bruce lee lift weights then he runs. And I've heard lift weight then go running is better.

Because you gonna need all the strength to weight lift safely. Then after your weight training, you are tire and kind of worn so then you go running to get cardio in and train the body to handle impact stress on body better.

Running and then weight lifting could cause you to have bad form or injury because of fatigue.

Another thing to consider is when you work on your kung fu technique do that then go running. Really good workout and better.

Your technique will be good and get cardio in from technique works and running.