Background: Muscle complexity and local dynamic stability (LDS) are important factors in the adaptability of wrestlers when they perform different techniques in the competition. Muscle complexity refers to the recruitment patterns of muscles to meet specific demands while LDS enhances precise and controlled movements in different tasks. However, it is unclear how these two biomechanical variables could show an expert performance in wrestling. Objective: This study aimed to compare the muscle complexity and adaptation patterns in elite and sub-elite wrestlers during performing different techniques. Materials and methods: Seventy-two junior Iranian male freestyle wrestlers were divided into elite (n = 39) and sub-elite groups (n = 33). Electromyography (EMG) activities of the biceps, triceps, anterior deltoid, and latissimus dorsi muscles were recorded during the execution of arm drag, double leg attack, and snap-down techniques. Muscle complexity and LDS were calculated using the fractal dimension (Higuchi algorithm) and Lyapunov's largest exponent method, respectively. Results and discussion: Elite wrestlers demonstrated higher complexity of EMG during the arm drag and double leg attack techniques in the triceps, biceps, anterior deltoid, and latissimus dorsi muscles compared to the sub-elite group which indicates likely their higher skill level. Additionally, elite wrestlers exhibited higher LDS in the biceps, anterior deltoid, and latissimus dorsi muscles compared to the sub-elite group. When comparing the complexity and LDS of muscles in each technique, elite wrestlers displayed greater consistency across different techniques than the sub-elite group, indicating most likely the efficiency of their neuromuscular system. Conclusion: Findings highlight that elite wrestlers maintain consistent complexity and LDS across the execution of techniques, indicating an optimal neuromuscular system while the inconsistency in sub-elite wrestlers may illustrate a challenge in their adaptation and learning a technique. Generally, analyzing the complexity and LDS of muscle EMG can be useful in evaluating skill levels and guiding targeted training to help sub-elite wrestlers progress towards the elite level.
