Summarize this article:

Stretch marks on areas like the back are especially common among individuals who gain mass in either the form of fat or muscle. If you are looking to intentionally add size, try to do so in a controlled fashion over the course of many months rather than packing it all on as quickly as possible. If you are specifically looking to build muscle, it may help to work with a trainer who can help you pace out your muscle growth. Using a lotion or skin oil regularly helps keep it hydrated and encourage new tissue growth. While new tissue can’t prevent stretch marks, it may help reduce the time it takes them to fade, which in turn may help you feel more comfortable with their appearance. Apply a moisturizing lotion every morning and again right before bed using a lotion brush to reach all the areas of your back. A balanced diet and regular exercise can help control rapid change in body size and provide your body with the nutrients it needs to encourage healthy skin growth. Try to eat a diet rich in protein and healthy fats, and with limited amounts of carbohydrates, saturated fats, and transfats. Moderate exercise for thirty to fifty minutes four to five times a week is also encouraged to help maintain a healthy body and prevent stretch marks on the back.

Summary:
Control rapid change in body size. Keep skin hydrated. Maintain a healthy lifestyle.