I was thinking the same in more serious vein.
I have a bit of hard time agreeing with the energy drain argument for not moving feet for precisely that reason. Are we saying that the followers have greater endurance or something about leading reduces endurance? May be there is an efficiency factor in how to step and move.
Someone at one time had posted about how many steps they took during 4 hours of dancing (either app or fitbit kind of device).
Doing back of envelope calculations:
1. 10,000 steps (2 feet to 2.5 feet) = 5 miles = 8Kms
2. Assuming you dance to an average 200 bpm song = average number of weight changes (1/4th are pauses), if you step/march every beat = 150 weight changes per minute.
3. However we know that we don't actually step 150 times in a minute. For most active leader who steps, a closer number of steps equivalent is more likely between 80 to 100 (skipping steps when leading things like turns, etc). Half of these are most likely in place. So hard to say if they are same as stepping forward or backward or sideways.
3. Average song of 5 minutes = 500 steps
4. Assuming you dance 50 minutes every hour = 5,000 steps = 2.5 miles = 4kms
That is equivalent of normal moderate pace of walking. I don't see most active dancer expending more energy than equivalent of walking at a moderate pace for 50 minutes.
People not in the best shape easily can do a 2-3 hours weekend hike on a flat terrain (in hot/warm weather). Dancers I think are in slightly better shape