GLOSSARY

The abdominal oblique muscles are two broad muscle layers in the lateral abdominal wall, the external oblique and internal oblique, whose fibres run obliquely and at right angles to each other.

Members

• External oblique: more superficial and larger; fibres run downwards and medially, like putting your hands in your front pockets.
• Internal oblique: deeper; fibres run upwards and medially, roughly perpendicular to the external oblique.

Shared Actions

• Bilateral: trunk flexion and raising intra-abdominal pressure.
• Unilateral: lateral flexion and rotation of the trunk.

Key Teaching Point: Trunk Rotation

To rotate the trunk to the right, the left external oblique and right internal oblique work together; the external oblique rotates the trunk to the opposite side and the internal oblique to the same side. These two muscles form a continuous chain from one side of the rib cage to the opposite side of the pelvis.

Relevance to Sport

• Rotational sports: golf, tennis, baseball, boxing, throwing, and hockey, transferring force from the legs to the arms.
• Exercises: wood chops, the Pallof press (anti-rotation), side planks, and rotational medicine-ball throws.
• Injury prevention: anti-rotation training helps control the trunk and protect the lumbar spine.