Final answer:
Commanders and various military leadership roles have the authority to use physical exercise as corrective action, aligning with historical and modern principles of military discipline.
Step-by-step explanation:
Commanders, First Sergeants, Drill Sergeants (DSs), Advanced Individual Training Platoon Sergeants (AIT PSGs), and Squad Leaders often have the authority to employ physical exercise as a form of corrective action. This is generally done within the context of military discipline and training. While this question appears to be about modern military practices, there is a similar principle in the historical document mentioned, such as 'If in training soldiers commands are habitually enforced, the army will be well-disciplined; if not, its discipline will be bad' from the second set of statements you provided. This concept was likely used historically and similarly applies today, affirming the first part of the student's question as true.