Shoulder Endurance and Glenohumeral Internal Rotation Effects on Writing Speed in College Students: An Observational Study

Background and Objective: Handwriting proficiency requires coordinated fine motor control and optimal shoulder function. This study examined correlations between shoulder rotational endurance glenohumeral internal rotation, and handwriting speed among college students. Methodology: An observational cross-sectional study recruited 100 college students aged 18-25 years following predetermined inclusion and exclusion criteria. Comprehensive demographic data were collected including age, anthropometric measurements, gender, and hand dominance. Handwriting speed was quantified using the standardized Word Per Minute (WPM) test, shoulder rotational endurance was assessed via the Shoulder Endurance Test (SET), and glenohumeral internal rotation was measured using universal goniometry techniques. Statistical analyses were performed Pearson correlation coefficients calculated to determine variable associations. Results: The study included 100 participants (30 males, 70 females) with mean age 19.61 ± 1.79 years, and handwriting speed 25.96 ± 4.84 words per minute. Mean shoulder endurance was 60.65 ± 22.32 seconds, while dominant hand internal rotation averaged 62.77 ± 6.10 degrees. Statistically significant positive correlations were identified between handwriting speed and shoulder endurance (r = 0.248, p = 0.013) and between handwriting speed and dominant hand glenohumeral internal rotation (r = 0.366, p = 0.010). Conclusion: Enhanced shoulder muscle endurance and improved internal rotation mobility are associated with increased writing speeds. These findings have implications for academic performance optimization and rehabilitation strategies targeting handwriting difficulties.