There is a key difference between CF's approach to training and *everyone* else's.
Everyone else does the same types of training over and over again, with small & gradual changes, allowing the body to adapt.
CF's intention is to not let the body adapt. Thus every workout is seen by the body as a new, different stressor...and the body is always off balance...this is perceived as a much greater stressor and is potentially not able to adapt over time past a certain point. Not allowing for adaptation means that the body's stress machinery also never adapts (see below).
This is why no one else in the world does "random" programming. It is too hard on the body over time.
Here are some examples from a recently linked site on CF.com on stress, which I find humorous as it would seem to explain why the stress response to CF isn't like that of other programs. Note the part about stress and digestion--you would be amazed how many CFers eat "perfect Paleo" and yet are still dealing with stress-induced IBS that goes away when they start training in a more sensible manner.
One of the most tragic aspects of the stress response is the way it gets hardwired at a young age — an early setback can permanently alter the way we deal with future stressors. The biological logic of this system is impeccable: If the world is a rough and scary place, then the brain assumes it should invest more in our stress machinery, which will make us extremely wary and alert. There’s also a positive feedback loop at work, so that chronic stress actually makes us more sensitive to the effects of stress.
Stress is a chemistry problem. When people feel stressed, a tiny circuit in the base of their brain triggers the release of glucocorticoids, a family of stress hormones that puts the body in a heightened state of alert. The molecules are named after their ability to rapidly increase levels of glucose in the blood, thus providing muscles with a burst of energy. They also shut down all nonessential bodily processes, such as digestion and the immune response. “This is just the body being efficient,” Sapolsky says. “When you’re being chased by a lion, you don’t want to waste resources on the small intestine. You’ll ovulate some other time. You need every ounce of energy just to get away.”
Confront your fears
When paratroopers are first learning to parachute, they experience a massive stress response. In fact, one study of Norwegian airmen found that this response started before the jump and lasted for hours afterward. But something interesting happened when the soldiers kept jumping out of planes. Instead of being stressed for hours at a time, they showed elevated levels of stress hormone only while in midair, which is precisely when they needed it. The chronic stress response that causes long-term harm had all but disappeared.
Don’t force yourself to exercise
While exercise is remarkably effective at blunting the stress response, at least for a few hours, this effect exists only if you want to exercise in the first place. After all, a big reason working out relieves stress is that it elevates your mood; when mice are forced to run in the lab, their levels of stress hormones spike. So when you force yourself to go to the gym and then suffer through 30 minutes on the treadmill (lamenting the experience the entire time), you don’t reduce your stress levels. In fact, you might be making things worse.