Does the athlete need to run with their cellular phone or does the tracker use their timing chip?
I've checked the website and it appears that you don't have to keep your cellular phone because the chip will automatically register the time and store the data. But before it can do that, the chip needs to be registered and initialized.
There is an official website where all the details about running and procedures are presented. Use the following link to reach that site: http://www.comrades.com/index.php/marathoncentre/race-information
