Pressure pain threshold on upper trapezius and levator scapulae muscles. Repeatability and relation to subjective symptoms in a working population.

The pressure pain threshold for the upper trapezius and levator scapulae muscles was studied in a working population with a mechanical algometer. The lower 95% confidence interval limits of the correlation coefficient describing intraobserver reliability varied from 0.71 to 0.92, measured in 93 men and 70 women. The values describing interobserver reliability varied from 0.68 to 0.79, measured only in men. The day-to-day repeatability was measured in 10 women and it proved to be acceptable. In general, women had lower pain threshold values than men. Low values were related to complaints in the neck and shoulder region. However, the values in the non-symptomatic population displayed wide variation. Though unsuited for use as a primary diagnostic or screening tool, the method shows promise for application in individual follow-up studies as an outcome measure in therapeutic trials.