Everyone draws their personal energy line across the sprint, then the lines are overlaid. Shared dips and peaks point straight at what needs discussing.
Draw the axes: sprint days horizontally, energy vertically.
Everyone draws their own energy curve, silently.
Put the lines together; find shared dips, peaks, and splits.
What caused the biggest shared dip? What fueled the peak?
One action to prevent the dip, one to repeat the peak.