To give full credit where it is due, most of the information put forth here I learned from Greg Nuckols at Strengtheory.com and through conversations with writer, researcher and biomechanist Andrew Vigotsky. In particular, these two articles of theirs helped clarify my understanding of the differences between conventional and sumo-style deadlifting which I would definitely recommend reading if this is a topic that interests you.
Should You Deadlift Conventional or Sumo? - Greg Nuckols
Calculating Joint Moments in the Squat - Andrew Vigotsky (via Bret Contreras)
A concept that I am increasingly encountering is the notion that sumo-style deadlifts are inherently and biomechanically easier than the conventional style deadlift--sometimes to the extent where pulling sumo is almost considered a cheat or not as valid of a lift. I actually used to believe this as well until I came across the two above links, which enlightened me to two main points about the differences and why one is NOT inherently easier than the other for all populations:
1) The amount of force required in the hips for both lifts are equal due to no change in hip extension moment arm length.
I used to think if standing wider brought your hips closer to the bar, it gives you a leverage advantage--but the leverage is identical regardless of the stance.
2) More quadriceps are activated in the sumo with less shear force on the spine compared to the conventional.
- The total distance of the bar path for a given individual will be less with the sumo than that with conventional, but this is more indicative of a difference in the amount of work performed and not absolute strength.
- Individual preference, comfort level and amount of time spent practicing each lift are also significant factors that help determine ones success with each style.
- If you have strong quadriceps and/or not as strong of a low back, or if you dislike the amount of shear force placed on the spine with conventional deadlifting, then sumo deadlifting might be your preference. Especially if you choose to refrain from rounded back deadlifting.
- If you have more difficulty getting the weight up off the floor and not as much difficulty locking out towards the top, conventional might be better for you.
- Regardless of what you choose, training both variations will have different benefits and can help address various issues.