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.
19 September 2021 in Journal of Orthopaedic Surgery and Research
Soccer players have a high risk of anterior cruciate ligament (ACL) injury, a potentially career-ending event. ACL rupture has been linked with abnormal neuromuscular control in the lower limb. Additionally, heading the ball with the unprotected head during game play is increasingly recognized as a major source of exposure to concussive and sub-concussive repetitive head impacts. This article provides a hypothesis of potential connection of ACL injury with ball heading in soccer players. The study reviews literature sources regarding the impact of neurocognitive alterations after ball headings in ACL injuries. Poor baseline neurocognitive performance or impairments in neurocognitive performance via sleep deprivation, psychological stress, or concussion can increase the risk for subsequent musculoskeletal injury.
Background/Objectives: Soccer players, particularly females, exhibit an increased risk of both concussions and Anterior Cruciate Ligament (ACL) injuries. Emerging evidence suggests that neurcognitive deficits following concussions may impair neuromuscular control, increasing ACL injury susceptibility. This study aims to explore the interplay between concussions, neuromuscular deficits, and ACL injury risk, while proposing targeted prevention strategies. Methods: A comprehensive review of current literature was conducted to analyze the biomechanical and neurophysiological impact of concussions on ACL injury risk. Key areas investigated include the effect of sub-concussive impacts on proprioception, reaction time, and postural stability, as well as sex-based differences in injury susceptibility. Results: Findings indicate that post-concussion neuromuscular impairments—such as altered proprioception, delayed reaction times, and compromised joint stability—heighten ACL injury risk. Female athletes, due to biomechanical and hormonal factors, are particularly vulnerable. Preventive measures, including neuromuscular training, cervical spine strengthening, and optimized return-to-play protocols, are essential to mitigate these risks. Conclusions: Longitudinal research is needed to further elucidate the connection between head trauma and ACL injuries. Implementing evidence-based interventions and policy changes, such as modifying heading exposure in youth athletes, may enhance player safety and reduce long-term injury burden in female soccer players.
Purpose: Anterior cruciate ligament reconstruction (ACLR) using the hamstring graft is commonly performed to restore knee stability; however, it induces significant neuromuscular and biomechanical changes, particularly in the hamstring. This study aimed to evaluate the changes in maximum effective angle, hamstring strength, and hamstring-to-quadriceps (H/Q) strength ratio at 3 and 6 months post-ACLR and compare these outcomes to a control group. Methods: This prospective controlled study included 20 ACLR patients and 20 age- and gender-matched controls. Hamstring peak torque, maximum effective angle (MEA), and the H/Q ratio were assessed using isokinetic dynamometry at 60°/s. The ACLR group was evaluated postoperatively at 3 and 6 months, while the control group underwent a single evaluation. Results: At 3 and 6 months, the ACLR group exhibited significantly lower MEA (26.3° ± 8.2 and 28.2° ± 9.4) compared to the control group (36.4° ± 12.0; p < 0.01). Hamstring peak torque and H/Q ratios were also lower in the ACLR group but showed slight improvements over time. The H/Q ratio increased significantly between 3 and 6 months (51% to 56%; p = 0.041). Conclusion: The use of hamstring graft in ACLR leads to persistent MEA and strength deficits despite rehabilitation. Advanced, targeted rehabilitation protocols are essential to address these deficits, optimize recovery, and reduce the risk of reinjury.
Periodization is a concept of systematic progression in training and rehabilitation. The rehabilitation literature, however, is scarce, with information about optimally designing resistance training programs based on periodization principles for injured athletes. This periodization model—reverse linear neuro periodization—is a model proposed for the long-term rehabilitation needed after an arthroscopic rotator cuff repair. With recent evidence supporting neural contributions to shoulder injuries and the rate of recovery, rehabilitation protocols may benefit from incorporating approaches that target the sensorimotor system. Integrating motor learning principles (external focus and differential learning) and new technologies (virtual reality, laser pointers, stroboscopic glasses) may bolster current shoulder rehabilitation protocols and improve patient recovery times and outcomes. Such an understanding allows well-informed sport rehabilitation specialists to better bridge the gap between the preparation for competition widely used by coaches and the treatment of injuries that may occur.
Background: Injury to the anterior cruciate ligament is one of the most common knee injuries. Following anterior cruciate ligament reconstruction, strength deficits and reduced quadriceps and hamstring muscle mass are common. Traditional strengthening protocols recommend the use of heavy loads. However, following surgery, heavy-load exercises are contraindicated to protect the joint and graft. Blood flow restriction resistance training is an alternative that optimizes muscle recovery. The aim of this study was to evaluate the effects of blood flow restriction resistance training on muscle mass and strength after ACLR. Methods: The Pubmed, Cochrane Library, and PEDro databases were used to constitute the corpus of this systematic review. The methodological quality of the studies was assessed with the Cochrane Collaboration’s analysis grid. Results: Thirty-four articles were identified in the initial search, and five randomized controlled trials were included in this review. Not all studies reported significant results regarding strength and muscle mass. Two of these studies observed a significant improvement in strength associated with blood flow restriction resistance training compared with the control group. A significant increase in muscle mass was observed in one study. Conclusions: The blood flow restriction resistance training method shows superior efficacy to training without occlusion, yet this device has not been shown to be more effective than heavy-load resistance training in terms of muscular strength and muscle mass. Blood flow restriction resistance training shows superior efficacy in both these variables when used with low loads. However, there are still few random controlled trials on this subject, and this review presents their limitations and biases. Future research is needed on guidelines for the application of blood flow restriction resistance training in clinical populations.