ADP 3-90, page 83

Enabling Operations 31 July 2019 ADP 3-90 5-3  Guard is a type of security operation done to protect the main body by fighting to gain time while preventing enemy ground observation of and direct fire against the main body. Units performing a guard cannot operate independently. They rely upon fires, functional support, and multifunctional support assets of the main body.  Screen is a type of security operation that primarily provides early warning to the protected force. 5-8. The cover, guard, and screen security operations employ increasing levels of combat power and provide increasing levels of security for a force’s main body. However, more combat power in the security force means less combat power for the main body. Area security preserves a commander’s freedom to move reserves, position fire support means, provide for command and control, and conduct sustaining operations. 5-9. All maneuver forces can conduct security operations. All three types of Army BCTs—armored, infantry, and Stryker—conduct security operations as part of their mission-essential task lists. Commanders ensure that subordinate units conduct security operations required by the situation. Habitual support relationships with attachments and standard operating procedures are required to obtain proficiency in the conduct of these operations. 5-10. Successful security operations depend on properly applying five fundamentals:  Provide early and accurate warning.  Provide reaction time and maneuver space.  Orient on the force, area, or facility.  Perform continuous reconnaissance.  Maintain enemy contact. (See FM 3-90-2 and FM 3-98 for additional information on the conduct of security operations.) TROOP MOVEMENT 5-11. Troop movement is the movement of Soldiers and units from one place to another by any available means. The ability of a commander to posture friendly forces for a decisive or shaping operation depends on the commander’s ability to move those forces. The essence of battlefield agility is the capability to conduct rapid and orderly movement to concentrate combat power at decisive points and times. Successful movement places troops and equipment at their destination at the proper time, ready for combat. The following are types of troop movements:  Administrative movement is a movement in which troops and vehicles are arranged to expedite their movement and conserve time and energy when no enemy ground interference is anticipated. Commanders only conduct administrative movements in secure areas. Commanders normally do not employ administrative movements once their units deploy into combat operations. The echelon logistic staff officer usually supervises these types of moves. (See FM 4-01 for a discussion of Army transportation operations.)  Approach march is the advance of a combat unit when direct contact with the enemy is intended. An approach march emphasizes speed over tactical deployment. Armored, Stryker, and infantry forces conduct tactical road marches and approach marches.  A tactical road march is a rapid movement used to relocate units within an area of operations to prepare for combat operations. The primary use of a tactical road march is rapid movement. However, the moving force employs security measures even when contact with enemy forces is not expected. During tactical road marches, commanders are always prepared to take immediate action if an enemy attacks. (See ATP 4-01.45 for a discussion of tactical convoy operations.) METHODS OF TROOP MOVEMENT 5-12. Troop movements are made by dismounted marches and mounted marches using vehicles. Units also use available transportation modes—motor transport, air, rail, and water—in various combinations. The method employed depends on the situation, size, and composition of the moving unit; distance the unit must cover; urgency of execution; and condition of the troops. It also depends on the availability, suitability, and capacity of the different means of transportation. Troop movements over extended distances have significant