Fouladi R.1, Rajabi R.1, Minoonejad H.1, Eslami M.2
1University of Tehran, Sport Sciences, Tehran, Iran, 2University of Mazandaran, Sport Sciences, Babolsar, Iran
Background: Hamstring strain injury (HSI) is one of the most common sport injuries with long term complications and poor function subsequently. On the other way, anterior cruciate ligament (ACL) injury is less common but far more serious. Hamstring has an important role in knee joint biomechanics and it has proven that some severe knee injuries such as ACL injury increases the risk of HSI; however, the functional deficits and knee joint biomechanical changes that occur after HSI need to be considered.
Purpose: This study aim to evaluate hip and knee joint kinematic changes after HSI during single leg jump-landing task as a common and high risk task for ACL injury preview.
Methods: Thirty-two male athletes (16 with HSI history and 16 healthy) all on regular exercise and sport activities, volunteered to participate in this study and all gave written consent. All participants in previous injured group had history of hamstring acute strain more than 3 months, without any other lower extremity injury and they had return to sport after rehabilitation and functional testing. They were closely matched with healthy athletes who had no history of lower extremity injury for 3 months, as a control group. Participants had single leg jump-landing task from the half of each person height after warm up. Following marker placement, participants had synchronous bilateral three dimensional (3D) lower limb (hip and knee) joint kinematic recorded initial contact of single-leg forward jump landings. Six high-speed (200 Hz) cameras (JVC) recorded synchronous motion data during all landings (3 trials for each leg). After data collection, SPSS 23 and statistical analysis such as paired T-test, Wilcoxon, student T-test and manvitney were used with α= 0.05.
Results: There was significant difference in hip joint kinematic, just in sagittal plan between HIS and healthy groups (p= 0.045). There were no significant differences in hip other dimensions and knee 3-dimensional analysis between both legs of HSI athletes and also between HSI and healthy groups at initial contact
(p ≥ 0.05).
Conclusion(s): Our findings in this study suggest that hamstring previous injury cannot change the knee joint kinematics. But we believe that risk of ACL injury is not just related to the knee joint kinematics and it can be affected by the other joints such as hip and also the other biomechanical factors of lower extremity. By considering the role of hamstring as a two joint muscle and its functional connection with the other lower limb muscles, this would suggest that other biomechanical factors are probably responsible for the HIS and ACL injury relationship and its better to be considered in future studies.
Implications: For return to sport after hamstring injury, its not sufficient paying attention to the muscle or just knee joint kinematics.
Funding acknowledgements: We thank for university of Tehran
Topic: Sport & sports injuries
Ethics approval: ethics committee of university of Tehran approved our work.
All authors, affiliations and abstracts have been published as submitted.
