Exploring the association between smartphone usage and upper trapezius myofascial pain syndrome among undergraduate medical students: a cross-sectional study at Udayana University

Background
Smartphones have become an essential component of daily human activities. However, maintaining a non-ergonomic posture during prolonged use can result in continuous muscle contractions and contribute to the development of trigger points, particularly in the upper trapezius muscle.

Objectives
This study aims to determine the association between smartphone usage and the presence of upper trapezius myofascial pain syndrome among undergraduate medical students.

Material and methods
This cross-sectional study involved undergraduate medical students at Udayana University. Data was collected through questionnaires and physical exams to assess sociodemographic profiles, smartphone usage characteristics (duration, typing style, screen size, body posture, addiction status), and the presence of upper trapezius myofascial pain syndrome. Associations between variables were analyzed using contingency coefficient tests.

Results
A total of 172 students met the inclusion criteria. The study revealed that 90.1% of respondents used smartphones for ≥ 4 hours, 92.4% used devices with screen sizes ≥ 6 inches, 48.8% adopted a slouched sitting posture, 83.7% typed with both hands, and 49.4% had smartphone addiction. Physical exams revealed that 30.2% of the students had upper trapezius myofascial pain syndrome. Associations were found between the presence of myofascial pain syndrome and smartphone usage duration (CC = 0.173, p = 0.021), posture (CC = 0.117, p = 0.564), and smartphone addiction (CC = 0.206, p = 0.006), but not with typing style (CC = 0.087, p = 0.254) or screen size (CC = 0.051, p = 0.536).

Conclusions
The study shows that smartphone usage duration, posture, and addiction are linked to upper trapezius myofascial pain syndrome, highlighting the importance of disciplined self-monitoring of device usage duration and posture improvement according to ergonomic recommendations.