When you're young, martial arts means fighting with others
When you're older, martial arts means fighting with yourself.

When your body declines, you face the hardest battles in the martial arts. I've often wondered if some aspects of taiji were constructs to maintain the Confucian seniority of elder masters. Obviously, at some point, the young fighter can beat the old fighter strictly on the power of youth (there are exceptions, of course, but those are remarkable cases). On another level, the therapeutic aspects of taiji are undeniable. Perhaps it was a construct for old fighters to stay healthy under the burden of their accumulated scar tissue.

My mom practiced taiji for a spell. It was a good social outlet for her and she felt it improved her golf game. Was it martial as in fighting? No, not at all. But my mom has different adversaries, the remainders of a long and fruitful life. After all, she had to contend with raising me.