Question about meta keywords

Lets say for example that "gain muscle" and "build muscle" are the top two searched phrases for the topic I'm writing about. When inserting the meta keywords, should I enter

muscle, build, gain

or would I enter

gain muscle, build muscle

?

 

Enter gain muscle build muscle. Try finding ones that have less sites listed in search engines also

 

I have had much higher success rate with:

muscle, build, gain

 

I agree, i would keep them all seperated, dont repeat any word.