Reliability and concurrent validity of two instruments for measuring cervical range of motion: effects of age and gender

This study set out to determine the reliability and concurrent validity of two instruments for measuring cervical range of motion and, using these instruments, to establish age and gender effects on cervical mobility. 84 asymptomatic subjects were investigated for age and gender effects on cervical range of motion using the CROM and single inclinometer. Thirty of these subjects also took part in the reliability study. Intraclass correlation coefficients (ICC) for inter- and intra-examiner reliability of the CROM were 0.88 and 0.96 (flexion/extension), 0.84 and 0.96 (lateral flexion) and 0.92 and 0.92 (rotation) respectively. Corresponding values for the inclinometer were 0.84 and 0.94; 0.82 and 0.92; and 0.81 and 0.89. Reliability of the CROM and single inclinometer was thus supported. Concurrent validity of the two instruments was supported for flexion/extension (0.80) and lateral flexion (0.79) but not for rotation (-0.18). Using both measuring devices, cervical mobility decreased with age in all planes of motion (p < 0.0001) but was not significantly affected by gender. Based on our findings, reassessment of normative values of cervical range of motion is indicated taking age, but not gender, into account.