For adolescents, shoulder broadening is caused by growth and development, due to the bones and muscles are in a state of rapid growth, especially the clavicle, shoulder blade parts of the development will be more obvious, it looks like the shoulders will become broader. For adults, the more common reason for shoulder broadening is body fat, with the body obesity, all parts of the subcutaneous fat will gradually accumulate, some patients shoulder and back fat increase more, it looks like the shoulders will become broader, back meat will also become more. If patients do long-term physical exercise, especially for the shoulder muscles, such as pull-ups, sit-ups, dumbbells, etc., it will make the back and arm muscles more, giving the visual effect that the shoulders become wider. In addition, the patient to carry out specialized physical training, such as military posture, dance practice, professional bodybuilding training, etc. will also make changes in the upper body shape, look straight posture, shoulder broadening. Generally speaking, shoulder broadening is not a disease and does not need to worry too much.