Assessment of gender-specific preventive cardiovascular knowledge among house staff: Potential impact on cardiovascular management

Background: Gender differences in cardiovascular prevention and treatment may be related to physicians' level of postgraduate training and gender.Objectives: This study was designed to assess resident physician knowledge concerning general and gender-specific preventive cardiology topics and to determine whether there were differences in that knowledge based on the physicians' level of postgraduate training or gender.Methods: A 29-item true/false questionnaire was administered to residents in a large, university-based internal medicine residency program. All questions were drawn from evidence-based practice guidelines, and a subset of questions pertained to gender-specific issues in cardiovascular disease prevention. Scores on the overall test and gender-specific subset were computed as a percentage of correct answers. Differences were compared by postgraduate year (PGY) of training and physician gender.Results: Of the 190 eligible residents, 159 (88 men, 67 women, 4 not specified) completed the questionnaire. Overall test scores differed significantly by PGY (PGY-1, 83.4% correct answers; PGY-2, 52.9%; PGY-3, 65.3%; P < 0.001 for each paired comparison), but did not differ significantly by physician gender (males, 73.5%; females, 70.0%). Performance on gender-specific items also differed by PGY (PGY-1, 72.2% vs PGY-2, 20.0%; P < 0.001; and PGY-1, 72.2% vs PGY-3, 45.1%; P < 0.001). Knowledge of gender-specific preventive cardiology did not differ significantly by physician gender (males, 56.4%; females, 49.0%).Conclusions: Residents in PGY-1 had better knowledge of preventive cardiology as assessed using this questionnaire than did residents in PGY-2 or PGY-3. Knowledge of general and gender-specific cardiology topics was not related to physician gender.     

Balance index score as a predictive factor for lower sports results or anterior cruciate ligament knee injuries in Croatian female athletes--preliminary study

Female athletes participating in high-risk sports suffer anterior cruciate ligament (ACL) knee injury at a 4- to 6-fold greater rate than do male athletes. ACL injuries result either from contact mechanisms or from certain unexplained non-contact mechanisms occurring during daily professional sports activities. The occurrence of non-contact injuries points to the existence of certain factors intrinsic to the knee that can lead to ACL rupture. When knee joint movement overcomes the static and the dynamic constraint systems, non-contact ACL injury may occur. Certain recent results suggest that balance and neuromuscular control play a central role in knee joint stability, protection and prevention of ACL injuries. The purpose of this study is to evaluate balance neuromuscular skills in healthy Croatian female athletes by measuring their balance index score, as well as to estimate a possible correlation between their balance index score and balance effectiveness. This study is conducted in an effort to reduce the risk of future injuries and thus prevent female athletes from withdrawing from sports prematurely. We analysed fifty-two female athletes in the high-risk sports of handball and volleyball, measuring for their static and dynamic balance index scores, using the Sport KAT 2000 testing system. This method may be used to monitor balance and coordination systems and may help to develop simpler measurements of neuromuscular control, which can be used to estimate risk predictors in athletes who withdraw from sports due to lower sports results or ruptured anterior cruciate ligament and to direct female athletes to more effective, targeted preventive interventions. The tested Croatian female athletes with lower sports results and ACL knee injury incurred after the testing were found to have a higher balance index score compared to healthy athletes. We therefore suggest that a higher balance index score can be used as an effective risk predictor for lower sports results and lesser sports motivation, anterior cruciate ligament injury and the ultimate decision to withdraw from active participation in sports. If the balance testing results prove to be effective in predicting the occurrence of ligament injuries during future sports activities, we suggest that prophylactic training programs be introduced during athlete training, since the prevention of an initial injury will be more effective than prevention of injury recurrence.     

Functional dyspepsia affects women more than men in daily life: A case-control study in primary care

Background: Little is known about possible gender differences among patients with functional dyspepsia (FD). Few studies have measured health-related quality of life (HRQoL) in patients with FD using a population-based control group as a reference.Objectives: This study aimed to determine the degree of HRQoL impairment among patients with FD, to assess the self-reported health impact resulting from the disease, and to analyze any gender differences.Methods: A questionnaire that included the HRQoL Short Form 36 (SF-36) Health Survey, Hospital Anxiety and Depression Scale, and other measurements was mailed to patients with FD identified from medical records. The control group was randomly selected from the general population in the same geographical area. Responses to the SF-36 were transferred to a standard scale ranging from 0 (the worst possible score) to 100 (the best possible score).Results: Responders were assigned to 2 gender-specific subgroups, each with 88 patients with FD and 344 randomly matched controls, all aged 18 to 65 years. Compared with the controls, the HRQoL of patients with FD was impaired in all SF-36 dimensions except one-role limitations caused by emotional problems. Female patients with FD had a significantly lower SF-36 score in the physical functioning dimension than did male patients (82.4 vs 90.5, respectively; P < 0.01). Both groups of patients with FD had impaired HRQoL compared with their respective control group in the dimensions of bodily pain (women: 69.3 vs 80.6, P < 0.001; and men: 75.8 vs 84.8, P < 0.001) and general health (women: 62.0 vs 75.6, P < 0.001; and men: 70.6 vs 78.6, P < 0.001). Additionally, women with FD had significant impairment compared with their respective control group in the dimensions of physical functioning (82.4 vs 89.3; P < 0.01) and physical role limitations (72.1 vs 85.9; P < 0.001). Depression was significantly more common among male patients with FD than among male controls (6.8% vs 2.0%, respectively; P < 0.05). More gastrointestinal comorbidity was reported among patients of both sexes compared with controls.Conclusions: This population-based case-control study reported HRQoL impairment overall among patients with FD. This impairment was more apparent in female patients than in female controls. Females with FD tended to be more negatively affected in their daily life than their male counterparts. These gender differences should be investigated further in future studies.     

Effect of limb dominance and sex on neuromuscular activation patterns in athletes under 12 performing unanticipated side-cuts

Non-contact ACL injuries are one of the most common injuries to the knee joint among adolescent/collegiate athletes, with sex and limb dominance being identified as risk factors. In children under 12 years of age (U12), these injuries occur less often and there is no sex-bias present. This study set out to explore if sex and/or limb dominance differences exist in neuromuscular activations in U12 athletes. Thirty-four U12 males and females had six bilateral muscles analyzed during unanticipated side-cuts. Principal component analysis was performed, capturing differences in overall magnitudes and timing of peak magnitudes. Two-way mixed-model ANOVAs determined significant limb effects with both sexes displaying (i) greater magnitudes in the lateral gastrocnemius and both hamstrings in the dominant limb and (ii) earlier timing of peak magnitudes in both gastrocnemii, both hamstrings and vastus medialis in the non-dominant limb, while no sex differences were identified. This study demonstrated that limb dominance, not sex, affects neuromuscular activation strategies in U12 athletes during unanticipated side-cuts. When developing injury prevention programs for younger athletes, an increased focus on balancing neuromuscular activations in both limbs could be beneficial in reducing the likelihood of ACL injuries in these athletes as they mature through puberty.     

Injuries in racket sports among Slovenian players

On the sample of 83 top Slovenian athletes we have studied the frequency of injuries among table tennis, tennis and badminton players, types of injuries and severity of injuries--the latter based on data of players absences from training and/or competition processes. The most liable parts to injuries are shoulder girdle (17.27%), spine (16.55%) and ankle (15.83%), while foot (10.07%) and wrist (12.23%) are slightly less liable to injuries. The most frequent injuries in racket sports pertain to muscle tissues. According to this data, the majority of injuries occur halfway through a training session or a competition event, mostly during a competition season. The injuries primarily pertain to muscle tissues; these are followed by joint and tendon injuries. There are no differences between male and female players. Compared to other racket sports players, table tennis players suffer from fewer injuries.     

Quadriceps and hamstrings prelanding myoelectric activity during landing from different heights among male and female athletes

ACL tear is a major concern among athletes, coaches and sports scientists. More than taking the athlete away from training and competition, ACL tear is a risk factor for early-onset of knee osteoarthritis, and, therefore addressing strategies to avoid such injury is pertinent not only for competitive athletes, but for all physically active subjects. Imbalances in the prelanding myoelectric activity of the hamstrings and quadriceps muscles have been linked to ACL injuries. We investigated the effect of landing from different heights on prelanding myoelectric activity of the hamstrings and quadriceps muscles in recreational athletes. Thirty recreational athletes (15 male and 15 female) performed three bilateral drop jumps from two different heights; 20 cm and 40 cm while myoelectric activity of the vastus medialis, rectus femoris, biceps femoris and medial hamstrings were collected. When increasing the height of drop landing tasks prelanding normalized myoelectric activity of the quadriceps was increased by 15–20% but no significant changes were found for the hamstrings. Female athletes exhibited higher activity of the medial hamstrings compared to their male counterparts. We concluded that increasing the height of drop landing tasks is associated with increased myoelectric activity of the quadriceps but not the hamstrings in recreational athletes. These differences in muscle activity may be related to increased risk for ACL injury when the height is increased. Female athletes demonstrated higher recruitment of the medial hamstrings.     

Part-time grouping of rabbit does in enriched housing: effects on performances,injury occurrence and enrichment use

Collective housing is perceived as a possible way to improve rabbit welfare, especially among adult females, which are normally individually housed. Part-time group housing seems to allow a better balance between welfare and health than continuous group housing, but practical implementation and consequences for reproductive performance have not been extensively studied. The aim of this work was to compare weight, feed intake, litter size, injury occurrence, body integrity, and spatial location of female rabbits housed part-time in group housing (PGH group, n = 32) or housed individually (IH group, n = 8). Females were grouped by opening connecting hatches between four individual enriched cages (platform, wood stick and gnawing block). Collective housing started 12 days after artificial insemination and was interrupted at the 10th day (instead of the 15th day later as originally planned) due to high injury rates and severe injuries caused by fighting. The proportion of injured females increased from 25% on the first day of grouping to 63% on the 10th day. Female weight gain during the experiment was similar in the two groups. Litter size at weaning was 9% lower in the PGH group than in the IH group (9.2 vs 10.0, P < 0.01). Platform use was recorded in 32% of the observations and was the highest during the 2 weeks before weaning (46% and 47% of total observations, P < 0.05). During the grouping period, there were at least two females in the same housing unit in 59.4% of the cases, at least two females were located on the same level in 31.3% of the cases. In conclusion, connecting individual cages is an ergonomic solution for part-time group housing, but does not prevent fights for the establishment of a social hierarchy. This is detrimental to the health and body integrity of female rabbits.     

Control of dynamic foot-ground interactions in male and female soccer athletes: Females exhibit reduced dexterity and higher limb stiffness during landing

Controlling dynamic interactions between the lower limb and ground is important for skilled locomotion and may influence injury risk in athletes. It is well known that female athletes sustain anterior cruciate ligament (ACL) tears at higher rates than male athletes, and exhibit lower extremity biomechanics thought to increase injury risk during sport maneuvers. The purpose of this study was to examine whether lower extremity dexterity (LED) – the ability to dynamically control endpoint force magnitude and direction as quantified by compressing an unstable spring with the lower limb at submaximal forces – is a potential contributing factor to the “at-risk” movement behavior exhibited by female athletes. We tested this hypothesis by comparing LED-test performance and single-limb drop jump biomechanics between 14 female and 14 male high school soccer players. We found that female athletes exhibited reduced LED-test performance (p=0.001) and higher limb stiffness during landing (p=0.008) calculated on average within 51 ms of foot contact. Females also exhibited higher coactivation at the ankle (p=0.001) and knee (p=0.02) before landing. No sex differences in sagittal plane joint angles and center of mass velocity at foot contact were observed. Collectively, our results raise the possibility that the higher leg stiffness observed in females during landing is an anticipatory behavior due in part to reduced lower extremity dexterity. The reduced lower extremity dexterity and compensatory stiffening strategy may contribute to the heightened risk of ACL injury in this population.     

Sex differences in intraventricular hemorrhage rates among very low birth weight newborns

Background: The influence of male or female sex on newborn outcomes has been recognized for >30 years. Several studies have observed higher mortality and morbidity in males than in females. It is not clear how this sex difference is sustained in postnatal complications such as intraventricular hemorrhage (IVH), especially in very low birth weight (VLBW) newborns.Objective: This study examined possible sex-related differences in IVH rates among VLBW neonates.Methods: In a retrospective observational study conducted in Hospital Privado, Córdoba, Argentina, data from 332 consecutive VLBW newborns in a 12-year period were reviewed. Maternal factors, labor and delivery characteristics, and neonatal parameters, including the results of cranial ultrasound examination to detect IVH, were compared for males and females. Bivariate and multivariate logistic regression analyses were performed.Results: A total of 322 VLBW newborns were included, 168 males and 154 females. Compared with female neonates, male neonates had a higher risk of overall IVH (26.8% vs 9.7%; odds ratio [OR] = 3.4 [95% CI, 1.8–6.4]; P < 0.001) and for grades III or IV on the Papile scale (16.1% vs 1.9%; OR = 9.6 [95% CI, 2.9–32.5]; P < 0.001). In the multivariate logistic regression model, male sex sustained the association with a greater risk of IVH (OR = 6.8 [95% CI, 3.8–12.0]).Conclusions: IVH was significantly associated with male sex in these VLBW newborns. Because other factors affect these differences, further research is required.     

Female protection in progressive renal disease is associated with estradiol attenuation of superoxide production

Background: Several types of renal disease progress at a faster rate in men compared with women, but the reasons for this sex difference are not well understood. Chronic renal disease is associated with elevated levels of toxic reactive oxygen species (ROS). Superoxide, the major ROS in the kidney, is generated by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase.Objective: To determine if female protection from renal disease progression is consistent with 17β-estradiol (E₂) attenuation of superoxide production, this study was conducted to assess superoxide production in the renal cortex of male and female control and renal wrap (RW) rats, as well as in ovariectomized rats treated with vehicle or E₂.Methods: Sprague-Dawley rats were divided into 2 sham operation male (Sham-M) and female (Sham-F) control groups, and 4 RW hypertensive groups: RW-M; RW-F; RW ovariectomized females treated with vehicle (RW-OVX); and RW ovariectomized females treated with E₂, supplied as a 0.24 mg/60-day release pellet (RW-OVX+E₂). All groups were maintained on a high-sodium (4% NaCl) diet for 6 weeks.Results: Mean (SEM) markers of renal injury and oxidative stress, including urinary protein (mg/24 h: RW-M, 298 [31] vs RW-F, 169 [22]; P < 0.001), microalbuminuria (RW/Sham arbitrary units [AU]/24 h: M, 8.78 [0.58] vs F, 4.31 [1.0]; P < 0.005), and malondialdehyde (nmol/24 h: RW-M, 167 [23] vs RW-F, 117 [8.5]; P < 0.05) levels, as well as mean glomerular volume (μm³ × 10⁶: RW-M, 2.25 [0.16] vs RW-F, 1.25 [0.04]; P < 0.001) and the glomerulosclerotic index (AU: RW-M, 2.64 [0.19] vs RW-F, 1.10 [0.09]; P < 0.001) were greater in both control and RW males compared with females in the same treatment groups. Though RW surgery increased mean arterial pressure in both male and female rats, no sex difference was observed. Under these conditions, mean (SEM) renal cortical NADPH oxidase activity was 1.3-fold higher in RW males compared with RW females (relative light units [RLU]/180 sec: RW-M, 4080 [240] vs RW-F, 3200 [260]; P < 0.05). Ovariectomy increased NADPH oxidase activity by 1.4-fold (RLU/180 sec: RW-OVX, 4520 [184]; P < 0.01) under conditions in which the mean glomerular volume and glomerulosclerotic index were both increased by 1.5-fold, whereas E₂ replacement (RLU/180 sec: RW-OVX+E₂, 2745 [440]) prevented these effects. Furthermore, the effects on NADPH oxidase activity were mirrored by changes in the protein abundance of NADPH oxidase subunit p22P^phox.Conclusion: These results suggest that E₂ protects the female kidney in part by attenuating injury-induced increases in renal superoxide production.     

Hip extension, knee flexion paradox: a new mechanism for non-contact ACL injury

Considering that an athlete performs at-risk sports activities countless times throughout the course of his or her career prior to the instance of anterior cruciate ligament (ACL) injury, one may conclude that non-contact ACL injury is a rare event. Nevertheless, the overall number of non-contact ACL injuries, both in the US and worldwide, remains alarming due to the growing number of recreational and professional athletes participating in high-risk activities. To date, numerous non-contact ACL injury mechanisms have been proposed, but none provides a detailed picture of sequence of events leading to injury and the exact cause of this injury remains elusive. In this perspective article, we propose a new conception of non-contact ACL injury mechanism that comprehensively integrates risk factors inside and outside the knee joint. The proposed mechanism is robust in the sense that it is biomechanically justifiable and addresses a number of confounding issues related to ACL injury.     

Impact of chronicity of injury on the proportion of mesenchymal stromal cells derived from anterior cruciate ligaments

Background aimsThe graft-healing potential of mesenchymal stromal cells (MSCs) derived from the remnants of ruptured anterior cruciate ligaments (ACLs) after ACL reconstruction may depend on the chronicity of the injury. The aim of this study was to assess the quantitative and phenotypic differences between MSCs isolated from ACL remnants in patients with (sub)acute and chronic tearing.MethodsTorn ACL remnants were harvested during ACL reconstruction from 41 patients, 24 with (sub)acute ACL (<6 months from injury to surgery) and 17 with chronic ACL (time interval >6 months) tears. MSCs isolated from these samples were assessed for quantitative and phenotypic differences, and the correlation between the proportion of MSCs and the chronicity of ACL tear was evaluated.ResultsAt passage 0, the mean proportion of MSCs (CD34⁻, CD44⁺, CD90⁺ and CD105⁺) was higher in (sub)acute than in chronic ACL tear samples (20.69% ± 7.82% versus 9.85% ± 8.01%, P < 0.001). At passages 1 and 2, however, MSC proportions did not differ significantly in the two groups. Time interval showed a negative correlation with MSC proportion only at passage 0 (r = −0.505, P < 0.001). The optimal cutoff value for time from injury to surgery yielding <10% freshly isolated ACL-MSCs, a percentage expected to have low tissue healing potential, was 23.5 months.ConclusionsThe proportion of freshly isolated MSCs was higher in samples from patients with (sub)acute tearing than in chronic ACL tearing and negatively correlated with the time interval between trauma and surgery.     

Improvements in Metabolic Control in Adults with Type 2 Diabetes Following Referral to a Diabetes Center, 2005–2010

Objective: We aimed to compare metabolic control in adults with diabetes in the general population to those newly referred to a diabetes center and after 1 year of specialty care.Methods: We performed a retrospective comparison of adults with diabetes aged ≥20 years data from the National Health and Nutrition Examination Survey (NHANES, n = 1,674) and a diabetes center (n = 3,128) from 2005–2010. NHANES participants represented the civilian, non-institutionalized U.S. population. Diabetes center referrals lived primarily around eastern Massachusetts. The proportion attaining targets for glycated hemoglobin A1c (A1c), blood pressure (BP), low-density lipoprotein (LDL) cholesterol, or all 3 (ABC control) and the proportion prescribed medications to lower A1c, BP, or cholesterol were evaluated.Results: Compared to the general sample, a smaller proportion of new diabetes center referrals had A1c <7% (<53 mmol/mol, 24% vs. 53%, P<.001), BP <130/80 mm Hg (38% vs. 50%, P<.001), and ABC control (5.6% vs. 17%, P<.001) but not LDL<100 mg/dL (<2.6 mmol/L, 54% vs. 53%, P = .65). After 1 year, more diabetes center referrals attained targets for A1c (40%), BP (38%), LDL (67%), and ABC control (15%) (P<.001 for all versus baseline). ABC control was not different between the general sample and diabetes center referrals at 1 year (P = .16). After 1 year, a greater percentage of diabetes center referrals compared to the general sample were prescribed medications to lower glucose (95% vs. 72%), BP (79% vs. 64%), and cholesterol (77% vs. 54%)(all P<.001).Conclusion: Compared to the general population, glycemic control was significantly worse for adults newly referred to the diabetes center. Within 1 year of specialty care, ABC control increased 270% in the setting of significant therapy escalation.Abbreviations:A1c = glycated hemoglobin A1cABC = composite of A1c, blood pressure, and cholesterolACEi = angiotensin-converting enzyme inhibitorARB = angiotensin receptor blockerBMI = body mass indexBP = blood pressureEHR = electronic health recordLDL = low-density lipoproteinNCHS = National Center for Health StatisticsNHANES = National Health and Nutrition Examination SurveyPCP = primary care provider     

Alterations to movement mechanics can greatly reduce anterior cruciate ligament loading without reducing performance

Anterior cruciate ligament (ACL) injuries are one of the most common and potentially debilitating sports injuries. Approximately 70% of ACL injuries occur without contact and are believed to be preventable. Jump stop movements are associated with many non-contact ACL injuries. It was hypothesized that an athlete performing a jump stop movement can reduce their peak tibial shear force (PTSF), a measure of ACL loading, without compromising performance, by modifying their knee flexion angle, shank angle, and foot contact location during landing. PTSF was calculated for fourteen female basketball players performing jump stops using their normal mechanics and mechanics modified to increase their knee flexion angle, decrease their shank angle relative to vertical and land more on their toes during landing. Every subject tested experienced drastic reductions in their PTSF (average reduction=56.4%) using modified movement mechanics. The athletes maintained or improved their jump height with the modified movement mechanics (an average increase in jump height of 2.5 cm). The hypothesis was supported: modifications to jump stop movement mechanics greatly reduced PTSF and therefore ACL loading without compromising performance. The results from this study identify crucial biomechanical quantities that athletes can easily modify to reduce ACL loading and therefore should be targeted in any physical activity training programs designed to reduce non-contact ACL injuries.     

Performance of Free Versus Total Cortisol Following Cosyntropin Stimulation Testing in an Outpatient Setting

Objective: Free cortisol (FC) is potentially superior to total cortisol (TC) measurements in selected clinical settings; however, the advantages of uniform use of FC in outpatient settings are unclear. The objectives of this study were to describe the dynamic response of FC during cosyntropin stimulation testing (CST) compared to TC and to determine the rates of discordance.Methods: This is a cross-sectional study of 295 stable patients who underwent CST in an outpatient Endocrine Testing Center. The main outcome measures were TC and FC measurements during CST.Results: The mean age of the 295 subjects was 49.1 (16.9) years. Of 218 females, 43 were taking estrogen therapy (ET) at the time of testing. Adrenal insufficiency (AI) was diagnosed in 41/295 (14%) patients. The FC concentrations were associated with TC concentrations at baseline (R² = 0.77, P<.001), 30 minutes (R² = 0.87, P<.001), and 60 minutes (R² = 0.90, P<.001). The FC cutoffs for AI were 873 and 1,170 ng/dL at 30 and 60 minutes, respectively. The FC had a more pronounced fold change from baseline to peak than TC (median 3.2 vs. 1.7, P<.001). Both TC and FC at baseline were higher in females on ET compared to those who were not and to males; however, peak TC and FC values were similar. In 3/43 females on ET, FC, and TC results were discordant (P = .003).Conclusion: We report 99% concordance of TC and FC measurements in a large outpatient cohort. The discordant rates were high in females treated with ET (7%). The FC measurements during CST in females on ET may provide a more rapid and accurate diagnosis of AI.Abbreviations:ACTH = adrenocorticotropic hormoneAI = adrenal insufficiencyCBG = corticosteroid-binding proteinCST = cosyntropin stimulation testingET = estrogen therapyFC = free cortisolfΔ = fold changeROC = receiver operating characteristicTC = total cortisol     

Serum vanadium concentrations in different sports modalities

AimsThe aim of this study was to compare serum vanadium (V) concentrations between athletes of different sports modalities and people who did not practise physical exercise regularly.MethodsOne hundred and twenty-one subjects divided into a control group (CG; n = 37; 1.75 ± 0.03 m; 79.45 ± 10.20 kg; 24.72 ± 6.06 years) and an athletes’ group (AG; n = 84; 1.77 ± 0.05 m; 66.34 ± 6.12 kg; 19.57 ± 1.95 years) participated in this research. AG were classified by sports modality: aerobic (AE; n = 26), anaerobic (ANA; n = 22); aerobic-anaerobic (AE-ANA; n = 36). Serum V concentrations were analysed by inductively coupled plasma mass spectrometry.ResultsAG showed higher V concentrations compared to CG (p < 0.01). AE obtained higher concentrations compared to ANA and AE-ANA (p < 0.05).ConclusionsPhysical training could increase serum V levels. Specifically, aerobic sports modalities could increase serum V levels to a greater extent than other sports modalities.     

Mechanisms and Risk Factors for Noncontact ACL Injury in Age Mature Athletes Who Engage in Field Or Court Sports: A Summary of the Literature Since 1980

ABSTRACT: Serpell, BG, Scarvell, JM, Ball, NB, and Smith, PN. Mechanisms and risk factors for noncontact ACL injury in age mature athletes who engage in field or court sports: A summary of literature since 1980. J Strength Cond Res 26(11): 3160-3176, 2012-Epidemiological data show that in the last 10 years alone the incidence and rate of anterior cruciate ligament (ACL) injuries have not changed appreciably. Furthermore, many ACL injuries appear to be noncontact in nature and sustained while engaging in some field or court sport. Thus, the need to investigate novel methods and adopt training strategies to prevent ACL injuries is paramount. To do so, however, requires an understanding of the mechanisms and risk factors for the injury. The aim of this review was to investigate the mechanisms and risk factors for noncontact ACL injuries in age mature athletes who compete in field or court sports. A search of the entire MEDLINE database for biomedicine was performed, and an iterative reference check was also conducted. A total of 87 articles disclosed met the eligibility criteria. Articles were grouped into 'themes'; 'anatomical and biomechanical mechanisms and risk factors,' 'intrinsic mechanisms and risk factors,' and 'extrinsic mechanisms and risk factors.' In this review, it is concluded that there are still a number of risk factors and mechanisms for noncontact ACL injury that are not well understood. However, the importance of dynamic knee joint stability is highlighted. It is also suggested that novel methods for preventing ACL injury be investigated and developed.     

The effects of gender on quadriceps muscle activation strategies during a maneuver that mimics a high ACL injury risk position.

While the increased incidence of serious knee injuries in female athletes is well established, the underlying neuromuscular mechanisms related to the elevated ACL injury rate has yet to be delineated. Video analysis of ACL injury during competitive sports play indicates a common body position associated with non-contact ACL injury; the tibia is externally rotated, the knee is close to full extension, the foot is planted and as the limb is decelerated it collapses into valgus. The purpose of the current prospective study was to evaluate gender differences in quadriceps muscle activation strategies when performing a physically challenging, but reproducible maneuver that mimics the high ACL injury risk position (in the absence of high velocity and high loads). Twenty physically active college-aged subjects (10 male and 10 female) performed multiple sets of the prescribed exercise. EMG recordings were employed to measure the ratio of activation between the medial and lateral quadriceps during the 4, 8, 12, 16, and 20th sets of exercise. Females demonstrated decreased RMS medial-to-lateral quadriceps ratios compared to males (F(1,18)=5.88, p=0.026). There was no main effect of set number on RMS quadriceps ratio (p>0.05). The results of this study suggest that females utilize neuromuscular activation strategies which may contribute to "dynamic valgus" and ACL rupture when performing high-risk maneuvers.