Spinal unloading after abdominal exercises

Background Intervertebral discs are exposed to compressive forces, which produces fluid loss. This loss decreases disc height, spinal length and consequently overall stature. The loss of stature has been associated with spine loading and low back pain. Abdominal exercises increase intra-abdominal pressure and unload the spine. The purpose of this study was to identify if abdominal exercises may produce acute spinal unloading compared to a known unloading position. Methods Nine subjects performed a loading protocol and an unloading protocol on three experimental sessions. The loading protocol consisted of three sets of military press, while three unloading protocols were: three sets of regular abdominal exercises, three sets of abdominal exercises performed in an inclined board or an unloading resting posture. Findings Abdominal exercises showed a greater recovery (mean (SD)) (regular = 87.8 (20.4)%; inclined = 70.1 (14.5)%) in comparison to the resting position (Fowler = 33.6 (14.1)%), although no significant differences were found between abdominal exercises in stature recovery (P = 0.07). Interpretation Abdominal exercises may be introduced between sets of resistance training to decrease the negative effect of compressive forces imposed during such highly stressing activities. Further studies are required to confirm the proposed underlying mechanisms.