Universal Needs and Cultural Obligations: An Exploratory Factor Structure of Physical Activity Motivation Among Vietnamese Medical Students

Introduction: Physical inactivity among medical students is prevalent, yet motivational instruments lack validation in Asian contexts. This study identified the latent factor structure of physical activity (PA) motivation among medical students in Vietnam, a high-pressure academic environment situated in a Confucian-heritage cultural context. Methods: Data from a cross-sectional survey (December 2024 – February 2025) of 413 medical students were used to evaluate an 11-item, Self-Determination Theory-based questionnaire with item content informed by the EMI-2 and BREQ-2. Two items were removed, yielding a 9-item scale. Exploratory factor analysis (maximum-likelihood extraction, direct oblimin rotation) was conducted. Factor retention was determined via parallel analysis, MAP test, Kaiser criterion, and scree plot. Reliability was assessed via internal consistency and split-half replication. Results: Sampling adequacy was acceptable (KMO=0.799). Most criteria (Kaiser criterion, scree plot, and parallel analysis) supported a three-factor model explaining 51.7% of total variance: (1) Health and Stress Relief (3 items; α=0.83), (2) Achievement and Social Engagement (4 items; α=0.74), and (3) a tentatively retained Obligatory Motivation factor (2 items; α=0.57; Spearman-Brown=0.58). Factors 1 and 2 correlated moderately (r=0.49). Split-half Tucker's congruence (0.91–1.00) indicated strong pattern replication. Conclusions: PA motivation in this cohort demonstrated a three-dimensional structure comprising health/stress-relief, achievement/social, and obligatory dimensions. As cultural constructs and PA behaviors were not directly measured, linking obligatory motives to collectivist norms remains a hypothesis specific to this single-institution sample, requiring cross-cultural validation in independent, more representative samples.