Intensity is often confused with intensiveness. Intensiveness is the degree of mental and physical effort that you put forth. The problem begins with the bodybuilding magazine definition of intensity, they've preached that anything less than 100% means you're wasting your time.
By their definition, a 20 rep squat at 60% of your max would be less intense than a 90% 3 RM squat. What takes longer to recovery? The first option, the 20 rep squat set at 60% of your max but it's less intense.
Don't really understand what the deal is. So to have a intense session you have to go all out and destory a muscle for 72 hours?
So that's more intense than training a bodypart once every 48-72 hours? Why is not training with higher reps one day and lower reps in a day or two not an option?
Think about the true definition of intensity then go into the gym and train intense.