Proper posture starts with a good understanding of the muscles that are involved in posture. Several different muscles are responsible for maintaining upright posture, and over time, poor posture can cause these muscles to lose strength.
Air Force. A major in the Air Force typically has duties as a senior staff officer at the squadron and wing level. In flying squadrons majors are generally flight commanders or assistant directors of operations. In the mission support and maintenance groups majors may occasionally be squadron commanders.
Sergeant Major Duties. Normally, a sergeant major is assigned to the largest Army and Marine Corps units, including battalions and aviation squadrons and above. The specific duties of a sergeant major usually depend on the size of the military unit to which he or she is assigned.