Now, I train fat loss clients, not powerlifters, so that's always my filter. So proper alignment beats higher poundages all of the time.
Said another way: No one hires me to take their deadlift from 360 pounds to 450 pounds. That's not me. People hire me for fat loss.
My fat loss clients tend to get stronger than most general fat loss clients out in the world, but that's only because that's part of getting them leaner.
1.) Getting lean is goal #1
2.) Getting stronger is only to support goal #1
There are some concessions I make in programs that I know won't get the client stronger as fast as if they followed straight strength programs. But it will get them leaner faster.
And that's the same way I feel about arching vs. bracing: If I have a client that sits at a desk all day, correcting their posture and getting them moving correctly will actually buy us some fat loss. On the Future of Program Design DVD, Alwyn Cosgrove says that taking someone to symmetrical two's on the FMS is good for 5 pounds of fat loss. For the readers who haven't heard of it, the FMS stands for "Functional Movement Screen", and rates seven movement patterns on a scale from 1-3. Basically if someone has a 1 on a movement pattern, that means that they can't do the movement correctly. If they are assymetrical left to right, they also can't do the movement correctly. It's a cool standard of checking movement. So I use that example because it's just such a clear standard.
So one of the biggest things we want to do with most clients is to lign up their spine and their hips. Most people who work at a desk are tilted back at their pelvis, arched at their low back, rounded at their upper back, and forward at their neck.
We want to train everything we can in that nice neutral s-curve the spine is supposed to have.
We want to get them good at finding neutral, and then load them so they maintain neutral.
So, honestly, I don't know if you're going to sacrifice a couple pounds or your deadlift and squat by being neutral, or if it's going to go up. I've got no idea because I don't care. I'm going to get you in neutral, and then we're going to make you stronger in neutral. And you're going to get leaner.
Here's the article that inspired this, it has a little bit different perspective: