What sort of training do you prefer doing and where?
I prefer interval training as I feel that it motivates me more rather than endurance training. Maybe its because I am impatient and like to get it over and done with quicker. I do feel that it is more effective, working the heart and increasing the heart rate at intervals. If you are running on a treadmill, try increasing the speed or increase the incline for a short period of time and then reducie it, repeat 5 times.