to take part in logrolling (= a sport in which two people try to stay standing on a floating tree branch or other long, rounded object, while trying to make the other person fall off)

Want to learn how to logroll? Here's what you do: Put a log in the water, then stand on top of it. 想学习如何玩水上踩滚木？ 这是你要做的：把一根木头放在水里，然后站在上面。

to turn a person who is lying down in one movement, keeping their spine (= the row of bones down the back) straight

Don't try to logroll the patient without enough help. 在没有足够帮助的情况下不要给患者滚木式翻身。