For boys, there is nothing wrong with having more leg muscles. If you must lose muscle, there are ways. You should pay attention to long-distance runners all over the country. They have less muscles and strong legs, and are stronger than ordinary people, but they are certainly not as good as professional bodybuilders.

If you practice like this, as long as you persist, you will have an effect. If you want to get better results, you should increase the time appropriately, but don't run all at once. You can rest for 5 minutes at a time.