This subject was just the focus of several long term research studies. A few are still ongoing with people that have been being followed for years.
The nut shell findings for almost all the studies say:
If you must do cardio and strenght on the same day, make every effort to do the cardio first. Putting the cardio after strength training has been shown to significantly reduce strength and hypertrophy improvement from resistance training done for either purpose. If possible, try to have an hour or more between the cardio and the strength training sessions. The longer the gap between, the more effective the strength training session will be. And the same applies if you must strength train close to a cardio workout time, only you need more time between the session to make the strength session as effective as if you didn’t perform a cardio workout after that a strength session. Doing serious cardio within 6 hours of finishing a strength or hypertrophy session was shown to reduce the effectiveness as much 60%.
And consuming a high quality protien source meal after the strength session was even more important if cardio was performe that day as well.
Read and research, read and research. That is where the information you seek will come from to make you a better instructor and a better athlete/exerciser.