I have been amazed as of late to watch some people around me show great amounts of strength. When your job isn't a physical one it is hard to define strength and it's value.
It is amazing. Whether it is Strength in Commitment, Dedication, Understanding or others it is a wonder to watch.
The best of all though is strength of character. Watching people go through trials and being challenged by many forces, the strength of character really shines through.
Just remember that strength as a grown up is not about being a bully or beating people up (even when we want to).