Which is better, traditional martial arts or modern fitness?

If you're talking purely about fitness, running is best. Jogging for 1 hour at a time, three times a week is fine. Martial arts stuff has a high chance of blowing up, and 60% of taijiquan practitioners have knee pain. In terms of time efficiency, running 3 hours a week is just as effective as practicing 2 hours of martial arts every day. As for your comment that people who practice traditional martial arts still have a lot of energy and stamina in their later years, those are the ones with low levels. Those with high levels are not in good health. In the past, many famous masters of Xingyi had bad legs and feet in their later years, and in recent times, for example, Chen Xiaowang, the master of Chen-style Taijiquan, had his joints replaced with fake ones after practicing. I have been practicing martial arts for 14 years and know the pros and cons.