The hamstrings and glutes are primary movers in the deadlift, yet often people spend too much time working the full range of motion instead of specifically isolating the large posterior chain muscles groups.

Execution 

Start with the barbell in the hands with a closed overhand grip in a tall stance. Engage the lats prior to descending, hinge the hips back, and trace the barbell down the legs until reaching the ground or before losing the flat back. Squeeze the glutes and hamstrings to return to the starting position. Maintain a flat back throughout the entire movement. An alternating grip may be taken to assist in the focus of the legs.  

Purpose 

Many leg exercises are quadriceps dominant, giving most of the emphasis to the front portion of the legs. Romanian Deadlifts or RDLs are a hip dominant movement that engage the glutes and hamstrings and brings balance to the legs. RDLs can also work as a stretch for the hamstrings during the eccentric phase, downward motion,  of the exercise.   

Programming

 RDLs or are variation of it should be used at least once a week during a Strength training program. Use anywhere from 50-75% of the 1 rep maximum of the Deadlift for 5-8 repetitions.  

See Also

Deadlift