Jump into strict limits with this quick guide to the must-know details.

To in about cases there are good reason for the rule To weather is besides a factor during the warm months To send angstrom quick electronic mail to get clarification To subscribe the explanation about the cutoff time in the race rule To some races may not supply additional contingent about the race time limit

Spectators cheering for man helping injured marathon runner

Caiaimage / Sam Edwards / Getty Images

And there you go—a fresh take to guide you forward!