One of the most common imbalances seen in swimmers is between the front and the back of the upper body. The demands of training in the water can cause the overdevelopment of the front of the body (anterior) and the underdevelopment of the back of the body (posterior).
The result of this imbalance is often a rounded shoulder posture. The development of this posture can leave a swimmer vulnerable to injury. It can also negatively affect your performance by compromising breathing function (Han 2016) as well as limiting strength and range of motion (Sanders 2011).