The reliability of assessing sternocleidomastoid muscle length and strength in adults with and without mild neck pain

Abstract

ABSTRACTBackground: The sternocleidomastoid (SCM) is an important cervical spine muscle. Weakness of the SCM muscle has been implicated with cervical problems. No studies have examined the reliability of assessing the SCM muscle length or strength. Also no studies exist that have looked to see if imbalances in SCM muscle length or strength exists between the left and right sides in those with and without neck pain. Objective: To determine the reliability of assessing the SCM muscle for length and strength and to see if SCM length could predict SCM strength in those with and without neck pain. Design: Cross-sectional study. Methods: Fifty-one subjects with and without mild neck pain. Analysis: Intratester reliability was assessed for SCM muscle length and SCM muscle strength. Differences in SCM length and strength were examined in those with and without neck pain. Results: Intratester reliability was shown to be excellent (ICC (2,2) > 0.90) for the left and right SCM when assessing muscle length and muscle strength for those with and without neck pain. No differences were noted when comparing left to right SCM between those with and without neck pain regarding muscle length or muscle strength. Neither regression models were able to predict SCM muscle strength from SCM muscle length. Conclusion: SCM muscle length and SCM strength can be reliably assessed using a bubble goniometer and HHD. No differences were found when comparing left to right SCM muscle length or strength in those with or without mild neck pain.