Interdependent Effect of Intrinsic Risk Factors on Non-Contact Lower Limb Injuries in Male Football Players: A Structural Equation Modeling Approach

<i>Background and Objectives</i>: Recent research has highlighted the importance of examining risk factors and their complex interrelationships in the development of lower limb injuries. This study aimed to investigate the direct, indirect, and mediating effects of endogenous neuromuscular and psychological risk factors on the incidence of non-contact lower limb injuries in football players. <i>Materials and Methods</i>: A sample of ninety-seven male football players underwent a structured preseason, on-field assessment. Demographic characteristics, injury history, and athlete burnout were collected through standardized questionnaires. Preseason evaluations included assessments of lower limb flexibility; isometric strength assessment of hamstring, hip abductors, and quadriceps using a handheld dynamometer; hamstring and core endurance; and the single-leg triple hop for distance test. All non-contact lower limb injuries were prospectively recorded throughout the competitive season. Partial Least Squares Structural Equation Modeling (PLS-SEM) method was applied to examine both direct and indirect associations between preseason risk factors and injury incidence. <i>Results</i>: Lower limb strength asymmetries (path coefficient (PC) 0.293, <i>p</i> = 0.004) and previous injuries (PC 0.233, <i>p</i> = 0.015) exhibited the strongest direct effects on the occurrence of new non-contact lower limb injuries. In addition, age acted as a moderating factor, amplifying the effect of lower limb strength asymmetries on injury risk. Moreover, previous injuries demonstrated both direct and indirect effects on neuromuscular characteristics and perceived burnout. Core and hamstring endurance tended to influence new injuries indirectly through strength asymmetries and were significantly affected by hamstring strength (PC 0.248, <i>p</i> = 0.015) and prior injuries (PC -0.207, <i>p</i> = 0.029). <i>Conclusions</i>: Injury prevention strategies should prioritize the improvement of core and hamstring endurance and the reduction in lower limb Strength Asymmetries, particularly among older football players. Furthermore, individualized preventive interventions for athletes with a previous history of injury are strongly recommended.