Effects of Weighted Seated Core Exercises on Immediate Postural Stability in Healthy Young Adults: An Exploratory Study

Objectives: This exploratory study investigated whether low-load, seated core exercises could produce immediate improvements in standing balance among healthy young adults, aiming to provide a foundation for safe, early-stage rehabilitation protocols. Methods: Ten healthy males performed seated core exercises consisted of alternating hip flexion 5 times per side while seated and maintaining bilateral shoulder flexion at 120-degree shoulder flexion under four load conditions: upper-limb weight only, a 400-g empty box, a 1-kg ball, and a 2-kg ball. Immediately following the exercise, participants performed a 10-s single-leg stance. Transversus abdominis (TrA) thickness was measured via wireless ultrasound at baseline, post-exercise, and during the stance. Center of pressure (CoP) sway was recorded concurrently to evaluate postural stability. Results: Left-side TrA thickness during stance increased significantly under the 1-kg and 2-kg load conditions compared to baseline (p < 0.05), although substantial missing data for the left-side measurements limited the robustness of this finding. No significant load-dependent effects were observed for CoP sway parameters (p > 0.05). A moderate positive correlation (rho = 0.43, p = 0.002) was found between right-side TrA thickness and CoP sway velocity during the single-leg stance. Conclusions: Low-load, seated core exercises do not yield immediate enhancements in standing stability in healthy populations. The results suggest that increased TrA thickness during a balance task may correlate with heightened postural instability rather than improved balance control. Further research is needed to determine whether these findings translate to clinical populations with impaired physical fitness.