Impact of a 12-Week Core Stability Training on Upper Trunk Stability, Trunk Mobility, and Postural Asymmetries in University Students

The present study aimed to investigate the effects of a 12-week Core Stability Training (CST) program on trunk mobility (twisting and bending), upper quarter dynamic balance (UQ-YBT scores), and postural asymmetry indices (Anterior—ATSI—and Posterior Trunk Symmetry Indices—POTSI) of university students. This study examined the effects of a 12-week CST program on trunk mobility and dynamic balance in 181 university students (70 females, 111 males; aged 18–24 years). Participants completed one supervised 90–100-min session per week. Baseline postural symmetry, assessed with the ATSI and POTSI, showed no sex differences. After training, trunk mobility improved significantly (p < 0.001). The female group increased twisting by 5.3° and bending by 6.5 cm, while the male group improved by 4.7–6.1° and 6.0–6.1 cm, respectively (η2 = 0.625–0.773). Dynamic balance measured by the UQ-YBT also improved in all directions (p < 0.001). Mean gains ranged from 4.0 to 9.7 points, with large effect sizes, especially in males (η2 up to 0.842). CST effectively enhanced trunk mobility and upper trunk stability in both sexes. Although postural asymmetry did not change, the program improved neuromuscular control and balance, demonstrating its value in promoting postural health among university students.