I was studying the strumming lesson towards the end of Guitar Fundamentals I last night and I noticed one of the things Lisa McCormick demonstrated and said to to do was to strum using your elbow and not your wrist.

I was just view the alternative picking technique instruction with Ben Lindholm and he advised to use your wrist and not your elbow.

Does the instruction differ because one involves strumming and the other picking?

Both are these are beginner's lessons so I am confused as to if one is "more" right than the other. Can someone clarify please?

Thx
Vic