When I was training 5-days a week in karate (as well as kickboxing, boxing) my weight training days were just 2-3 days a week and I did NO cardio at all. They were strictly for weights. What I did was set aside separate training periods for plyometric drills as well as did alot of heavy bag training - on days when I did not weight train. Also, alot of sparring.
Strength and speed associated for the martial arts would most likely benefit from explosive drills like plyometrics. Also, sprinting (and how about interval rope jumping?). But tell me, honestly how many "rounds" can you perform on the heavy bag? Less than 5? 3? Before you are truly "winded". You'll get quite a workout from the heavy bag. The kind that would help you in martial arts. Just my thoughts.....Patricia :-)
But, I'm still curious as to what Charles Staley has to say - I respect his opinions tremendously!