Sex Differences in Neck Muscle Mechanical Responses to Writing at a Fixed-Height University Desk

Introduction Musculoskeletal disorders associated with muscular strain on the neck and shoulders affect women in administration more often than men. Ergonomic guidelines have historically been derived from male models, often ignoring biomechanical differences between the sexes. This study aims to quantify the acute mechanical response of the neck muscles of men and women to a standardized writing task at university desks of the same height and 0° inclination.

The research involved 57 healthy university students (34 women, 23 men; age 19-24 years). Muscle tone (F), stiffness (S), and viscoelastic decrement (D) in the sternocleidomastoideus muscle (SCM), trapezius muscle (UT), and semispinalis capitis muscle (SSC) were assessed by the non-invasive MyotonPRO device before and after 20 min of continuous writing.

In the entire cohort, a significant change before and after exercise was found only in the UT decrement (p = 0.021). Gender differences were found in the change in muscle tone (ΔF), SCM (p = 0.031), and SSC (p = 0.039). On average, SCM tone increased slightly in men (+0.120 Hz) and decreased in women (-0.294 Hz), while SSC tone decreased in men (-0.374 Hz) and increased in women (+0.450 Hz).

A twenty-minute writing task at a university desk with a fixed height was associated with measurable acute changes in selected mechanical properties of the neck muscles and with differences between the sexes in the direction of change in the tone of SCM and SSC. The clinical relevance of these findings remains unclear and should be validated in larger studies with detailed anthropometric and ergonomic evaluation and longer follow-up.