THE INFLUENCE OF BODY-SIZE ON LINEAR MEASUREMENTS USED TO REFLECT CERVICAL RANGE OF MOTION

Background and Purpose. The purposes of the study were to demonstrate that linear measurements of cervical range of motion are confounded by differences in body size when comparisons are made between groups and to introduce an alternative measure of range of motion that adjusts f or variation in body size. Subjects. The sample consisted of 42 subjec ts (25 female, 17 male) with chronic posttraumatic headaches. Methods. Using a tape measure, a physical therapist measured the distance betw een two anatomical landmarks with the subject's neck in the anatomical neutral position and with the subject's neck fully laterally flexed, rotated, and forward flexed. Range of motion was effected with two mea surements: the distance between the landmarks at full flexion/rotation and the proportion of distance traversed between the landmarks. Resul ts. The end-of-range values were significantly correlated with body si ze. No significant correlations emerged between the proportion-of-dist ance values and body size. Conclusion and Discussion. Linear measureme nts of cervical motion are potentially confounded by body size when su bjects of nonequivalent size are compared. Proportion-of-distance meas urement is presented as a more valid alternative to end-of-range measu rement.