"This is a big effort for me."
Translation:זה מאמץ גדול בשבילי.
Yes, but not exactly like you think. The word מאמץ is a noun. Nouns don't have a שורש , they have something called "משקל", but you can say that מאמץ is basically has the same meaning as the שורש of אמץ -meaning to try= to put an effort. However אמיץ=brave (what you referred as strength) is an adjective, so he doesn't have a שורש at all, only verbs do. To sum up - אמיץ(brave) has nothing to do with אמץ (the שורש meaning effort) I hope you understand :)