Investigation of the validity and reliability of four objective techniques for measuring forward shoulder posture

Clinicians often rely on visual inspection and descriptive terms to documents a patient's forward shoulder posture. The purpose of this study was to assess the validity and intrarater reliability of four objective techniques to measure forward shoulder posture. Subjects were 25 males and 24 females. Subjects had a lateral cervical spine radiograph taken, from which the horizontal distance from the C7 spinous process to the anterior tip of the left anterior acromion process was measured. Subjects then proceeded twice through a random order of four measurements: the Baylor square, the double square, the Sahrmann technique, and scapular position. These results were then used to determine the intrarater reliability of each technique. Multiple regression analyses were performed on each measure's mean scores to determine both the correlation with and the predictive value for the radiographic measurement. The intraclass correlation coefficients for intrarater reliability ranged from .89 to .91. The correlation coefficients ranged from -.33 to .77, and the coefficients of determination ranged from .10 to .59 (N = 49). The researchers demonstrated clinical reliability for each technique; however, validity compared with the radiographic measurement could not be established. These techniques may have clinical value in objectively measuring change in a patient's shoulder posture as a result of a treatment program. Before any of these measures could be universally recommended in clinical practice, future research is necessary to establish interrater reliability and assess each technique's ability to detect postural changes over time.