UCS is described as a muscle imbalance pattern located within the cervical and thoracic spine region. These imbalances have been shown to produce elevation and forward movement of the shoulders, winging of the scapula, and a forward extension of the head. These changes, in turn, lead to overstress of the cervical cranial junction and shoulders, which can cause neck and/or jaw pain, headaches, and shoulder problems. The purpose of this study was to determine if quantifiable differences existed in active range of motion, muscle strength and muscle endurance capacity between a group of patients with Upper Crossed Syndrome (UCS) and an asymptomatic group. A case-control experiment was completed. The case group consisted of 17 subjects with UCS, recruited through physical therapy and chiropractic clinics. The control group consisted of 17 healthy subjects, which were matched for age, gender and BMI on a group level. Isometric strength and endurance tests were completed. Neck range of motion was assessed about three axes. Significant differences in strength generating ability (neck flexion/extension, shoulder internal/external rotation, shoulder abduction/adduction) and range of motion (neck bending, neck rotation) were evident between the two groups. Endurance measures though, were comparable between groups. The results show that it is possible to use objective measures to distinguish between people with UCS and healthy controls, and thus demonstrate the possibility to move from a subjective to a quantitative objective diagnostic approach. / Master of Science