Effect of functional electrical stimulation on maximum joint angles and gait asymmetry in female athletes post-anterior cruciate ligament reconstruction when crossing obstacles

Background Functional electrical stimulation (FES) can effectively stimulate muscle contraction and has shown great potential in improving human motor function. Female athletes post-anterior cruciate ligament reconstruction (post-ACLR) have pervasive bilateral asymmetries. Moreover, asymmetric gait is often considered one of the risk factors for falls. Methods Twenty female athletes post-ACLR were divided into the FES group and the control (CON) group to cross different obstacle heights (30%, 20%, and 10% of the leg length (LL). The two-way repeated analysis of variance was employed to examine the effects between groups and heights, as well as Bonferroni post-hoc comparison and an independent samples t-test. Results The maximum hip and knee joint angles of the leading and trailing limbs were lower in the FES group than in the CON group (all, P  < 0.05). The swing time, gait asymmetry (GA), stance time GA, and swing/stance time GA decreased when crossing obstacles with heights 30% and 20% of the LL (all, P  < 0.05). Furthermore, when crossing 30% LL-high obstacles, the step length was shorter in the FES group than in the CON group ( P  < 0.05). Conclusions The maximum joint angles of the hip and knee following FES When crossing obstacles with heights 30% and 20% of the LL, the GA between the leading and trailing limbs would be reduced in female athletes owing to their increased lower neuromuscular control ability. Trial registration This trial was prospectively registered with the Chinese Clinical Trial Registry (ChiCTR2100053942) on 04/12/2024.