When I switched from conventional to sumo, I went from 335 1RM (actual) to 390 1RM (actual). I haven't looked back. My body lends itself to sumo, though. I never thought to try it until Sara suggested it. Very happy.

There's actually an equation that helps determine if you might be better suited for conventional or sumo.

http://forum.bodybuilding.com/showthread.php?t=108595111&p=181075901#post181075901

It depends on what you're training for. If you're training for a sport, such as football, you should really be deadlifting conventional. Strongman contests don't allow sumo style, so you're forced to lift conventional.

If you're training for powerlifting, it's not quite as simple. Ultimately, you have to go with which style is more comfortable, but you can determine which method will allow you to lift the most weight biomechanically. To do so, follow this method.

1. Secure a tape measure to the wall with the zero end at the floor. Make sure the metric side (centimeters) is what you are using.

2. Stand with your back against the wall. Measure from the top of your shoulder to the floor. This will give you your total body measurement.

3. With a straight arm and your hand in a fist, measure from the top of your shoulder to the middle of your fist. This is your total arm length.

4. Raise your thigh to determine where your thigh rotates into your pelvis. Once located, lower your leg to the floor and measure from the top of the shoulder to this point. This is your trunk length. Also, subtract this measurement from your total body measurement to give you your lower body length.

Record these measurements and perform the following calculations:

1. Divide "trunk length" by "arm length".
2. Divide "trunk length" by "lower body length".

The resultant numbers will tell you the following:

1. Arm to trunk length ratio. Example: If your truk is 50 cm and your armi is 65 cm, divide 65 into 50=0.77. This indicates that your trunk is 77% of your arm length or that your arm is 23% longer than your trunk.

2. Trunk to lower body length ratio.

These numbers will help you determine which method, conventional or sumo, will allow you to lift the most weight by biomechanical standards.

CONVENTIONAL
If your trunk to arm ratio is less than 0.82 and your trunk to lower body length is less than 0.55, you should consider the conventional style. With your arms longer than your trunk, you'll finish the pull with the bar below your hip joint. This finishing position indicates that the initial starting position of your trunk (trunk angle) will be larger (more upright). This would indicate more activity from the quads as well as the hamstrings and glutes. A more upright trunk angle will also create a larger knee angle at the starting position, making the shift of the shoulders, knee, and hip more uniform-that is, they rotate in a biomechanically correct sequence.

SUMO
If your ratios are larger than 0.82 and 0.55, the initial starting angle of your trunk would be smaller (more inclined) and will therefore position you in a biomechanically ineffecient position. With your trunk more inclined, the activity of your trunk and hip extension muscles will have to follow a different, more inefficient pattern. This will basically result in increased activity from your hamstrings and glutes and decreased activity from the quads. This will also increase stress on your erectors and particularly the lower back and could cause rounding of your upper back. The solution would be sumo.

Hope this helps.

Saw stars trying to pull sumo (couldn't even make it move off the floor), but got it alright pulling conventional.

Typically the initial break off the floor is harder sumo but the lock out is easier and the other way around for conventional.

I doubt many people could just make the jump to sumo and hit a 1rm pb straight away, you will need time to build up the hips and quads,

My advice would be to train both styles and over time you will find the position you are best in.

I was hitting PRs pretty quickly when I moved from conventional to sumo. However, I think I am particularly suited to sumos. It was not immediate as you still need to practice form and get the right muscles firing and tendons/ligaments up to speed so to speak, but it was within a few weeks.

In my case, my form (horrendous back rounding) was holding me back for conventionals, and the change in position lead to me having far less of an issue with back rounding (as well as just having levers suited to sumo). That being said, I think that point is actually an argument to doing both rather than just swapping them out completely. (Although, for full disclosure, I only do sumo now).

I'm built for sumo (short torso and arms) and conventional DLs just are not good for me. That being said, I do a lot of hip/glute stuff for DL: heavy KB swings, glute bridges, hip thrusts. A lot of my recent gains have come from nitpicking my setup; there's almost always room for improvement there.

I started sumo-ing when I hit a pretty low traditional DL plateau. Knew I could haul more, just had issues with the form. I probably jumped 20lbs within a week or so of starting sumo, but my PR for deadlifts was really low to begin with. I'm 5' 2" so everything on me is short, haha, it really helped. Mixed grip also helped too. However something is up with my deadlifts because apparently they stress my left pectoral muscle...?? so weird. it's always tight and sore after I deadlift. I think my form might be off.

I started sumo-ing when I hit a pretty low traditional DL plateau. Knew I could haul more, just had issues with the form. I probably jumped 20lbs within a week or so of starting sumo, but my PR for deadlifts was really low to begin with. I'm 5' 2" so everything on me is short, haha, it really helped. Mixed grip also helped too. However something is up with my deadlifts because apparently they stress my left pectoral muscle...?? so weird. it's always tight and sore after I deadlift. I think my form might be off.

Do you use mixed grip on all your lifts - warm up included? Do you switch the grips?