Shoulder dysfunction inhibits 80% of competitive swimmers from performing optimally. The most common contributing factor to shoulder dysfunction is an altered scapula position. A standard for the distance between T4 and the medial border of the scapula is lacking. Measurements of the distance between T4 and the root of the scapula were made and the relationship of the distance and the function of trapezius middle fibres at resting length was tested. A Vernier caliper® (ICC 0.94) was used to measure the distance from T4 to the medial border of the scapula. Exercises and stretches to retrain and strengthen the middle fibres of the trapezius specifically were performed twice a week, scheduled around the swimmers’ regular training and strengthening sessions, for six weeks. The results showed that palpation of the scapula to measure the distance between T4 and the spinal root is reliable and valid. A normalisation index should be used to adjust for body build and posture. Furthermore, the distance between the thoracic spine and the scapula did not change, regardless of the statistical improvement in the function of trapezius middle fibres (p < 0.05). The research results are of importance for clinical practice, evaluation and treatment programmes for physiotherapists. The data obtained from this study can serve as a baseline for further studies.