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Imanibrouj S, Jafarnezhadgero A, Sheikhalizade H, Mousavi S H. Effect of Sand Surface Training on Knee and Ankle Co-contraction in Individuals With Pronated Feet and ACL Reconstruction. PTJ 2026; 16 (S1) :401-412
URL: http://ptj.uswr.ac.ir/article-1-671-en.html

Purpose: The human skeletal-muscular system operates as an interconnected framework, meaning that changes in one part can influence other areas and potentially disrupt fundamental motor skills, such as walking. This study aimed to assess the impact of sand-surface training on co-contraction of the knee and ankle muscles in individuals with pronated feet and anterior cruciate ligament reconstruction (ACLR) during walking.
Methods: Twenty-eight adult males with pronated feet and ACLR were divided into two equal groups (intervention group [IG] and control group [CG]). The participants were instructed to maintain a steady pace of approximately 1.2 m/s along an 18 m pathway. Muscle activity was monitored using a surface bipolar electromyography (EMG) system before and after the tests. The intervention cohort participated in an eight-week sand-based walking training regimen, incorporating consistent jogging, long-stride walking, bounding movements, galloping, and brief sprints, conducted thrice weekly. Conversely, the CG completed a comparable training protocol on a stable surface. 
Results: The results revealed significantly greater directed knee flexor/extensor co-contraction during the loading phase (P=0.010) in the IG (but not in the CG). Furthermore, findings revealed a substantial decrease in directed knee mediolateral muscle co-contraction during the propulsion phase in the IG (but not in the CG) (P=0.001). 
Conclusion: In accordance with our results, it can be concluded that sand training may affect the knee joint co-contraction pattern in adult males with pronated feet and ACLR.