Rating: 3 / 5
I just got these poles and once you get them locked in they are great. I've put my full weight on them, no problem.
As others have said the trick I found was to pull them all the way out to the big red stop section and then begin tightening them down. Loosen just barely so they slide again and push them down to the proper length and try to re-tighten. Most of the times this works, sometimes you need to do it a few times to get them to lock.
Because of the annoyance to get them to lock I am giving them a 3 otherwise they would be a 5 for me.