Ab,

Good topic and I experienced this as well. I think gaining initial buy-in is a common problem in many company-level organizations. One way to approach the problem after taking command is setting up some “easy wins” to gain initial trust from subordinate leaders and Soldiers. Culture and organizational change takes time, effort, and buy-in (as you mentioned). Drastic change from the start can cause long-term problems (or setbacks) for an organization. Change really occurs from small, incremental steps towards an end state, especially at the beginning of a change effort. Since you mentioned physical fitness in your example, one thing a new commander in your situation can implement to get an “easy win” is a rigorous unit physical challenge tied to their command philosophy in-briefs. This type of event will set the tone for your physical fitness priority, encourages teamwork within the platoons, squads, etc., and builds esprit de corps within the entire company. After a few of these events/opportunities where  subordinates start believing in your philosophy, you are more likely to have the buy-in needed to start implementing change across the organization.