Reproducibility of isometric strength: measurement of neck muscles

Objective. To evaluate the repeatability of an advanced method of measuring the strength of functionally different groups of neck muscles using an isometric apparatus. Design. A repeated measures design was used within and between sessions. Background. Chronic neck pain has been associated with poor isometric neck strength. In rehabilitation, strength measurements may thus help to evaluate the basic condition and show whether or not treatments and exercises have been beneficial for improving strength. Previous tests have concentrated on testing strength while trying to bend forwards and backwards, but no biomechanics device, able to test rotator muscles, has been presented. Method. The new isometric measurement device was used to test flexion, extension and also rotation strengths of normal subjects (n = 33). Results. Intratester repeatability was good with regard to all measured parameters. Conclusions. With both tests performed on the same day and test comparisons between days, intratest repeatability was good with regard to all measured parameters.