xthumbtack
Then I'm sure you're use to that feeling pushing yourself to a critical threshold, and then forcing yourself to continue on for a lot longer then you originally thought you could handle. That's all you really have to do for running.
Horrible advice.
Really. The worst.
gonk
You should never push your body to the point of actual, physical pain during exercise. This means you are either doing the exercise improperly or you have done it for too long, too hard.
This is not conducive to health, weightloss, or general well-being.
My rule of thumb is, schedule exercise, make plans for it. But, if you feel ANYTHING is amiss with your body, you have unexplained aches and pains, just aren't feeling it as you start your routine, stop, leave the gym at once, let your body recover a bit more and come back later.
Overtraining and pushing yourself past maximum is just asking for injuries that may possibly become permanent.
Back pain, for one, is a sign that running posture may be incorrect, or you may simply be pushing yourself too hard. I'd look into correcting the issues with the back pain BEFORE I'd go around telling people to "run past the point of utter exhaustion and pain." That will make the back pain just get worse and worse.
confused