But all the evening's dances were concise, and their energy never flagged.

When energy flagged, there was no war to denounce, nor did the group turn to rousing polemics on social justice.

For some reason, though, my energy never flagged.

More than a decade later, her energy has not flagged.

But in the last year or so the genre's energy has flagged slightly, and skeptics have questioned its staying power.

Warriors carried sunflower cakes to eat when their energy flagged.

She was still a tense woman and her energy had not flagged.

Then something happened; as the plant's energy flagged, another force seemed to take over.

He was the only musician to perform in all five works, but his precision and energy in these demanding scores never flagged.