We are sleep training our 4 month old twins and my question is when I put them down for a nap and they cry themselves to sleep they then awaken within a half hour, should I continue the sleep training or go and get them from their cribs? They also wake each other up when they cry.
You will find vastly different opinions on this, but I think four months is awfully young to let kids cry themselves to sleep. I know it's hard -- it's extremely hard, and with twins it's more than twice as hard. That said, children that young cannot reason, and although you can condition them in the way you describe, I fear the broader effects will be all negative.
I am a father of seven, so believe me when I tell you I know it's a difficult period to endure.
You didn't ask, but one thing we've had luck with is laying down with them when they nap. If they feel, smell, sense the presence of mom or dad, they settle much easier. Heck, catch a couple of winks while you're at it -- you deserve it. And once they settle, you can peel yourself away while they continue to nap.
Much easier said than done, and in the interest of full disclosure, I have never had multiples.
Good work trying to help your twins sleep it is so important.
Short Answer is yes, if they wake up from a nap, nap time is over.
We have Irish twins and had to move them to separate rooms while sleep training. If that is an option for you perhaps that will help with one waking the other up. The thing to remember is you can't force your children to sleep you can only give them the best opportunity to sleep. If they are naturally waking up it is probably their natural sleep/wake cycle that is doing so. You can try adjusting the nap time earlier to see if that helps. Also every child's nap needs are different.
4 months does seem a little earlier for a cry it out, but each child is different and it may be best for yours, only you can make that decision. We had to use cry it out at about 6 months for one of our children but for the other we sat in the room and over time moved further and further out of the room while she fell asleep. We tried sleeping with our children but that just kept them (and us) up. So keep experimenting and see what works best for you and your family.