.13).ConclusionHeading frequency in male semi-professional football could be determined with a rate of 5.7 headings per match and field player. Cross referencing CI and seasonal reported head injuries revealed a very low number of reported head injuries.

The Effect of Single Sport Specialization in Youth Sports: A Prospective Cohort Study

Objectives:Large numbers of youth participate in both team and individual sports. In recent years, sports specialization has become increasingly popularized in younger athletes. There is concern that early sports specialization increases the risk of overuse injuries in youth athletes. The purpose of this investigation was to determine the prevalence of sport specialization in youth athletes, and prospectively examine whether specialization correlates with an increased incidence of athletic injury.Methods:895 high school freshman athletes were enrolled starting in 2016, with the intent of following them through the completion of their high school careers. They were recruited from 3 high schools within the same school district. Sports specialization was defined as participating in a single sport in excess of 6 months of the year at the exclusion of other sports. Athletes’ demographic information, sport commitment and injury history were collected through a sports specialization and injury survey. The same athletes were queried again at the conclusion of each season to collect injury information. Athletic training records were used to corroborate, in order to ensure capture of all injuries reported to health care personnel.Results:Of the 895 athletes, 216 (24.1%) reported sport specialization at some point during their high school sports careers. Specialized athletes were exposed to significantly more sports activity (8.41 hours/week vs 7.10 hours/week, p<0.00001 ). They were also much more likely (70.6% vs 25.1%, p< .00001) to compete on a club or travel team for their sport. Male athletes were more likely to specialize than females (27.0% vs 19.3%, p<0.0072). Baseball (12.1% of specialized athletes vs 4.9% of all athletes, p<0.000032) main sport athletes were the only athletes significantly more likely to report specialization. Specialized athletes were significantly more likely than their nonspecialized counterparts to report an injury (39.8% vs 33.2%, p< 0.0271). These athletes suffered from higher severity injuries, requiring more time to recover than their peers. (p<0.0483). Despite the higher propensity for injury in specialized athletes and greater tendency for specialization in males, female athletes were more likely to report injures (p<0.0053). The most common reported injuries were of the knee, ankle, and head (18.6%, 18.2%, 16.6% of all injuries respectively). Season ending injuries were also most commonly knee, ankle, and head injuries (48.5%, 15.2%, 12.1% respectively), with 30.3% of all reported season ending injuries being ACL tears.Conclusions:Specialized student athletes tend to have significantly more injuries than non-specialized athletes, as well as more severe injuries than non-specialized athletes. This is one of the largest and most comprehensive studies to date, evaluating the effect of sports specialization on the incidence of athletic injury in high school athletes.

SINGLE LEG SQUAT COMPENSATIONS ASSOCIATE WITH SOFTBALL PITCHING PATHOMECHANICS IN ADOLESCENT SOFTBALL PITCHERS

Background:Softball pitchers have an eminent propensity for injury due to the high repetition and ballistic nature of the pitch. As such, trunk pathomechanics during pitching have been associated with upper extremity pain. The single leg squat (SLS) is a simple diagnostic tool used to examine LPHC and trunk stability. Research shows a lack of LPHC stability is often associated with altered pitching mechanics consequently increasing pain and injury susceptibility.Hypothesis/Purpose:The purpose of this study was to examine the relationship between trunk compensatory kinematics during the SLS and kinematics during foot contact of the windmill pitch. The authors hypothesized there would be a relationship between SLS compensations and pitch kinematics previously associated with injury. In using a simple clinical assessment such as the SLS, athletes, coaches, parents, and clinicians can identify potential risk factors that may predispose the athlete to injurious movement patterns.Methods:Fifty-five youth and high school softball pitchers (12.6±2.2 years, 160.0±11.0 cm, 60.8±15.5 kg) were recruited to participate. Kinematic data were collected at 100Hz using an electromagnetic tracking device. Participants were asked to complete a SLS on their stride leg (contralateral to their throwing arm), then throw 3 fastballs at maximal effort. Values of trunk flexion, trunk lateral flexion, and trunk rotation at peak depth of the SLS were used as the dependent variables in three separate backward elimination regression analyses. Independent variables examined at foot contact of the pitch included: trunk flexion, trunk lateral flexion, trunk rotation, center of mass, stride length, and stride knee valgus.Results:The SLS trunk rotation regression, F(1,56) = 4.980, p = .030, revealed trunk flexion significantly predicted SLS trunk rotation (SE = .068, t = 2.232, p = .030) and explained approximately 7% of variance (Adj. R2 = .066). The SLS trunk flexion regression, F(1,56) = 5.755, p = .020, revealed stride knee valgus significantly predicted SLS trunk flexion (SE = .256, t = 2.399, p = .020) and explained approximately 8% of variance (Adj. R2 = .078).Conclusion/Significance:Additional trunk rotation and trunk flexion at peak depth of the SLS indicate increased knee valgus and trunk flexion at foot contact of the pitch, both of which suggest poor LPHC stability, may increase the potential for injury. Athletes, coaches and clinicians should acknowledge the risk of poor LPHC in softball pitching and implement exercises to improve LPHC stability in effort to decrease pitching pathomechanics and associated pain.

Effects Of Adolescent Sports Specialization On NFL And MLS Players’ Injury Propensity

Adolescent single sport specialization has been linked to a higher rate of overuse injuries and has even been shown to be detrimental to the health and career longevity of NBA players (Rugg et al). PURPOSE: To evaluate a potential relationship between adolescent sports specialization and injury propensity in elite NFL and MLS players. METHODS: 570 first and second round NFL draft selections from 2010-2018 and 202 first round MLS draft selections from 2005-2018 with reliable sport specialization, injury history, and playing career data were identified. Publicly verified internet sources were used to classify adolescent sport participation, number and type of severe injuries sustained during pro football or soccer games, and number of total possible games played and missed due to injury. Subjects for each league were divided into 2 cohorts: multisport (MS) and single sport (SS). Sports specialization comparisons were made as follows: (1) Average % of games missed due to injury (APGM) using 2 sample T test and (2) % of players who sustained at least 1 major injury (%MI) using one-tailed Fisher’s exact test. RESULTS: APGM was lower in the NFL MS group (11.4±0.7% vs 18.7±2.3%; p<.01) but not in the MLS MS group (6.51±1.9% vs 5.8±1.0%; p=0.377) [Figure 1]. %MI was also lower in the NFL MS group (54.2 vs 68.8%; p<0.01) but not in the MLS MS group (41.7 vs. 35.1%, p=0.4528) [Figure 2].Figure 1: APGM Sports Specialization Comparison in NFL and MLSFigure 2: %MI Sports Specialization Comparison in NFL and MLSCONCLUSION: Adolescent MS specialization contributes to a reduction in injury predisposition in NFL athletes but not in MLS athletes.

Identifying the Factors Contributing to the Severity of Truck-Involved Crashes in Shanghai River-Crossing Tunnel.

The impact that trucks have on crash severity has long been a concern in crash analysis literature. Furthermore, if a truck crash happens in a tunnel, this would result in more serious casualties due to closure and the complexity of the tunnel. However, no studies have been reported to analyze traffic crashes that happened in tunnels and develop crash databases and statistical models to explore the influence of contributing factors on tunnel truck crashes. This paper summarizes a study that aims to examine the impact of risk factors such as driver factor, environmental factor, vehicle factor, and tunnel factor on truck crashes injury propensity based on tunnel crashes data obtained from Shanghai, China. An ordered logit model was developed to analyze injury crashes and property damage only crashes. The driver factor, environmental factor, vehicle factor, and tunnel factor were explored to identify the relationship between these factors and crashes and the severity of crashes. Results show that increased injury severity is associated with driver factors, such as male drivers, older drivers, fatigue driving, drunkenness, safety belt used improperly, and unfamiliarity with vehicles. Late night (00:00–06:59) and afternoon rushing hours (16:30–18:59), weekdays, snow or icy road conditions, combination truck, overload, and single vehicle were also found to significantly increase the probability of injury severity. In addition, tunnel factors including two lanes, high speed limits (≥80 km/h), zone 3, extra-long tunnels (over 3000 m) are also significantly associated with a higher risk of severe injury. So, the gender, age of driver, mid-night to dawn and afternoon peak hours, weekdays, snowy or icy road conditions, the interior zone of a tunnel, the combination truck, overloaded trucks, and extra-long tunnels are associated with higher crash severity. Identification of these contributing factors for tunnel truck crashes can provide valuable information to help with new and improved tunnel safety control measures.

Few training sessions between return to play and first match appearance are associated with an increased propensity for injury: a prospective cohort study of male professional football players during 16 consecutive seasons

BackgroundIt has been hypothesised that injury risk after return to play following an injury absence is influenced by the amount of training completed before return to competition.AimTo analyse if the...

Effect of leg dominance on early functional outcomes and return to sports after anterior cruciate ligament reconstruction

The effect of leg dominance on anterior cruciate ligament (ACL) injuries has been studied with some studies noting a propensity for injuries in the non-dominant leg. Its effect on post-ACL reconstruction recovery, however, is not well known. The authors hypothesize that dominant limb injuries undergo rehabilitation faster and positively affect early functional outcome scores and return to sports and set about studying these effects. This is a retrospective study of 254 patients from a single institution who underwent ACL reconstruction for acute ACL ruptures and the results were compared between patients with dominant and non-dominant limb injuries. Objective measurements including the KT-1000, single-leg hop distance and Biodex knee extension peak torque were used to evaluate recovery. Pre- and post-operative functional outcome scores such as the International Knee Documentation Committee (IKDC), Tegner activity score and Lysholm knee scale were documented. Early functional outcomes were similar. Minimal clinically important difference (MCID) improvement in IKDC scores was achieved in 69.7% of the dominant versus 66.0% of the non-dominant injury group (p = 0.99), 75.2% versus 79.6% (p = 0.45) for the Lysholm knee scale, and 81.6% versus 84.9% (p = 0.50) for the Tegner activity score. The majority of patients in both subgroups had a return of at least 80% of peak knee flexion and extension peak torque at 5.4 months post-operatively; 92.9% of subjects with a non-dominant leg injury and 87.2% with a dominant leg injury had returned to their pre-injury sports 1 year from surgery. Results from this study suggest that despite theoretical differences, leg dominance does not have a significant impact on short-term functional outcomes and return to sports. Objective measurements suggest that limb strength recovers at a comparable rate. Injuries to either leg demonstrate equally positive improvement post-ACL reconstruction given the same post-operative rehabilitation. III, retrospective comparative study. III, retrospective cohort study.

Interfibrillar shear behavior is altered in aging tendon fascicles.

Tendon elongation involves both stretching and sliding between adjacent fascicles and fibers. Hence, age-related changes in tendon matrix properties may alter sliding behavior and thereby affect injury thresholds. The objective of this study was to investigate the effects of age on interfibrillar shear behavior in partial cut tendon fascicles. Cine microscopic imaging was used to track deformation patterns of intact and partial cut fascicles from mature (9months, n = 10) and aged (32months, n = 10) rat tail tendons. Finite element (FE) models coupled with experimental data provided insight into age-related changes in tissue constitutive properties that could give rise to age-dependent behavior. Intact fascicles from aged tendons exhibited a 28% lower linear region modulus and reduced toe region when compared to fascicles from mature tendons. Partial cut tendon fascicles consistently exhibited a shearing plane that extended longitudinally from the tip of the cut. Both mature and aged fascicles exhibited distinct failure that was observable in differential displacement across the shearing plane. However, aged fascicles exhibited 11-20% higher grip-to-grip strain at failure and tended to exhibit more variable and greater differential displacement at failure, when compared to mature fascicles. FE models suggest that this age-related change in shear behavior arises from a reduction in interfibrillar shear modulus with age. These data suggest that aging alters interfibrillar failure mechanisms and hence may contribute to the increased propensity for injury that is commonly seen in older tendons.

Gender differences in the consumption of alcohol mixed with caffeine and risk of injury.

There is increasing evidence suggesting the consumption of caffeinated alcoholic beverages is associated with risks over and above alcohol use on its own; however, research in this area remains limited. We examined whether gender differences existed in the relationship between the combined use of alcohol and caffeine (Alc + Caff) and risk for injury. This emergency department study utilised case-control and case-crossover analyses to examine in situ session specific Alc + Caff use and injury risk for men and women, while controlling for socio-demographic variables, dose of alcohol and caffeine, other substance use, risk-taking propensity and context. The sample comprised 2804 individuals aged 18-years or older who presented to three hospital emergency departments in British Columbia. A relationship between Alc + Caff use and increased risk of injury was confirmed. Further, gender differences were found in the risk relationship between Alc + Caff use and injury. Women were found to have a higher risk injury propensity following Alc + Caff use in both the case-control (OR = 3.10, 95% CI = 1.78, 5.84) and case-crossover analyses (OR = 3.21, 95% CI = 1.69, 6.12), relative to men (OR = 1.69, 95% CI = 1.30, 2.30; OR = 1.38, 95% CI = 1.08, 1.86). These results remained even after controlling for demographic factors, risk-taking, context and other substance use. Women may be at higher risk of injury than men following the consumption of alcohol mixed with caffeine. The findings offer support for differential low-risk drinking guidelines for men and women and the restriction and regulation of the sale and availability of caffeinated alcoholic beverages.

In vivo assessment of the interaction of patellar tendon tibial shaft angle and anterior cruciate ligament elongation during flexion

A potential cause of non-contact anterior cruciate ligament (ACL) injury is landing on an extended knee. In line with this hypothesis, studies have shown that the ACL is elongated with decreasing knee flexion angle. Furthermore, at low flexion angles the patellar tendon is oriented to increase the anterior shear component of force acting on the tibia. This indicates that knee extension represents a position in which the ACL is taut, and thus may have an increased propensity for injury, particularly in the presence of excessive force acting via the patellar tendon. However, there is very little in vivo data to describe how patellar tendon orientation and ACL elongation interact during flexion. Therefore, this study measured the patellar tendon tibial shaft angle (indicative of the relative magnitude of the shear component of force acting via the patellar tendon) and ACL length in vivo as subjects performed a quasi-static lunge at varying knee flexion angles. Spearman rho rank correlations within each individual revealed that flexion angles were inversely correlated to both ACL length (rho = −0.94 ± 0.07, mean ± standard deviation, p < 0.05) and patellar tendon tibial shaft angle (rho = −0.99 ± 0.01, p < 0.05). These findings indicate that when the knee is extended, the ACL is both elongated and the patellar tendon tibial shaft angle is increased, resulting in a relative increase in anterior shear force on the tibia acting via the patellar tendon. Therefore, these data support the hypothesis that landing with the knee in extension is a high risk scenario for ACL injury.