An anterior cruciate ligament (ACL) injury is an important cause of rest in athletes. In most cases, ACL injuries do not require external contact and they are associated with biomechanical risk factors that increase ACL tension. The increase of the hip flexion angle (HF) is included within these. The ACL requires cooperation of the periarticular musculature of the knee, muscle groups, hip stabilizers and CORE muscles; consequently, fatigue caused by exercise would alter the balance and put this ligament at risk. The objective of the study is to determine the angular behavior for HF before and after a physical load (a standardized training) in children between 11 and 12 years old. A non-randomized clinical study was carried out. The sample consisted of 50 soccer school students born between 11 and 12 years old. The angular behavior of HF was compared before and after performing a training session. The angular behavior was measured through the Drop Jump test (DJ), with data obtained by inertial sensors. After the exercise, there was a significant increase in HF. It was concluded that the angular behavior of HF increases significantly in both extremities after training and that preventive measures must be applied for neuromuscular control of the hip. Show less

Background The Anterior Cruciate Ligament (ACL) injury is uncommon, but constitutes an important percentage of the lesions requiring more than 8 weeks of recovery in sports. Most ACL injuries do not require external contact and are associated with biomechanical risk factors that stress this ligament ACL: like an increase in knee valgus angle (KV) and hip flexion (HF) and a decreased in knee flexion (KF). The ACL requires muscle cooperation to resist the load; however, when there is fatigue, the protective capacity of the musculature would decrease. The objective of the study is to analyze the angular behavior before and after a physical load for HF in children of 14-15 years old. Hypothesis The physical load applied in a single training session is enough to change some biomechanical risk factors of ACL injury. Study Design Experimental study Level of Evidence 2b Methods The sample consisted of 50 students from different soccer schools between 14-15 years old. We analyzed the hip angular behavior of hip flexion before and after a training session. The angles where obtained from inertioal sensor while the students performed a Drop Jump test from a 30 centimeters drawer. Results Statistically significant differences were found in the differences between pre physical load HF / post-load HF (p = 0.00053), right pre physical load HF / right post- load HF (p = 0.0086) and left post- load (p = 0.0248206). Conclusions It was concluded that the angular behavior of HF increases significantly in both post-training limbs, after performing a physical load. Clinical Relevance This study analyzed the importance of using prevention injury programs since early stages, and give importance to the eccentric role of hamstring, gluteus and core exercises. Show less