The barbell stiff-legged deadlift targets the hamstrings, glutes, lower and upper back, as well as the core. It is a popular accessory movement for the deadlift, but also a muscle-building hamstring movement.
Benefits
Stretches and engages the hamstrings and lower back to a greater degree than a bent knee position
Also works the calves, quads, and forearms indirectly
The barbell variation allows for heavier loading than with dumbbells