A pressure algometer is an instrument that, when pressed against the body surface, can measure pressure only. It would tend to reduce the variation among the subjects, and diminish the observer bias and variation by the standardization of the pressure application. So it has been successfully employed for the assessment of general sensitivity to pain. Localized tenderness, as measured by pressure algometer, can be the diagnostic hallmark of tender spots and trigger points. But this technique may be influenced by such factors as sex, time, obesity etc.

The purpose of this study was to obtain the information about various factors to be considered influencing pressure pain threshold. Also the inter- and intraobserver reproducibility of pressure pain threshold were studied.

We examined 95 normal Korean young adults over 7 muscles in the upper trunks and concluded the following.

1) The pain threshold of levator scapulae is the highest one and that of trapezius is the lowest one.

2) There was no significant difference in pressure pain threshold between two observers.

3) This method shows high reproducibility in pain threshold measurement at 30 min or one day after.

4) There is no significant correlation between pressure pain threshold and body mass index.