Strumming technique vs. Alt. Picking technique

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

When starting out you do strum mostly holding your wrist still while your elbow sings your hand up and down.

When finger picking your fingers need to stay close to the strings at all times. So moving at your elbow would not work. Moving your wrist only, your fingers stay closer to the strings.

Think of it as Chopping versus Carving.

If you have a cleaver and chop a piece meat, you have to swing (more arm motion)

If you want to carve a piece of meat to specification, you need to use smaller, more precise motions

They differ because what you're trying to do is different. Using the above example, it's the same piece of meat but it is being handled in different ways and for different reasons.

The same for guitar; you are strumming because you are playing a broader rhythm which takes more motion.You would pick single notes in a solo using less motion and different muscle groups because you are trying to hit smaller, more precise notes.