Objective: The strength of a group of muscles can be measured by muscle strength test, employing a force measuring instrument. In order to monitor the effectiveness of a therapeutic or training programs we need a reliable technique which is also accurate in repeated measurements. The purpose of this study was to examine the reliability of an isometric neck muscle force measurement device. 

Materials & Methods: Thirty seven healthy non athlete subjects (18 males and 19 females, aged 18-25) participated in this analytical study. The maximal isometric contractions of the neck extensor and flexor muscles were measured in different times and different days and by two different testers. A new sensitive “load cell” was applied to our previously designed neck muscle force measurement apparatus.

Results: The results of the inter-trail, test retest, and inter rater reliability (0.86 < ICC < 0.98 , 2.2< Sw <5.1 N) indicated that the neck muscle force measurements were highly repeatable and less variable between measurements. There were no statistically significant differences in neck muscle force measurements, between times, between days and between retsters. Maximum isometric contractions were significantly higher in males than in the females (p < 0.001). Women’s neck muscle strengths were 30.8% and 46.1% of men in cervical extension and cervical flexion.

Conclusion: In this study we used a new model (Isometer 2) of our previous apparatus (Isometer). The isometric strength of neck flexor and extensor muscles which was measured by Isometer 2 appeared to be a reliable and useful method for measuring the force of the neck extensor and flexor muscles.