When is the Anti-G Straining Maneuver (AGSM) most effective?

The Anti-G Straining Maneuver (AGSM) is most effective when the techniques of tightening the muscles and coordinating breathing are applied simultaneously. This method is designed to maintain blood flow to the brain during high G-force situations, preventing G-induced Loss Of Consciousness (GLOC). By tightening the muscles and controlling breathing, a pilot can increase venous return to the heart and improve cerebral perfusion, which is critical when experiencing high G forces.

During high-G scenarios, effective execution of AGSM involves engaging core and leg muscles while using a specific breathing technique to avoid blackout. Coordination in breathing ensures that air pressure in the chest cavity is maintained to support blood flow and prevent pooling of blood in the lower extremities.

The other options are less effective because they don't incorporate the critical muscle tightening and breathing coordination needed for AGSM to work effectively. For example, executing AGSM during rapid descents or while the aircraft is level does not take full advantage of the techniques necessary to counteract G-forces effectively, and reliance solely on verbal commands does not provide the pilot with the physiological benefits of the maneuver.