Here are the main muscle groups worked by the sumo deadlift. Like other deadlift variations, the sumo deadlift works the glutes, hamstrings, and back (posterior chain). However, the sumo deadlift works slightly different muscle groups than the standard and hex bar deadlifts.

The sumo deadlift works the glutes to a great extent. By splaying the feet and deforming them outward, the hips are placed in an external rotation position, which works the glutes to a higher level.

While the conventional and Romanian deadlifts are more beneficial for the hamstrings, the hamstrings are still the primary muscles for the sumo deadlift. That said, if a lifter wants to work the hamstrings more specifically, they may prefer to do the Romanian deadlift.

Due to the position of the feet in the sumo deadlift, professional athletes must achieve better knee flexion to perform the sumo deadlift. Therefore, the sumo deadlift targets the quadriceps (responsible for extending the knees) more than the Romanian and conventional deadlifts. This is similar to the oblique deadlift. In short, with this deadlift variation, you can squat more, and therefore use your thighs more.

The lower back muscle group, also known as the erector spinae. Keeping the spine stable during the extension phase of the lift works the erector spinae muscles of the back. Since the sumo deadlift is usually a heavy deadlift, it reduces back strength. Unlike the conventional and Romanian deadlifts, the sumo deadlift has a more vertical upper body. This allows the other back muscles to relax a little.

The upper back and trapezius muscles maintain proper torso position and help pull the bar upward. As opposed to the standard deadlift, the sumo deadlift is an additional vertical pull. It is an excellent exercise to develop a thick, strong grip and upper back muscles.