Objective: The purpose of this study is to evaluate the effects of cold air application on the pressure threshold of myofascial trigger points.

Method: The 60 patients with myofascial trigger points in unilateral infraspinatus muscle were divided into 3 groups with equal number and cold air was applied using CRAis (Kyung-won Century, Korea) for 1, 3 and 5 minutes. We examined the changes of pressure threshold in myofascial trigger points before, immediately after and 30 minutes after cold air application. Also we examined the changes of pressure threshold of contralateral infraspinatus muscles.

Results: 1) The pressure threshold of trigger point in infraspinatus muscle were increased immediately and 30 minutes after the cold air application as assessed by the pressure algometer (p＜0.05).

2) There was no significant correlations in the changes of pressure threshold among 3 groups after the cold air application (p＞0.05).

3) There was no significant correlations among the age, the body mass index and the changes of pressure threshold in myofascial trigger points (p＞0.05).

Conclusion: We conclude that the cold air application is a effective method for treatment of myofascial trigger points.

Objective: The purpose of this study is to evaluate the effects of the cold air application on the subjective pain threshold of knee joint pain.

Method: We recorded the changes of the pain threshold in 60 patients before and after cold air application who complaint of knee joint pain. Patients were divided into 3 groups randomly with each 20 patients and each group received cold air application for 30 seconds, 1 minute, 3 minutes. Cold air of CRAis (Kyung-won Century, Korea) was applied to the anterior portion of the knee with a temperature of ⁣30^oC. The changes of the pain threshold was estimated by visual analogue scale.

Results: In 30 seconds treating group, VAS score was lowered 2.25±1.16 and 2.26±1.13 immediately after, and 30 minutes after cold air application, respectively (P＜0.05). In 1 minutes treating group, VAS score was lowered 1.65±2.58 and 2.41±2.59 immediately after and 30 minutes after cold air application, respectively (P＜0.05). In 3 minutes treating group, VAS score was lowered 1.94±1.80 and 2.10±2.3 immediately after and 30 minutes after cold air application, respectively (P＜0.05). The VAS score was lowered significantly after cold air application in all groups, but there's no significant correlation between change of VAS score and cold air application time. In group with initial VAS score greater than 5, the VAS score was more decreased after cold air application.

Conclusion: Cold air application for 30 seconds using CRAis machine is useful treatment method for knee joint pain.