Locking-out -- good or bad for the joints?

[EndoToMeso]

Good day fellow lifters,

Does anyone have any science-based proof about locking-out? Whether it's bad or good for the joints.

There are two main theories, one suggesting locking-out, because joints are strongest in that position, and the second one suggesting not locking out , because that is extra-work for joints.


I tried searching in pubmed and other scientific databases but found nothing good and clear. I'm especially interested in knee locking while doing squats, leg press and elbow locking while doing bench press.

Thanks for your input.