I have been training for a long time (as a natural) as well, and I also found that whenever I trained bodyparts more than once a week, I rapidly become overtrained, get more joint aches and pain and don't sleep as well. I tried most every training concepts under the sun. Whenever I tried HD or a variant of it (Dorian's take or Doggcrapp) I always ended up injured and had to stop training for months to rehab. So I went to the other extreme of the spectrum and went to High Volume and developped tendonitis in elbows and shoulders. So I agree that there has to be a happy medium, especially if training longevity is a goal.