Originally Posted by
Lightning Pilot
While I mostly agree, when giving advice to "push through pain" one needs to define, as precisely as possible, "pain." The reason is that anyone who needs that advice probably has no clue what you mean.
Under my definitions, a certain amount of discomfort is normal and good. Breathing hard, burning legs, sweating, etc. That's not pain. If you're really in pain, that's a sign of injury, and you should back off!
Although sometimes it's hard to be sure when normal burning quads starts to become something more serious. When in doubt, back off before trying again. There! you've just invented intervals!