I just finished an internship at Gold's Gym and for the last 8 hours I assisted in boot camp classes. To me boot camp makes you creative when coming up with new workouts. You can mix strength with cardio and give them a great workout. I gave them a good warm up, dynamic stretching then went to some "old school stuff" jumping jacks, squat thrusts, mountain climbers. I did a bunch of different exercises for abs and core, then I would use kettlebells,med balls and dumb bells for strength. To me this was alot more fun then a one on one with a client.