Hold yourself in the highest regard. When you try these affirmations, listen to what comes back from your own thoughts. If there are contradictions, be gentle with them. Be gentle with yourself.
I still want to get in better shape. I want my health to be an advantage in my older days. I want my kids to look up to me, and know that they are still several years from being able to beat me on the tennis court, or sprinting across any random field we come upon. I want my kids, but mainly myself, to be proud of me.