RLE Good Morning
The RLE (rear leg elevated) good morning is a single leg variation of the good morning that places more emphasis on hip stability than posterior chain strength.
Set up as you would for a good morning
and place one foot on a bench or box behind you. Set your back tightly in a complete arch and hinge at the hips as far as you can without losing any arch in your back, unlocking the knees as you hinge, allowing them to remain slightly bent until you return to standing vertically, straightening them as you straighten the hips.
The RLE good morning requires more stabilization at the hip, so is less effective for general posterior chain strength and more effective for improving stability.
Sets of 5-8 reps are most common, but as many as 15-20 reps can be used, particularly in a rehab situation.