Anterior Cruciate Ligament Injury Prevention Training Research Articles

Association Between the Medial-Lateral Quadriceps and Hamstring Muscle Thickness and the Knee Kinematics and Kinetics During Single-Leg Landing.

Muscle thickness can influence the joint kinematics and/or kinetics during dynamic activities. The relationship between the muscle thickness of individual quadriceps and hamstrings or medial-to-lateral thigh muscle thickness ratio and the knee kinematics/kinetics with respect to anterior cruciate ligament (ACL) injury risk remains unclear. Higher medial-to-lateral thigh muscle thickness ratio would be associated with lower knee valgus angle/moment and lower tibial internal rotation angle/moment during single-leg landing. Cross-sectional. Level 4. Muscle thickness of the vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), and semitendinosus (ST) of 30 healthy participants (16 males and 14 females) were measured using ultrasound. Knee joint kinematics and kinetics during single-leg landing were obtained. Stepwise multiple regression analysis, a follow-up Fisher's r to z test to examine the sex as a moderator, and independent t tests to evaluate sex difference were performed. Both knee valgus moment (R2 = 0.466, P < 0.001) and tibial external rotation moment (R2 = 0.330, P < 0.001) at peak anterior tibial shear force during single-leg landing were negatively correlated with medial-to-lateral (ie, (VM+ST):(VL+BF)) thickness ratio regardless of sex, whereas medial-to-lateral thigh muscle thickness ratio was not correlated with knee valgus and tibial external rotation angles. Male participants exhibited higher (VM+ST):(VL+BF) thickness ratio than female participants (P = 0.005), and lower knee valgus moment (P = 0.04) and tibial external rotation moment (P = 0.05), as well. The knee joint moments in frontal and transverse planes during single-leg landing were associated with the medial-to-lateral thigh muscle thickness ratio; thus, the medial-lateral thigh muscle thickness could be a potential contributor to frontal and transverse plane knee joint loading during dynamic movement. Strength training that aims to selectively strengthen the medial/lateral thigh muscles might be considered in a new ACL injury prevention training program to alter the biomechanical parameters associated with ACL injuries.

Latest Trends in Neuromuscular Training to Prevent Anterior Cruciate Ligament Injury: A Literature Review

PURPOSE: Anterior cruciate ligament (ACL) injuries are the most common in sports and have doubled in the past 20 years. This study aimed to analyze the latest trends and changes in training programs for ACL injury prevention.METHODS: In this study, literature was searched using academic search sites, such as ‘PubMed’, ‘Google Scholar’, and ‘Wiley Online Library’. The literature published between 2015 and 2021 was used.RESULTS: Eleven papers were selected based on the literature selection criteria. Five warm-up exercise papers and six ACL injury prevention training program papers emphasized neuromuscular training.CONCLUSIONS: The ACL injury prevention program can be applied in warm-up exercises and training programs. It consists of an exercise form that includes multidimensional components such as plyometrics, muscle strength, balance, and agility. The key to the ACL injury prevention program is to reflect multidimensional components in neuromuscular training and to obtain a significant effect, and it is recommended to participate in regular training for 12-18 sessions and at least 6 months. In addition, it is suggested to utilize the ACL injury prevention program presented in this study until an individual study for ACL injury prevention by sports type is conducted.

Meta-analysis of meta-analyses of anterior cruciate ligament injury reduction training programs.

Several meta-analyses have been published on the effectiveness of anterior cruciate ligament (ACL) injury prevention training programs to reduce ACL injury risk, with various degrees of risk reduction reported. The purpose of this research was to perform a systematic review and meta-analysis of overlapping meta-analyses evaluating the effectiveness of ACL injury prevention training programs so as to summarize the amount of reduction in risk for all ACL and non-contact ACL injuries into a single source, and determine if there were sex differences in the relative efficacy of ACL injury prevention training programs. Five databases (Medline, PubMed, Embase, CINAHL, and Cochrane) were searched to identify meta-analyses that evaluated the effectiveness of ACL injury prevention training programs on ACL injury risk. ACL injury data were extracted and the results from each meta-analysis were combined using a summary meta-analysis based on odds ratios (OR). Eight meta-analyses met eligibility criteria. Six of the eight only included data for female athletes. Summary meta-analysis showed an overall 50% reduction (OR = 0.5 [0.41-0.59]; I2 = 15%) in the risk of all ACL injuries in all athletes and a 67% reduction (OR = 0.33 [0.27-0.41]; I2 = 15%) for non-contact ACL injuries in females. This paper combines all previous meta-analyses into a single source and shows conclusive evidence that ACL injury prevention programs reduce the risk of all ACL injuries by half in all athletes and non-contact ACL injuries by two-thirds in female athletes. There is insufficient data to make conclusions as to the effectiveness of ACL injury prevention programs in male athletes. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2696-2708, 2018.

Effect of Hip-Focused Injury Prevention Training for Anterior Cruciate Ligament Injury Reduction in Female Basketball Players: A 12-Year Prospective Intervention Study

Background: Programs to prevent anterior cruciate ligament (ACL) injuries in female basketball players are scarce. Also, ACL injury prevention training that focuses on hip joint function has not been reported. Purpose: To determine the effectiveness of a hip-focused ACL injury prevention program in female basketball players. Study Design: Cohort study; Level of evidence, 2. Methods: A prospective intervention study was conducted for 12 years. Incidence rates of ACL injuries were collected in the first 4 years (observation period) from college female basketball players. After the observation period, a hip-focused ACL injury prevention program was implemented for 8 years (intervention period). A total of 309 players (mean ± SD age, 19.6 ± 1.2 years; height, 163.7 ± 5.6 cm; weight, 59.1 ± 5.1 kg; body mass index, 22.0 ± 1.4) were tracked in the observation period and compared with 448 players (age, 19.6 ± 1.1 years; height, 162.6 ± 5.8 cm; weight, 58.0 ± 5.7 kg; body mass index, 21.9 ± 1.5) who participated in the intervention period. Athlete-exposures (AEs), ACL numbers and mechanisms of injury (MOIs), relative risk (RR), absolute risk reduction (ARR), numbers needed to treat (NNT), and compliance were analyzed. Results: There were 16 ACL injuries (13 noncontact MOIs) in the 4-year observation period, whereas 9 ACL injuries (8 noncontact MOIs) were recorded in the 8-year intervention period. The overall ACL injury incidence was 0.25/1000 AEs in the 4-year observation period compared with 0.10/1000 AEs in the 8-year intervention period, respectively. Compared with the 4-year observation period, significant RR reduction was observed (0.38; 95% CI, 0.17-0.87; P = .017) with ARR and NNT of 0.032 (95% CI, 0.027-0.037) and 31.6 (95% CI, 27.1-37.7), respectively, in the 8-year intervention period. The noncontact ACL injury incidence was 0.21 per 1000 AEs during the 4-year observation period compared with 0.08/1000 AEs in the 8-year intervention period, which also showed significant RR reduction (0.37; 95% CI, 0.15-0.92; P = .026), with ARR and NNT of 0.024 (95% CI, 0.020-0.029) and 41.3 (95% CI, 34.6-51.3), respectively. The mean compliance rate during the intervention periods (8 years) was 89%. Conclusion: A hip-focused injury prevention program demonstrated significant reduction in the incidence of ACL injury in female collegiate basketball players.

Effect of Injury Prevention Training Program on Kinematics of Drop Jump Tasks: Evaluation with Landing Error Scoring System and Three-Dimensional Kinematic Analysis

The ACL injury prevention program we designed could effectively correct the risky motion pattern associated with increased risk for ACL injury. The Landing Error Scoring System (LESS) has been shown to be a reliable clinical screening tool that was developed to identify individuals at increased risk for noncontact anterior cruciate ligament (ACL) injury through evaluation of landing biomechanics during the drop vertical jump (DVJ) test. In the present study, we developed an ACL injury prevention training program and applied the program to the subjects. Kinematic characteristics during DVJ were assessed by LESS scoring and three dimensional motion analysis system before and after the training intervention. The purpose of this study was to examine whether the training intervention can correct (alter) the kinematics of jump-landing task using the two evaluation systems. Study subjects: Ten female healthy volunteers participated in the study (average age; 20.6 years). The injury prevention training program consisted of turn jump, plyometric exercise, and strengthening training (approximately 20 minutes for one set of exercise) was conducted 3 days a week for a period of 6 weeks. Kinematic analysis using LESS and motion analysis system was performed before and after completion of the whole training program. Jump-landing task according to the LESS protocol. All subjects performed 3 test DVJ trials according to the LESS protocol described by Padua et al. Analysis of video images for LESS scoring. Frontal and sagittal view video data were acquired using standard HD video camcorders (HDR-CX560, Sony, Tokyo, Japan) that were positioned according to the LESS protocol. Three-dimensional motion analysis using Point Cluster Technique Simultaneously, three-dimensional kinematics data were collected using an 8-camera motion analysis system (Vicon motion system, Oxford, UK) with ground reaction forces recorded using a force plate. In order to accurately analyze the sequential change in tibio-femoral spatial relationship at the knee, the Point Cluster Technique (PCT) was utilized. Testing procedure included attachment of multiple reflective markers and use of the special program to analyze the three-dimensional motion for extension/flexion, varus/valgus rotation, internal/external rotation of the tibia with respect to the femur. LESS score at the post-training trial (4.8) was significantly smaller than that for the Pre-training trial (6.2) (P < 0.05) (figure1). Regarding the motion analysis results, the peak knee valgus angle at the post-training trial (5.0°) was significantly smaller than that at the pre-training trial (8.2°) (P < 0.05) ; however, peak knee flexion and tibial rotation angles were not significantly different between pre- and post-training trials. As regards the correlation between the LESS and motion analysis results, significant correlation was found between peak knee valgus angle and LESS score at the pre-training trial (R=0.83, P < 0.05) and the post-training trial (R=0.95, P < 0.05). All subjects experienced internal tibial rotation after toe contact. In addition, there was a moderate correlation between the peak internal tibial rotation angle and the LESS score at both the pre-training and post-training trials (R=0.64 and 0.43 respectively). The results of the present study showed that The ACL injury prevention program successfully decreased knee valgus angle and LESS score. Therefore, the potential effectiveness of the training intervention was confirmed.

ACL Injury Prevention Training Results in Modification of Hip and Knee Mechanics During a Drop-Landing Task.

Background:Injury prevention training has been shown to be effective in reducing the incidence of noncontact anterior cruciate ligament (ACL) injury; however, the underlying reason for the success of these training programs is unclear.Purpose:To investigate whether an ACL injury prevention program that has been shown to reduce the incidence of ACL injury alters sagittal plane hip and knee biomechanics during a drop-landing task.Study Design:Descriptive laboratory study.Methods:Thirty female club soccer players (age range, 11-17 years) with no history of knee injury participated in this study. Kinematics and ground-reaction forces were collected while each participant performed a drop-landing task prior to and immediately after participation in a 12-week ACL injury prevention training program.Results:After ACL injury prevention training, participants demonstrated decreased knee extensor moments (P = .03), increased energy absorption at the hip (P = .04), decreased knee-to-hip extensor moment ratios (P = .05), and decreased knee-to-hip energy absorption ratios (P = .03).Conclusion:Participation in an ACL injury prevention training program decreased reliance on the knee extensor muscles and improved use of the hip extensor muscles, which may explain the protective effect of this type of training program on ACL injury.Clinical Relevance:Based on these findings, clinicians can better understand how ACL injury prevention training, such as the Prevent Injury and Enhance Performance (PEP) Program, may change movement behavior at both the hip and knee. Furthermore, the study findings may support the implementation of the PEP Program, or a similar program, for clinicians aiming to improve use of the hip in an effort to reduce knee loading and consequent injuries.

The Effect of Abdominal Muscle Activation Techniques on Trunk and Lower Limb Mechanics During the Single-Leg Squat Task in Females.

Females suffer 4 to 6 times more noncontact anterior cruciate ligament (ACL) injuries than males due to neuromuscular control deficits of the hip musculature leading to increases in hip adduction angle, knee abduction angle, and knee abduction moment during dynamic tasks such as single-leg squats. Lateral trunk displacement has been further related to ACL injury risk in females, leading to the incorporation of core strength/stability exercises in ACL preventative training programs. However, the direct mechanism relating lateral trunk displacement and lower limb ACL risk factors is not well established. To assess the relationship between lateral trunk displacement and lower limb measures of ACL injury risk by altering trunk control through abdominal activation techniques during single-leg squats in healthy females. Interventional study setting: movement and posture laboratory. A total of 13 healthy females (21.3 [0.88]y, 1.68 [0.07]m, and 58.27 [5.46]kg). Trunk position and lower limb kinematics were recorded using an optoelectric motion capture system during single-leg squats under differing conditions of abdominal muscle activation (abdominal hollowing, abdominal bracing, and control), confirmed using surface electromyography. Lateral trunk displacement, peak hip adduction angle, peak knee abduction angle/moment, and average muscle activity from bilateral internal oblique, external oblique, and erector spinae muscles. No differences were observed for peak lateral trunk displacement, peak hip adduction angle, or peak knee abduction angle/moment. Abdominal hollowing and bracing elicited greater muscle activation than the control condition, and bracing was greater than hollowing in 4 of 6 muscles recorded. The lack of reduction in trunk, hip, and knee measures of ACL injury risk during abdominal hollowing and bracing suggests that these techniques alone may provide minimal benefit in ACL injury prevention training.

Sensorimotor Cortex Neuroplasticity Following Neuromuscular Training Augmented With Real Time Biofeedback

Non-contact anterior cruciate ligament (ACL) injury is associated with motor coordination errors leading to comprised knee positioning and resultant knee loads that exceed ligament structural integrity. The nature of the ACL injury event (non-contact) and typical occurrence during high neurocognitive demand situations indicate a nervous system mechanism underlying the inciting event associated with injury. A better understanding of the neural contribution to ACL injury prevention training may enhance the ability to target the underlying mechanisms associated with injury risk. However, it is unknown what neuroplastic mechanisms contribute to the improved motor control documented after neuromuscular training. PURPOSE: To compare the knee sensorimotor cortex activation level before and after neuromuscular control training. METHODS: Ten high school female soccer participants from the local community (age: 15.7±0.95 years; height: 168.4±4.60 cm; mass: 59.91±5.62 kg.) were included in the analysis. fMRI data were collected during performance of a unilateral knee motor task of the left knee consisting of repeated cycles of extension-flexion before and after neuromuscular training. The activation level (blood oxygen level dependent signal) was calculated within the sensorimotor cortex as the primary region of interest. The neuromuscular training program consisted of 6 weeks of standardized ACL injury prevention training augmented with real time feedback designed to reduce movement related knee injury risk factors. RESULTS: Sensorimotor cortex activation increased after training (cluster data: voxels:1120; p<.0001; z-max: 8.55; MNI coordinate peak voxel:12,-26,80; %signal difference: 0.37±0.81) relative to pre-training. CONCLUSIONS: The sensorimotor increased activation associated with neuromuscular training is similar to motor recovery after injury and after long-duration (weeks) motor skill training. The increased sensorimotor cortex activation indicates the cortical representation may be functionally increased for knee motor control after the focused intervention. Future work with expanded sample sizes will map whole brain connectivity and other brain region activation changes associated with neuromuscular training.

Effect of Fatigue Protocols on Lower Limb Neuromuscular Function and Implications for Anterior Cruciate Ligament Injury Prevention Training: A Systematic Review

Background: Approximately two-thirds of anterior cruciate ligament (ACL) tears are sustained during noncontact situations when an athlete is cutting, pivoting, decelerating, or landing from a jump. Some investigators have postulated that fatigue may result in deleterious alterations in lower limb biomechanics during these activities that could increase the risk of noncontact ACL injuries. However, prior studies have noted a wide variation in fatigue protocols, athletic tasks studied, and effects of fatigue on lower limb kinetics and kinematics. Purpose: First, to determine if fatigue uniformly alters lower limb biomechanics during athletic tasks that are associated with noncontact ACL injuries. Second, to determine if changes should be made in ACL injury prevention training programs to alter the deleterious effects of fatigue on lower limb kinetics and kinematics. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review of the literature using MEDLINE was performed. Key terms were fatigue, neuromuscular, exercise, hop test, and single-legged function tests. Inclusion criteria were original research studies involving healthy participants, use of a fatigue protocol, study of at least 1 lower limb task that involved landing from a hop or jump or cutting, and analysis of at least 1 biomechanical variable. Results: Thirty-seven studies involving 806 athletes (485 female, 321 male; mean age, 22.7 years) met the inclusion criteria. General fatigue protocols were used in 20 investigations, peripheral protocols were used in 17 studies, and 21 different athletic tasks were studied (13 single-legged, 8 double-legged). There was no consistency among investigations regarding the effects of fatigue on hip, knee, or ankle joint angles and moments or surface electromyography muscle activation patterns. The fatigue protocols typically did not produce statistically significant changes in ground-reaction forces. Conclusion: Published fatigue protocols did not uniformly produce alterations in lower limb neuromuscular factors that heighten the risk of noncontact ACL injuries. Therefore, justification does not currently exist for major changes in ACL injury prevention training programs to account for potential fatigue effects. However, the effect of fatigue related to ACL injuries is worthy of further investigation, including the refinement of protocols and methods of analysis.

Optimization of the anterior cruciate ligament injury prevention paradigm: novel feedback techniques to enhance motor learning and reduce injury risk.

Primary anterior cruciate ligament (ACL) injury prevention programs effectively reduce ACL injury risk in the short term. Despite these programs, ACL injury incidence is still high, making it imperative to continue to improve current prevention strategies. A potential limitation of current ACL injury prevention training may be a deficit in the transfer of conscious, optimal movement strategies rehearsed during training sessions to automatic movements required for athletic activities and unanticipated events on the field. Instructional strategies with an internal focus of attention have traditionally been utilized, but may not be optimal for the acquisition of the control of complex motor skills required for sports. Conversely, external-focus instructional strategies may enhance skill acquisition more efficiently and increase the transfer of improved motor skills to sports activities. The current article will present insights gained from the motor-learning domain that may enhance neuromuscular training programs via improved skill development and increased retention and transfer to sports activities, which may reduce ACL injury incidence in the long term.

Anterior Cruciate Ligament Injury Prevention Training in Female Athletes

Context:Many anterior cruciate ligament (ACL) injury prevention training programs have been published, but few have assessed the effects of training on both ACL injury rates and athletic performance tests.Objective:To determine if ACL injury prevention programs have a positive influence on both injury rates and athletic performance tests in female athletes.Data sources:In August 2011, a search was conducted (1995–August 2011) of the PubMed, Science Direct, and CINAHL databases.Study selection:Selected studies determined the effect of ACL intervention training programs on ACL incidence rates (determined by athlete-exposures) and athletic performance tests, such as isokinetic strength, vertical jump height, speed, agility, and dynamic balance. Because no single article contained both criteria, investigations were cross-referenced to obtain data on both factors from the same training programs.Data extraction:The authors reviewed the selected studies for cohort population numbers, age, sports, duration of study, program components, duration of training, number of athlete-exposures, ACL injury incidence rates, and results of athletic performance tests.Results:Initially, 57 studies were identified that described 42 ACL injury prevention training programs. Of these, 17 studies that investigated 5 programs met the inclusion criteria. Two programs significantly reduced ACL injury rates and improved athletic performance tests: Sportsmetrics and the Prevent Injury and Enhance Performance program (PEP). Sportsmetrics produced significant increases in lower extremity and abdominal strength, vertical jump height, estimated maximal aerobic power, speed, and agility. Prevent Injury and Enhance Performance significantly improved isokinetic knee flexion strength but did not improve vertical jump height, speed, or agility. The other 3 programs (Myklebust, the “11,” and Knee Ligament Injury Prevention) did not improve both ACL injury rates and athletic performance tests.Conclusions:Only the Sportsmetrics and PEP ACL intervention training programs had a positive influence on injury reduction and athletic performance tests.