Is it ever 'beneficial' to sacrifice form for weight on a dead lift?

[FenixAmmo]

Let's say on your third rep on a set of five you can feel your lower back rounding. Or, you power through all five reps thinking you have good form, but in reviewing your video, you see you had a rounded back on the last two.

In the first scenario, would/should you:

1. Call it quits at three reps and consider adjusting the weight on your next workout, or

2. Do your last two reps with a likely rounded back

In the second scenario, did you 'gain' anything by completing the last two reps with poor form?

I'm not asking for 'permission' to have bad form - rather, I am wondering if there is any adaptation benefit to be gained by struggling through the last two reps with a rounded back? Risk of injury aside, of course.

[Mark Rippetoe]

It is never beneficial, and it is never desirable. It is sometimes necessary, like 3rd attempt at a meet. Adjust your training loads to permit the heaviest weight with the best low-back position, and work up from there.