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Background. Most football players (58%) around the world are younger than 18 years and almost three quarters of these young players are under the age of 14 years old. The characteristics of football injuries in children aged 7-12 years old are different from those of the young and adult players. Objectives. The aim of this systematic review was to evaluate effects of FIFA 11+ and 11+ Kids warm-up programs in preventing the injuries on the pre-adolescents football players. Methods. PubMed and Science Direct databases were used using the search terms including FIFA 11+, 11+ kids, injury prevention, football, and pre-adolescent. A total of 520 studies were identified, of which 10 met the inclusion criteria of the review. Methodological quality of the studies were assessed through the PEDro score. Results. The 11+ Kids exercises reduce the injury and improve the physical fitness factors such as balance, jumping activities and lower limb isokinetic strength. Although 11+ exercises are designed for players aged over 14 years, they result in an improvement in movement patterns, stability, and trunk muscle endurance. The methodology quality of the randomized studies was in the range of 4 to 7 (out of 10) and the mean score of the studies was obtained 5.6, indicating moderate quality of the methodology. Conclusion. 11+ program alone or in a combination with the newlydeveloped 11+ Kids program may be helpful in preventing the injury and improving the performance, especially if implemented for a longer period or with more exercise sessions per week.

Objectives: Children aged 10 to 12 years often show dangerous maneuvers during landing, which include increased knee valgus, placing them at higher risk of anterior cruciate ligament (ACL) injuries. The study aimed to investigate the relation of the trunk and hip kinematics with the peak knee abduction angle during single-leg landing among preadolescent female soccer players. Methods: Thirty-six preadolescent female soccer players aged 10 to 12 years attended the study. Participants did a static trial and after that performed landing trials. A single-leg landing was applied to assess the landing kinematics. A three-dimensional motion capture system was applied to analyze trunk, hip, and knee kinematics. Results: Pearson correlation coefficient demonstrated a significantly positive relationship between peak hip internal rotation angle (r=0.361) (P=0.03) and peak knee abduction angle. Furthermore, no significant relationship was identified between peak hip adduction (r=-0.102) (P=0.55), peak trunk rotation (r=0.239) (P=0.16), peak trunk lateral flexion (r=0.052) (P=0.76), and peak valgus knee. Discussion: Peak hip rotation angle was correlated with the valgus knee with a weak correlation value among preadolescent female soccer players. Future studies should consider kinematic risk factors related to ACL injuries in combination with neuromuscular control trunk and hip during more demanding tasks.

Background: Changes in knee muscle activity remain years after Anterior Cruciate Ligament (ACL) surgery. However, the literature on the successful or unsuccessful recovery of lower limb muscle activation during jump landing is controversial. Objectives: The present review intended to compare the surface Electromyography (EMG) of knee muscle activity in healthy and Anterior Cruciate Ligament Reconstruction (ACLR) groups in jump landing tasks. Methods: PubMed, Embase, and Web of Science databases were searched papers from 1990 to 2020 using the keywords “anterior cruciate ligament or ACL, EMG or Electromyography or Muscle activation, Landing or Jumping or Hopping”. After screening the titles, abstracts, and full text of the collected articles, 7 studies met the inclusion criteria of this review. The Critical Appraisal Skills Program tool was used for the quality assessment of the included papers. Results: The present research results suggested earlier onset muscle activity for quadriceps and hamstring in ACLR subjects, compared to healthy subjects. Furthermore, the ratio of activation of quadriceps/hamstring in the ACLR group was higher than that in the healthy individuals considering the type of rehabilitation, the time elapsed from surgery, and gender. The methodological quality of the observational studies ranged from 6 to 8 out of 12 that reflects the overall quality of the methodology. Conclusion: According to this review, we can conclude that the ACLR group exhibited different neuromuscular strategies in the pre-landing phase that might increase the recurrent risk of ACL injury.

This study aimed to investigate the effects of the 8-week FIFA 11+ Kids program on kinematic risk factors for ACL injury in preadolescent female soccer players during single-leg drop landing. For this, 36 preadolescent female soccer players (10–12 years old) were randomly allocated to the FIFA 11+ Kids program and control groups (18 players per group). The intervention group performed the FIFA 11+ Kids warm-up program twice per week for 8 weeks, while the control group continued with regular warm-up. Trunk, hip, and knee peak angles (from initial ground contact to peak knee flexion) were collected during the single-leg drop landing using a 3D motion capture system. A repeated measure ANOVA was used to analyze groups over time. Significant group × time interactions were found for the peak knee flexion, with a medium effect size (p = 0.05; effect size = 0.11), and peak hip internal rotation angles, with a large effect size (p < 0.01; effect size = 0.28). We found that the FIFA 11+ Kids program was effective in improving knee flexion and hip internal rotation, likely resulting in reducing ACL stress during single-leg drop landing in young soccer players.