Injury

Introduction: Since people experience fatigue after anterior cruciate ligament injury during exercises, it is important to understand how fatigue affects the biomechanical movement patterns. Therefore, this study aimed to investigate the effect of fatigue on ground reaction force variables during single-leg landing in athletes with a history of an anterior cruciate ligament sprain. Methods: it was a case-control study conducted in the University Laboratory. The sample consisted of 36 male athletes who were divided into three groups: 12 people with Anterior Cruciate Ligament Reconstruction (ACLR), 12 people with Anterior Cruciate Ligament Deficiency (ACLD), and 12 people as the control group. Fatigue was induced via the repetitive sets of double-leg squats (n=8), which were interspersed with the sets of countermovement jumps (n=2) and single-leg landings (n=3) until squats were no longer possible. A 2×2 repeated-measures multivariate analysis of variance was used to detect the main effects of group (ACLD, ACLR, control) and fatigue state (prefatigue, postfatigue) on the ground reaction forces variables. Results: The results showed a significant decrease in the peak vertical force and internal-external ground reaction force in the ACLD group after fatigue. Regardless of the fatigue state, the peak vertical ground reaction force in ACLD and ACLR groups was significantly lower than that in the control group. Conclusion: The athletes with the ACL injury, regardless of the selective treatment type, use compensatory strategies to reduce the contact forces on the lower extremity, compared with healthy athletes.

Background: Taekwondo is a traditional Iranian martial art currently practiced in over 206 countries around the world. Aim: The present study aims to provide fundamental information on injuries in Iranian elite Taekwondo athletes. Materials and Methods: A total of 200 Iran Taekwondo national team athletes (means±standard deviations: Age: 28.8±10.7 years, Height: 175.7±9.2 cm, Weight: 69±14.7 kg) participated in this retrospective study. The data was collected based on the injury surveillance system during 2021. The questionnaire included personal information and Taekwondo-related injuries information. Data was illustrated using descriptive methods and was analyzed using the Chi-Square test ( P <0.05). Results: The overall injury occurred during training was more than competition ( P <0.05). The occurrence of acute injury was higher than chronic ( P <0.05), and the most prevalent types of injuries were strain, rupture, and muscle spasm. The number of injuries that occurred in the lower extremity was higher than in other parts ( P <0.05), and the knee was the most vulnerable joint ( P <0.05). The most important cause of injuries was fatigue ( P <0.05). The non-contact injury was the most significant injury mechanism ( P <0.05). The severity of injury in Iranian elite Taekwondo athletes was high ( P <0.05). Conclusion: It can be concluded that injuries during training were more than competition, acute injury was more than chronic, strain was the most common type of injury, and the most vulnerable joint was the knee. Fatigue was the leading cause of injuries in elite Taekwondo athletes. So, in designing an injury prevention program, these factors should be considered.

Background: Fatigue as one of the physiological factors can affect the physical performance of athletes. This issue is more important in young athletes and can expose them to injury. Aim: The purpose of this research was to investigate the effect of functional fatigue on the performance and landing mechanics of adolescence taekwondo athletes. Materials and Methods: This was a semi-experimental study. Participants were 20 male teenage taekwondo players. Pre-fatigue measurements included side-jump tests, figure-8 hop tests, and single-leg triple jump tests, as well as a lower limb biomechanics assessment using a landing error scoring system. After the functional fatigue protocol was applied, all the pre-fatigue variables were evaluated again. In order to examine the intra-group changes of the research variables in the pre and post-test stages, the paired t-test at a significance level of P≤0.05 was used. Results: The paired-t test results revealed that following fatigue induction, performance in the side-jump and figure-8 hop tests significantly deteriorated (P<0.05). Additionally, performance in the single-leg triple hop test declined (P<0.05). Moreover, landing error significantly increased (P<0.05). Conclusion: The finding of this study indicated that after applying fatigue, the subjects' performance decreased and the biomechanical error of the lower limbs increased. Fatigue can significantly impact adolescent taekwondo athletes' performance and biomechanics. So, taekwondo coaches should implement effective strategies to mitigate fatigue, enhance athletes' conditioning, and optimize their performance in training and competitions.