Background: Anterior cruciate ligament (ACL) injury is associated with various consequences all over the knee (e.g. meniscal tear and osteoarthritis). Spinal core stabilizers play an important role in stabilizing the knee and preventing injury, but with minimal supporting evidence. Objective: To identify the relationship between non-contact ACL injury and core muscles weakness. Methods: Sixty subjects with their ages ranged from 20 to 40 years old, allocated into two equal groups; Group A(ACL group): with non-contact ACL injury, and Group B (control group): Age matched healthy volunteer all are free from chronic or acute knee injuries. Each participant was assessed for Transversusabdominis (TrA) thickness (in static and dynamic situations) using rehabilitative ultrasound imaging (RUSI) and endurance of TrA using pressure biofeedback. Results: There were a significant decrease in static and dynamic muscle thickness and TrA endurance in ACL group compared with that of normal group (p ≤0.01), weak positive significant correlations for TrA endurance with dynamic thickness (r = 0.27, p = 0.03) Conclusion: TrA strength and endurance can help in prevention and treatment of non- contact ACL injury.
