Sumo Deadlifts
Why use them?
1. Many powerlifters choose them because they actually decrease range of motion by 14%, so it clearly has some benefits for those who are built for it.
2. Generally speaking, a wider stance will carry over better to a squat than a conventional stance — especially if you squat with a wide stance.
3. Sumo pulls are aided more by deadlift and squat suits, which provide more "pop" in the bottom position — where most sumo pullers tend to miss.
4. Many heavier lifters opt to pull sumo because their bellies get in the way of pulling from the ground conventionally. This "shift" generally takes place during the jump from the 242 to 275-pound weight classes, at least in my experience.
5. Sumo pulls tend to be better in the short-term for those with flexibility limitations and in the long-term for those with longer femurs.
6. The wider stance increases recruitment of the adductors and more medial hamstrings, so they offer variety in a bodybuilding context.
Notes:
1. Sumo deadlifting can really beat up on your hips; anterior hip pain is very common in sumo-style pullers. Make sure you're finishing with your glutes on each rep (prevents anterior glide of the femoral head, which can irritate the joint capsule), and be sure to never go longer than four straight weeks pulling sumo-style without a break from it. Many powerlifters will wear squat briefs when pulling sumo just to protect their hips.
2. Stance-width is a very individual thing. In the video above, my stance is out wider. Tony Gentilcore, on the other hand, tends to pull with a narrower stance: