Acute Exercise-Specific Changes in Sagittal and Coronal Spinal Alignment After Common Core Exercises

Background: Core exercises are widely prescribed, yet their immediate, exercise-specific mechanical effects on spinal alignment remain unclear because most evidence derives from multi-exercise programs. Non-invasive tools capable of detecting acute postural changes could support a better characterization of exercise-specific acute postural responses. This study evaluated whether common core exercises determine distinct acute changes in sagittal and coronal alignment. Methods: Eighty healthy young adults without evident postural abnormalities (23 ± 5.6 years) were block-randomized to crunch (CE), plank (PE), Russian Twist (RE), or control (CG). Rasterstereography recorded spinal postural parameters immediately before and after each condition. Primary outcomes were pre–post change scores (Δ = post − pre) analyzed with linear models and Holm-adjusted planned contrasts versus CG. Results: Versus CG, CE showed greater reductions in sagittal imbalance (Δ −6.75 ± 9.88; adjusted p = 0.034), cervical arrow (Δ −6.15 ± 7.85; adjusted p = 0.011), and kyphosis angle (adjusted p < 0.001). PE differed from CG only for coronal imbalance (Δ −4.25 ± 3.81; adjusted p = 0.022), showing a shift toward more negative values. RE differed from CG only for kyphosis angle (adjusted p = 0.036). Lumbar arrow did not show between-group differences. Conclusions: A single bout of core exercise can transiently modulate selected sagittal and coronal alignment parameters in healthy young adults without evident postural abnormalities, with effects depending on exercise modality. These findings should be considered exploratory, and their clinical significance remains uncertain.