I take it that you're looking for an Up With People song called "I Want To Be Strong" - right?
I have the 1966 Up With People book, How to Create You Own Sing-Out and it's not in that book. This site makes me think the song was from another tour, possibly called "Up with People! in Hollywood."
We used to sing "Up With People" as the theme song for a church group I belonged to in college, and I kinda liked the song. I saw an "Up With People" performance in Sacramento in the 1980's, and felt it bordered on right-wing, jingoistic propaganda.
They're still in business - their Website is http://www.upwithpeople.org/.
-Joe Offer-