Originally Posted by Iride01

What exactly are you calling complete failure? Accelerating or climbing as fast as one can until you can't stay at that anaerobic level anymore? And have to slow down to or below your lactate threshold or whatever level lets you continue to ride.

Or are we talking about a 90 minute or so ride ridden entirely as hard as you can and arrive at the finish line not able to do more than pedal a resting or slower pace?