Below are the key muscle groups functioned by the sumo deadlift. Like various other deadlift variants, the sumo deadlift works the glutes, hamstrings, and also back (posterior chain). Nevertheless, some small difference between in the muscle mass worked from the sumo deadlift vs. standard deadlift vs. trap bar deadlift.

The sumo deadlift works the glutes to a great extent. By spreading the feet and deforming outward, the hips are in external rotation, which in turn engages the glutes to a higher level.

Although the traditional deadlift and Romanian deadlift are more beneficial to the hamstrings, the hamstrings are still the main muscles in the sumo deadlift. That said, if a lifter wants to target the hamstrings more specifically, they may be more inclined to perform the Romanian deadlift.

Due to the positioning of the feet in the sumo deadlift, professional athletes must achieve better knee flexion in order to perform the sumo deadlift. Therefore, the sumo deadlift targets the quadriceps (responsible for extending the knee) more than the Romanian deadlift and the regular deadlift. This is similar to the slash deadlift. In short, you squat more with this deadlift variant and therefore use your thighs more.

The lower back muscle group, also known as the erectors. Keeping the spine stable throughout the stretch phase of the lift works the back erectors. Considering that sumo deadlifts are usually large deadlifts, this reduces back strength. Unlike traditional deadlifts and Romanian deadlifts, the upper body of the sumo deadlift is more vertical. This allows various other back muscles to relax a bit.

The upper back and traps maintain proper trunk placement and also help the bar pull up. Contrary to the standard deadlift, the sumo deadlift is an additional vertical pull. And it is a great exercise for building thick, strong catch and upper back muscles.