Come back slowly.

Just because you think that you are ready to return it may not be the case. Even if the injured area feels fine, the injury may not have healed completely.

Start off with walking or jogging.

This will depend on the length of your layoff. If you have done some cross-training in the meantime then it may not be necessary. Try to judge your physical condition honestly as trying to do too much can result in the old injury happening again.

Do not push yourself too much.

Even when you have been in training for a few weeks after your injury, ensure that you do not push yourself too hard. Never increase your weekly distance by more than 10% at one time.

Continue to eat well.

Ensure that you stick with your current diet and do not cut back on food. You will need nutrients to help your body mend the injured area and any weight you gain will be lost when you restart training.