Background: Considering the importance of physical health among school-aged students, evaluating the effects of common spinal postural deviations on respiratory function and core muscle performance is essential. This study aimed to compare the respiratory pattern and core muscle function in students with and without postural thoracic hyperkyphosis.
Methods: In this cross-sectional comparative study, 88 male and female middle and high school students in Karaj, Iran, aged 13–18 years in 2024, with and without postural thoracic hyperkyphosis, were recruited voluntarily. The thoracic kyphosis angle was assessed using a flexible ruler. Core muscle endurance was evaluated using McGill’s trunk endurance tests, including trunk flexor, trunk extensor, and lateral trunk endurance tests. Respiratory pattern was assessed by measuring changes in chest and abdominal circumference.
Results: No significant differences were observed between groups in flexor endurance (P = 0.119, d = -0.34, 95% CI: -0.76 to 0.08), extensor endurance (P = 0.723, d = -0.07, 95% CI: -0.49 to 0.35), or lateral muscle endurance (P = 0.197, d = 0.29, 95% CI: -0.13 to 0.71). However, statistically significant differences were found in abdominal breathing excursion (P = 0.006, d = 0.59, 95% CI: 0.17 to 1.01) and thoracic breathing excursion (P = 0.001, d = 0.74, 95% CI: 0.30 to 1.18), with the healthy group demonstrating significantly greater thoracic and abdominal excursion.
Conclusion: Thoracic postural hyperkyphosis in students may be associated with alterations in respiratory pattern. Therefore, respiratory function assessment along with postural evaluation may be considered in corrective exercise interventions.