Great article by Mark Rippetoe. Excellent read for those of us who take physical training as seriously as self defense training. His points about adaptation to the physical and psychological stress of lifting weights, IMO, transfer directly to self defense training.
http://www.t-nation.com/free_online_article/most_recent/the_biggest_training_fallacy_of_all&cr=Exercise and training are two different things. Exercise is physical activity for its own sake, a workout done for the effect it produces today, during the workout or right after you're through.
Training is physical activity done with a longer-term goal in mind, the constituent workouts of which are specifically designed to produce that goal. If a program of physical activity isn't designed to get you stronger or faster or better conditioned by producing a specific stress to which a specific desirable adaptation can occur, you don't get to call it training. It's just exercise.
- Shawn