Running a marathon after an injury can be a daunting task. However, with a proper training plan, it is possible to prepare for a marathon in a month. The key to success is to gradually increase the intensity of your workouts and listen to your body. Start with light running and build up the distance and intensity of your runs. Cross-training activities, such as biking and swimming, can be used to supplement your running. Additionally, focus on proper nutrition, rest and hydration. With these steps and a positive attitude, you will be ready to tackle the marathon in a month.