Systematic video analysis of ACL injuries in professional male football (soccer): injury mechanisms, situational patterns and biomechanics study on 134 consecutive cases

Virtual reality-based therapy after anterior cruciate ligament injury effectively reduces pain and improves knee function, movement patterns, and dynamic balance: A systematic review and meta-analysis

PURPOSE

Virtual reality-based therapy (VRBT) may be an effective physical therapy complement employed in the rehabilitation of patients with anterior cruciate ligament (ACL) injury. This study aims to assess the effectiveness of VRBT in improving pain, knee function, strength, proprioception, flexion range of motion (ROM), and dynamic balance after ACL injury.

METHODS

We conducted this systematic review with meta-analysis following PRISMA criteria. Since inception to June 2024, we searched in PubMed Medline, WOS, SCOPUS, CINAHL and PEDro without publication date and language restrictions. Randomised controlled trials (RCTs), comprising only patients with ACL injury, that assess the effectiveness of VRBT compared to classical interventions on the outcomes of interest were included. PEDro scale was employed to analyze the methodological quality of the RCTs included. Cohen's standardised mean difference (SMD) and its 95% confidence interval (95% CI) was used to calculate the pooled effect in meta-analyses.

RESULTS

Nine RCTs, providing data from 330 participants (26.96 ± 3.11 years, 85% males) were included. The RCTs included showed good methodological quality (PEDro scale = 6.88 points), being, performance and detection biases, the most common biases reported. Meta-analyses showed that VRBT was more effective than classical interventions in reducing pain (SMD = -1.15; 95% CI -1.85 to -0.45; p = 0.001; I2 = 0%), and increasing knee function (SMD = 1.71; 95% CI 0.93 to 2.5; p < 0.001; I2 = 0%), strength (SMD = 0.82; 95% CI 0.4-1.23; p < 0.001; I2 = 0%) and flexion ROM (SMD = 0.7; 95% CI 0.37-1.01; p < 0.001; I2 = 0%). Additionally, VRBT improved postero-medial (SMD = 0.46; 95% CI 0.01-0.9; p = 0.045; I2 = 15.1%) and postero-lateral CoP excursion (SMD = 0.75; 95% CI 0.3-1.21; p = 0.001; I2 = 0%), being effective in improving dynamic balance.

CONCLUSION

VRBT is an effective physical therapy complement to be included in the ACL's rehabilitation programmes due to reduces pain and increases knee function, strength, ROM and dynamic balance after ACL injury.

LEVEL OF EVIDENCE

Level II.

A Systematic Video Analysis of Anterior Cruciate Ligament Injuries in Professional Female Basketball Players

BACKGROUND

Anterior cruciate ligament (ACL) injuries are common in female basketball players, who have a 2 to 3 times higher risk for an ACL injury than their male counterparts. Improving our understanding of the situations and biomechanics that result in an ACL injury in basketball players may support the design of more effective programs to mitigate the injury risk.

PURPOSE

To describe the injury mechanisms, situational patterns, and biomechanics of ACL injuries during matches in professional female basketball players.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 105 ACL injuries in professional female European basketball leagues from the 2018 to 2023 seasons were identified. There were 41 (39%) injury videos analyzed for injury mechanisms and situational patterns, while biomechanical analysis was possible in 33 cases. There were 3 independent reviewers who rated each video. Data according to player position, phase of the match, and location on the court were also evaluated (n = 41). Analysis regarding neurocognitive perturbation was assessed in 41 cases (100%).

RESULTS

Most injuries (n = 28 [68%]) occurred during offensive possession. Indirect contact injuries were more prevalent (n = 23 [56%]) than noncontact injuries (n = 18 [44%]). Overall, 3 main situational patterns constituted 95% of injuries: offensive cut (n = 20 [49%]), defensive cut (n = 12 [29%]), and landing from a jump (n = 7 [17%]). Injuries involving a knee-dominant pattern with valgus were identified in 64% of cases. Injuries were evenly distributed between the first (53%) and second (47%) halves of a game. Half (50%) occurred within the first 10 minutes of effective playing time, and the most frequent months of injury were October and November (44%; early season). Nearly half (46%) of the injuries occurred in small forwards, with 59% of injuries occurring in zone 5. Neurocognitive errors were seen in 56% of injuries, while 92% of defensive injuries showed signs of neurocognitive errors.

CONCLUSION

ACL injuries in professional female basketball players were caused by indirect contact or noncontact, involving offensive and defensive cuts as well as landing from a jump. Biomechanical analysis confirmed a multiplanar mechanism with a knee-dominant pattern and valgus. Most injuries occurred early in the season and within the first 20 effective minutes played (89%), making accumulated fatigue an unlikely risk factor for ACL injuries in basketball players.

The early peak knee abduction moment waveform is a novel risk factor predicting anterior cruciate ligament injury in young athletes: A prospective study

PURPOSE

In this study, prospective data were used to evaluate whether the early peak knee abduction moment waveform is associated with the risk of anterior cruciate ligament (ACL) injury.

METHODS

Biomechanical data from 84 athletes who participated in the study as adolescents were analysed after cross-referencing national health registry data to confirm ACL reconstruction in the subsequent years. The knee abduction moment waveform shape was obtained with cluster analysis for the first 100 ms of a cutting manoeuvre (1776 trials in total) and classified as either containing an early peak knee abduction moment or not, and the odds ratio for later ACL injury was then calculated. Additionally, discrete kinematic and kinetic variables were extracted, and tested against the risk of ACL injury using mixed model logistic regression.

RESULTS

Of 84 athletes, 8 (all female) sustained a total of 13 ACL injuries in the years after motion analysis data collection. Six clusters of knee abduction moment waveform shapes were identified. Two clusters containing 446 trials were classified as an early peak knee abduction waveform. This waveform was associated with a 7.2-fold increase in the risk of ACL injury (95% confidence interval: 2.4-24.6; p < 0.001). Of the kinematic and kinetic variables tested, only the knee abduction angle at initial contact was associated with an increased risk of ACL injury (p < 0.001).

CONCLUSION

This is the first study to confirm the association between the early peak knee abduction moment waveform and the risk of ACL injury. Using waveforms, instead of discrete peak values of the knee abduction moment, may better represent risky movement patterns. Replicating these findings in a larger cohort will support the use of this method to screen athletes for risk and guide targeted preventive interventions and their efficacy.

LEVEL OF EVIDENCE

Level II.

On-field kinematics of cut maneuvers in football players: Are wearable sensors reliable for assessing anterior cruciate ligament injury risk?

The aim of the present study was to present the reliability and normative values of wearable inertial sensors kinematics during football-specific cut maneuver tasks collected on the football field for assessing anterior cruciate ligament (ACL) injury risk. Forty-seven academy football players (age 15.9 ± 2.4 years, female n = 20) performed a planned 90° change of direction within the Agility T-test and unplanned football-specific changes of direction (FS deceiving action). Kinematics was collected through eight wearable inertial sensors (100 hz, MTw Awinda, Movella). Intraclass correlation coefficient and Root Mean Square Error were used to inspect test-retest and side-to-side reliability of peak and waveform kinematics. Normative kinematics was compared between male and female players (t-test with Cohen's d, p < 0.05). Test-retest reliability was moderate-to-excellent in most of the parameters (r=0.40-0.92). Side-to-side reliability was worse than test-retest (both movement tasks). Female players showed worse movement quality than males with greater peak values on the frontal and transverse planes at the knee, pelvis and trunk and smaller knee and trunk flexion (d = 0.50-1.1 in Agility T-test, = 0.39-0.73 in FS deceiving action). The on-field cut maneuver kinematics by wearable sensors demonstrated sufficient reliability for most joints. Reliability and normative values might help to objectify ACL injury prevention programs in football academies.

Editorial commentary: Video Analysis of Football (Soccer) Injury Can Guide Rehabilitation and Recovery

Video-analysis has emerged as a powerful tool to systematically inspect musculoskeletal injuries in sport, allowing determination of: injury mechanism (non-contact, indirect contact, or direct contact), situational pattern, and biomechanics. Approximately 90% of ACL injuries in professional football players happen without direct contact at the knee level. Non-contact ACL injury increases the risk of sustaining a second ACL injury by seven times (compared to contact injuries); female football players tend to exhibit even higher rates of injuries without contact. Football ACL injuries generally occur during defensive actions (pressing or tackling), and Achilles tendon ruptures during offensive movements. Biomechanical risks of football ACL injury revealed during video analysis include dynamic knee valgus loading, trunk-pelvis instability, and heel footstrike. Finally, neurocognitive concerns may be linked to injury mechanism, situational pattern, and biomechanics. For example, ACL injury due to neurocognitive prediction error during pressing is seen in over 90% of cases. Integrating corrective biomechanics, movement techniques, and neurocognitive training with on field rehabilitation may enhance recovery and mitigate risk of future injury.

The Effect of the FIFA 11+ Warm-Up Program on Knee Instability and Motor Performance in Male Youth Soccer Players

This study aimed to investigate the effect of the FIFA 11+ program on knee instability and motor performance in male youth soccer players. Thirty male youth soccer players were divided into two groups: the experimental group (FIFA+) performed the FIFA 11+ program for 10 weeks, while the control group followed their usual warm-up routine. Dynamic knee valgus (DKV) and squat depth were assessed using a Microsoft Azure Kinect camera and dynaknee software. Maximal isometric muscle force was measured with a dynamometer. The Y Balance test was used to evaluate dynamic balance, while a countermovement jump test assessed lower limb power. The knee range of motion was measured with a goniometer, and the t-test was used to evaluate agility. After the intervention, the FIFA+ group showed a significant decrease in DKV and squat depth (p < 0.05), while the control group showed no significant changes (p > 0.05). Both groups improved in motor performance, with slight progress noted in the FIFA+ group. However, neither group demonstrated significant improvement in dynamic balance (p > 0.05). While the FIFA 11+ program may not substantially enhance overall motor performance or match the effectiveness of other training regimens, it shows potential for addressing biomechanical deficiencies and reducing the risk of injuries, particularly those related to dynamic knee valgus.

Effects of Anticipation and Dual-Tasking on Lower Limb Biomechanics While Performing Change-of-Direction Tasks in Physically Active Individuals: A Systematic Review with Meta-Analysis

BACKGROUND

Anterior cruciate ligament (ACL) injuries are highly prevalent in team sport athletes and often occur while performing change-of-direction (COD) tasks in combination with high cognitive demands, such as decision making or divided attention. Given the expanding body of research in this field, an updated literature review is warranted, as the most recent meta-analysis on this topic included original studies published up to November 2020.

OBJECTIVE

The aim of this systematic review was to examine the effects of anticipation and/or dual-tasking on lower limb biomechanics during COD tasks in healthy individuals.

DESIGN

Systematic review with meta-analysis.

DATA SOURCES

A systematic literature search was conducted in the electronic databases PubMed, Web of Science, CINAHL and SPORTDiscus from inception until February 2024. The included studies examined the effects of anticipation and/or dual-tasking on knee kinetics and kinematics in the frontal and sagittal planes during COD tasks.

METHODS

A multilevel meta-analysis was performed to aggregate the results of studies comparing unanticipated versus anticipated CODs on lower limb biomechanics. Due to the limited available literature on dual-task versus single-task conditions, this aspect was analyzed qualitatively.

RESULTS

The meta-analysis included 17 studies involving 355 individuals from different sports (e.g., soccer, American Football). No statistically significant differences were found between unanticipated and anticipated CODs for knee abduction and flexion moments as well as knee abduction angles (p > 0.05). Significantly higher knee flexion angles were found in unanticipated CODs (SMD = 0.74, 95% CI: 0.30-1.19; p < 0.01). Qualitative analyses of six studies including 171 individuals provided initial evidence for higher knee abduction moments and flexion angles during anticipated CODs while performing a secondary task concurrently.

CONCLUSION

Findings from quantitative and qualitative analyses indicate that anticipation and dual-tasking during COD performance have an impact on injury-related aspects of lower limb biomechanics. Hence, cognitive challenges should be implemented in injury risk screening and preventive strategies. Further studies with high methodological quality are needed to improve the understanding of the biomechanical and cognitive interplay in injury-threatening situations.

PROSPERO REGISTRATION NUMBER

CRD42023433074.

DATE OF REGISTRATION

13.10.2023.

A higher incidence of chondral injuries on the medial femoral condyle in concomitant ACL ruptures, no significant difference in treatment: A systematic review

PURPOSE

The associated damage to articular cartilage in anterior cruciate ligament (ACL) injured patients is a well-recognized phenomenon; however, there is a relative paucity in the literature regarding the different treatment techniques and outcomes. The purpose of this systematic review was to identify patients treated for acute ACL rupture and associated cartilage injury, with interest in the surgical management of these chondral injuries and any difference in patient-reported outcome measures (PROMs) differing techniques.

METHODS

A systematic review was performed looking for treatment or management of International Cartilage Repair Society grade 3 or 4 articular cartilage injury at the time of ACL reconstruction.

RESULTS

Seventeen studies fit the criteria, a total of 892 patients were included, 64.6% were male with a mean age of 33.7 and the average time to follow-up was 41.7 months. 68.2% of the lesions were on the medial femoral condyle (MFC) with a mean lesion size of 3.9 cm2. Six different operative methods of dealing with chondral lesions were identified, there was no significant difference in PROMs between the techniques, although there was a significant difference between the preoperative and postoperative outcome measures.

CONCLUSIONS

The systematic review found that chondral defects on the MFC are more common in concomitant ACL injuries, despite the pattern of bone bruising being more common on the lateral femoral condyle as reported in the literature. It also found no significant difference in the PROMs between the six different techniques identified for the concomitant management of ACL reconstruction and chondral defects.

LEVEL OF EVIDENCE

Level II.

Neuromuscular Control Deficits After Anterior Cruciate Ligament Reconstruction: A Pilot Study Using Single-Leg Functional Tests and Electromyography

Purpose: This study aimed to evaluate neuromuscular control and muscle activation patterns in individuals following anterior cruciate ligament (ACL) reconstruction, compared to healthy controls. Methods: A cross-sectional comparative study was conducted following STROBE guidelines, including 16 participants (ACL group: n = 9; control group: n = 7). Participants performed the single-leg squat (SLS) test and the single-leg drop landing (SLDL) test. Neuromuscular control was assessed using the Qualitative Analysis of Single-Leg Loading Score (QASLS), while gluteus medius and vastus medialis activation were recorded using surface electromyography. Results: The ACL group showed significantly higher QASLSs in the SLS test (p = 0.0113), indicating poorer movement quality, while no difference was found in the SLDL test (p = 0.5484). Gluteus medius activation was lower in the ACL group during the SLS test (p = 0.0564), and vastus medialis activation was higher but not significantly different (p = 0.095). Conclusions: These findings highlight persistent neuromuscular deficits post-ACL-reconstruction, particularly in SLS tasks, reinforcing the need for targeted rehabilitation strategies focusing on hip stabilization and quadriceps motor control to optimize movement quality and reduce reinjury risk.

Age not a primary risk factor for ACL injury-A comprehensive review of ACL injury and reinjury risk factors confounded by young patient age

Revision surgery after anterior cruciate ligament reconstruction (ACL-R) is hypothesized to be the result of an interplay between factors associated with the anatomy, physiological characteristics and environment of the patient. The multifactorial nature of revision ACL-R risk is difficult to quantify, and evidence regarding the independent roles of potentially important variables is inconsistent throughout the literature. Young patient age is often cited as one of the most prominent risk factors for reinjury after ACL-R. However, the association between a non-modifiable variable such as patient age and revision ACL-R risk is likely to be a spurious correlation due to the confounding effect of more important variables. From the perspective of healthcare professionals aiming to mitigate revision ACL-R risk through targeted interventions, awareness of factors like generalized joint hypermobility, bone morphology, muscle strength imbalances, and genetic factors is critical for the individualized risk assessment of patients with ACL injury. The aim of this current concepts article is to raise awareness of the essential anatomical, physiological, and activity-related risk factors associated with ACL injury and reinjury risk that are likely captured and confounded by patient age. LEVEL OF EVIDENCE: Level V.

Injury risk reduction programs including balance training reduce the incidence of anterior cruciate ligament injuries in soccer players: a systematic review and meta-analysis

BACKGROUND

Anterior cruciate ligament (ACL) injuries are exceedingly common among soccer players and severely impact their careers and health. This study evaluates the effects of injury risk reduction programs, including balance training exercises, on the incidence of ACL injuries in soccer players through a meta-analysis. The aim is to promote the health of soccer players, enhance their athletic performance, and provide valuable insights for further research in the field of sports medicine.

METHODS

This study strictly adheres to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A comprehensive literature search was conducted through PubMed, EBSCO, and Web of Science databases, covering all entries from the inception of the databases until February 2024.

RESULTS

Eligible studies were individually assessed using the Cochrane Risk of Bias Tool version 2, and the quality of the evidence obtained was rigorously evaluated using the GRADE approach. Data analysis and processing were performed using Stata 18 software. Eight studies were ultimately selected for inclusion in the meta-analysis, encompassing 20,336 participants and 1,512,099 exposure hours, with 190 cases of ACL injuries identified among soccer players. The pooled results indicated that, compared to the control group, groups using injury risk reduction programs that included balance training had a 58% reduction in the overall rate of ACL injuries per 1,000 exposure hours (IRR 0.42, 95% CI: 0.27 to 0.66). The overall study heterogeneity was low, with an I2value of 33.3% and a P-value of 0.186. Subgroup analyses showed that in trials involving male participants, the rate of ACL injuries per 1,000 exposure hours was reduced by 50% compared to the control group (IRR 0.50, 95% CI: 0.29 to 0.88), with an I2 value of 44.8% and P = 0.178. In trials involving female participants, ACL injuries were reduced by 61% (IRR 0.39, 95% CI: 0.24 to 0.62), with an I2 value of 42.5% and P = 0.157. In trials with participants training less than three times per week, ACL injuries were reduced by 43% per 1,000 exposure hours compared to the control group (IRR 0.57, 95% CI: 0.35 to 0.93), with an I2 value of 0.00% and P = 0.727. In trials with participants training three times or more per week, ACL injuries were reduced by 57% (IRR 0.43, 95% CI: 0.21 to 0.88), with an I2 value of 28.2% and P = 0.238. In trials with participants training for 20 min or more per week, the rate of ACL injuries per 1,000 exposure hours was reduced by 50% compared to the control group (IRR 0.50, 95% CI: 0.26 to 0.93), with an I2 value of 1.2% and P = 0.363. In trials with participants training less than 20 min per week, ACL injuries were reduced by 46% (IRR 0.54, 95% CI: 0.33 to 0.91), with an I2 value of 0.00% and P = 0.544.

CONCLUSION

In summary, injury risk reduction programs that include balance training significantly reduce the risk of ACL injuries in soccer players. The reduction in injuries is more pronounced in female athletes, and high-frequency training along with longer-duration interventions further enhance the preventative effects.

Drop jump vertical kinetics identify male youth soccer players at greater risk of non-contact knee injury

OBJECTIVES

To determine associations between drop-jump vertical kinetics and acute non-contact knee injury-risk in male youth soccer players.

DESIGN

Prospective cohort study.

SETTING

Professional soccer academies.

PARTICIPANTS

Youth soccer players (n = 264).

MAIN OUTCOME MEASURES

Drop-jump vertical kinetics; injury epidemiology. Associations between kinetics and injury were assessed using binary logistic regression. Differences between injured and uninjured groups were compared using statistical parametric mapping.

RESULTS

Peak braking: peak propulsive force ratio (OR = 1.59, 1.10-2.29, p < 0.05), propulsive work (OR = 0.53, 0.28-0.99, p < 0.05) and vertical stiffness (OR = 1.68, 1.13-2.52, p < 0.05) were associated with risk of sustaining a knee injury. All variables demonstrated 'unusable' or 'weak' levels of predictive ability in identifying players who would become injured (AUC 0.568-0.663).

CONCLUSIONS

Drop-jump vertical kinetics that characterise the shape of the force-time waveform provide insight to acute non-contact knee injury-risk in male youth soccer players. Large transient spikes in force in the early phase of ground contact, coupled with reduced propulsive forces are a risk factor for acute non-contact knee injury in male youth soccer players. Variables are not sensitive enough to predict injury but provide additional training targets to help mitigate risk in this population.

Effectiveness of Neuromuscular Training in Preventing Lower Limb Soccer Injuries: A Systematic Review and Meta-Analysis

Background: Soccer is associated with a high risk of injuries, mainly affecting the lower limbs, leading to significant consequences for player performance and career longevity. Neuromuscular training (NMT) has been proposed as an effective preventive strategy, but its impact varies across different populations and implementation strategies. Methods: A systematic review was conducted following PRISMA guidelines. A comprehensive search of PubMed, MEDLINE, and SPORTDiscus identified randomized controlled trials, cohort studies, and systematic reviews examining the effects of NMT on lower limb injury prevention in soccer players. Study quality was assessed using the Downs and Black tool, and injury incidence rate ratios were analyzed. Results: Eleven studies, encompassing over 10,000 soccer players, were included. NMT interventions, particularly FIFA 11+, significantly reduced injury rates compared to standard warm-ups. Higher adherence and coach education enhanced program effectiveness. Female players benefited more, particularly in ACL injury prevention. No significant differences were observed between shorter (10 min) and standard (20 min) NMT protocols. Conclusions: NMT effectively reduces lower limb injuries in soccer, with adherence and proper coaching being key determinants of success. Future research should optimize program design and long-term adherence strategies to maximize benefits across all player demographics.

High Return to Competition Rate After On-Field Rehabilitation in Competitive Male Soccer Players After ACL Reconstruction: GPS Tracking in 100 Consecutive Cases

Background

Despite published guidelines describing on-field rehabilitation (OFR) frameworks for soccer, available evidence for practitioners who work with players with anterior cruciate ligament reconstruction (ACLR) is limited.

Purpose

To document the activity and workloads completed by a large cohort of amateur and professional soccer players during OFR following ACLR after completing their indoor rehabilitation and to establish their return to competition (RTC) outcomes.

Study Design

Case series; Level of evidence, 4.

Methods

OFR measurements/activities, global positioning system (GPS), and heart rate data were collected from 100 male 11-a-side soccer players with ACLR undergoing a criteria-based rehabilitation process, concluding with a 5-stage OFR program. Consent was obtained directly from the players involved in this study before completing a follow-up questionnaire to document RTC outcomes. Differences between the level of play (professional and amateur) and 5 OFR stages were investigated using separate linear mixed models.

Results

A minimum 9-month follow-up was possible for 97 players (97%), with a median time of 2.3 years after ACLR and 84% RTC, with higher rates in professionals (100%) than amateurs (80%). Ten (10%) players sustained an ACL reinjury. Professionals completed more OFR sessions (20.6 ± 7.7 vs 13.2 ± 7.7; P < .001) over a shorter period (44.7 ± 30.3 vs 59.3 ± 28.5 days; P = .044) and achieved higher workloads mostly in the high-intensity GPS metrics in each OFR stage. Typical external workload outputs in the final OFR stage aligned with team training demands for the total distance (TD) (106%), high-intensity distance (HID) (104%), peak speed (PS) (88%), acceleration distance (ACC) (110%), and deceleration distance (DEC) (48%), but they were lower compared with match play demands (TD: 44%; HID: 51%; PS: 82%; ACC: 63%; and DEC: 26%).

Conclusion

High RTC rates were reported in those players who participated in OFR after indoor rehabilitation. Completion of all five OFR stages almost prepared them for team training demands; however, workloads remain low compared to match play.

Neurophysiology of ACL Injury

The neurophysiology of ACL injury extends beyond the mechanical rupture of the ligament to encompass profound alterations in the central and peripheral nervous systems, impacting sensorimotor integration and neuromuscular control. The ACL, densely populated with mechanoreceptors, plays a critical role in joint proprioception, dynamically regulating knee stability through complex neural circuits that connect to the spinal cord and brain. When disrupted by injury, these neural pathways contribute to delayed muscular activation, altered motor planning, and compromised joint stability. Such neuromechanical deficits increase the likelihood of reinjury and highlight the need for comprehensive neuroplastic rehabilitation. Neuroplastic therapy, employing tools like external focus strategies, stroboscopic glasses, smartboards, and virtual reality, aims to restore and enhance neural connectivity, sensory integration, and motor coordination. These advanced tools target distinct phases of motor learning, promoting automaticity and resilience in movement patterns. By integrating visual-cognitive, proprioceptive, and reflexive controls, this therapeutic approach not only accelerates recovery but also optimizes performance and reduces the risk of re-injury, representing a paradigm shift in ACL rehabilitation.

Acute effect of technique modification training on 180° change of direction performance and kinematics in adolescent male soccer players

Introduction

Change of direction (COD) maneuvers are frequently performed during soccer games and are critical for performance. Adolescent players often display immature COD maneuvers, suggesting that COD technique modification training may be a more effective approach for adolescent athletes. This study investigated the acute effects of COD modification training on COD performance and kinematics in male adolescent soccer players.

Methods

Twenty-nine male junior high school soccer players participated in this study and were divided into two groups: 16 players underwent 15-min COD technique modification training (COD group), while 13 players engaged in 15-min linear sprint training. The participants performed Pro-Agility and 20-m sprint tests before and after the intervention, and the total times were measured. COD deficit (CODD) was calculated as the difference between these times. Center of mass (COM) velocity and trunk and lower limb kinematics were computed from three-dimensional kinematic data collected during the Pro-Agility test using a markerless motion capture system. Each section of the Pro-Agility test was divided into acceleration and deceleration phases based on the COM velocity; Stop marks the moment of direction change. Two-way (group and time) mixed ANOVA was conducted with Bonferroni corrections for post-hoc comparisons.

Results

No significant interactions were observed in the total time of the Pro-Agility test, CODD, 20-m sprint time, or average acceleration and deceleration in each phase (p > 0.05). On the other hand, the COD group showed significant interactions and improvements in average deceleration from final foot (FF) contact to Stop (p = 0.012, g = 0.639), penultimate foot hip flexion angle at Stop (p = 0.042, g = 0.496), COM-FF horizontal distance at Stop (p = 0.008, g = 0.650), and FF ground contact time (p < 0.001, g = 0.803).

Conclusion

A 15-min COD technique modification training led to partial, immediate improvements in kinematic parameters among adolescent soccer players but did not enhance overall COD performance or acceleration/deceleration ability.

Cluster analysis of cutting technique-a valuable approach for assessing anterior cruciate ligament injury risk?

Background

Despite extensive efforts to pinpoint singular biomechanical risk factors for anterior cruciate ligament (ACL) injuries, research findings are still inconclusive. By combining multiple biomechanical variables, cluster analyses could help us identify safe and risky cutting technique strategies.

Purpose

To identify common movement strategies during cutting maneuvers and to assess their association with ACL injury risk.

Methods

A total of 754 female elite handball and football players, including 59 with a history of ACL injury, performed a sport-specific cutting task while 3D biomechanics were recorded. Over an 8-year follow-up period, 43 of these players sustained a primary ACL injury and 13 players a secondary ACL injury. Cutting technique was described using 36 discrete kinematic variables. To identify different cutting techniques, we employed a K-means clustering algorithm on data subsets involving different numbers of kinematic variables (36, 13 and 5 variables) and different sports (handball, football, and both combined). To assess the impact of the identified cutting technique clusters on ACL injury risk, we compared the proportion of injured players between these clusters using the Fisher-Freeman-Halton Exact test and adjusted rand indices (ARI).

Results

We identified two distinguishable cutting technique clusters in the subset involving both sports and five kinematics variables (average silhouette score, ASS = 0.35). However, these clusters were formed based on sport- or task-related differences (Fisher's p < 0.001, ARI = 0.83) rather than injury-related differences (Fisher's p = 0.417, ARI = 0.00). We also found two cutting technique clusters in the handball (ASS = 0.23) and football (ASS = 0.30) subsets with five kinematic variables. However, none of these clusters appeared to be associated with ACL injury risk (Fisher's p > 0.05, ARI = 0.00).

Conclusion

No safe or risky cutting technique strategies could be discerned among female elite handball and football players. Cluster analysis of cutting technique, using a K-means algorithm, did not prove to be a valuable approach for assessing ACL injury risk in this dataset.

Plastic deformation of anterior cruciate ligament: listen to the patient, do not just rely on imaging

PURPOSE

Diagnosing plastic deformation of the anterior cruciate ligament (ACL) is challenging: patients may not report knee instability, and MRI may not confirm the lesion, delaying adequate treatment. This study analyzed clinical findings and complaints in patients with a confirmed diagnosis of plastic deformation of the ACL.

METHODS

Data on complaints, physical, imaging and arthroscopic assessment, and subjective evaluation of 15 patients with undiagnosed or delayed ACL insufficiency from plastic deformation of the ACL (Group 1) and 30 patients who underwent an ACL reconstruction following complete tear of the ACL diagnosed clinically and at imaging (Group 2) were compared and analyzed.

RESULTS

A knee effusion was reported in both study groups, occurring within the first 4 h after the index knee injury, and it was statistically more significant in the complete ACL tear group. All patients reported low values (zero, one, and two) on a scale from zero to 10 in their confidence in performing high-intensity pivoting sports and physical activities. All patients reported that they did not feel comfortable in performing changing direction pivoting on their injured knee.

CONCLUSION

Plastic deformation of the ACL may not be clearly manifest clinically and on MRI, and physical exam may present subtle findings that do not allow to fully assess the function of the injured ligament. Therefore, surgeons should listen to the patient, not just rely on imaging, taking into account the patient's report of how the knee is working and their complaints as they remain the leading guide for decision-making.

LEVEL OF EVIDENCE IV

Diagnostic studies - Investigating a diagnostic test.

Video Analysis of Acute Lower Extremity Injury Mechanisms in Soccer Demonstrates Most Anterior Cruciate Ligament, Achilles, and Muscle Injuries Occur Without Direct Contact: A Systematic Review and Meta-analysis

PURPOSE

To systematically review the literature for studies using video analysis to evaluate acute lower extremity injury mechanisms in soccer players.

METHODS

The study was preregistered on PROSPERO. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Three databases were searched for Level I to IV studies that quantified lower extremity injury mechanisms in soccer players using video analysis. Data recorded included study demographics, injury type, mechanisms, contact, phase of play, timing, and sagittal plane kinematics. Study methodological quality was analyzed using the Quality Appraisal for Sports Injury Video Analysis Studies scale. Forest plots of proportions were generated for injuries occurring in the first versus second half, defensive versus offensive phase, and contact versus noncontact injury.

RESULTS

Nineteen articles (mean Quality Appraisal for Sports Injury Video Analysis Studies score 14.3 ± 1.9; all Level IV evidence, 1,652 videos, 17 professional males, 1 professional female, 1 both male/female) were included. Anterior cruciate ligament (ACL) tears (49% [42%-55%]), muscle strains (hamstring: 71% [47%-87%]), and Achilles tears (80%-83%) had a high percentage of noncontact (NC) injury mechanisms. Direct and indirect contact-predominant injuries include medial collateral ligament sprains (14% NC) and foot/ankle sprains (6% [4%-10%] NC). Most ACL injuries (68% [61%-75%]) occurred while defending, and quadriceps strains (81%-89%) occurred while attacking.

CONCLUSIONS

In soccer, video analysis shows that a high proportion of acute ACL, Achilles, and muscle injuries occur through noncontact mechanisms, while medial collateral ligament and foot/ankle injuries usually happen with direct contact. ACL injuries are more likely to be sustained when defending, specifically when pressing/tackling, and muscle injuries result from sprinting, kicking, and lunging. Most noncontact-predominant injuries occurred at a higher percentage in the first half, whereas contact-predominant injuries occurred at a higher percentage in the second half.

LEVEL OF EVIDENCE

Level IV, systematic review and meta-analysis of Level IV studies.

3D kinematics of noncontact and indirect contact ACL injuries in elite male football players

PURPOSE

Our primary goal was to deepen the understanding of the mechanisms leading to anterior cruciate ligament (ACL) injuries by reconstructing the three-dimensional (3D) joint kinematics of ACL injuries that occurred in professional male football matches. In particular, we aimed to compare the time courses of trunk and injured limb joint angles between noncontact and indirect contact injury mechanisms.

METHODS

In this cross-sectional observational study, we analysed a total of 27 cases (18 noncontact, 9 indirect contact). Whole-body 3D kinematics preceding and during ACL injuries was reconstructed using the Model-Based Image-Matching technique, implemented in Blender. For each injury, television footage from multiple perspectives (≥2, nine frames per view) were used, and Euler's joint angles across all the anatomical planes were extracted. The joint angle time courses of both the trunk and the injured limb, comprising 12 waveforms in total, were compared between injury mechanisms and Statistical Parametric Mapping was used to detect significant clusters.

RESULTS

Compared to noncontact injuries, indirect contact cases showed a lower hip abduction (-16°, p = 0.003), knee internal rotation (~3°, p < 0.001) at the initial contact with the ground, and ankle dorsiflexion (~7°, p = 0.035) at instants before the initial ground contact. These differences resulted from the player's adaptation to the sudden (yet variable) mechanical perturbation due to the contact with the opponent.

CONCLUSION

Mechanical interactions with other players impact segmental kinematics before and during ACL injuries in professional male football. These findings reinforce the importance of considering the sport-specificity of mechanisms in injury prevention.

LEVEL OF EVIDENCE

Level IV.

The Neuroplastic Outcomes from Impaired Sensory Expectations (NOISE) hypothesis: How ACL dysfunction impacts sensory perception and knee stability

BACKGROUND

The anterior cruciate ligament (ACL) is integral to maintaining knee joint stability but is susceptible to rupture during physical activity. Despite surgical restoration of passive or mechanical stability, patients struggle to regain strength and prior level of function. Recent efforts have focused on understanding how ACL-related changes in the nervous system contribute to deficits in sensorimotor control following injury and reconstruction. We hypothesize that these challenges are partially due to an increase in sensorimotor uncertainty, a state that reduces the precision of movement control.

OBJECTIVES

This review proposes the ACL NOISE (Neuroplastic Outcomes from Impaired Sensory Expectations) hypothesis, reframing current literature to provide a case that increased sensory noise following ACL injury and reconstruction disrupts sensory predictions, which are anticipations of immediate sensory outcomes or motor commands. This disruption in sensory predictions may contribute to altered neurophysiology, such as cross-modal brain activity, and other persistent clinical deficits.

DESIGN

Narrative review RESULTS/FINDINGS: Following ACL injury and reconstruction, the knee and nervous system experience various neurophysiological alterations to overcome elevated sensory uncertainty and inaccurate sensory predictions, contributing to persistent motor deficits.

CONCLUSIONS

We provide a theoretical case based on compelling evidence that suggests prolonged impairment after ACL injury may be secondary to uncertainty in knee sensory perception. Future research should consider testing the NOISE hypothesis by creating a paradigm that examines dynamic joint stability in response to unexpected perturbations. This approach would help assess motor coordination errors and drive the development of clinical strategies aimed at reducing sensory uncertainty following ACL reconstruction.

Posterior Trunk Pulling Perturbation Increased Variables Associated With Anterior Cruciate Ligament Loading in Both Sagittal and Frontal Planes During Landing

Trunk perturbation before initial ground contact (IC) is associated with increased anterior cruciate ligament (ACL) injury risk. The purpose of this study was to determine the effect of midflight anterior and posterior pulling perturbation applied to the upper trunk on ACL loading variables during landings. Participants performed double-leg vertical jumps with and without anterior or posterior pulling perturbation. The perturbation was created by a customized device, pulling participants through a freely dropping slam ball before IC. Whole-body kinematics and ground reaction forces were collected using optoreflective cameras and force plates. Data from 31 participants were included for analysis. The posterior pulling perturbation resulted in the significantly smallest peak trunk and knee flexion angles, the greatest peak knee abduction angle, and peak knee extension and adduction moments during landings. The anterior pulling perturbation resulted in the significantly greatest peak trunk flexion angle and smallest peak knee extension moment among all conditions, and significantly greater peak knee flexion angle, smaller peak knee abduction angle, and smaller peak knee adduction moment compared to the posterior pulling perturbation. The findings suggest increased ACL loading variables and potential injury risk associated with midflight posterior pulling perturbation and provide information for understanding indirect-contact ACL injury mechanisms.

Systematic Video Analysis of ACL Injuries in Male Professional English Soccer Players: A Study of 124 Cases

Background

Improving our understanding of the situations and biomechanics that result in anterior cruciate ligament (ACL) injury will support the design of effective injury risk mitigation programs. A few video analyses have been published in recent years, but not specifically involving English soccer.

Purpose

To describe the mechanisms, situational patterns, and biomechanics (kinematics) of ACL injuries of players involved in matches involving teams in the top 2 tiers of professional English soccer (the Premier League and the Championship).

Study Design

Case series; Level of evidence, 4.

Methods

We identified 148 consecutive ACL injuries across 11 seasons of professional English soccer. Overall, 124 (84%) injury videos were analyzed for mechanism and situational patterns, while biomechanical analysis was possible in 91 injuries. Three independent reviewers evaluated each video. ACL injury epidemiology (month, timing within the match, and location on the playing field at the time of injury) was also reported.

Results

More injuries occurred in defensive (n = 79; 64%) than offensive (n = 45; 36%) playing situations; 24 (19%) injuries were direct contact, 52 (42%) indirect contact, and 47 (38%) noncontact. Of the indirect and non-contact ACL injuries (n = 100), most (91%) occurred during 4 main situational patterns: (1) pressing/tackling (n = 50; 50%); (2) being tackled (n = 18; 18%), (3) landing from a jump (n = 13; 13%), and (4) regaining balance after kicking (n = 10; 10%). These injuries generally involved a knee flexion strategy (with minimal hip/trunk flexion and reduced plantarflexion) in the sagittal plane and appearance of knee valgus in most cases (70%; 96% of identifiable cases). More (n = 71; 57%) injuries occurred in the first half of matches than in the second half (P < .01).

Conclusion

Indirect contact rather than noncontact was the main ACL injury mechanism in male elite English soccer players. Four main situational patterns were described, with pressing/tackling and being tackled accounting for two-thirds of all indirect and noncontact injuries. Biomechanical analysis confirmed a multiplanar mechanism, with knee loading patterning in the sagittal plane accompanied with dynamic valgus. More injuries occurred in the first half of matches.

Combined Anterior Cruciate Ligament and Anteromedial Oblique Ligament Reconstruction Using the Rectus Femoris Tendon: Description of Surgical Technique

We present a technique for combined anterior cruciate ligament and anteromedial oblique ligament reconstruction using the rectus femoris tendon graft. Anatomic anterior cruciate ligament reconstruction and anteromedial reinforcement are performed with a single rectus femoris graft. The rectus femoris tendon graft is harvested in a reproducible and minimally invasive approach. The surgical technique requires no special instruments and consists of 3 bone tunnels. Fixation is performed with interference screws.

Adding secondary cognitive tasks to drop vertical jumps alters the landing mechanics of athletes with anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) reinjury rates among athletes remain very high despite screening protocols designed to assess readiness for return to sport. To better identify biomechanical risk factors for ACL injury, combining neurocognitive challenges and high-impact tasks would more closely resemble sporting demands. We investigated the influence of secondary cognitive tasks on landing mechanics during bilateral drop vertical jumps (DVJs) among athletes following ACL reconstruction and whether sex affected these results. We also assessed whether adding secondary cognitive tasks to DVJs influenced loading asymmetries. Forty individuals (20 males) performed three DVJ conditions: (1) without secondary cognitive tasks (DVJ), (2) with secondary cognitive tasks targeting fast decision-making and inhibitory control of the motor action (DVJmot), and (3) with secondary cognitive tasks targeting fast decision-making, inhibitory control, attention, and short-term memory (DVJcogmot). We collected movement mechanics time-series data during the first 100 ms of landing using a motion capture system and force plates and compared outcomes between the three DVJs using functional t-tests. Secondary cognitive tasks altered trunk, hip, knee, and ankle landing mechanics (adjusted p-values < 0.05), representing more upright and stiffer landings. Loading asymmetries were increased by unloading the injured limb (adjusted p-values < 0.05). We found no differences between DVJmot and DVJcogmot or between males and females. Adding secondary cognitive tasks to DVJs better identifies landing mechanics associated with an increased ACL injury risk and inadequate rehabilitation. Future research should focus on optimizing the challenge point of the cognitive and motor tasks and how to best integrate them in RTS testing.

Performance effects of functional knee brace removal and prolonged use in healthy male athlete: Lower extremity power, acceleration, speed, and agility

OBJECTIVES

Knee braces were introduced to sports 30 years ago. However, knee brace use for non-contact anterior cruciate ligament injury prevention intervention remains contentious due to concerns about performance hindrances. Since knee brace use is a potential modifiable risk factor, we aimed to investigate the effect of discounting and continued functional knee brace (FKB) on lower extremity power-vertical jump (VJ), acceleration, speed, and agility performance.

DESIGN

Prospective cohort crossover study.

METHODS

Twenty-seven healthy male athletes performed seven tests, over six days of 12 test sessions (S), during three test conditions (non-braced, braced, and removed brace or continued brace use). This study focuses on VJ, acceleration, speed, and agility performance during S12 when athletes were randomly selected to remove the FKB after 17.5 h or continue using the FKB for 21.0 h.

RESULTS

After brace removal, nonsignificant performance levels improved in the VJ (2.7 %; 95 % CI 52.5-62.8; Cohen's effect size (ES) = trivial), acceleration (1.8 %; 95 % CI 0.500-0.562; ES = small), and agility (0.5 %; 95 % CI 9.25-10.13; ES = trivial), while a nonsignificant slower speed was recorded (0.5 %; 95 % CI 1.81-1.95; ES = trivial). Continued brace use led to a nonsignificant performance improvement in all tests; VJ (3.1 %; 95 % CI 53.5-60.2; ES = small), acceleration (1.5 %; 95 % CI 0.511-0.561; ES = trivial), speed (1.0 %; 95 % CI 1.83-1.95; ES = trivial), and agility (1.8 %; 95 % CI 9.26-10.04; ES = trivial).

CONCLUSIONS

Removal of FKB led to improved performance in three performance tests, while continued brace use improved performance in all four tests.

The Protective Role of the FIFA 11+ Training Program on the Valgus Loading of the Knee in Academy Soccer Players Across a Season

Background: Improper neuromuscular control with excessive dynamic valgus loading of the knee has been identified as one of the main anterior cruciate ligament injury risk factors. This study aimed to analyze the impact of the FIFA 11+ training program on the valgus loading of the knee in academy soccer players over a competitive season. Methods: A prospective study was conducted on 85 players. The drop vertical jump test was carried out before the match and at the end of the same match at the beginning and at the end of the season over a period of 11 months. Results: An increase of the varus angle on the right limb was noted between the start and the end of the season at the beginning of the match (-4.7 ± 8.9 versus -6.9 ± 6, p = 0.003) and between the start and the end of the match in values measured at the beginning of the season (-4.7 ± 8.9 versus -7.7 ± 9, p < 0.001). An increase of the flexion angle of both limbs was noted between the start and the end of the season in values measured at the start of the match (left limb 76.8 ± 32.8 versus 98.6 ± 17.2, p < 0.001; right limb 76.4 ± 32.8 versus 96.1 ± 16.1, p < 0.001) and between the start and the end of the season in values measured at the end of the match (left limb 92.8 ± 19.1 versus 98.5 ± 16.3, p = 0.002; right limb 92.6 ± 19.2 versus 96.7 ± 14.5, p = 0.013). Conclusions: A decrease in dynamic valgus angle and an increase in knee flexion angle measured with the DVJ test were noted between the start and the end of the season, suggesting a protective role of the FIFA 11+ training program.

Sport-specific differences in ACL injury, treatment and return to sports: Basketball

Basketball is an intense, fast-paced game that is physically, highly demanding. Certain aspects of the game, such as the quick pivoting and cutting movements, predispose the players to serious knee injuries, including anterior cruciate ligament (ACL) tears. While an ACL tear can be a devastating condition for players, multidisciplinary management of the injury can provide the players with a reasonable chance to return to play at the pre-injury level. This article aims to review the general principles and guidelines for the management of ACL injury in basketball players. The diagnosis, surgical treatment, rehabilitation and return to sports are discussed from European and North American perspectives. With a comprehensive and multidisciplinary approach to this condition, medical professionals can provide injured basketball players with a favourable prognosis for returning to play at the pre-injury level. To return to normal life and basketball after ACL reconstruction, the proposed approach includes (1) the selection of the appropriate surgical graft and technique, (2) maintaining a healthy and persistent mental state during rehabilitation, and (3) following a scientific rehabilitation programme based on personalized recovery. LEVEL OF EVIDENCE: Level V.

Acute Effects of Unplanned and Planned Hop-Landing Training on Neurocognitive Function and Knee Biomechanics

Background

Athletes with decreased baseline neurocognitive function may experience noncontact anterior cruciate ligament (ACL) injury in unanticipated athletic situations. Many ACL injury prevention programs (IPPs) focus on improving closed-skill movements (eg, planned landing). However, the more open-skill movements (eg, unplanned reactive movements) required in unpredictable sports scenarios are commonly absent from ACL IPPs, and the acute effects of open-skill training on neurocognitive function remain unclear.

Purpose

To investigate the acute effects of unplanned versus planned training on neurocognitive function and knee biomechanics associated with ACL injury risk during the side-step cutting motion.

Study Design

Controlled laboratory study.

Methods

A total of 32 adult recreational athletes (16 female, 16 male) were randomly assigned to either an unplanned training (UT) group or a control (CON) group. The UT group performed unplanned hop-landing training while the CON group performed planned hop-landing training. Both before and after the training, neurocognitive function was evaluated using the Trail Making Test-part B and Stroop Color and Word Test. Additionally, unanticipated and anticipated side-step cutting tasks were performed while 3-dimensional kinematic and kinetic data for the dominant leg were collected. Neurocognitive test scores and biomechanical variables relevant to ACL injury were analyzed using 2-way repeated-measures analysis of variance to determine the main effects of training, group, and training × group interaction.

Results

Trail Making Test-part B and Stroop Color and Word Test scores significantly improved from pre- to posttraining in both groups (P < .001 for both). There was a significant training × group interaction for peak knee abduction angle during the unanticipated side-step cutting task (pre- vs posttraining: -8.81°± 7.23° vs -7.40°± 7.24° [UT group]; -8.23°± 9.40° vs -9.99°± 9.83° [CON group]; P = .02) and for peak vertical ground-reaction force during the anticipated side-step cutting task (pre- vs posttraining: 3.86 ± 0.59 vs 4.08 ± 0.74 percentage body weight [%BW] [UT group]; 3.70 ± 0.62 vs 3.34 ± 0.62 %BW [CON group]; P = .04).

Conclusion

Study findings showed a significant training × group interaction for knee abduction angle during the unanticipated side-step cutting task with unplanned training and for vertical ground-reaction force during the anticipated side-step cutting task with planned training.

Clinical Relevance

Designing ACL IPPs based on the sport type (ie, open skill or closed skill) may contribute to better preparation.

A Robotic Clamped-Kinematic System to Study Knee Ligament Injury

Knee ligament injury is among the most common sports injuries and is associated with long recovery periods and low return-to-sport rates. Unfortunately, the mechanics of ligament injury are difficult to study in vivo, and computational studies provide limited insight. The objective of this study was to implement and validate a robotic system capable of reproducing natural six degree-of-freedom clamped-kinematic trajectories on human cadaver knees (meaning that positions and orientations are rigidly controlled and resultant loads are measured). To accomplish this, we leveraged the field's recent access to high-fidelity bone kinematics from dynamic biplanar radiography (DBR), and implemented these kinematics in a coordinate frame built around the knee's natural flexion-extension axis. We assessed our system's capabilities in the context of ACL injury, by moving seven cadaveric knee specimens through kinematics derived from walking, running, drop jump, and ACL injury. We then used robotically simulated clinical stability tests to evaluate the hypothesis that knee stability would be only reduced by the motions intended to injure the knee. Our results show that the structural integrity of the knee was not compromised by non-injurious motions, while the injury motion produced a clinically relevant ACL injury with characteristic anterior and valgus instability. We also demonstrated that our robotic system can provide direct measurements of reaction loads during a variety of motions, and facilitate gross evaluation of ligament failure mechanisms. Clamped-kinematic robotic evaluation of cadaver knees has the potential to deepen understanding of the mechanics of knee ligament injury.

The "11 to Perf Score", a Test for Professional Players Returning to Soccer After Anterior Cruciate Ligament Reconstruction

Rupture of the anterior cruciate ligament (ACL) is common among soccer players. Although there are no strict recommendations for the return to sport, more and more practitioners are having their patients perform isokinetic and even composite tests. However, these tests have not yet been shown to be predictive of re-injury, and are not specific to professional footballers. Objectives: The "11 to Perf" is a test designed to help professional footballers return to sport after ACL reconstruction. Its originality lies in its integration of soccer practice with specific tests. The aim of this article is to present the "11 to Perf" evaluation method. Methods: A prospective cohort study was conducted at the Centre National du Football (FIFA center) in Clairefontaine, including professional footballers who have undergone anterior cruciate ligament surgery and rehabilitation. Tests include clinical assessments, jumping, agility, psychological and isokinetic tests and match simulation. Conclusions: The "11 to Perf" is a composite test designed to assess the return to sport of professional footballers after ACL reconstruction. Its predictive capacity for recurrence should be assessed in the future.

Frequency and intensity of change of directions in German Bundesliga soccer

The aim of this study was to investigate the change of direction (COD) frequencies and intensities of high-performance soccer players of the German Bundesliga independent of tactical and match context. COD data were collected from 18 German Bundesliga soccer teams (season 2016-2017; 308 fixtures) by an optical tracking system (OTS) (TRACAB). CODs were tracked using a modified algorithm and were sub-categorized by entry velocity (<3.0 m⋅s-1, 3.0-5.5 m⋅s-1, 5.5-7.0 m⋅s-1 and >7.0 m⋅s-1) and COD angle (20-59°, 60-119° and 120-180°). COD metric frequencies were compared between playing positions (goalkeepers, centre backs, full-backs, central midfielders, wide midfielders, and strikers). In general, regardless of entry velocity or COD angle, central midfielders consistently executed the highest number of COD actions during matches compared to the other playing positions. About ≈ 55% and ≈ 38% of CODs were <3.0 m⋅s-1 and <5.5 m⋅s-1, whereas ≈ 7% were >5.5 m⋅s-1. The distribution of COD angle types was ≈ 5% for 20-59°, ≈25% 60-119° and ≈ 70% for 120-180° COD angles. Our data provide insights into the COD demands of high-performance soccer in the German Bundesliga in terms of entry velocity and COD angles and their combination based on a large dataset of OTS data, which provides insights to facilitate the development of physical conditioning strategies, position-specific external load management, and multidirectional speed training with adequate test battery selection and return-to-play protocols for soccer players.

A systematic video analysis of 21 anterior cruciate ligament injuries in elite netball players during games

This systematic video analysis of 21 anterior cruciate ligament (ACL) injuries sustained by elite-level netball players during televised games, describes the situation, movement pattern and player behaviour, providing insight regarding the injury mechanism. Seventeen of the ACL injuries occurred from jump-landing actions and only two from cutting manoeuvres. A common scenario was identified for 11 players. In this scenario, players were decelerating rapidly after jumping to receive a high pass, utilising a double-footed landing with a wide base of support (WBOS). Deceleration appeared to be applied predominantly via the injured leg with the knee extended and foot planted. Often the players appeared unbalanced on landing leaning too far back. ACL injury risk was possibly exacerbated by the players head turning away from the injured side. A further compressive knee moment may have been placed on the lateral aspect of the knee by bringing the ball from a high position to a low position at the estimated time of injury. Players may benefit from landing technique training programmes that encourage shoulder-width foot landings, with ≥30° knee flexion, a small amount of plantar-flexion and good balance. Incorporating challenges to players balance and ability to cope with perturbations may also be beneficial. Training programmes should include instruction on securing the ball in a stable above pelvis-level position after receiving a pass and bringing their whole body around during landing into the direction of their next pass, rather than simply turning their head to look.

Forces experienced at different levels of the musculoskeletal system during horizontal decelerations

Horizontal decelerations are frequently performed during team sports and are closely linked to sports performance and injury. This study aims to provide a comprehensive description of the kinetic demands of decelerations at the whole-body, structural, and tissue-specific levels of the musculoskeletal system. Team-sports athletes performed maximal-effort horizontal decelerations whilst full-body kinematics and ground reaction forces (GRFs) were recorded. A musculoskeletal model was used to determine whole-body (GRFs), structural (ankle, knee, and hip joint moments and contact forces), and tissue (twelve lower-limb muscle forces) loads. External GRFs in this study, especially in the horizontal direction, were up to six times those experienced during accelerated or constant-speed running reported in the literature. To cope with these high external forces, large joint moments (hip immediately after touchdown; ankle and knee during mid and late stance) and contact forces (ankle, knee, hip immediately after touchdown) were observed. Furthermore, eccentric force requirements of the tibialis anterior, soleus, quadriceps, and gluteal muscles were particularly high. The presented loading patterns provide the first empirical explanations for why decelerating movements are amongst the most challenging in team sports and can help inform deceleration-specific training prescription to target horizontal deceleration performance, or fatigue and injury resistance in team-sports athletes.

A systematic review and network meta-analysis on the effectiveness of exercise-based interventions for reducing the injury incidence in youth team-sport players. Part 2: an analysis by movement patterns

The objectives of this network meta-analysis were: (a) to estimate and compare the pooled effects of some injury prevention programs (IPPs) whose exercise-based components were categorized using a movement pattern-specific taxonomy on reducing overall and some specific body regions (lower extremity, thigh, knee, and ankle) injury incidences in youth team sport athletes and (b) to explore the individual effects of these components on the injury incidence rates (IIRs) previously mentioned. Searches were performed in PubMed, Web of Science, SPORTDiscus, and Cochrane Library. Eligible criteria were: exercise-based interventions comprised of exercises involving athletic motor skill competencies and evaluated against a control group, overall IIRs were reported, and youth (≤19 years old) team sport players. For the current analysis, a taxonomy based on movement patterns was employed for exercise component identification (upper body pushing and pulling; lower body concentric and eccentric; core; mechanics; acceleration; and lower body stability). Pooled effects were calculated by frequentist random effects pairwise and network meta-analyses. Nineteen studies were included. Most of the IPPs exhibit risk reduction when compared to their control groups on overall, lower extremity, and ankle injuries. Interventions comprised of lower body concentric and eccentric, core, mechanics, and lower body stability exercises were the most effective measures for reducing these injuries. None of the IPPs demonstrated to be effective for reducing thigh injuries, and contradictory results were found for knee injuries. Individual analysis at component level revealed that the lower body (bilateral and unilateral, concentric, and eccentric) component was the only one associated with a significant reduction on overall injuries. Indirect evidence suggests that interventions incorporating lower body concentric and eccentric, core, mechanics, and lower body stability exercises might be the most effective for reducing overall, lower extremity, and ankle injuries in youth team sports.

Do healthy athletes exhibit at-risk biomechanics for anterior cruciate ligament injury during pivoting movements?

A consistent injury mechanism involving multiple joints has been highlighted in athletes experiencing anterior cruciate ligament (ACL) rupture. However, if and to what extent healthy athletes incur an unsafe biomechanical profile during high-dynamics movements is unknown. The present study aimed to investigate the occurrence of the ACL risk profile in a competitive pivoting sports population.Thirty-four athletes (22.8 ± 4.1 y) performed a frontal deceleration and a change of direction at 90°. Full-body kinematics was collected through 15 wearable inertial sensors (Awinda, Xsens). Nine ACL risk factors were defined based on four categories: limited lower limb flexion, valgus collapse, foot rotation and trunk rotation. A movement trial was considered 'at-risk' in the presence of at least 5 simultaneous risk factors. The rate of athletes with at-risk movements was assessed and multivariate regression for associated outcomes was conducted.The overall rate of injury profile occurrence was 9-12%. The injury profile was identified at least in one trial in 24 athletes (71%) and three trials in 5 athletes (15%). Significant associations were found for higher approaching speed (OR = 4.3) and female sex (OR = 4.8). A large occurrence of the typical ACL injury biomechanical profile was noticed. Large screenings are advisable to identify at-risk athletes and promote preventative strategies.

Motivation Unraveled: Giving Choice to Football Players to Improve Anterior Cruciate Ligament Injury Prevention

ABSTRACT

Benjaminse, A, Nijmeijer, EM, Gokeler, A, Broekhaar, DC, and Cortes, N. Motivation unraveled: giving choice to football players to improve anterior cruciate ligament injury prevention. J Strength Cond Res 38(12): e735-e743, 2024-Providing athletes some control over a training session facilitates motor skill acquisition. This is a promising concept to use in anterior cruciate ligament (ACL) injury prevention, as the key for risk reduction is to improve quality of movement. The goal of this study was to better understand why improved motor learning occurred when football players had the opportunity to choose when to receive feedback when practicing sidestep cutting (SSC) movements. Healthy male recreational football players ( n = 22, 22.9 ± 1.7 years, 185.5 ± 7.2 cm, 79.3 ± 9.2 kg) were included and assigned to the self-control (SC) or the yoked (YK) group. The players performed anticipated and unanticipated SSC. They received video instructions and were instructed to "copy the movement of the model to the best of their ability." During the training blocks, the SC group could ask for feedback, whereas the YK group could not. Cutting movement assessment scores (CMAS) were measured to test quality of movement and the Intrinsic Motivation Inventory was administered to measure constructs of motivation. In the anticipated condition, SC group showed better scores in immediate post and the retention test compared with pretest ( p < 0.001), whereas the YK group showed worse scores in the retention test compared with immediate posttest ( p = 0.001). Perceived competence ( p = 0.017) and self-efficacy ( p = 0.032) were consistent factors that correlated with improved CMAS in the SC group. This has given us innovative insights into underlying mechanisms optimizing the quality of movement, necessary to improve current ACL injury prevention approaches.

Direct contact and very rapid valgus distortion characterise the injury mechanism of anterior cruciate ligament ruptures in judo

PURPOSE

To analyse anterior cruciate ligament (ACL) rupture (ACLR) injury mechanisms in competitive judo using systematic video analysis, focusing on contact situations and biomechanics.

METHODS

Seventeen videos of judo competitions wherein athletes developed ACLRs were included and retrospectively evaluated by five analysts. In all videos, the moment of initial contact and the index frame were defined. The judo techniques leading to the injury; the occurrence of direct contact, indirect contact or noncontact mechanisms; the time interval between the initial contact and index frame; the positions of the hip, knee and foot in relation to the initial contact and index frame; and the balance status during the initial contact and index frame were recorded.

RESULTS

Eleven (65%) of ACLRs in judo involved direct contact. The mean time interval between initial contact and index frame was 15 ± 22 ms. Thirteen (77%) athletes were not balanced at initial contact. In the index frame, the hip was abducted in all cases and in combination with internal rotation in 12 (71%) cases. From initial contact to index frame, hip flexion increased in all cases; at index frame, the knee joint was internally rotated relative to the trunk in 12 (71%) cases, and the knee flexion angles increased from the initial contact. In the index frame, the foot was externally rotated relative to the knee in 12 (71%) cases, and severe valgus development of the knee with valgus collapse was observed in 14 (82%) cases.

CONCLUSIONS

A direct attack on the knee was the most common injury mechanism observed. Valgus distortion appears to be the most important component of the mechanism of injury. With this knowledge, 'modified defence reactions' for specific judo techniques can be developed to reduce the injury risk.

LEVEL OF EVIDENCE

Level IV.

A New Algorithm for Extra-Articular Reinforcement in ACL Injury Based on Rotational Instability

Background

The results of surgical reconstructions of the anterior cruciate ligament (ACL) are improving with the association of extra-articular reinforcements, such as anterolateral ligament reconstruction and Lemaire tenodesis. However, ACL injury can occur through various mechanisms, and when there are valgus and external rotation of the tibia, anteromedial rotational instability (AMRI) may develop. Articular reinforcement in the anteromedial quadrant, in the topography of the anterior oblique ligament (AOL), can be an important tool for patients with ACL injury and external rotation instability.

Indications

The physical examination under anesthesia in patients undergoing ACL reconstruction who are candidates for extra-articular reinforcements provides important information about rotational instability. Patients with instability in external rotation may benefit from anteromedial reinforcement in the AOL's topography.

Technique Description

We propose an algorithm to be followed in patients with ACL injury and indication for extra-articular reinforcement. Patients with a positive pivot shift, indicating internal rotation instability of the knee, should undergo anterolateral reinforcements, as well as those patients with joint hyperlaxity. The algorithm suggests performing the anterior drawer in external rotation (ADER) test. When positive in isolation, anteromedial reinforcement is indicated. When the physical examination shows both positive ADER and pivot shift, both medial and lateral extra-articular reinforcement could be performed.

Results

This new type of extra-articular reinforcement, in the AOL's topography, appears to be an important tool for improving surgical outcomes in ACL reconstructions. AMRI is a risk factor for central pivot reconstruction failure and should be investigated and treated, as proposed by the algorithm.

Conclusions

Clinical examination of the ACL-injured knee, preferably under anesthesia, should include internal rotational and external rotational examination (pivot-shift and ADER tests). AMRI, when detected, should be treated, and the AOL reconstruction seems to be a good alternative. We propose a new algorithm based on rotational instability to make our extra-articular reinforcement in ACL patients.

Patient Consent Disclosure Statement

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Anterior cruciate ligament injuries in elite badminton athletes: 84% Return to sport, half return to performance

PURPOSE

Badminton requires fast and pivoting movements, putting athletes at risk of sustaining an anterior cruciate ligament (ACL) injury. The primary purpose is to investigate the return to sport (RTS) and the return to performance (RTP) after an ACL injury in elite badminton athletes. The secondary purpose is to describe ACL injury mechanisms in elite badminton players.

METHODS

Athletes within the top 200 of the Badminton World Federation World Ranking who sustained an ACL injury between January 2001 and December 2021 were retrospectively included. An anonymous online survey was created in eight languages. RTS, RTP and contributing factors were analysed among athletes aiming to RTP. The injury mechanism was analysed in all participants.

RESULTS

Sixty-six athletes from 32 countries were included. Fifty-seven athletes (86.4%) aimed to RTP. Forty-eight out of 57 (84.2%) did RTS. Twenty-nine (50.9%) managed to successfully RTP. Forty-nine (74.2%) of ACL injuries occurred during a competition, 14 (21.2%) occured during training. Thirty-one (49.2%) occurred in the rear court backhand side and 47 (74.6%) occurred during landing after a jump.

CONCLUSION

Forty-eight out of 57 (84.2%) athletes managed to RTS. Half of the athletes managed to successfully RTP. Most of the ACL injuries occurred during competition, in the rear court backhand side and during landing after a jump.

LEVEL OF EVIDENCE

Level III.

What do we know about beach soccer injuries? Systematic video analysis of four consecutive years with 580 match injuries

The aim of the present study was to evaluate the characteristics of match injury in male beach soccer players. Video recordings of all official beach soccer tournaments in which the European national male beach soccer teams participated from 2018 to 2021 were analysed by two sports medicine specialists retrospectively. Regarding each injury, data including the mechanism, location of the injury, whether the injury led to time-loss, and the relationship of the injury to the bicycle kick (BK), etc. were documented. A total of 632 injuries were documented, corresponding to 234.9 injuries/1000 player hours. Video footage was available for 580 injuries. Whilst 79.8% of medical attention injuries occurred due to opponent contact, 19.5% of time-loss injuries occurred due to non-contact, and 12.2% of indirect opponent contact (p < 0.01). The most common location of the BK related injury was the head/neck (68.7%), whereas most common location of the BK unrelated injury was the lower extremity (54.1%) (p < 0.01). The findings demonstrated that beach soccer injury incidence was quite high; the most common injury location was head/neck and head/neck injuries were associated with BK. In light of these results, some rule regulations, particularly those associated with BK, and the use of protective equipment should be considered to prevent these injuries.

Task-Driven Neurophysiological qEEG Baseline Performance Capabilities in Healthy, Uninjured Division-I College Athletes

Background

Athletic performance can be measured with a variety of clinical and functional assessment techniques. There is a need to better understand the relationship between the brain's electrical activity and the body's physiological performance capabilities in real-time while performing physical tasks related to sport. Orthopedic functional assessments used to monitor the neuroplastic properties of the central nervous system lack objectivity and/or pertinent functionality specific to sport. The ability to assess brain wave activity with physiological metrics during functional exercises associated with sport has proven to be difficult and impractical in real-time sport settings. Quantitative electroencephalography or qEEG brain mapping is a unique, real-time comprehensive assessment of brain electrical activity performed in combination with physiometrics which offers insight to neurophysiological brain-to-body function. Brain neuroplasticity has been associated with differences in musculoskeletal performance among athletes, however comparative real-time normal data to benchmark performance capabilities is limited.

Purpose/Design

This prospective, descriptive case series evaluated performance of task-driven activities using an innovative neurophysiological assessment technique of qEEG monitored neurophysiological responses to establish a comparative benchmark of performance capabilities in healthy, uninjured Division-I athletes.

Methods

Twenty-eight healthy uninjured females (n=11) and males (n=17) NCAA Division-I athletes participated in real-time neurophysiological assessment using a Bluetooth, wireless 21-channel dry EEG headset while performing functional activities.

Results

Uninjured athletes experienced standard and regulated fluctuations of brain wave activity in key performance indicators of attention, workload capacity and sensorimotor rhythm (SMR) asymmetries.

Conclusion

qEEG neurophysiological real-time assessment concurrent with functional activities in uninjured, Division-I athletes may provide a performance capability benchmark. Real-time neurophysiological data can be used to monitor athletes' preparedness to participate in sport, rehabilitation progressions, assist in development of injury prevention programs, and return to play decisions. While this paper focuses on healthy, uninjured participants, results underscore the need to discen pre-injury benchmarks.

Level of Evidence

4.

Anterior cruciate ligament injury prevention in sport: biomechanically informed approaches

This paper reviews a series of studies contributing to a framework for preventing anterior cruciate ligament (ACL) injuries in sport. As the majority of these injuries are non-contact in nature, theoretically, these injuries are preventable. The studies presented in this paper focus on understanding biomechanical countermeasures of ACL injury and how this knowledge can inform both screening and training intervention research and practice in sport. These countermeasures include: 1) modifying an athlete's technique to reduce externally applied loads to the knee; 2) increasing the muscle support around the knee and hip to counter elevated loads applied to the knee and; 3) improving an athlete's perception during dynamic sports tasks to increase planning time to coordinate desirable movement patterns. By furthering the empirical evidence of modifiable biomechanical countermeasures of ACL injury risk, we can better understand best practices for developing interventions on a mass scale to prevent ACL injuries in the sporting community.

Studying Contact Replays: Investigating Mechanisms, Management and Game Exposures (SCRIMMAGE) for brain health in the Australasian National Rugby League: a protocol for a database design

Concussions in contact sports are challenging for athletes, health professionals and sporting bodies to prevent, detect and manage. Design of interventions for primary prevention, early recognition of concussion and continuing to improve postconcussion management are essential for protecting athletes and promoting brain health. Over the last decade, there have been advancements in video technology for analysing head impact events and improvements in the clinical management of concussions. This study protocol describes how researchers, clinicians and staff from the Australasian National Rugby League (NRL) have brought these advancements together and developed a database of videos with head impact events and clinical outcomes. The intended outputs from this work will enhance the understanding of head impact events in NRL, from biomechanical and gameplay factors to concussion and return to play outcomes. Publishing this protocol increases the transparency of this large-scale effort to better identify head impacts and their relationship to concussions and player movement behaviour to contextualise these variables to generate new knowledge and support the reproducibility of these emerging findings. Between 2017 and 2023, over 5250 head contact cases were recorded in the database, from which >1700 head injury assessments were performed, and >600 concussions were diagnosed. Future studies using these data are planned to inform both primary and secondary injury prevention initiatives, such as risk analysis and prediction of game scenarios that result in concussion, as well as investigation of features and factors that help to inform the duration of recovery and return to play.

Preliminary identification of somatic mutations profile in ACL injury

Anterior cruciate ligament (ACL) injury is a common orthopedic disease with a high incidence, long recovery time, and often requiring surgical treatment. However, the susceptibility factors for ACL injury are currently unclear, and there is a lack of analysis on the differences in the ligament itself. Previous studies have focused on germline mutations, with less research on somatic mutations. To determine the role of somatic mutations in ACL injuries, we recruited seven patients between the ages of 20 and 39 years diagnosed with ACL injuries, collected their peripheral blood, injured ligament ends, and healthy ligament ends tissues, and performed exome sequencing with gene function enrichment analysis. We detected multiple gene mutations and gene deletions, which were only present in some of the samples. Unfortunately, it was not possible to determine whether these somatic mutations are related to ligament structure or function, or are involved in ACL injury. However, this study provides valuable clues for future in-depth research.

ACL injury characteristics in badminton : A registry study with prospectively collected data on sports related epidemiology and injury mechanism of 539 badminton players

Background

Over recent years, more anterior cruciate ligament (ACL) ruptures in badminton players have occurred. Little is known about the injury mechanism in badminton. The hypothesis is that most ACL injuries occur with single leg landings on the non-dominant leg in the backhand side or with lunge movements in the forehand side on the dominant leg. To inform prevention strategies the aim of this study was to investigate the mechanism of ACL injuries in badminton, specifically if ACL injuries occur in certain positions on the badminton court and/or with certain movements. Secondary aims were to investigate differences among gender, age groups and between recreational and tournament players.

Methods

The study, ACL Denmark, investigate ACL ruptures in a cohort of 90.610 participants diagnosed between 2000 and 2018. Of those, 539 participants reported ACL rupture during badminton and filled in an online questionnaire in December 2021-January 2022 on the injury mechanism and other injury characteristics. Data is presented as numbers, percentage, means (SD) and median (IQR) with chi square test or Fischers exact test for dichotomous outcomes.

Results

Most participants played badminton (n = 435, 81 %) as primary sport and 155 (29 %) reported to play on a competitive level (Tegner score 8). The rear court (n = 285, 40 %) was the most frequent location of injury but with a high percentage on the front and midcourt (n = 154, 22 %). The rear court was more prevalent among players aged 18-29 (p < 0.001). The most prevalent movement preceding the ACL injury was the scissor kick jump on the rear court (100, 19 %) followed by lunge at the net (70, 13 %) and lunge at the rear court (69, 13 %). One hundred and six players (15 %) were injured preceded by a deceptive shot from the opponent. The dominant leg was mainly injured in the forehand side and the non-dominant leg mainly in the backhand side.

Conclusion

The most prevalent movement preceding the ACL injury was the lunge followed by the scissor kick jump. The rear court was the primary location of ACL injury in badminton and the dominant knee has a higher risk of injury in the forehand side and the non-dominant knee in the backhand side. More focus on the technical performance of lunge and scissor kick jumps and development of a badminton specific ACL injury prevention program is needed in badminton.

A comparative video analysis of hamstring injuries mechanism and situational pattern in men's and women's football (soccer)

PURPOSE

To describe the injury mechanism and situational patterns of severe (absence >28 days) hamstring muscle injuries in professional male and female football (soccer) players.

METHODS

The data for males were sourced from Serie A clubs participating in both national and international competitions from 2018 to 2021. For the female cohort, hamstring injuries were identified during matches of the top national/international competitions from 2017 to 2023. Video footage was obtained, and three raters categorised injury mechanisms and situational patterns. Injuries were also examined according to the month, minute and location.

RESULTS

A total of 129 severe hamstring injuries were identified, with 64 occurring in females and 65 in males. Video analysis was possible for 29 (45%) female cases and 61 (94%) male cases. Female injuries had longer lay-off times (97.8 ± 77.1 days) than males (39.6 ± 20.9 days). Females had a higher proportion of indirect contact injuries (34%) than males (13%) and a lower proportion of non-contact injuries (66% vs. 87%). Four situational patterns were identified: running was the most common for both sexes, representing 59% of female injuries and 41% of male injuries. Over-stretching injuries were split across open and CKC scenarios but collectively explained nearly half (48%) of male injuries but only one in five (21%) female injuries. Kicking injuries had a higher proportion in females (17%) than males (10%). Injuries were more common in the second half for females and the first half for males.

CONCLUSION

Females had a higher proportion of indirect contact, running and kicking injuries and a lower proportion of non-contact and stretch-type injuries than males. Understanding injury patterns can inform tailored prevention programs, considering sex-specific differences.

LEVEL OF EVIDENCE

Level IV.

An ecological dynamics approach to ACL injury risk research: a current opinion

Research of non-contact anterior cruciate ligament (ACL) injury risk aims to identify modifiable risk factors that are linked to the mechanisms of injury. Information from these studies is then used in the development of injury prevention programmes. However, ACL injury risk research often leans towards methods with three limitations: 1) a poor preservation of the athlete-environment relationship that limits the generalisability of results, 2) the use of a strictly biomechanical approach to injury causation that is incomplete for the description of injury mechanisms, 3) and a reductionist analysis that neglects profound information regarding human movement. This current opinion proposes three principles from an ecological dynamics perspective that address these limitations. First, it is argued that, to improve the generalisability of findings, research requires a well-preserved athlete-environment relationship. Second, the merit of including behaviour and the playing situation in the model of injury causation is presented. Third, this paper advocates that research benefits from conducting non-reductionist analysis (i.e., more holistic) that provides profound information regarding human movement. Together, these principles facilitate an ecological dynamics approach to injury risk research that helps to expand our understanding of injury mechanisms and thus contributes to the development of preventative measures.

Clinical Utility of Qualitative Change of Direction Movement Assessment in ACL Injury Risk Evaluation

Anterior cruciate ligament (ACL) injuries are complex and influenced by numerous internal and external risk factors that should be considered to effectively mitigate injury and facilitate informed return to sport decision-making. Among these risk factors, movement quality exhibited during sport-specific tasks has been identified as a significant predictor of injury occurrence. Particularly, change of direction (COD) movements, when performed with sub-optimal movement quality, such as knee valgus and lateral trunk flexion, are prominent mechanisms of ACL injury in multidirectional sports. Unfortunately, the formal and objective assessment of COD movement quality is underutilized in clinical and sports practice, with existing methods often confined to expensive, sophisticated laboratory settings impractical for everyday clinicians. The purpose of this clinical commentary is to demonstrate the necessity of integrating COD movement assessments to screen for potential ACL injury risk, particularly among higher-risk populations. The authors will review cost-effective and clinic-friendly objective tests used to qualitatively screen COD movements, such as the Cutting Movement Assessment Score and The Expanded Cutting Alignment Tool. Additionally, this commentary will discuss key considerations when assessing COD movement.

Level of Evidence

5.

Systematic video analysis of ACL injuries in professional Spanish male football (soccer): injury mechanisms, situational patterns, biomechanics and neurocognitive errors - a study on 115 consecutive cases

Objective

A few video analysis studies have been published in recent years, but none specifically on Spanish football. We aimed to describe the mechanisms, situational patterns, biomechanics and neurocognitive errors related to anterior cruciate ligament (ACL) injuries in professional Spanish football matches.

Methods

We identified 167 consecutive ACL injuries across 12 seasons of the top two leagues in Spanish football. 115 (69%) injury videos were analysed for mechanism and situational pattern, while biomechanical analysis was possible in 81 cases. Neurocognitive errors were investigated for all non-contact injuries. Three independent reviewers evaluated each video. ACL injury epidemiology-month, timing within the match and pitch location at the time of injury was also documented.

Results

More injuries occurred in defensive (n=68, 59%) than offensive (n=48, 41%) (p<0.01) playing situations. 16 (14%) injuries were direct contact, 49 (43%) indirect contact and 50 (43%) non-contact. Most injuries (89%) occurred during four main situational patterns: (1) pressing/tackling (n=47, 47%); (2) tackled (n=23, 23%); (3) landing from a jump (n=12, 12%) and regaining balance after kicking (n=6, 6%). Injuries generally involved a knee-dominant loading strategy in the sagittal plane with abducted hip and knee valgus. Of the non-contact injuries, 39 (78%) were deemed to involve a neurocognitive error. More (58%) injuries occurred in the first half of matches (p<0.01).

Conclusions

ACL injuries in Spanish football occurred similarly with non-contact and indirect contact mechanisms (44%). Four in five non-contact injuries involved a neurocognitive error. Most injuries occurred during four previously identified situational patterns, with more injuries earlier in the match.