Which of the following actions is NOT part of the Anti-G straining maneuver?

The Anti-G straining maneuver is a series of actions designed to help pilots counteract the effects of high G-forces, particularly during maneuvers that could lead to G-induced Loss Of Consciousness (GLOC). Rapidly blinking to maintain visual focus is not part of this maneuver.

In contrast, tightening leg and abdominal muscles, using controlled breathing techniques, and maintaining a positive posture in the seat are all integral to the Anti-G straining maneuver. These actions help maintain blood flow to the brain and prevent blood pooling in the lower extremities during high G conditions. Controlled breathing techniques, such as withholding and strategically exhaling during G forces, are vital for managing internal pressure and ensuring sufficient blood circulation. Tightening muscles helps to create a "clamping" effect to keep blood from pooling away from the brain. Lastly, maintaining an upright posture assists in maximizing blood flow towards the head.

This combination of techniques helps pilots withstand substantial G-forces, whereas rapidly blinking does not contribute to counteracting the physiological effects of G-forces as needed in this context.