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Background: The demands of professional tennis, including physical and psychological aspects, contribute to the frequency of retirements at elite levels of the sport. Purpose: The aim of this study was to explore the frequency of injuries and the factors that influence the retirements of professional tennis players competing in the Davis Cup over the last two decades. Study Design: Retrospective cohort study. Methods: The data set includes data from 6,060 men's singles matches that included 1,814,141 games from Davis Cup ties played between 2000 to 2019. Factors that might influence the retirements were studied by means of generalized linear models using Poisson distribution. Incidence rates by 1000 games and incidence rate ratios of retirements are provided as association measures. Results: The retirement incidence was 1.05 per 1000 games [95% CI: 0.90, 1.21]. The main risk factors associated with retirements were matches played on hard courts (IRR: 2.52 [95% CI: 1.32, 4.83]) and matches played in the final two matches of the tie and in a best-of-5-set format (IRR: 2.63 [95% CI: 1.69, 4.09] and IRR: 5.52 [95% CI: 3.50, 8.69], respectively). The most common injuries that led to retirements were those affecting the lower extremities, specifically involving muscular or tendinous tissues. Conclusion: This study provides valuable insights for coaches, players, support teams, and epidemiologists regarding retirements and their associated risk factors in Davis Cup tournaments. These findings may guide future research and inform strategies aimed at managing player health and performance in professional tennis. Level of evidence: Level 2b. [ABSTRACT FROM AUTHOR]

Context: Six months is the expected time frame to return to sport (RTS) after hip arthroscopy for femoroacetabular impingement syndrome (FAIS). Objective: The primary aims of this study were to (1) report the RTS rate of physically active individuals 6 months after arthroscopic surgery for FAIS and (2) compare the self-reported hip function between those who were able to RTS against those who had not. Design: Cohort study. Setting: The Ohio State University Wexner Medical Center. Patients: A total of 42 physically active individuals scheduled for hip arthroscopy for FAIS. Main Outcome Measures: Self-reported function, including preinjury and current activity levels and ability to participate in sport, were collected on 42 individuals with FAIS prior to surgery and at 6-month follow-up. Participants were allocated into 2 groups based on self-reported RTS status at 6-manth follow-up. Separate 2-way analyses of variance were used to test the interaction of groups (those who did/did not RTS). Main effects were reported in the absence of statistically significant interactions (P< .05). Results: Altogether, 28 of 42 participants (66%) returned for 6-month follow-up; 5 of the 14 participants (35.7%) lost to follow-up underwent contralateral hip surgery within the study time frame. At the 6-month follow-up, 16 of the remaining 28 participants (57.1%) reported that they had returned to sport, 5 of whom returned at their prior level of participation. There was no statistically significant interaction of group and time for either hip outcome score subscale (P > .20). Self-reported hip function improved over time, regardless of group (P<.001). Participants in the yRTS group demonstrated higher hip outcome score-sport scores than did the nRTS group, regardless of time (P = .04). Conclusions: Though just over half of participants returned to sport 6 months after hip arthroscopy for FAIS, only 18% returned to their previous level of sports participation. Participants who returned to sport reported better function than those who did not, but self-reported hip function improved over time regardless of group. The most commonly reported reasons for not returning to sport were weakness (69.6%), fear (65.2%), and pain (56.5%). [ABSTRACT FROM AUTHOR]

Background: Despite knee extensor and flexor strength reportedly being associated with injury risk, including rupture of the anterior cruciate ligament in girls, there is limited evidence for the longitudinal changes in lower extremity strength. Purpose: To investigate the sex-specific relationship with longitudinal changes of knee extensor and flexor strength associated with maturation. Study design: Cohort study; Level of evidence, 2. Methods: Adolescent boys and girls (N = 257; 208 adolsecent girls) participating in high school basketball, volleyball, and soccer were assessed longitudinally in at least 2 different pubertal stages. Pubertal status (prepubertal, pubertal, and postpubertal) was determined with the modified Pubertal Maturation Observation Scale questionnaire. After a warm-up of 5 submaximal repetitions, participants were tested for concentric peak isokinetic strength for knee extension and flexion at 300 deg/s over 10 repetitions and normalized to body weight. Linear mixed models were used to test for the effect of pubertal stage, sex, and their interaction. Results: Significant interactions were identified that indicated different maturational trajectories for knee muscle strength for adolescent boys and girls, particularly between prepubertal and pubertal stages, in which boys demonstrated greater mass normalized knee extensor increases than girls (right, +12% vs +5%; left, +13% vs +7%; P <.001). For knee flexors, boys demonstrated increased strength, while girls demonstrated decreased relative knee flexor strength (right, +4% vs −1%, P =.03; left, +3 vs −3%, P =.009). Conclusion: The findings of this study support a differential effect of sex and maturation on important knee strength outcomes that may have implications for knee injury reduction, particularly in adolescent girls as they mature. [ABSTRACT FROM AUTHOR]

Background: Investigators have proposed that various physical head and neck characteristics, such as neck strength and head and neck size, are associated with protection from mild traumatic brain injury (mTBI/concussion). Objectives: To systematically review the literature and investigate potential relationships between physical head and neck characteristics and mTBI risk in athletic and military populations. Methods: A comprehensive search of seven databases was conducted: MEDLINE, EMBASE, CINAHL, Scopus, SPORTDiscus, Cochrane Library, and Web of Science. Potential studies were systematically screened and reviewed. Studies on military and athletic cohorts were included if they assessed the relationship between physical head-neck characteristics and mTBI risk or proxy risk measures such as head impact kinematics. Results: The systematic search yielded a total of 11,723 original records. From these, 22 studies met our inclusion criteria (10 longitudinal, 12 cross-sectional). Relevant to our PECO (Population, Exposure, Comparator, and Outcomes) question, exposures included mTBI incidence and head impact kinematics (acceleration, velocity, displacement) for impacts during sport play and training and in controlled laboratory conditions. Outcome characteristics included head and neck size (circumference, mass, length, ratios between these measures), neck strength and endurance, and rate of force development of neck muscles. Discussion: We found mixed evidence for head and neck characteristics acting as risk factors for and protective factors against mTBI and increased susceptibility to head impacts. Head-neck strength and size variables were at times associated with protection against mTBI incidence and reduced impact kinematics (14/22 studies found one or more head-neck variable to be associated with protection); however, some studies did not find these relationships (8/22 studies found no significant associations or relationships). Interestingly, two studies found stronger and larger athletes were more at risk of sustaining high impacts during sport. Strength and size metrics may have some predictive power, but impact mitigation seems to be influenced by many other variables, such as behaviour, sex, and impact anticipation. A meta-analysis could not be performed due to heterogeneity in study design and reporting. Conclusion: There is mixed evidence in the literature for the protective capacity of head and neck characteristics. We suggest field-based mTBI research in the future should include more dynamic anthropometric metrics, such as neck stiffness and response to perturbation. In addition, laboratory-based mTBI studies should aim to standardise design and reporting to help further uncover these complicated relationships. [ABSTRACT FROM AUTHOR]

Context: Due to the limitations of single-center studies in achieving appropriate sampling with relatively rare disorders, multicenter collaborations have been proposed to achieve desired sampling levels. However, documented reliability of biomechanical data is necessary for multicenter injury-prevention studies and is currently unavailable. Objective: To measure the reliability of 3-dimensional (3D) biomechanical waveforms from kinetic and kinematic variables during a single-leg landing (SLL) performed at 3 separate testing facilities. Design: Multicenter reliability study. Setting: 3 laboratories. Patients: 25 female junior varsity and varsity high school volleyball players who visited each facility over a 1-mo period. Intervention: Subjects were instrumented with 43 reflective markers to record 3D motion as they performed SLLs. During the SLL the athlete balanced on 1 leg, dropped down off of a 31-cm-high box, and landed on the same leg. Kinematic and kinetic data from both legs were processed from 2 trials across the 3 laboratories. Main Outcome Measures: Coefficients of multiple correlations (CMC) were used to statistically compare each joint angle and moment waveform for the first 500 ms of landing. Results: Average CMC for lower-extremity sagittal-plane motion was excellent between laboratories (hip .98, knee .95, ankle .99). Average CMC for lower-extremity frontal-plane motion was also excellent between laboratories (hip .98, knee .80, ankle .93). Kinetic waveforms were repeatable in each plane of rotation (3-center mean CMC ≥.71), while knee sagittal-plane moments were the most consistent measure across sites (3-center mean CMC ≥.94). Conclusions: CMC waveform comparisons were similar relative to the joint measured to previously published reports of between-sessions reliability of sagittal- and frontal-plane biomechanics performed at a single institution. Continued research is needed to further standardize technology and methods to help ensure that highly reliable results can be achieved with multicenter biomechanical screening models. [ABSTRACT FROM AUTHOR]

Objectives: To determine if sport specialization increases the risk of anterior knee pain in adolescent female athletes. Design: Retrospective cohort epidemiology study. Methods: Female basketball, soccer, and volleyball players (N = 546) were recruited from a single county public school district in Kentucky consisting of 5 middle schools and 4 high schools. A total of 357 multisport and 189 single-sport (66 basketball, 57 soccer, and 66 volleyball) athlete subjects were included due to their diagnosis of patellofemoral pain (PFP) on physical exam. Testing consisted of a standardized history and physician-administered physical examination to determine the presence of PFP. This study compared self-reported multisport athletes with sport-specialized athletes participating in only 1 sport. The sports-participation data were normalized by sport season, with each sport accounting for 1 season of exposure. Incidence rate ratios and 95% confidence intervals (CI) were calculated and used to determine significant differences between athletes who specialized in sport in early youth and multisport athletes. Results: Specialization in a single sport increased the relative risk of PFP incidence 1.5-fold (95% CI 1.0–2.2, P = .038) for cumulative PFP diagnoses. Specific diagnoses such as Sinding Larsen Johansson/ patellar tendinopathy (95% CI 1.5–10.1, P = .005) and Osgood Schlatter disease (95% CI 1.5–10.1, P = .005) demonstrated a 4-fold greater relative risk in single-sport compared with multisport athletes. Incidence of other specific PFP diagnoses such as fat pad, plica, trauma, pes anserine bursitis, and iliotibial-band tendonitis was not different between single-sport and multisport participants (P > .05). Conclusion: Early sport specialization in female adolescents is associated with increased risk of anterior knee-pain disorders including PFP, Osgood Schlatter, Sinding Larsen-Johansson compared with multisport athletes. [ABSTRACT FROM AUTHOR]

Background: Quadriceps weakness is a predictor of long-term knee function and strength recovery can vary from months to years after anterior cruciate ligament reconstruction (ACLR). However, few studies evaluate quadriceps strength and self-reported function within the first several weeks after ACLR. Hypothesis/Purpose: To examine changes over time in quadriceps strength symmetry, quadriceps peak torque, and self-reported knee function prior to and at six, 12, and 24 weeks post-ACLR. The hypotheses were 1) quadriceps strength symmetry, bilateral quadriceps peak torque, and patient-reported function would improve over time from pre-ACLR to 24 weeks post-ACLR and 2) significant improvements in patient-reported function, but not strength symmetry, would occur between time points. Study Design: Prospective, cohort study Methods: Thirty participants completed four testing sessions: pre-surgery and six, 12, and 24 weeks post-ACLR. Isometric quadriceps strength testing was performed at six weeks and isokinetic quadriceps strength was measured at all other testing points. Quadriceps index was calculated to evaluate between limb quadriceps strength symmetry. The Knee injury and Osteoarthritis Outcome Score (KOOS) and International Knee Documentation Committee Subjective Knee Evaluation Form (IKDC) were administered at each time point. A repeated-measures analysis of variance evaluated changes over time, with post-hoc comparisons to determine at which time-point significant changes occurred. Results: Quadriceps strength symmetry, involved limb quadriceps peak torque and all patient-reported outcome scores increased over time (p<0.02). Post-hoc tests showed that neither self-reported outcomes, nor quadriceps index improved between pre-surgery and six-weeks post-ACLR. From six to 12 weeks post-ACLR, scores on IKDC and KOOS Pain, Symptoms, Quality of Life, and Sport subscales improved (p≤0.003). From 12 to 24 weeks post-ACLR, quadriceps strength symmetry, involved limb quadriceps peak torque, KOOS-Symptoms, Quality of Life, and Sport subscales and the IKDC improved (p≤0.01). Uninvolved limb quadriceps peak torque did not change across any time point (p≥0.18). Conclusion: Patient-reported knee function increased between six and 24 weeks post-ACLR, while increases in involved limb quadriceps strength and quadriceps strength symmetry were not noted until 12-24 weeks post-ACLR. Level of Evidence: 2b, individual cohort study [ABSTRACT FROM AUTHOR]

Context: As high school female athletes demonstrate a rate of noncontact anterior cruciate ligament (ACL) injury 3-6 times higher than their male counterparts, research suggests that sagittal-plane hip strength plays a role in factors associated with ACL injuries. Objective: To determine if gender or age affect hip-abductor strength in a functional standing position in young female and male athletes. Design: Prospective cohort design. Setting: Biomechanical laboratory. Participants: Over a 3-y time period, 852 isokinetic hip-abduction evaluations were conducted on 351 (272 female, 79 male) adolescent soccer and basketball players. Intervention: Before testing, athletes were secured in a standing position, facing the dynamometer head, with a strap secured from the uninvolved side and extending around the waist just above the iliac crest. The dynamometer head was positioned in line with the body in the coronal plane by aligning the axis of rotation of the dynamometer with the center of hip rotation. Subjects performed 5 maximum-effort repetitions at a speed of 120°/s. The peak torque was recorded and normalized to body mass. All test trials were conducted by a single tester to limit potential interrater test error. Main Outcome Measure: Standing isokinetic hip-abduction torque. Results: Hip-abduction torque increased in both males and females with age (P < .001) on both the dominant and nondominant sides. A significant interaction of gender and age was observed (P < .001), which indicated that males experienced greater increases in peak torque relative to body weight than did females as they matured. Conclusions: Males exhibit a significant increase in normative hip-abduction strength, while females do not. Future study may determine if the absence of similar increased relative hip-abduction strength in adolescent females, as they age, may be related to their increased risk of ACL injury compared with males. [ABSTRACT FROM AUTHOR]

Context: Anterior cruciate ligament (ACL) injuries are prevalent in female athletes. Specific factors have possible links to increasing a female athlete's chances of suffering an ACL injury. However, it is unclear if augmented feedback may be able to decrease possible risk factors. Objective: To compare the effects of task-specific feedback on a repeated tuck-jump maneuver. Design: Double-blind randomized controlled trial. Setting: Sports-medicine biodynamics center. Patients: 37 female subjects (14.7 ± 1.5 y, 160.9 ± 6.8 cm, 54.5 ± 7.2 kg). Intervention: All athletes received standard off-season training consisting of strength training, plyometrics, and conditioning. They were also videotaped during each session while running on a treadmill at a standardized speed (8 miles/h) and while performing a repeated tuck-jump maneuver for 10 s. The augmented feedback group (AF) received feedback on deficiencies present in a 10-s tuck jump, while the control group (CTRL) received feedback on 10-s treadmill running. Main Outcome Measures: Outcome measurements of tuck-jump deficits were scored by a blinded rater to determine the effects of group (CTRL vs AF) and time (pre- vs posttesting) on changes in measured deficits. Results: A significant interaction of time by group was noted with the task-specific feedback training (P = .03). The AF group reduced deficits measured during the tuck-jump assessment by 23.6%, while the CTRL training reduced deficits by 10.6%. Conclusions: The results of the current study indicate that task-specific feedback is effective for reducing biomechanical risk factors associated with ACL injury. The data also indicate that specific components of the tuck-jump assessment are potentially more modifiable than others. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to characterize lower extremity passive muscle stiffness in a young, healthy, athletic population. It was hypothesized that males would exhibit greater stiffness than females and that hamstring stiffness would increase with increased passive hamstring stretch.Methods: Male (n = 52, age 16.0 ± 1.3 years, height 180.3 ± 7.9 cm, weight 73.1 ± 11.8 kg) and female (n = 89, age 15.6 ± 1.3 years, height 169.7 ± 8.1 cm, weight 65.2 ± 13.2 kg) high school basketball athletes were recruited for this study. Shear wave elastography (SWE) was used to measure shear wave velocity (m/s) of the biceps femoris muscle at three leg positions (40%, 60%, and 80%) of the maximum passive 90-90 straight-leg raise position for each leg. Hamstring stiffness (kPa) was quantified from the SWE elastogram using custom processing software.Results: Hamstring stiffness was significantly greater for males than females at every position on both the dominant and non-dominant limbs (p < 0.05). Hamstring stiffness was greater on the non-dominant limb than the dominant for females at the 40% position. Stiffness at 60% was greater than stiffness at 40% for males on both the dominant and non-dominant limbs. However, stiffness at 60% was greater than stiffness at 80% on the male non-dominant limb. Females demonstrated higher stiffness at 40% than both 60% and 80% for the dominant and non-dominant limbs.Conclusion: Healthy male basketball players had higher hamstring muscle stiffness than female players. Future studies may investigate what factors contribute to the large variability observed in muscle stiffness, resulting in mixed results on the effects of leg dominance and stretching positions. [ABSTRACT FROM AUTHOR]

Background: Recent studies indicate concussion increases risk of musculoskeletal injury in specific groups of patients. The purpose of this study was to determine the odds of anterior cruciate ligament (ACL) injury after concussion in a population-based cohort. Methods: International Classification of Diseases, 9th and 10th Revision (ICD-9, ICD-10) codes relevant to the diagnosis and treatment of a concussion and ACL tear were utilized to search the Rochester Epidemiology Project (REP) between 2000 and 2017. A total of 1653 unique patients with acute, isolated ACL tears were identified. Medical records for cases were reviewed to confirm ACL tear diagnosis and to determine history of concussion within 3 years prior to the ACL injury. Cases were matched by age, sex, and REP availability date to patients without an ACL tear (1:3 match), resulting in 4959 controls. The medical records of the matched control patients were reviewed to determine history of concussion. Results: 39 patients with a concussion suffered an ACL injury up to 3 years after the concussion. The rate of prior concussion was higher in ACL-injured cases (2.4%) compared to matched controls with no ACL injury (1.5%). This corresponds to an odds ratio of 1.6 (95% CI 1.1–2.4; p = 0.015). Conclusions: Although activity level could not be assessed, there are increased odds of ACL injury after concussion in a general population. Based on the evidence of increased odds of musculoskeletal injury after concussion, standard clinical assessments should consider concussion symptom resolution as well as assessment of neuromuscular factors associated with risk of injuries. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) injuries are a common cause of time loss in sports. Approximately one-third of ACL reconstructed athletes who return to sport suffer secondary injury. The presence of fatigue during athletic performance has been hypothesized to increase susceptibility to ACL injury. However, the relative role of fatigue in secondary ACL failures remains unexplored. Purpose: To assess how time elapsed within a game and within a season associate with secondary ACL injury occurrence in international professional athletes and American collegiate athletes. Study Design: Retrospective cohort analysis Methods: The public domain was searched for secondary ACL injuries that occurred during competitive matches between 2000-2018. Demographics (age, height, weight), side of injury, type of injury (contact, noncontact), and timing of injury within competition and within season were determined for each case. Results: Sixty-seven secondary ACL injuries were identified. Within-game, there were no differences in the distribution of ACL injures across each quarter of game time (p = 0.284). This was consistent between sport (p = 0.120-0.448). Within-season, there were no differences in the distribution of secondary ACL injures across each quarter of the season (p = 0.491). This was again consistent between sport (p = 0.151-0.872). Relative risk was not found to be significantly greater for any combination of season and game. Conclusion: The results of the current study indicate that the occurrences of secondary ACL injuries were equally distributed with respect to in-game and in-season timing. Both in-game and in-season timing were not significantly different across each individual sport examined. These results implicate that overall there is not an association between fatigue and secondary ACL injury occurrence in professional athletes. Level of Evidence: 3 [ABSTRACT FROM AUTHOR]

The purpose of this study was to identify alterations in preparatory muscle activation patterns across different drop heights in female athletes. Sixteen female high school volleyball players performed the drop vertical jump from three different drop heights. Surface electromyography of the quadriceps and hamstrings were collected during the movement trials. As the drop height increased, muscle activation of the quadriceps during preparatory phase also increased (p < .05). However, the hamstrings activation showed no similar increases relative to drop height. Female athletes appear to preferentially rely on increased quadriceps activation, without an increase in hamstrings activation, with increased plyometric intensity. The resultant decreased activation ratio of the hamstrings relative to quadriceps before landing may represent altered dynamic knee stability and may contribute to the increased risk of ACL injury in female athletes. [ABSTRACT FROM AUTHOR]

Context: Early sport specialization, or the participation in 1 sport year-round to the exclusion of all others, is a growing concern in youth athletics because of its possible association with musculoskeletal injury. The underlying injury risk may be the result of coordination differences that sport-specialized athletes have been speculated to exhibit relative to multisport athletes; however, little evidence exists to support or refute this notion. Objective: To examine relative hip- and knee-joint angularmotion variability among adolescent sport-specialized and multisport female adolescent athletes to determine how sport specialization may affect coordination. Design: Cohort study. Setting: Research laboratory. Patients or Other Participants: A total of 366 sportspecialized and 366 multisport adolescent female basketball, soccer, and volleyball players. Intervention(s): Drop--vertical-jump (DVJ) assessment. Main Outcome Measure(s): Average coupling-angle variability (CAV) for hip flexion and knee flexion, knee flexion and ankle flexion, hip flexion and knee abduction, knee flexion and knee abduction, knee flexion and knee internal rotation, and knee abduction and knee internal rotation. Results: The sport-specialized group exhibited increased coupling variability in dominant-limb hip flexion and knee flexion (P=.015), knee flexion and knee abduction (P=.014), and knee flexion and knee internal rotation (P=.048) while landing during the DVJ, although they had small effect sizes (η²=0.010, 0.010, and 0.007, respectively). No differences were present between groups for any of the other CAV measures of the dominant limb, and no differences were found for any CAV measures of the nondominant limb (all P values > .05). Conclusions: Sport specialization was associated with increased variability of critical hip- and knee-joint couplings responsible for effective landing during the DVJ. Altered coordination strategies that involve the hip and knee joints may underlie unstable landings, inefficient force-absorption strategies, or greater contact forces that can place the lower extremities at risk for injury (or a combination of these). [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) tears and concomitant medial collateral ligament (MCL) injuries are known to occur during dynamic athletic tasks that place combinatorial frontal and transverse plane loads on the knee. A mechanical impact simulator that produces clinical presentation of ACL injury allows for the quantification of individual loading contributors leading to ACL failure. Purpose/Hypothesis: The objective was to delineate the relationship between knee abduction moment, anterior tibial shear, and internal tibial rotation applied at the knee and ACL strain during physiologically defined simulations of impact at a knee flexion angle representative of initial contact landing from a jump. The hypothesis tested was that before ACL failure, abduction moment would induce greater change in ACL strain during landing than either anterior shear or internal rotation. Study Design: Controlled laboratory study. Methods: Nineteen cadaveric specimens were subjected to simulated landings in the mechanical impact simulator. During simulations, external knee abduction moment, internal tibial rotation moment, and anterior tibial shear loads were derived from a previously analyzed in vivo cohort and applied to the knee in varying magnitudes with respect to injury risk classification. Implanted strain gauges were used to track knee ligament displacement throughout simulation. Kruskal-Wallis tests were used to assess strain differences among loading factors, with Wilcoxon each pair post hoc tests used to assess differences of magnitude within each loading. Results: Each loading factor significantly increased ACL strain (P < .005). Within factors, the high-risk magnitude of each factor significantly increased ACL strain relative to the baseline condition (P≤ .002). However, relative to knee abduction moment specifically, ACL strain increased with each increased risk magnitude (P≤ .015). Conclusion: Increased risk levels of each load factor contributed to increased levels of ACL strain during a simulated jump landing. The behavior of increased strain between levels of increased risk loading was most prevalent for changes in knee abduction moment. This behavior was observed in the ACL and MCL. Clinical Relevance: Knee abduction moment may be the predominant precursor to ACL injury and concomitant MCL injury. As knee abduction occurs within the frontal plane, primary preventative focus should incorporate reduction of frontal plane knee loading in landing and cutting tasks, but secondary reduction of transverse plane loading could further increase intervention efficacy. Constraint of motion in these planes should restrict peak ACL strain magnitudes during athletic performance. [ABSTRACT FROM AUTHOR]

Background: Clinical management of sport-related concussion typically involves a symptom checklist, clinical examination of mental status, and neurocognitive testing. However, recent studies have identified unresolved, impaired sensorimotor function after athletes return to sport. A review and meta-analysis of all current literature regarding risk of subsequent musculoskeletal (MSK) injury after concussion has yet to be published in the medical literature. Purpose/Hypothesis: To determine the odds that athletes will sustain MSK injury after concussion. It was hypothesized a priori that concussion would increase the risk for MSK injury. Study Design: Systematic review and meta-analysis. Methods: PubMed and Google Scholar were searched from January 2000 to November 2017. Reference lists of the included studies were manually searched. Two reviewers independently searched the literature for studies published in English that reported MSK injury after athletes returned to play following a concussion. Two independent reviewers completed data extraction using PRISMA guidelines and assessed study quality using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies from the National Institutes of Health. Random effects meta-analyses were used to calculate odds ratio (OR) and incidence rate ratio (IRR) of MSK injury after concussion. The primary study outcome of interest was the number of athletes who sustained MSK injury after concussion. Results: Eight studies met inclusion criteria for meta-analysis. Meta-analysis results indicated that athletes who had a concussion had 2 times greater odds of sustaining a MSK injury than athletes without concussion (OR, 2.11; 95% CI, 1.46-3.06). In addition, athletes with concussion demonstrated a higher incidence of MSK injury after return to sport compared with nonconcussed athletes (IRR, 1.67; 95% CI, 1.42-1.96). Further analysis showed that both male and female athletes with concussion were at an increased risk of MSK injury compared with their respective same-sex, nonconcussed controls (OR > 1.56, P <.01). Conclusion: Based on the evidence of higher risk of MSK injuries after concussion, standard clinical assessments for athletes with concussion should include not only physical symptoms and cognitive function before return to sport but also neuromuscular risk factors associated with increased risk for MSK injuries. [ABSTRACT FROM AUTHOR]

Background: Psychological responses after anterior cruciate ligament (ACL) injury and ACL reconstruction (ACLR) have been identified as predictors of return to sport but have not been investigated in relation to further injury. Purpose/Hypothesis: To determine whether psychological readiness to return to sport is associated with second ACL injury. It was hypothesized a priori that at both preoperative and 12-month postoperative time points, patients who sustained a second ACL injury would have lower psychological readiness than patients who did not have a second injury. Study Design: Cohort study; Level of evidence, 2. Methods: Patients who had a primary ACLR procedure between June 2014 and June 2016 completed the ACL–Return to Sport after Injury (ACL-RSI) (short version) scale before their ACLR and repeated the scale at 12 months after surgery to assess psychological readiness to return to sport. Patients were followed for a minimum of 2 years (range, 2-4 years) after surgery to determine further injury. The primary outcome was the relationship between ACL-RSI scores and the incidence of second ACL injury. Results: In 329 patients who returned to sport after ACLR, 52 (16%) sustained a second ACL injury. No difference in psychological readiness was observed at the preoperative time point, but patients who sustained a second injury trended toward lower psychological readiness at 12 months compared with noninjured patients (60.9 vs 67.2 points; P = .11). Younger (≤20 years) patients with injury had significantly lower psychological readiness to return to sport than young noninjured patients (60.8 vs 71.5 points; P = .02), but no difference was found in older patients (60.9 vs 64.6 points; P = .58). In younger patients, receiver operating characteristic curve analysis revealed a cutoff score of 76.7 points with 90% sensitivity to identify younger patients who sustained a second ACL injury. Conclusion: Younger patients with lower psychological readiness are at higher risk for a second ACL injury after return to sport. [ABSTRACT FROM AUTHOR]

Background: Database research is being used in orthopaedic literature with increased regularity. The main limitation of database research is the absence of diagnosis and treatment verification afforded by medical chart review. This absence may limit the accuracy of some conclusions and recommendations produced by database research. Hypothesis/Purpose: The purpose was to describe the accuracy of 1 database (Rochester Epidemiology Project) used in orthopaedic research to detect isolated anterior cruciate ligament (ACL) tears and to discuss the limitations of database research. It was hypothesized that diagnostic codes alone are unlikely to be accurate in identifying patients with ACL tears. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A population-based historical cohort study was performed with the Rochester Epidemiology Project database. All subjects had International Classification of Diseases, Ninth Revision, diagnosis codes consistent with ACL tears between January 1, 1990, and December 31, 2010. The medical records of all subjects were reviewed in detail to confirm the accuracy of diagnosis and gather data on injury type, laterality, associated meniscal injuries, magnetic resonance imaging findings, and treatment details. Results: A total of 3494 patients had codes consistent with ACL tears, and 2288 of them were confirmed through chart review to have an isolated ACL tear (65.5%). Among these were 1841 patients (52.7%) with an ACL tear within 1 year of injury and an additional 447 (12.8%) with an ACL tear >1 year from injury. Thirty-nine patients (1.1%) had a partial ACL tear diagnosed on magnetic resonance imaging, 48 (1.4%) had an isolated posterior cruciate ligament tear, and 22 (0.6%) had a combined ACL–posterior cruciate ligament injury. Twenty-four patients (0.7%) had ACL reconstruction before the study period. The remaining 1073 patients (30.7%) had diagnostic codes consistent with an ACL tear but did not have a cruciate ligament injury. Conclusion: This study demonstrates low accuracy with the use of diagnostic codes alone to identify an ACL tear. Database studies offer unique benefits to the medical literature, but the inherent limitations should be taken into account when these data are used to counsel patients, dictate clinical management, or make health care policy decisions. Information from a health care database is most accurate when accompanied by verification of diagnosis, treatment, and outcomes with medical chart review. [ABSTRACT FROM AUTHOR]

Background: Female athletes are at an increased risk of developing patellofemoral pain (PFP) relative to male athletes. The unique effects of maturation may compound that risk. Hypothesis/Purpose: The purpose was to evaluate the neuromuscular control mechanisms that are adaptive to pubertal maturation and determine their relative contribution to PFP development. It was hypothesized that aberrant landing mechanics (reduced sagittal-plane and increased frontal- and transverse-plane kinematics and kinetics) would be associated with an increased risk for PFP. Study Design: Cohort study; Level of evidence, 2. Methods: There were 506 high school female athletes who completed a detailed medical history, the Anterior Knee Pain Scale, and a knee examination for the diagnosis of PFP and attended follow-up appointments. Athletes performed a drop vertical jump task instrumented with force plates, and biomechanical measures generated from standard 3-dimensional biomechanical analyses were used to classify participants into high- or low-risk knee and hip landing profiles for the development of PFP. The biomechanical measures used in the knee landing profile included sagittal-plane knee range of motion, peak knee abduction angle, peak knee abduction moment, and peak-to-peak transverse-plane knee moment. The biomechanical measures used in the hip landing profile included sagittal-plane hip range of motion, peak hip extensor moment, peak abductor moment, and peak hip rotator moment. Testing was conducted at sport-specific preseason appointments over the course of 2 years, and changes in pubertal status, landing profile, and PFP development were documented. Results: Female athletes with high-risk hip landing profiles experienced increased hip flexion and decreased abductor, rotator, and extensor moments. Participants with high-risk hip landing profiles who transitioned to postpubertal status at follow-up had higher odds (odds ratio, 2.1 [95% CI, 1.1-4.0]; P = .02) of moving to a low-risk hip landing profile compared with those who had not reached postpubertal status at follow-up. Participants with high-risk knee landing profiles experienced decreased knee flexion and increased knee abduction, external abductor, and external rotator moments. Pubertal maturation was not associated with a change in the high-risk knee landing profile at follow-up. Conclusion: The progression from prepubertal to postpubertal status may have a protective effect on high-risk hip mechanics but no similar adaptations in high-risk knee mechanics during maturation. These data indicate that before puberty, maladaptive hip mechanics may contribute to PFP, while aberrant knee mechanics associated with PFP are sustained throughout the maturational process in young female athletes. [ABSTRACT FROM AUTHOR]

Background: The efficacy of a neuromuscular training (NMT) program to ameliorate known hip biomechanical risk factors for athletes with anterior cruciate ligament reconstruction (ACLR) is currently unknown. Purpose/Hypothesis: The purpose was to quantify the effects of an NMT program on hip biomechanics among athletes with ACLR and to compare posttraining hip biomechanics with a control group. The hypotheses were that known hip biomechanical risk factors of anterior cruciate ligament (ACL) injury would be significantly reduced among athletes with ACLR after the NMT program and that posttraining hip biomechanics between the ACLR and control cohorts would not differ. Study Design: Controlled laboratory study. Methods: Twenty-eight athletes (n = 18, ACLR; n = 10, uninjured) completed a 12-session NMT program. Biomechanical evaluation of a jump-landing task was done before and after completion of the program. Repeated measures analysis of variance was performed to understand the effect of NMT within the ACLR cohort. Two-way analysis of variance was used to compare both groups. Post hoc testing was done for significant interactions. Hip biomechanical variables at initial contact are reported. Results: The athletes with ACLR who completed the NMT program had a significant session × limb interaction (P = .01) for hip external rotation moment and a significant main effect of session for hip flexion angle (P = .049) and moment (P < .001). There was a significant change for the involved (P = .04; 528% increase) and uninvolved (P = .04; 57% decrease) limbs from pre- to posttraining for hip rotation moment. The ACLR cohort had an increase in hip flexion angle (14% change) and a decrease in hip flexion moment (65% change) from pre- to posttraining. Posttraining comparison for these same hip biomechanical variables of interest revealed no significant interactions (P > .05) between the ACLR and control cohorts. There was a significant main effect of group (P = .02) for hip flexion angle, as the ACLR cohort demonstrated greater hip flexion angle than that of the control group. Conclusion: For athletes with ACLR, hip biomechanical measures of ACL injury risk show significant improvements after completion of an NMT program. Clinical Relevance: Athletes with ACLR who are participating in an NMT program may ameliorate known hip biomechanical risk factors for an ACL injury. [ABSTRACT FROM AUTHOR]

Background: First-time lateral patellar dislocation is a common orthopaedic injury. The purposes of this study were to (1) evaluate the incidence of first-time lateral patellar dislocation in a geographically-determined population, (2) report trends over time in the incidence of dislocation, and (3) describe the rate of surgical treatment.Hypothesis: The rate of patellar dislocation is highest among adolescent patients.Study Design: Cohort study.Level Of Evidence: Level 3.Methods: The study population included 609 individuals identified through a multidisciplinary geographic cohort county database who were diagnosed with first-episode lateral patellar dislocation between 1990 and 2010. The complete medical records were reviewed to confirm the diagnosis and to evaluate details of injury and treatment. Age- and sex-specific incidence rates were calculated and adjusted to the 2010 US population. Poisson regression analyses were performed to examine incidence trends by age, sex, and calendar period.Results: The overall age- and sex-adjusted annual incidence of patellar dislocation was 23.2 (95% CI, 21.2-24.9) per 100,000 person-years. The annual incidence was similar between male and female patients and highest among adolescents aged 14 to 18 years (147.7/100,000 person-years). The mean age at dislocation was 21.4 ± 9.9 years, and 331 patients (54.4%) were female. During the study period, there was a significant decline in the incidence of patellar dislocation among men aged 19 to 25 years ( P = 0.002) and girls aged 14 to 18 years ( P = 0.025). Eighty patients received surgical treatment during the study period, including 66 patients (10.8%) for recurrent instability and 14 patients (2.3%) for acute osteochondral injury.Conclusion: With an annual incidence of 23.2 per 100,000 person-years, lateral patellar dislocation is a frequently encountered orthopaedic injury. The incidence of dislocation among adolescent patients in this cohort is higher than previously reported. Despite a decrease in the annual incidence of dislocation in adolescent girls, the overall incidence of patellar dislocation remained relatively constant over a 21-year observation period.Clinical Relevance: This study demonstrates that the incidence of patellar dislocation in adolescents is greater than previously reported. [ABSTRACT FROM AUTHOR]

Context: The fourth edition of the Preparticipation Physical Evaluation recommends functional testing for the musculoskeletal portion of the examination; however, normative data across sex and grade level are limited. Establishing normative data can provide clinicians reference points with which to compare their patients, potentially aiding in the development of future injury-risk assessments and injury-mitigation programs. Objective: To establish normative functional performance and limb-symmetry data for high school-aged male and female athletes in the United States. Design: Cross-sectional study. Setting: Athletic training facilities and gymnasiums across the United States. Patients or Other Participants: A total of 3951 male and female athletes who participated on high school-sponsored basketball, football, lacrosse, or soccer teams enrolled in this nationwide study. Main Outcome Measure(s): Functional performance testing consisted of 3 evaluations. Ankle-joint range of motion, balance, and lower extremity muscular power and landing control were assessed via the weight-bearing ankle-dorsiflexion-lunge, single-legged anterior-reach, and anterior single-legged hop-for-distance (SLHOP) tests, respectively. We used 2-way analyses of variance and χ² analyses to examine the effects of sex and grade level on ankle-dorsiflexion-lunge, single-legged anterior-reach, and SLHOP test performance and symmetry. Results: The SLHOP performance differed between sexes (males = 187.8% ± 33.1% of limb length, females = 157.5% ± 27.8% of limb length; t = 30.3, P < .001). A Cohen d value of 0.97 indicated a large effect of sex on SLHOP performance. We observed differences for SLHOP and ankle-dorsiflexion-lunge performance among grade levels, but these differences were not clinically meaningful. Conclusions: We demonstrated differences in normative data for lower extremity functional performance during preparticipation physical evaluations across sex and grade levels. The results of this study will allow clinicians to compare sex- and grade-specific functional performances and implement approaches for preventing musculoskeletal injuries in high school-aged athletes. [ABSTRACT FROM AUTHOR]

Context: An estimated 40 million school-aged children (age range = 5-18 years) participate annually in sports in the United States, generating approximately 4 million sport-related injuries and requiring 2.6 million emergency department visits at a cost of nearly $2 billion. Objective: To determine the effects of a school-based neuromuscular training (NMT) program on sport-related injury incidence across 3 sports at the high school and middle school levels, focusing particularly on knee and ankle injuries. Design: Randomized controlled clinical trial. Setting: A total of 5 middle schools and 4 high schools in a single-county public school district. Patients or Other Participants: A total of 474 girls (222 middle school, 252 high school; age = 14.0 ± 1.7 years, height = 161.0 ± 8.1 cm, mass = 55.4 ± 12.2 kg) were cluster randomized to an NMT (CORE; n = 259 athletes) or sham (SHAM; n = 215 athletes) intervention group by team within each sport (basketball, soccer, and volleyball). Intervention(s): The CORE intervention consisted of exercises focused on the trunk and lower extremity, whereas the SHAM protocol consisted of resisted running using elastic bands. Each intervention was implemented at the start of the season and continued until the last competition. An athletic trainer evaluated athletes weekly for sport-related injuries. The coach recorded each athlete-exposure (AE), which was defined as 1 athlete participating in 1 coach-directed session (game or practice). Main Outcome Measure(s): Injury rates were calculated overall, by sport, and by competition level. We also calculated rates of specific knee and ankle injuries. A mixed-model approach was used to account for multiple injuries per athlete. Results: Overall, the CORE group reported 107 injuries (rate = 5.34 injuries/1000 AEs), and the SHAM group reported 134 injuries (rate = 8.54 injuries/1000 AEs; F1,578 = 18.65, P < .001). Basketball (rate = 4.99 injuries/1000 AEs) and volleyball (rate = 5.74 injuries/1000 AEs) athletes in the CORE group demonstrated lower injury incidences than basketball (rate = 7.72 injuries/1000 AEs) and volleyball (rate = 11.63 injuries/1000 AEs; F1,275 = 9.46, P = .002 and F1,149 = 11.36, P = .001, respectively) athletes in the SHAM group. The CORE intervention appeared to have a greater protective effect on knee injuries at the middle school level (knee-injury incidence rate = 4.16 injuries/1000 AEs) than the SHAM intervention (knee-injury incidence rate = 7.04 injuries/1000 AEs; F1,261 = 5.36, P = .02). We did not observe differences between groups for ankle injuries (F1,578 = 1.02, P = .31). Conclusions: Participation in an NMT intervention program resulted in a reduced injury incidence relative to participation in a SHAM intervention. This protective benefit of NMT was demonstrated at both the high school and middle school levels. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) injures incur over USD 2 billion in annual medical costs and prevention has become a topic of interest in biomechanics. However, literature conflicts persist over how knee rotations contribute to ACL strain and ligament injury. To maximize the efficacy of ACL injury prevention, the effects of underlying mechanics need to be better understood.Questions/purposes: We applied robotically controlled, in vivo-derived kinematic stimuli to the knee to assess ligament biomechanics in a cadaver model. We asked: (1) Does the application of abduction rotation increase ACL and medial collateral ligament (MCL) strain relative to the normal condition? (2) Does the application of internal tibial rotation impact ACL strain relative to the neutral condition? (3) Does combined abduction and internal tibial rotation increase ligament strain more than either individual contribution?Methods: A six-degree-of-freedom robotic manipulator was used to position 17 cadaveric specimens free from knee pathology outside of low-grade osteoarthritis (age, 47 ± 8 years; 13 males, four females) into orientations that mimic initial contact recorded from in vivo male and female drop vertical jump and sidestep cutting activities. Four-degree rotational perturbations were applied in both directions from the neutral alignment position (creating an 8° range) for each frontal, transverse, and combined planes while ACL and MCL strains were continuously recorded with DVRT strain gauges implanted directly on each ligament. Analysis of variance models with least significant difference post hoc analysis were used to assess differences in ligament strain and joint loading between sex, ligament condition, or motion task and rotation type.Results: For the female drop vertical jump simulation in the intact knee, isolated abduction and combined abduction/internal rotational stimuli produced the greatest change in strain from the neutral position as compared with all other stimuli within the ACL (1.5% ± 1.0%, p ≤ 0.035; 1.8% ± 1.3%, p ≤ 0.005) and MCL (1.8% ± 1.0%, p < 0.001; 1.6% ± 1.3%, p < 0.001) compared with all other applied stimuli. There were no differences in mean peak ACL strain between any rotational stimuli (largest mean difference = 2.0%; 95% confidence interval [CI], -0.9% to 5.0%; p = 0.070). These trends were consistent for all four simulated tasks. Peak ACL strain in the intact knee was larger than peak MCL strain for all applied rotational stimuli in the drop vertical jump simulations (smallest mean difference = 2.1%; 95% CI, -0.4% to 4.5%; p = 0.047).Conclusions: Kinematically constrained cadaveric knee models using peak strain as an outcome variable require greater than 4° rotational perturbations to elicit changes in intraarticular ligaments.Clinical Relevance: Because combined rotations and isolated abduction produced greater change in strain relative to the neutral position for the ACL and MCL than any other rotational stimuli in this cadaver study, hypotheses for in vivo investigations aimed toward injury prevention that focuses on the reduction of frontal plane knee motion should be considered. Furthermore, reduced strain in the MCL versus the ACL may help explain why only 30% of ACL ruptures exhibit concomitant MCL injuries. [ABSTRACT FROM AUTHOR]

Background: Bone-patellar tendon-bone (bone-tendon-bone) and four-strand hamstring tendon grafts (hamstring) are the most commonly utilized autografts for primary anterior cruciate ligament (ACL) reconstruction. Existing clinical trials, registry studies, and meta-analyses offer conflicting opinions regarding the most favorable graft choice.Questions/purposes: Which graft type for ACL reconstruction (bone-tendon-bone or hamstring) has a higher risk of (1) graft rupture and/or (2) graft laxity?Methods: We performed a meta-analysis of randomized controlled trials (RCTs), prospective cohort studies, and high-quality national registry studies to compare the outcomes of primary ACL reconstruction with bone-tendon-bone autograft or hamstring autograft. Studies that compared these graft types were identified through a comprehensive search of electronic databases (PubMed, MEDLINE, EMBASE, and the Cochrane Library). Two independent reviewers utilized the Jadad scale for RCT study quality and the Modified Coleman Methodology Score for prospective comparative and registry study quality. The included studies were analyzed for the primary outcome measure of graft rupture with or without revision ACL surgery. In surviving grafts, secondary outcomes of graft laxity were quantified by KT1000/2000™ testing, a positive pivot shift test, and a positive Lachman test. Meta-analysis was performed with Review Manager. A total of 47,613 ACL reconstructions (39,768 bone-tendon-bone and 7845 hamstring) from 14 RCTs, 10 prospective comparative studies, and one high-quality national registry study were included in this meta-analysis. Mean age was 28 years in both groups. Sixty-three percent of patients in the bone-tendon-bone cohort were men versus 57% of patients in the hamstring cohort. Mean followup was 68 ± 55 months.Results: Two hundred twelve of 7560 (2.80%) bone-tendon-bone grafts ruptured compared with 1123 of 39,510 (2.84%) in the hamstring group (odds ratio = 0.83, 95% confidence interval, 0.72-0.96; p = 0.01). The number needed to treat analysis found that 235 patients would need to be treated with a bone-tendon-bone graft over a hamstring tendon graft to prevent one graft rupture. Instrumented laxity analysis showed that 22% (318 of 1433) of patients in the bone-tendon-bone group had laxity compared with 18% (869 of 4783) in the hamstring tendon group (odds ratio = 0.86; p = 0.16). Pivot shift analysis showed a positive pivot shift in 19% (291 of 1508) of the bone-tendon-bone group compared with 17% (844 of 5062) in the hamstring group (odds ratio = 0.89; p = 0.51). Lachman testing showed a positive Lachman in 25% (71 of 280) of patients receiving bone-tendon-bone grafts compared with 25% (73 of 288) in the hamstring group (odds ratio = 0.96; p = 0.84).Conclusions: In this meta-analysis of short- to mid-term followup after primary ACL reconstruction, hamstring autografts failed at a higher rate than bone-tendon-bone autografts. However, failure rates were low in each group, the difference observed was small, and we observed few differences between graft types in terms of laxity. Both graft types remain viable options for primary ACL reconstruction, and the difference in failure rate should be one part of a larger conversation with each individual patient about graft selection that should also include potential differences in donor site morbidity, complication rates, and patient-reported outcome measures. Continued prospective collection of patient data will be important going forward as we attempt to further characterize the potential differences in outcomes attributable to graft selection.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Previous investigations of single-camera 3D motion analysis camera systems validity have yielded mixed results for clinical applications. Purpose: The purpose of the current study was to determine the validity of a single-camera 3D motion analysis system for subject standing height, vertical jump height, and broad jump length. It was hypothesized that single-camera system values would demonstrate high correlation to the values obtained from accepted standard clinical measurements. Study Design: Experimental in vivo validation study. Methods: Twelve subjects (age 20.6 ± 4.9 years) from a cohort that included high school to adult athletes who participate in sports at a recreational or competitive level entered and completed the study. Performance measurements for standing height, vertical jump height, and broad jump length were measured with standard clinical measurements and a single-camera 3D motion system. Result: Single-camera system measurements were significantly different than clinical measures for standing height (p < 0.01) and vertical jump height (p < 0.01). There was no statistically significant difference between single-camera system measures and clinical measures for broad jump distance (p > 0.07). The relative performance of subjects was highly correlated between single-camera and clinical measurements (r²> 0.80). Conclusions: Single-camera measurements lacked precision along the vertical axis of motion, but correlated well with clinically accepted measurements for standing height, broad jump length, and vertical jump height. The single-camera system may be capable of making accurate performance assessments in the horizontal plane, but should be limited to relative assessments along the vertical axis of motion. Additional refinement to increase the data reporting accuracy of the motion system along the vertical axis should be considered before relying on this single-camera 3D motion analysis system over clinical techniques to measure vertical jump and standing broad jump performances. Level of Evidence: 2b [ABSTRACT FROM AUTHOR]

Background: Previous reliability investigations of single-camera three dimensional (3D) motion analysis systems have reported mixed results. Purpose: The purpose of the current study was to determine the intra- and inter-rater reliability of a single-camera 3D motion analysis system for subject standing height, vertical jump height, and broad jump length. Study Design: Experimental in vivo reliability study. Participants: Twelve subjects (age 20.6 ± 4.9 years) from a cohort that included high school to adult athletes who participated in sports at a recreational or competitive level entered and completed the study. Performance measurements were collected by a single-camera 3D motion analysis system and two human testers for standard clinical techniques. Inter- and intra-class correlation coefficients (ICC (2,k), ICC (2,1)) were determined. Result: Intra-tester and inter-tester reliability were excellent (ICC ≥ 0.935) for single-camera system measured variables. Singlecamera system measurements were slightly more reliable than clinical measurements for intra-tester ratings (ICC difference 0.020) for the standing broad jump. Single-camera system measurements were slightly less reliable than clinical measures for both intra- and inter-specimen standing height (mean ICC difference 0.003 and 0.043, respectively) and vertical jump height (mean ICC difference 0.017 and 0.036, respectively). Conclusions: The excellent reliability and previously demonstrated validity of the single-camera system along the anterior-posterior axis indicates that single-camera motion analysis may be a valid surrogate for clinically accepted manual measurements of performance in the horizontal plane. However, this single-camera 3D motion analysis system is likewise reliable, but inaccurate, for vertically oriented performance measurements. Level of Evidence: 2b [ABSTRACT FROM AUTHOR]

Background: The effects of targeted neuromuscular training (TNMT) on movement biomechanics associated with the risk of anterior cruciate ligament (ACL) injuries are currently unknown. Purpose/Hypotheses: To determine the effectiveness of TNMT specifically designed to increase trunk control and hip strength. The hypotheses were that (1) TNMT would decrease biomechanical and neuromuscular factors related to an increased ACL injury risk and (2) TNMT would decrease these biomechanical and neuromuscular factors to a greater extent in athletes identified as being at a high risk for future ACL injuries. Study Design: Controlled laboratory study. Methods: Female athletes who participated in jumping, cutting, and pivoting sports underwent 3-dimensional biomechanical testing before the season and after completing TNMT. During testing, athletes performed 3 different types of tasks: (1) drop vertical jump, (2) single-leg drop, and (3) single-leg cross drop. Analysis of covariance was used to examine the treatment effects of TNMT designed to enhance core and hip strength on biomechanical and neuromuscular characteristics. Differences were also evaluated by risk profile. Differences were considered statistically significant at P < .05. Results: TNMT significantly increased hip external rotation moments and moment impulses, increased peak trunk flexion, and decreased peak trunk extension. Athletes with a high risk before the intervention (risk profile III) had a more significant treatment effect of TNMT than low-risk groups (risk profiles I and II). Conclusion: TNMT significantly improved proximal biomechanics, including increased hip external rotation moments and moment impulses, increased peak trunk flexion, and decreased peak trunk extension. TNMT that focuses exclusively on proximal leg and trunk risk factors is not, however, adequate to induce significant changes in frontal-plane knee loading. Biomechanical changes varied across the risk profile groups, with higher risk groups exhibiting greater improvements in their biomechanics. [ABSTRACT FROM AUTHOR]

Background: Second anterior cruciate ligament (ACL) tears after reconstruction occur at a reported rate of 20% to 30%. This high frequency indicates that there may be factors that predispose an athlete to graft failure and ACL tears of the contralateral knee. Purpose: To determine the incidence of second ACL injuries in a geographic population-based cohort over a 10-year observation period. Study Design: Descriptive epidemiological study. Methods: International Classification of Diseases, 9th Revision (ICD-9) codes relevant to the diagnosis of an ACL tear and the procedure code for ACL reconstruction were searched across the Rochester Epidemiology Project, a multidisciplinary county database, between the years of 1990 and 2000. This cohort of patients was tracked for subsequent ACL injuries through December 31, 2015. The authors identified 1041 patients with acute, isolated ACL tears. These patients were stratified by primary and secondary tears, sex, age, activity level, side of injury, sex by side of injury, and graft type. Results: Of the 1041 unique patients with a diagnosed ACL tear in Olmsted County, Minnesota, from 1990 to 2000, there were 66 (6.0%) second ACL tears; 66.7% of these tears occurred on the contralateral side. A second ACL injury was influenced by graft type (P < .0001), election of ACL reconstruction (P = .0060), and sex by side of injury (P = .0072). Nonparametric analysis of graft disruption by graft type demonstrated a higher prevalence of second ACL tears with allografts compared with hamstring (P = .0499) or patellar tendon autografts (P = .0012). Conclusion: The incidence of second ACL tears in this population-based cohort was 6.0%, with 66.7% of these tears occurring on the contralateral side from the original injury. There was a high population incidence of second ACL injuries in female patients younger than age 20 years. The utilization of patellar tendon autografts significantly reduced the risk of second ACL injuries compared with allografts or hamstring autografts in this cohort. [ABSTRACT FROM AUTHOR]

Context: Fewer athletic injuries and lower anterior cruciate ligament injury incidence rates were noted in studies of neuromuscular-training (NMT) interventions that had high compliance rates. However, several groups have demonstrated that preventive NMT interventions were limited by low compliance rates. Objective: To descriptively analyze coach and athlete compliance with preventive NMT and compare the compliance between study arms as well as among school levels and sports. Design: Randomized, controlled clinical trial. Setting: Middle and high school athletic programs. Participants or Other Participants: A total of 52 teams, comprising 547 female athletes, were randomly assigned to the experimental or control group and followed for 1 athletic season. Intervention(s): The experimental group (n = 30 teams [301 athletes]: 12 basketball teams [125 athletes], 6 soccer teams [74 athletes], and 12 volleyball teams [102 athletes]) participated in an NMT program aimed at reducing traumatic knee injuries through a trunk-stabilization and hip-strengthening program. The control group (n = 22 teams [246 athletes]: 11 basketball teams [116 athletes], 5 soccer teams [68 athletes], and 6 volleyball teams [62 athletes]) performed a resistive rubber-band running program. Main Outcome Measure(s): Compliance with the assigned intervention protocols (3 times per week during the preseason [mean = 3.4 weeks] and 2 times per week in-season [mean = 11.9 weeks] of coaches [coach compliance] and athletes [athlete compliance]) was measured descriptively. Using an independent t test, we compared coach and athlete compliance between the study arms. A 2-way analysis of variance was calculated to compare differences between coach and athlete compliance by school level (middle and high schools) and sport (basketball, soccer, and volleyball). Results: The protocols were completed at a mean rate of 1.3 ± 1.1 times per week during the preseason and 1.2 ± 0.5 times per week in-season. A total of 88.4% of athletes completed 2/3 of the intervention sessions. Coach compliance was greater in the experimental group than in the control group (P = .014). Coach compliance did not differ by sport but was greater at the high school than the middle school (P = .001) level. Athlete compliance did not differ by study arm, sport, or school level. Conclusions: Athletes received instruction in about 50% of each protocol. Nearly 90% of athletes performed more than 2/3 of the assigned NMT interventions. The assigned intervention was performed more often in the experimental arm compared with the control arm. Coaches at the high school level complied with the given protocol more than middle school coaches did. Athletes complied well with the protocol, but coaches did not, especially at the middle school level. [ABSTRACT FROM AUTHOR]

The authors examined the efficacy of an 8-week regimen combining repetitive task-specific practice (RTP) with a myoelectric brace (RTP+Myomo) on paretic upper extremity (UE; use in valued activities, perceived recovery, and reaching kinematics) in 12 subjects (4 men; M age = 53.5 years; mean time poststroke = 61.7 months). Seven subjects were administered RTP+Myomo therapy, and 5 were administered RTP only. Both groups participated in individualized, 45-min therapy sessions occurring 3 days/week over an 8-week period. The arm, hand ability, activities of daily living, and perceptions of recovery subscales of the Stroke Impact Scale (SIS), as well as UE reaching kinematics, assessed before and after the intervention. Subjects in the RTP+Myomo group showed greater improvements on all SIS subscales, with the recovery scale reaching statistical significance (p = .03). Subjects in the RTP-only group showed a greater increase in hand velocity in the reach up task (p = .02), but no changes were observed in the range of shoulder flexion or elbow extension during reaching. None of the changes in kinematic outcome measures significantly correlated with any of the changes in SIS subscales. RTP integrating myoelectric bracing may be more beneficial than RTP only in improving self-reported function and perceptions of overall recovery. The authors observed no changes in the range of elbow extension, and no relationship between self-reported improvements and changes in reaching kinematics. [ABSTRACT FROM AUTHOR]

Background: The widespread use of anterior cruciate ligament (ACL) injury prevention interventions has not been effective in reducing the injury incidence among female athletes who participate in high-risk sports. Purpose/Hypothesis: The purpose of this study was to determine if biomechanical and neuromuscular factors that contribute to the knee abduction moment (KAM), a predictor of future ACL injuries, could be used to characterize athletes by a distinct factor. Specifically, we hypothesized that a priori selected biomechanical and neuromuscular factors would characterize participants into distinct at-risk profiles. Study Design: Controlled laboratory study. Methods: A total of 624 female athletes who participated in jumping, cutting, and pivoting sports underwent testing before their competitive season. During testing, athletes performed drop-jump tasks from which biomechanical measures were captured. Using data from these tasks, latent profile analysis (LPA) was conducted to identify distinct profiles based on preintervention biomechanical and neuromuscular measures. As a validation, we examined whether the profile membership was a significant predictor of the KAM. Results: LPA using 6 preintervention biomechanical measures selected a priori resulted in 3 distinct profiles, including a low (profile 1), moderate (profile 2), and high (profile 3) risk for ACL injuries. Athletes with profiles 2 and 3 had a significantly higher KAM compared with those with profile 1 (P < .05). Conclusion: This is the first study to use LPA of biomechanical landing data to create ACL injury risk profiles. Three distinct risk groups were identified based on differences in the peak KAM. Clinical Relevance: These findings demonstrate the existence of discernable groups of athletes that may benefit from injury prevention interventions. Study Registration: ClinicalTrials.gov NCT identifier: NCT01034527. [ABSTRACT FROM AUTHOR]

Background: Knee laxity in the setting of suspected anterior cruciate ligament (ACL) injury is frequently assessed through physical examination using the Lachman, pivot-shift, and anterior drawer tests. The degree of laxity noted on these examinations may influence treatment decisions and prognosis. Hypothesis: Increased preoperative knee laxity would be associated with increased risk of subsequent revision ACL reconstruction and worse patient-reported outcomes 2 years postoperatively. Study Design: Cohort study; Level of evidence, 2. Methods: From an ongoing prospective cohort study, 2333 patients who underwent primary isolated ACL reconstruction without collateral or posterior cruciate ligament injury were identified. Patients reported by the operating surgeons as having an International Knee Documentation Committee (IKDC) grade D for Lachman, anterior drawer, or pivot-shift examination were classified as having high-grade laxity. Multiple logistic regression modeling was used to evaluate whether having high-grade preoperative laxity was associated with increased odds of undergoing revision ACL reconstruction within 2 years of the index procedure, controlling for patient age, sex, Marx activity level, level of competition, and graft type. Multiple linear regression modeling was used to evaluate whether having high-grade preoperative laxity was associated with worse IKDC score or Knee injury and Osteoarthritis Outcome Score Knee-Related Quality of Life subscale (KOOS-QOL) scores at a minimum 2 years postoperatively, controlling for baseline score, patient age, ethnicity, sex, body mass index, marital status, smoking status, sport participation, competition level, Marx activity rating score, graft type, and articular cartilage and meniscus status. Results: Pre-reconstruction laxity data were available for 2325 patients (99.7%). Two-year revision data were available for 2259 patients (96.8%), and patient-reported outcomes were available for 1979 patients (84.8%). High-grade preoperative laxity was noted in 743 patients (31.9%). The mean postoperative IKDC score was 81.8 ± 15.9, and the mean KOOS-QOL score was 72.0 ± 22.0. The presence of high-grade pre-reconstruction laxity was associated with significantly increased odds of ACL graft revision (odds ratio [OR] = 1.87 [95% CI, 1.19-2.95]; P = .007). The presence of high-grade pre-reconstruction laxity was not associated with any difference in postoperative IKDC (β = −0.56, P = .44) or KOOS-QOL (β = 0.04, P = .97). Conclusion: The presence of high-grade pre-reconstruction knee laxity as assessed by manual physical examination under anesthesia is associated with significantly increased odds of revision ACL surgery but has no association with patient-reported outcome scores at 2 years after ACL reconstruction. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to determine key components in neuromuscular training that optimise ACL injury reduction in female athletes using meta-regression analyses.Design: Systematic review and meta-regression.Data Sources: The literature search was performed in PubMed and EBSCO.Eligibility Criteria: Inclusion criteria for the current analysis were: (1) documented the number of ACL injuries, (2) employed a neuromuscular training intervention that aimed to reduce ACL injuries, (3) had a comparison group, (4) used a prospective control study design and (5) recruited female athletes as participants. Two independent reviewers extracted studies which met the inclusion criteria. Methodological quality of included study and strength of recommendation were evaluated. Number of ACL injuries and participants in control and intervention groups, age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and status of verbal feedback were extracted.Results: The meta-regression analyses identified age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and utilisation of verbal feedback as significant predictors of ACL injury reduction (p=0.01 in fixed-effects model, p=0.03 in random-effects model). Inclusion of 1 of the 4 components in neuromuscular training could reduce ACL injury risk by 17.2-17.7% in female athletes. No significant heterogeneity and publication bias effects were detected. Strength of recommendation was rated as A (recommendation based on consistent and good-quality patient-oriented study evidence).Conclusions: Age of participants, dosage of neuromuscular training, exercise variations within neuromuscular training and utilisation of verbal feedback are predictors that influence the optimisation of prophylactic effects of neuromuscular training and the resultant ACL injury reduction in female athletes. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this epidemiologic study was to quantify the incidence, expense, and concomitant injuries for anterior cruciate ligament reconstruction (ACLR) procedures in the USA from 2003 to 2011 that required an inpatient stay. It was hypothesized that the relative reported rates of concomitant knee injuries would be greater with the MCL and menisci compared to all other concomitant knee injuries.Methods: The National Inpatient Sample from 2003 to 2011 was retrospectively sampled using ICD-9-CM codes to identify ACLR patients and to extrapolate national averages.Results: Between the years of 2003-2011, an average of 9,037 ± 1,728 inpatient hospitalization included ACLRs, of which 4,252 ± 1,824 were primarily due to the ACLR. Inpatient visits primarily due to ACLR involved an average hospitalization of 1.7 ± 0.2 days and cost $30,118 ± 9,066 per patient. Knee injuries that were commonly reported along with inpatient ACLRs included medial meniscus damage (18.1 %), lateral meniscus damage (16.8 %), collateral ligament repairs (12.3 %), and medial collateral ligament strains (6.9 %). Prevalence of meniscus injuries was consistent across years, but MCL-related injuries increased over time.Conclusions: ACLR-related inpatient hospitalizations account for approximately 7.1 % of the total ACLRs performed annually in the USA. Inpatient ACLR procedures continue to decrease in frequency; however, the mean cost per patient increased. Meniscus and collateral ligament injuries were the most commonly reported concomitant knee injuries. The clinical relevance of this investigation is that it informs, on a large clinical cohort of patients, the current state of incidence and expense for ACLR surgeries in an inpatient setting.Level Of Evidence: Prognostic, retrospective study, Level II. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this investigation was to estimate and document the reliability and validity of the Anterior Knee Pain Scale (AKPS) and to estimate its relative prediction accuracy of anterior knee pain in young females.Methods: Data from a prospective, epidemiologic study to diagnose patellofemoral knee pain among female athletes (n = 499) using the Anterior Knee Pain Scale (AKPS). Data were treated in 4 phases (descriptive phase, reliability phase, scale refinement phase) and a final validation stage that was focused on an effort to test and document the validation of the AKPS short form and perform head-to-head comparisons of the 6-item short form with the original, 13-item form.Results: The AKPS was reduced from 13 items (αCoeff = 0.77, σSEM = 0.004) to 6 items (αCoeff = 0.78, σSEM = 0.004). Point-biserial correlations with patellofemoral pain diagnosis were comparable: r [498] = 0.70 (R(2) = 0.49, short form) and r [498] = 0.71 (R(2) = 0.51, long form), as was sensitivity: 84% (short form) and 80% (long form), and specificity: 89% (short form) and 90% (long form; AUC = 0.94 both).Conclusion: The current analyses indicate that a subset of measures from the AKPS is responsive to patellofemoral pain symptoms and may support screening for related diagnoses. A simpler and quicker scale optimized for diagnostic accuracy could reduce the demand on patients, clinicians and research teams focused on the identification and management of patellofemoral pain.Level Of Evidence: III. [ABSTRACT FROM AUTHOR]

STUDY DESIGN: Cross-sectional. OBJECTIVES: To compare performance on the modified Star Excursion Balance Test (SEBT) between participants with anterior cruciate ligament reconstruction (ACLR) at the time of return to sport and uninjured control participants, BACKGROUND: The modified SEBT is a clinical tool to assess neuromuscular control deficits. Deficits in dynamic stability and neuromuscular control persist after ACLR, but assessment with the modified SEBT in this population at the time of return to sport has not been reported. METHODS: Sixty-six participants (mean age, 17.6 years) at the time of return to sport following unilateral primary ACLR (ACLR group) and 47 uninjured participants (mean age, 17.0 years) serving as a control group participated. For the modified SEBT, the anterior, posteromedial, and posterolateral reach distances were recorded. Lower extremity muscle strength was quantified with isokinetic dynamometry. Independent-sample t tests were used to evaluate performance differences between the ACLR group and the control group and between the ACLR subgroups. In the ACLR group, bivariate correlations determined the association of modified SEBT performance with time since surgery and lower extremity muscle strength. RESULTS: The ACLR group had lower anterior reach distances on the involved and uninvolved limbs compared to the control group. There were no differences observed between groups in reach distances for the posteromedial and posterolateral directions or in limb symmetry indices for any of the reach directions. In the ACLR group, time from surgery and meniscal status at the time of ACLR did not influence modified SEBT performance, whereas participants with patellar bone-tendon-bone grafts had a lower posterolateral reach distance compared to those with hamstring grafts. In the ACLR group, involved-limb hip abduction strength positively correlated with all reach distances, and quadriceps strength positively correlated with posterolateral reach. CONCLUSION: At the time of return to sport, participants post-ACLR demonstrated reduced modified SEBT anterior reach in both involved and uninvolved limbs compared to uninjured participants, with no other group differences. In the ACLR group, modified SEBT reach distance was associated with lower extremity muscle strength, but not with time from reconstruction or meniscal status at the time of ACLR. Lower extremity muscle strength and graft type may interact to influence modified SEBT posterior reach performance, but this requires further study. LEVEL OF EVIDENCE: Prognosis, level 2b-. [ABSTRACT FROM AUTHOR]

Purpose/Background: Injury screening methods that use three-dimensional (3D) motion analysis accurately predict the risk of injuries, yet are expensive. There is great need for valid, cost-effective techniques that can be used in large-scale assessments. Utilizing two-dimensional (2D) measures of lateral trunk motion may identify athletes at risk for lower extremity injury. The purpose of this research was to determine the strength of the relationships between 2D and 3D calculations of lateral trunk angle for female athletes performing a single-leg cross drop landing. Methods: Twenty-one high-school female volleyball players performed a single-leg cross drop landing onto a force plate. The 3D angular trunk motion was calculated, and four different 2D measures of lateral trunk angle were calculated for both left and right landing leg. A one-way multivariate analysis of variance was used to compare 2D measures to the 3D measurements, and Pearson correlations were used to determine the strength of these relationships. Results: The angle formed by the medial shoulder joint center, medial ASIS, and vertical line (LTA4) was similar to the 3D measures of lateral trunk angle during landing (r-values ≥ 0.62; p-values ≤ 0.003; mean differences, -1.0° to 1.2°). Conclusions: Given the recent focus on the role of the trunk in lower extremity injury, using the 2D LTA4 assessment may expand existing assessments into a composite model that can more accurately assess female athletes at risk for injury than models that do not include trunk analysis. Clinical Relevance: Existing models that enable clinicians to effectively identify female athletes at risk for lower extremity injury may be enhanced by including accurate assessments of lateral trunk motion. [ABSTRACT FROM AUTHOR]

The article presents research which examined the occurrence of second anterior cruciate ligament (ACL) injuries following primary ACL repair. Topics covered include the ability of athlete who underwent the repair to return to sport and the recurrence rate of the injuries among athletes. The study concludes that patients are at a greatest risk to suffer a subsequent ACL injury compared with those without a history of ACL injuries.

PURPOSE/BACKGROUND: Multi-center collaborations provide a powerful alternative to overcome the inherent limitations to single-center investigations. Specifically, multi-center projects can support large-scale prospective, longitudinal studies that investigate relatively uncommon outcomes, such as anterior cruciate ligament injury. This project was conceived to assess within- and between-center reliability of an affordable, clinical nomogram utilizing two-dimensional video methods to screen for risk of knee injury. The authors hypothesized that the two-dimensional screening methods would provide good-to-excellent reliability within and between institutions for assessment of frontal and sagittal plane biomechanics. METHODS: Nineteen female, high school athletes participated. Two-dimensional video kinematics of the lower extremity during a drop vertical jump task were collected on all 19 study participants at each of the three facilities. Within-center and between-center reliability were assessed with intra- and inter-class correlation coefficients. RESULTS: Within-center reliability of the clinical nomogram variables was consistently excellent, but between-center reliability was fair-to-good. Within-center intra-class correlation coefficient for all nomogram variables combined was 0.98, while combined between-center inter-class correlation coefficient was 0.63. CONCLUSIONS: Injury risk screening protocols were reliable within and repeatable between centers. These results demonstrate the feasibility of multi-site biomechanical studies and establish a framework for further dissemination of injury risk screening algorithms. Specifically, multi-center studies may allow for further validation and optimization of two-dimensional video screening tools. LEVEL OF EVIDENCE: 2b. [ABSTRACT FROM AUTHOR]

The article reports on research which was conducted to investigate the compliance effects a trunk and hip focused integrative neuromuscular training (INT) exercise regimen had on hip abductor strength in young female athletes. Researchers evaluated 21 high school volleyball players.They found that the effectiveness of the INT's ability to increase hip abductor strength was dependent on compliance.

Context: Integrative neuromuscular training (INT) has successfully enhanced physical fitness and reduced abnormal biomechanics, which appear to decrease injury rates in adolescent female athletes. If not addressed at the proper time, low levels of physical fitness and abnormal mechanics may predispose female athletes to an increased risk of musculoskeletal injuries. Objectives: To evaluate sex-specific effects of INT on selected measures of health- and skill-related fitness in children during physical education (PE). Design: Cohort study. Setting: Public primary school. Patients or Other Participants: Forty children (16 boys, 24 girls; age = 7.6 ± 0.3 years, height = 124.5 ± 6.4 cm, mass = 29.5 ± 7.6 kg) from 2 second-grade PE classes. Intervention(s): The classes were randomized into the PE-plus-INT group (10 boys, 11 girls) or the control group (6 boys, 13 girls) that participated in traditional PE. The INT was performed 2 times per week during the first approximately 15 minutes of each PE class and consisted of body weight exercises. Main Outcome Measure(s): Push-up, curl-up, standing long jump, single-legged hop, single-legged balance, sit-and-reach flexibility test, shuttle run, and 0.8-km run. Results: At baseline, the boys demonstrated higher levels of performance in most of the fitness measurements as evidenced by greater performance on the push-up, standing long jump, single-legged hop, shuttle run, and 0.8-km run (P < .05). In the evaluation of the training effects, we found intervention effects in the girls for enhanced INT-induced gains in performance relative to the control group on the curl-up, long jump, single-legged hop, and 0.8-km run (P < .05) after controlling for baseline. Boys did not demonstrate similar adaptations from the INT program (P ≥ .05). Conclusions: These data indicate that INT is an effective and time-efficient addition to PE for enhancing motor skills and promoting physical activity in children. Seven-year-old girls appeared to be more sensitive to the effects of INT than 7-year-old boys. Future research is warranted to confirm these effects in larger cohorts of children. [ABSTRACT FROM AUTHOR]

The article evaluates the relationships between anterior cruciate ligament (ACL) strain and anterior knee laxity measurements using arthrometry during both a drawer test and simulated bipedal landing. The study found significant link between arthrometry displacement collected during laxity tests and concurrent ACL strain calculated from differential variable reluctance transducer (DVRT) measurements. Instrumented measures of anterior knee laxity also predict peak ACL strain during landing.

The article provides a systematic review of autograft and nonirradiated allograft tissue for anterior cruciate ligament reconstruction (ACLR). The review included nine studies and determined whether the use of nonirradiated allograft tissue is linked with poorer outcomes when compared with autografts. The researchers found no significant differences in graft failure rate, postoperative laxity, or patient-reported outcome scores in the systematic review.

The article investigates the relative anterior cruciate ligament (ACL) and medial collateral ligament (MCL) strain patterns during physiological simulation of high-risk dynamic landing conditions. A novel in sim approach is used to examine ACL and MCL strain following knee abduction and internal tibial rotation moments. It looks at the determinants of resultant ACL:MCL strain ratio levels. The importance of understanding injury mechanisms for injury prevention strategies is also emphasized.

The article discusses a study regarding the need to produce a simple, yet effective method for screening and targeting possible deficiencies related to increased anterior cruciate ligament (ACL) injury risk. The results revealed that providing athletes with augmented feedback on deficits identified by the tuck jump assessment has a positive effect on their biomechanics during a different drop vertical jump task which is related to increased ACL injury risk.

The article reports a study which systematically reviewed and synthesized the scientific literature regarding the influence of age of neuromuscular training (NMT) implementation on the effectiveness for reduction of anterior cruciate ligament (ACL) injury incidence. The findings of this meta-analysis revealed an age-related association between NMT implementation and reduction of ACL incidence. This supports initiating integrative NMT programs during early adolescence.

Objective: Examine longitudinal changes in trunk, hip, and knee kinematics in maturing boys during an unanticipated cutting task. Design: Prospective cohort study. Setting: Biomechanical laboratory. Participants: Forty-two high-school male basketball, volleyball, and soccer athletes. Assessment of Risk Factors: Trunk, hip, and knee range-of-motion (RoM), peak angles, and angles at initial contact during an unanticipated 45 degrees sidestep cutting task were estimated using laboratory-based three-dimensional optoelectronic motion capture. Maturation was classified using a modified Pubertal Maturational Observational Scale (PMOS) into prepubertal, midpubertal, or postpubertal stages. Main Outcome Measures: Trunk total RoM in frontal, sagittal, and transverse planes; peak trunk flexion, right lateral flexion and right rotation angles; hip total RoM in frontal, sagittal, and transverse planes; hip flexion angle at initial contact; peak hip flexion and adduction angles; knee total RoM in frontal, sagittal, and transverse planes; knee flexion angle at initial contact; peak knee flexion and abduction angles. Results: As boys matured, there was a decrease in hip sagittal-plane RoM (49.02 degrees to 43.45 degrees, Benjamini–Hochberg adjusted P = 0.027), hip flexion at initial contact (29.33 degrees to 23.08 degrees, P = 0.018), and peak hip flexion (38.66 degrees to 32.71 degrees, P = 0.046), and an increase in trunk contralateral rotation (17.47 degrees to 25.05 degrees, P = 0.027). Conclusions: Maturing male athletes adopted a more erect cutting strategy that is associated with greater knee joint loading. Knee kinematic changes that increase knee joint loading were not observed in this cohort. [ABSTRACT FROM AUTHOR]

The article mentions the longitudinal documentation of serum cartilage oligomeric matrix protein (sCOMP) and determines the changes in Patient-reported-outcomes (PROs) in collegiate soccer athletes during a season. It states that a biomarker for cartilage degradation known as (sCOMP) has been shown to be elevated after intense exercise. It concludes that sCOMP levels do change during a soccer season.

The article discusses a study to evaluate whether compliance with neuromuscular training is associated with reduced incidence of anterior cruciate ligament (ACL) injury in young female athletes. The findings of the study demonstrated that an inverse dose-response relationship exists between compliance with neuromuscular training and the incidence of ACL injury. The best way to prevent ACL injuries is by attending and completing recommended neuromuscular sessions.