When will I see changes in my body and start gaining muscles?

Last updated on July 23, 2022



I have a question about muscle building. First of all, I am an ectomorph. I am 5’7 and have very narrow bones compared to the other 9th graders at school. I am 15 years old and I am in the latter half of stage 3 [ 3.8-3.9]. My questions are :

  • When will I see a change in my body structure without exercising? 
  • Why is it difficult for me to gain muscle and other kids in my grade can do it easily?


Years ago, Dr. William Shelton started classifying people into three basic categories: ectomorph, mesomorph, and endomorph. The categories are not absolute and there are people who are in between, but the categories help with discussing broad trends. These categories typically apply to adults. While you are growing, it may be difficult to determine where you fit.

Ectomorphs tend to be skinny and taller. They have smaller joints and lean muscles. What makes them slim is that they have a higher metabolism. The plus side is that they can eat freely and not worry about their weight. The negative side is that it is hard for them to put on muscle.

When you are in your growth spurt phase (Stage 3), you are burning a lot of calories to fuel your growth. It is not until you reach stage 4 that you will have enough spare energy to start building muscle. If you are an ectomorph, then it will seem that no matter how much you work out, your muscles don’t appear to get larger. You still get stronger, but it just doesn’t show up in the size of your muscles. However, if you don’t exercise, you won’t get muscle growth or additional strength.