I call this running your race. If you run someone else's race you'll probably fail.

When I started running, it was really hard at first. So I was looking for information on running and found a website where a marathon runner had put up an article on pacing yourself. He ran one marathon, tried to keep up with the lead runners, and ended up walking the last several miles. In the next race he paced himself better by running slower at first and slowing down throughout the race. His overall time went down considerably because he finished the race running instead of walking.

I've applied that to all sorts of cardio exercises and it works. If you pay attention to your body, you'll know how fast to push. Slow down throughout the workout, and go further. You'll end up not only going further, but faster overall. Run your race and don't pay attention to someone else's pace.