Which abdominal muscle pair is most involved in maintaining intra-abdominal pressure during lifting?

• A. Rectus abdominis and external obliques
• B. External obliques and rectus abdominis
• C. Psoas major and iliacus
• D. Transverse abdominis and internal obliques

Answer: (D)

Maintaining intra-abdominal pressure during lifting comes from bracing the core with muscles that encircle and compress the abdomen. The transverse abdominis acts like a natural corset, wrapping around the abdomen and increasing pressure when it contracts. The internal obliques work with the transverse abdominis to further compress the abdomen, helping to stiffen the thoracolumbar region and stabilize the spine during lifting. This coordinated contraction creates a rigid abdominal wall and a safer spine under load.

The other pair primarily contributes to movement rather than just stabilization. The rectus abdominis and external obliques are more about moving the trunk—flexing or rotating—so they don’t provide the deepest stabilizing brace for lifting. The psoas major and iliacus are hip flexors and lumbar flexors, not the main players in increasing intra-abdominal pressure. So the combination of the transverse abdominis and internal obliques best achieves the bracing needed to maintain IAP during lifting.