"I run two meters."
Translation:Ik ren twee meter.
Technically, you could run such a race with a negative time: Your shoulders (plus parts of your torso) can pass the finish line between the "get set" and the starting gun.
For example: This athlete has her shoulders (and part of her torso) about 20 cm past the starting line. https://a.espncdn.com/photo/2009/1023/rise_e_richards2_sy_480.jpg
The infinitve for ren is rennen btw. The e in ren is short, to maintain the short e you have to use two n's. It is explained here: http://blogs.transparent.com/dutch/spelling-in-dutch-part-two/.
The difference between rennen and hardlopen is that hardlopen is the verb for the sport, and running just the activity. So you would translate the run in I had to run to make it in time with the verb rennen. But if you want to say To lose weight, I started running you'd use hardlopen. So rennen is more casual, and hardlopen more serious.