(HealthDay News) -- If you're considering running a marathon, you'll need a carefully planned training schedule to avoid injury. Here are suggestions on how to prepare for the race, courtesy of the Cleveland Clinic:

• Start training at least 18 weeks before the marathon. Ideally, you should have been running regularly for at least a year before the actual race.
• Take time off every week from running to let your body rest and prevent injury. You should not run every day.
• Follow up a very strenuous run with an easier day. By alternating strenuous and lighter workouts, you'll help prevent injury.
• Three weeks before the marathon should be your last long run. Your body will need that time before the marathon to rest.