Background and Objective: Anterior cruciate ligament rupture is among the most common sports injuries and has substantial consequences for function, return to sport, and knee-joint health. This study aimed to determine the effect of a fatigue protocol on the frequency spectrum of ground reaction forces during running in men with pronated feet following anterior cruciate ligament reconstruction.
Methods: This clinical trial was conducted at the University of Mohaghegh Ardabili and included 15 men with pronated feet who had undergone anterior cruciate ligament reconstruction and 15 healthy men. Participants in the intervention group had undergone unilateral anterior cruciate ligament reconstruction using a hamstring autograft 4-8 months before the study. Participants first ran along an 18-m track while ground reaction forces were recorded using a force plate positioned at the midpoint. After completing the fatigue protocol, ground reaction force data were recorded again during running.
Results: Changes in the 99.5% power frequency of the mediolateral (2.72±2.31) and anteroposterior (2.35±1.11) ground reaction force components were greater in the intervention group than in the healthy group (-1.24±2.96 and -1.42±4.17, respectively; P<0.05). Within-group analysis showed that the 99.5% power frequency values for the mediolateral ground reaction force component after fatigue in the anterior cruciate ligament reconstruction group with pronated feet (16.16±1.75 and 12.00±1.98, respectively) were higher than the corresponding values before fatigue (13.85±2.36 and 10.16±2.26, respectively) (P<0.05).
Conclusion: Fatigue may affect balance control, particularly in individuals who have undergone anterior cruciate ligament reconstruction. Reduced balance may also decrease running speed.