If it's _painful_ you are doing it wrong

https://www.lesswrong.com/posts/bx3gkHJehRCYZAF3r/pain-is-no...

This is really terrible advice that just discourages people.

You absolutely can get significant improvements without (much) pain. DOMS during the initial stages is going to be the most uncomfortable part. Once you're past it, you don't need to push yourself to a breaking point, just to the point of mild exhaustion.

This will provide you enough resistance to gain muscle mass and improve the bone density to healthy levels.