Paredes, RicardoPereira, SoraiaCrasto, CarlosGuedes, DianaMontes, António MesquitaAlves, LeonelArias-Buría, José L.C. Guedes, DianaMesquita Montes, António2025-12-162025-12-162025-10Paredes, R., Crasto, C., Montes, A. M., André, A., Pereira, S., Guedes, D., Alves, L., & Arias-Buría, J. L. (2025). Electromyographic assessment of agonist and antagonist muscles related to the anterior cruciate ligament following surgical Reconstruction: A Cross-Sectional study. Journal of Electromyography and Kinesiology, 84, 103044. https://doi.org/10.1016/j.jelekin.2025.1030441050-6411http://hdl.handle.net/10400.22/31211Following anterior cruciate ligament reconstruction (ACLR), neuromuscular control alterations may persist, increasing the risk of reinjury. This study aimed to investigate electromyographic (EMG) muscle activation and the co-contraction index (CCI) of ACL-related agonist and antagonist muscles during side- hop tasks in ACLR individuals, offering novel insights into neuromuscular strategies during dynamic tasks. A cross-sectional study was conducted with 15 ACLR individuals and 15 participants without ACL injury (N-ACLR). Participants performed side-hop tasks while kinematic, kinetic, and EMG data were recorded during the preparatory and loading phases. Statistical analyses were performed at a 95 % confidence level. During ipsilateral side hops, ACLR individuals exhibited higher semitendinosus (ST) activity in the initial contact (IC) and risk phases and increased quadriceps:hamstrings (Q:H) CCI in the risk phase compared to N-ACLR (p < 0.05). In contralateral side hops, ACLR individuals demonstrated higher Q:H CCI in the preparatory phase and higher vastus lateralis:biceps femoris (VL:BF) CCI in the IC and risk phases (p < 0.05). ACLR individuals display altered neuromuscular strategies during side-hop tasks compared to N-ACLR, highlighting adaptations in muscle activation and co-contraction patterns.engKneeAnterior cruciate ligamentMotor controlMuscle activityElectromyographyjournal article10.1016/j.jelekin.2025.1030441873-5711