Academic-year differences and psychophysiological associations with objective spinal parameters in physiotherapy students: a cross-sectional DIERS formetric 4D study.

BACKGROUND: Physiotherapy students are exposed to differing physical and psychological demands across classroom-based and clinical stages of training. Although musculoskeletal symptoms, stress, sleep quality and burnout have been widely investigated in healthcare students, these factors have rarely been examined together using objective three-dimensional spinal assessment. This study compared spinal parameters between third- and fourth-year physiotherapy students and examined their associations with academic-year-related physical exposure, psychophysiological factors, sleep quality, and physical activity.

METHODS: In this cross-sectional study, 132 healthy physiotherapy students (70 third year and 62 fourth year) underwent three-dimensional spinal assessment using the DIERS Formetric 4D system. Trunk length, kyphotic angle and lordotic angle were recorded. Sleep quality, anxiety, burnout and physical activity were evaluated using the Pittsburgh Sleep Quality Index, State-Trait Anxiety Inventory, Maslach Burnout Inventory and International Physical Activity Questionnaire. Group comparisons were performed, followed by hierarchical multiple linear regression analyses to examine independent associations and bootstrap mediation analyses to explore indirect associations. Multivariable analyses were adjusted for relevant anthropometric, academic-year, school-based standing and sitting, and physical activity variables.

RESULTS: Fourth-year students reported longer school-based standing and shorter sitting durations than third-year students (both p < 0.001), alongside lower trait anxiety and burnout scores and higher walking activity. No statistically significant between-group differences were observed in trunk length, kyphotic angle, or lordotic angle; kyphotic angle was numerically lower in fourth-year students but did not reach statistical significance (p = 0.051). In the fully adjusted hierarchical model, trait anxiety (β = - 0.148, p = 0.022) and poorer sleep quality (PSQI; β = - 0.139, p = 0.032) were independently associated with shorter trunk length, whereas academic-year group and school-based standing and sitting durations were not. The final model explained 68.4% of trunk-length variance. Exploratory mediation analysis identified a significant indirect association between emotional exhaustion and trunk length through sleep quality (B = - 0.300, 95% bootstrap CI - 0.686 to - 0.062, p = 0.048), while the corresponding direct and total associations were not statistically significant.

CONCLUSIONS: Objective spinal parameters did not differ significantly between third- and fourth-year physiotherapy students despite marked differences in their school-based standing and sitting exposure. Trunk length was independently associated with trait anxiety and sleep quality after multivariable adjustment, while exploratory analysis identified an indirect association between emotional exhaustion and trunk length through sleep quality. Given the cross-sectional design, these findings should be interpreted as associations rather than temporal or causal relationships. Collectively, the results highlight the potential value of educational strategies that extend beyond ergonomic considerations to integrate biomechanical, psychological, and recovery-related factors during physiotherapy training.

TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT06851780 registered on October 28, 2024.