The ability to lift heavy weights, run, swim or workout in the gym may well improve your overall fitness level.
But this kind of fitness only helps to a certain degree in internal kung fu training.

A student must learn how to use their body in a very different way.
The body needs to become agile, flexible, adaptive, sensitive and strong.
Engorged biceps are not going to help.

Remember that your aim is not to make an impression.
You can accomplish this by looking at various ways to lessen your presence:

1. Attire
2. Deception
3. Keep to yourself
4. Possessions
5. Slow
6. Soft
7. Sound
8. Talk