When a trainee starts training they often do not realize how much their body can handle.  They do not quite know how hard they can work past what they believe to be exhaustion.  Try the “breakdown” or “drop set” protocol to help educate your athletes about what intensity really is.  Have them execute a set in the normal manner, with sound posture and perfect repetitions eliminating momentum, to the point of momentary muscular failure.  Once they have reached failure, quickly reduce the weight on the barbell, dumbbell, or machine by approximately twenty percent.  Try to do this in less than twenty seconds.  Then ask the trainee to work to failure again.  When the athlete reaches twelve or more perfect reps on the first set and six or more on the second, or more than eighteen combine reps in two sets, increase the weight for the next workout.