Electromyographic and Strength Analysis of Biceps and Triceps: Implications for Muscle Efficiency and Fatigue

Introduction. Work-related musculoskeletal disorders (WMSDs)are linked to repetitive strain and muscle imbalances in the upper limbs. While biceps activation is well studied, triceps endurance and its role in workplace fatigue prevention remain underexplored. Understanding how maximal EMG activation relates to muscle efficiencyand fatigue resistance is crucial for optimizing ergonomics and reducing injury risks.
Aim of the study. This study investigates the ergonomic implications of biceps and triceps function, focusing on strength ratios, neuromuscular activation, and fatigue resistance. Additionally, it explores spectral frequency components and their role in sustaining optimal muscle performance in repetitive workplace tasks.
Materials and methods. The study included 23 participants (mean age: 24.7 ± 4.1 years), with 22 right-handed. Dynamometry and EMG data were collected at rest and maximal effort for biceps and triceps on both arms. Functional ratios (biceps/triceps strength, rest/maximal activation) and spectrum frequency comparisons were analyzed to assess fatigue resistance and ergonomic strain. Data was processed using Jamovi.
Results. Biceps exhibited higher force output than triceps, with significant differences between arms (p < 0.001). Mean values for the dominant biceps/triceps were 135.6 ± 21.3 N and 98.4 ± 19.2 N, while non-dominant values were 129.2 ± 25.1 N and 94.7 ± 20.6 N. Higher baseline EMG activityin the biceps, especially in the non-dominant arm (178 ± 30.5 Hz vs. 142 ± 29.8 Hz, p < 0.001), suggests increasedstrain and potential for overuse injuries. During maximal effort, triceps showed higher activation frequencies (162 ± 23.7 Hz vs. 129 ± 21.4 Hz in the dominant arm, p < 0.001), indicating better fatigue resistanc eand a stabilizing role in load-bearing tasks. Spectral analysis revealed distinct fatigue patterns, with triceps showing greater resistance to frequency shifts under prolonged exertion, emphasizing its role in sustained repetitive tasks. Triceps activation is more load-dependent than biceps, making it essential for stabilizing force output and preventing fatigue-related injuries.
Conclusions. This study identifies distinct neuromuscular activation and strength differences between biceps and triceps, with variations based on dominance, functional demands, and fatigue resistance. Biceps exhibited chronic tension at rest, increasing overuse injury risk, while triceps maintained stable activation, enhancing fatigue resistance.