Your form needs work. I have no clue what you look like from the front, but from the side, you need work.

Your sumo pull should look just like your squat. Knees out hard, back arched, chest up. Your back was rounded over and you just made it much harder than you needed to. The rounded back will tend to make you raise your hips first and put the bar out in front of the shoulders. This will make it very tough on the back and hard to lockout.

If you can't arch your back hard and sit down to get the bar, you need to really work on your flexibility because this will also help your squat.

It's your choice as to which form you use. It depends on how you want to pull at the meet. Whatever you choose, work that technique.

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Matt Rhodes