Preliminary evaluation of arm muscle strength testing for early detection of work-related upper limb disorders

Objective. This study aims to evaluate arm muscle testing techniques in healthy individuals as a preliminary step towards incorporating these methods into compulsory medical exams (CMEs) for early detection of work-related upper limb disorders (WURLDs).

Methods. Six muscle groups (deltoids, biceps brachii, brachioradialis, triceps brachii, wrist flexors, and extensors) were examined using clinical muscle strength testing, dynamometry and surface electromyography (sEMG) in 26 healthy individuals. BMI was recorded. Thermography was used to detect trigger points. Data analysis was performed using IBM SPSS 27.

Results. Significant correlations were observed between clinical assessments and dynamometry in the deltoids (p=0.007, 95% CI [0.02, 0.62]), brachioradialis (p=0.045, 95% CI [0.01, 0.57]), and triceps (p=0.019, 95% CI [0.03, 0.64]), as well as between dynamometry and sEMG in the deltoids (p=0.039, 95% CI [0.01, 0.56]), brachioradialis (p=0.093, 95% CI [0.00, 0.52]), and triceps (p=0.170, 95% CI [0.02, 0.54]). Correlations were found between BMI and muscle strength in the deltoids (right: r=0.51, p=0.007, 95% CI [0.15, 0.75]; left: r=0.45, p=0.019, 95% CI [0.08, 0.71]), biceps (right: r=0.42, p=0.026, 95% CI [0.05, 0.68]; left: r=0.40, p=0.035, 95% CI [0.03, 0.66]), and right brachioradialis (r=0.37, p=0.045, 95% CI [0.01, 0.65]). Overweight individuals were more likely to have detectable brachioradialis trigger points on thermography.

Conclusions. These findings show significant correlations between clinical and instrumental examination methods, supporting the potential integration of these techniques into CMEs for early detection of WURLDs. Future research should focus on larger sample sizes and longitudinal studies to validate these findings.