Which of the following is NOT a type of PRT training?

The correct answer is underwater, as it does not fall under the categories of Physical Readiness Training (PRT) in the context of the Army Combat Fitness Test (ACFT). PRT focuses on improving physical readiness through specific, effective training types that enhance the physical, mental, and emotional well-being of soldiers.

On-ground training involves exercises that are performed while standing or lying on the ground, emphasizing body conditioning and strength. Combatives training is another type used to develop hand-to-hand combat skills and physical fitness. Off-ground training includes exercises done while utilizing equipment like pull-up bars or other apparatus that elevate the body from the ground, enhancing strength and endurance.

In contrast, underwater training is not standard practice within the framework of Army PRT, as it introduces elements that are not directly related to the core objectives of the ACFT or the general physical fitness standards expected of soldiers.