Ergonomic evaluation of upper extremities muscle activity pattern during 60-min smartphone texting.

This article investigates the effects of prolonged (1-hour) smartphone texting on muscle activity, posture, and discomfort among young Indian adults aged 20–28. Using surface electromyography (sEMG) and gyroscope measurements, the study found that sustained texting significantly increased muscle activity in the sternocleidomastoid (SCM), trapezius pars descendens (TRP), extensor digitorum (EDM), and abductor pollicis brevis (APB) muscles by 1.5 to 1.9 times, with average head and lower-arm flexion angles of approximately 27° and 83°, respectively. This posture elevated mechanical loads on the cervical spine by 4.6 times and tripled subjective discomfort, indicating a heightened risk of musculoskeletal disorders (MSD) related to prolonged smartphone use. The findings highlight the potential health risks of extended smartphone use in sitting postures and suggest implications for other activities involving sustained flexed upper body positions.